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Title: More Letters of Charles Darwin Volume II

Author: Charles Darwin

Editors: Francis Darwin and A.C. Seward

July, 2001 [Etext #2740]

Project Gutenberg Etext of More Letters of Charles Darwin Vol. 2
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All biographical footnotes of both volumes appear at the end of Volume II.

All other notes by Charles Darwin's editors appear in the text, in brackets
() with a Chapter/Note or Letter/Note number.









"You will never know how much I owe to you for your constant kindness and





1843-1882 (Continued) (1867-1882.)

Kew, January 20th, 1867.

Prof. Miquel, of Utrecht, begs me to ask you for your carte, and offers his
in return. I grieve to bother you on such a subject. I am sick and tired
of this carte correspondence. I cannot conceive what Humboldt's Pyrenean
violet is: no such is mentioned in Webb, and no alpine one at all. I am
sorry I forgot to mention the stronger African affinity of the eastern
Canary Islands. Thank you for mentioning it. I cannot admit, without
further analysis, that most of the peculiar Atlantic Islands genera were
derived from Europe, and have since become extinct there. I have rather
thought that many are only altered forms of existing European genera; but
this is a very difficult point, and would require a careful study of such
genera and allies with this object in view. The subject has often
presented itself to me as a grand one for analytic botany. No doubt its
establishment would account for the community of the peculiar genera on the
several groups and islets, but whilst so many species are common we must
allow for a good deal of migration of peculiar genera too.

By Jove! I will write out next mail to the Governor of St. Helena for boxes
of earth, and you shall have them to grow. Thanks for telling me of having
suggested to me the working out of proportions of plants with irregular
flowers in islands. I thought it was a deuced deal too good an idea to
have arisen spontaneously in my block, though I did not recollect your
having done so. No doubt your suggestion was crystallised in some corner
of my sensorium. I should like to work out the point.

Have you Kerguelen Land amongst your volcanic islands? I have a curious
book of a sealer who was wrecked on the island, and who mentions a volcanic
mountain and hot springs at the S.W. end; it is called the "Wreck of the
Favourite." (378/1. "Narrative of the Wreck of the 'Favourite' on the
Island of Desolation; detailing the Adventures, Sufferings and Privations
of John Munn; an Historical Account of the Island and its Whale and Sea
Fisheries." Edited by W.B. Clarke: London, 1850.)

Down, March 17th, 1867.

It is a long time since I have written, but I cannot boast that I have
refrained from charity towards you, but from having lots of work...You ask
what I have been doing. Nothing but blackening proofs with corrections. I
do not believe any man in England naturally writes so vile a style as I

In your paper on "Insular Floras" (page 9) there is what I must think an
error, which I before pointed out to you: viz., you say that the plants
which are wholly distinct from those of nearest continent are often very
common instead of very rare. (379/1. "Insular Floras," pamphlet reprinted
from the "Gardeners' Chronicle," page 9: "As a general rule the species of
the mother continent are proportionally the most abundant, and cover the
greatest surface of the islands. The peculiar species are rarer, the
peculiar genera of continental affinity are rarer still; whilst the plants
having no affinity with those of the mother continent are often very
common." In a letter of March 20th, 1867, Sir Joseph explains that in the
case of the Atlantic islands it is the "peculiar genera of EUROPEAN
AFFINITY that are so rare," while Clethra, Dracaena and the Laurels, which
have no European affinity, are common.) Etty (379/2. Mr. Darwin's
daughter, now Mrs. Litchfield.), who has read your paper with great
interest, was confounded by this sentence. By the way, I have stumbled on
two old notes: one, that twenty-two species of European birds occasionally
arrive as chance wanderers to the Azores; and, secondly, that trunks of
American trees have been known to be washed on the shores of the Canary
Islands by the Gulf-stream, which returns southward from the Azores. What
poor papers those of A. Murray are in "Gardeners' Chronicle." What
conclusions he draws from a single Carabus (379/3. "Dr. Hooker on Insular
Floras" ("Gardeners' Chronicle," 1867, pages 152, 181). The reference to
the Carabidous beetle (Aplothorax) is at page 181.), and that a widely
ranging genus! He seems to me conceited; you and I are fair game
geologically, but he refers to Lyell, as if his opinion on a geological
point was worth no more than his own. I have just bought, but not read a
sentence of, Murray's big book (379/4. "Geographical Distribution of
Mammals," 1866.), second-hand, for 30s., new, so I do not envy the
publishers. It is clear to me that the man cannot reason. I have had a
very nice letter from Scott at Calcutta (379/5. See Letter 150.): he has
been making some good observations on the acclimatisation of seeds from
plants of same species, grown in different countries, and likewise on how
far European plants will stand the climate of Calcutta. He says he is
astonished how well some flourish, and he maintains, if the land were
unoccupied, several could easily cross, spreading by seed, the Tropics from
north to south, so he knows how to please me; but I have told him to be
cautious, else he will have dragons down on him...

As the Azores are only about two-and-a-half times more distant from America
(in the same latitude) than from Europe, on the occasional migration view
(especially as oceanic currents come directly from West Indies and Florida,
and heavy gales of wind blow from the same direction), a large percentage
of the flora ought to be American; as it is, we have only the Sanicula, and
at present we have no explanation of this apparent anomaly, or only a
feeble indication of an explanation in the birds of the Azores being all

Down, March 21st [1867].

Many thanks for your pleasant and very amusing letter. You have been
treated shamefully by Etty and me, but now that I know the facts, the
sentence seems to me quite clear. Nevertheless, as we have both blundered,
it would be well to modify the sentence something as follows: "whilst, on
the other hand, the plants which are related to those of distant
continents, but have no affinity with those of the mother continent, are
often very common." I forget whether you explain this circumstance, but it
seems to me very mysterious (380/1. Sir Joseph Hooker wrote (March 23rd,
1867): "I see you 'smell a rat' in the matter of insular plants that are
related to those of [a] distant continent being common. Yes, my beloved
friend, let me make a clean breast of it. I only found it out after the
lecture was in print!...I have been waiting ever since to 'think it out,'
and write to you about it, coherently. I thought it best to squeeze it in,
anyhow or anywhere, rather than leave so curious a fact unnoticed.")...Do
always remember that nothing in the world gives us so much pleasure as
seeing you here whenever you can come. I chuckle over what you say of And.
Murray, but I must grapple with his book some day.

Down, October 31st [1867].

Mr. [J.P. Mansel] Weale sent to me from Natal a small packet of dry locust
dung, under 1/2 oz., with the statement that it is believed that they
introduce new plants into a district. (381/1. See Volume I., Letter 221.)
This statement, however, must be very doubtful. From this packet seven
plants have germinated, belonging to at least two kinds of grasses. There
is no error, for I dissected some of the seeds out of the middle of the
pellets. It deserves notice that locusts are sometimes blown far out to
sea. I caught one 370 miles from Africa, and I have heard of much greater
distances. You might like to hear the following case, as it relates to a
migratory bird belonging to the most wandering of all orders--viz. the
woodcock. (381/2. "Origin," Edition VI., page 328.) The tarsus was
firmly coated with mud, weighing when dry 9 grains, and from this the
Juncus bufonius, or toad rush, germinated. By the way, the locust case
verifies what I said in the "Origin," that many possible means of
distribution would be hereafter discovered. I quite agree about the
extreme difficulty of the distribution of land mollusca. You will have
seen in the last edition of "Origin" (381/3. "Origin," Edition IV., page
429. The reference is to MM. Marten's (381/4. For Marten's read Martins'
[the name is wrongly spelt in the "Origin of Species."]) experiments on
seeds "in a box in the actual sea.") that my observations on the effects of
sea-water have been confirmed. I still suspect that the legs of birds
which roost on the ground may be an efficient means; but I was interrupted
when going to make trials on this subject, and have never resumed it.

We shall be in London in the middle of latter part of November, when I
shall much enjoy seeing you. Emma sends her love, and many thanks for Lady
Lyell's note.

Down, Wednesday [1867].

I daresay there is a great deal of truth in your remarks on the glacial
affair, but we are in a muddle, and shall never agree. I am bigoted to the
last inch, and will not yield. I cannot think how you can attach so much
weight to the physicists, seeing how Hopkins, Hennessey, Haughton, and
Thomson have enormously disagreed about the rate of cooling of the crust;
remembering Herschel's speculations about cold space (382/1. The reader
will find some account of Herschel's views in Lyell's "Principles," 1872,
Edition XI., Volume I., page 283.), and bearing in mind all the recent
speculations on change of axis, I will maintain to the death that your case
of Fernando Po and Abyssinia is worth ten times more than the belief of a
dozen physicists. (382/2. See "Origin," Edition VI., page 337: "Dr.
Hooker has also lately shown that several of the plants living on the upper
parts of the lofty island of Fernando Po and on the neighbouring Cameroon
mountains, in the Gulf of Guinea, are closely related to those in the
mountains of Abyssinia, and likewise to those of temperate Europe." Darwin
evidently means that such facts as these are better evidence of the
gigantic periods of time occupied by evolutionary changes than the
discordant conclusions of the physicists. See "Linn. Soc. Journ." Volume
VII., page 180, for Hooker's general conclusions; also Hooker and Ball's
"Marocco," Appendix F, page 421. For the case of Fernando Po see Hooker
("Linn. Soc. Journ." VI., 1861, page 3, where he sums up: "Hence the result
of comparing Clarence Peak flora [Fernando Po] with that of the African
continent is--(1) the intimate relationship with Abyssinia, of whose flora
it is a member, and from which it is separated by 1800 miles of absolutely
unexplored country; (2) the curious relationship with the East African
islands, which are still farther off; (3) the almost total dissimilarity
from the Cape flora." For Sir J.D. Hooker's general conclusions on the
Cameroon plants see "Linn. Soc. Journ." VII., page 180. More recently
equally striking cases have come to light: for instance, the existence of a
Mediterranean genus, Adenocarpus, in the Cameroons and on Kilima Njaro, and
nowhere else in Africa; and the probable migration of South African forms
along the highlands from the Natal District to Abysinnia. See Hooker,
"Linn. Soc. Journ." XIV., 1874, pages 144-5.) Your remarks on my regarding
temperate plants and disregarding the tropical plants made me at first
uncomfortable, but I soon recovered. You say that all botanists would
agree that many tropical plants could not withstand a somewhat cooler
climate. But I have come not to care at all for general beliefs without
the special facts. I have suffered too often from this: thus I found in
every book the general statement that a host of flowers were fertilised in
the bud, that seeds could not withstand salt water, etc., etc. I would far
more trust such graphic accounts as that by you of the mixed vegetation on
the Himalayas and other such accounts. And with respect to tropical plants
withstanding the slowly coming on cool period, I trust to such facts as
yours (and others) about seeds of the same species from mountains and
plains having acquired a slightly different climatal constitution. I know
all that I have said will excite in you savage contempt towards me. Do not
answer this rigmarole, but attack me to your heart's content, and to that
of mine, whenever you can come here, and may it be soon.

Kew, 1870.

(383/1. The following extract from a letter of Sir J.D. Hooker shows the
tables reversed between the correspondents.)

Grove is disgusted at your being disquieted about W. Thomson. Tell George
from me not to sit upon you with his mathematics. When I threatened your
tropical cooling views with the facts of the physicists, you snubbed me and
the facts sweetly, over and over again; and now, because a scarecrow of x+y
has been raised on the selfsame facts, you boo-boo. Take another dose of
Huxley's penultimate G. S. Address, and send George back to college.
(383/2. Huxley's Anniversary Address to the Geological Society, 1869
("Collected Essays," VIII., page 305). This is a criticism of Lord
Kelvin's paper "On Geological Time" ("Trans. Geolog. Soc. Glasgow," III.).
At page 336 Mr. Huxley deals with Lord Kelvin's "third line of argument,
based on the temperature of the interior of the earth." This was no doubt
the point most disturbing to Mr. Darwin, since it led Lord Kelvin to ask
(as quoted by Huxley), "Are modern geologists prepared to say that all life
was killed off the earth 50,000, 100,000, or 200,000 years ago?" Mr.
Huxley, after criticising Lord Kelvin's data and conclusion, gives his
conviction that the case against Geology has broken down. With regard to
evolution, Huxley (page 328) ingeniously points out a case of circular
reasoning. "But it may be said that it is biology, and not geology, which
asks for so much time--that the succession of life demands vast intervals;
but this appears to me to be reasoning in a circle. Biology takes her time
from geology. The only reason we have for believing in the slow rate of
the change in living forms is the fact that they persist through a series
of deposits which, geology informs us, have taken a long while to make. If
the geological clock is wrong, all the naturalist will have to do is to
modify his notions of the rapidity of change accordingly.")

February 3rd [1868].

I am now reading Miquel on "Flora of Japan" (384/1. Miquel, "Flore du
Japon": "Archives Neerlandaises" ii., 1867.), and like it: it is rather a
relief to me (though, of course, not new to you) to find so very much in
common with Asia. I wonder if A. Murray's (384/2. "Geographical
Distribution of Mammals," by Andrew Murray, 1866. See Chapter V., page 47.
See Letter 379.) notion can be correct, that a [profound] arm of the sea
penetrated the west coast of N. America, and prevented the Asiatico-Japan
element colonising that side of the continent so much as the eastern side;
or will climate suffice? I shall to the day of my death keep up my full
interest in Geographical Distribution, but I doubt whether I shall ever
have strength to come in any fuller detail than in the "Origin" to this
grand subject. In fact, I do not suppose any man could master so
comprehensive a subject as it now has become, if all kingdoms of nature are
included. I have read Murray's book, and am disappointed--though, as you
said, here and there clever thoughts occur. How strange it is, that his
view not affording the least explanation of the innumerable adaptations
everywhere to be seen apparently does not in the least trouble his mind.
One of the most curious cases which he adduces seems to me to be the two
allied fresh-water, highly peculiar porpoises in the Ganges and Indus; and
the more distantly allied form of the Amazons. Do you remember his
explanation of an arm of the sea becoming cut off, like the Caspian,
converted into fresh-water, and then divided into two lakes (by upheaval),
giving rise to two great rivers. But no light is thus thrown on the
affinity of the Amazon form. I now find from Flower's paper (384/3.
"Zoolog. Trans." VI., 1869, page 115. The toothed whales are divided into
the Physeteridae, the Delphinidae, and the Platanistidae, which latter is
placed between the two other families, and is divided into the sub-families
Iniinae and Platanistinae.) that these fresh-water porpoises form two sub-
families, making an extremely isolated and intermediate, very small family.
Hence to us they are clearly remnants of a large group; and I cannot doubt
we here have a good instance precisely like that of ganoid fishes, of a
large ancient marine group, preserved exclusively in fresh-water, where
there has been less competition, and consequently little modification.
(384/4. See Volume I., Letter 95.) What a grand fact that is which Miquel
gives of the beech not extending beyond the Caucasus, and then reappearing
in Japan, like your Himalayan Pinus, and the cedar of Lebanon. (384/5. For
Pinus read Deodar. The essential identity of the deodar and the cedar of
Lebanon was pointed out in Hooker's "Himalayan Journals" in 1854 (Volume
I., page 257.n). In the "Nat. History Review," January, 1862, the question
is more fully dealt with by him, and the distribution discussed. The
nearest point at which cedars occur is the Bulgar-dagh chain of Taurus--250
miles from Lebanon. Under the name of Cedrus atlantica the tree occurs in
mass on the borders of Tunis, and as Deodar it first appears to the east in
the cedar forests of Afghanistan. Sir J.D. Hooker supposes that, during a
period of greater cold, the cedars on the Taurus and on Lebanon lived many
thousand feet nearer the sea-level, and spread much farther to the east,
meeting similar belts of trees descending and spreading westward from
Afghanistan along the Persian mountains.) I know of nothing that gives one
such an idea of the recent mutations in the surface of the land as these
living "outlyers." In the geological sense we must, I suppose, admit that
every yard of land has been successively covered with a beech forest
between the Caucasus and Japan!

I have not yet seen (for I have not sent to the station) Falconer's works.
When you say that you sigh to think how poor your reprinted memoirs would
appear, on my soul I should like to shake you till your bones rattled for
talking such nonsense. Do you sigh over the "Insular Floras," the
Introduction to New Zealand Flora, to Australia, your Arctic Flora, and
dear Galapagos, etc., etc., etc.? In imagination I am grinding my teeth
and choking you till I put sense into you. Farewell. I have amused myself
by writing an audaciously long letter. By the way, we heard yesterday that
George has won the second Smith's Prize, which I am excessively glad of, as
the Second Wrangler by no means always succeeds. The examination consists
exclusively of [the] most difficult subjects, which such men as Stokes,
Cayley, and Adams can set.

March 8th, 1868.

...While writing a few pages on the northern alpine forms of plants on the
Java mountains I wanted a few cases to refer to like Teneriffe, where there
are no northern forms and scarcely any alpine. I expected the volcanoes of
Hawaii would be a good case, and asked Dr. Seemann about them. It seems a
man has lately published a list of Hawaiian plants, and the mountains swarm
with European alpine genera and some species! (385/1. "This turns out to
be inaccurate, or greatly exaggerated. There are no true alpines, and the
European genera are comparatively few. See my 'Island Life,' page 323."--
A.R.W.) Is not this most extraordinary, and a puzzler? They are, I
believe, truly oceanic islands, in the absence of mammals and the extreme
poverty of birds and insects, and they are within the Tropics.

Will not that be a hard nut for you when you come to treat in detail on
geographical distribution? I enclose Seemann's note, which please return
when you have copied the list, if of any use to you.

Down, February 21st [1870].

I read yesterday the notes on Round Island (386/1. In Wallace's "Island
Life," page 410, Round Island is described as an islet "only about a mile
across, and situated about fourteen miles north-east of Mauritius."
Wallace mentions a snake, a python belonging to the peculiar and distinct
genus Casarea, as found on Round Island, and nowhere else in the world.
The palm Latania Loddigesii is quoted by Wallace as "confined to Round
Island and two other adjacent islets." See Baker's "Flora of the Mauritius
and the Seychelles." Mr. Wallace says that, judging from the soundings,
Round Island was connected with Mauritius, and that when it was "first
separated [it] would have been both much larger and much nearer the main
island.") which I owe to you. Was there ever such an enigma? If, in the
course of a week or two, you can find time to let me hear what you think, I
should very much like to hear: or we hope to be at Erasmus' on March 4th
for a week. Would there be any chance of your coming to luncheon then?
What a case it is. Palms, screw-pines, four snakes--not one being in main
island--lizards, insects, and not one land bird. But, above everything,
such a proportion of individual monocotyledons! The conditions do not seem
very different from the Tuff Galapagos Island, but, as far as I remember,
very few monocotyledons there. Then, again, the island seems to have been
elevated. I wonder much whether it stands out in the line of any oceanic
current, which does not so forcibly strike the main island? But why, oh,
why should so many monocotyledons have come there? or why should they have
survived there more than on the main island, if once connected? So, again,
I cannot conceive that four snakes should have become extinct in Mauritius
and survived on Round Island. For a moment I thought that Mauritius might
be the newer island, but the enormous degradation which the outer ring of
rocks has undergone flatly contradicts this, and the marine remains on the
summit of Round Island indicate the island to be comparatively new--unless,
indeed, they are fossil and extinct marine remains. Do tell me what you
think. There never was such an enigma. I rather lean to separate
immigration, with, of course, subsequent modification; some forms, of
course, also coming from Mauritius. Speaking of Mauritius reminds me that
I was so much pleased the day before yesterday by reading a review of a
book on the geology of St. Helena, by an officer who knew nothing of my
hurried observations, but confirms nearly all that I have said on the
general structure of the island, and on its marvellous denudation. The
geology of that island was like a novel.

Down, March 28th, 1876.

(387/1. The following refers to Blytt's "Essay on the Immigration of the
Norwegian Flora during Alternating Rainy and Dry Periods," Christiania,

I thank you sincerely for your kindness in having sent me your work on the
"Immigration of the Norwegian Flora," which has interested me in the
highest degree. Your view, supported as it is by various facts, appears to
me the most important contribution towards understanding the present
distribution of plants, which has appeared since Forbes' essay on the
effects of the Glacial Period.

Down, June 19th, 1876.

I hope you will allow me to suggest an observation, should any opportunity
occur, on a point which has interested me for many years--viz., how do the
coleoptera which inhabit the nests of ants colonise a new nest? Mr.
Wallace, in reference to the presence of such coleoptera in Madeira,
suggests that their ova may be attached to the winged female ants, and that
these are occasionally blown across the ocean to the island. It would be
very interesting to discover whether the ova are adhesive, and whether the
female coleoptera are guided by instinct to attach them to the female ants
(388/1. Dr. Sharp is good enough to tell us that he is not aware of any
such adaptation. Broadly speaking, the distribution of the nest-inhabiting
beetles is due to co-migration with the ants, though in some cases the ants
transport the beetles. Sitaris and Meloe are beetles which live "at the
expense of bees of the genus Anthophora." The eggs are laid not in but
near the bees' nest; in the early stage the larva is active and has the
instinct to seize any hairy object near it, and in this way they are
carried by the Anthophora to the nest. Dr. Sharp states that no such
preliminary stage is known in the ant's-nest beetles. For an account of
Sitaris and Meloe, see Sharp's "Insects," II., page 272.); or whether the
larvae pass through an early stage, as with Sitaris or Meloe, or cling to
the bodies of the females. This note obviously requires no answer. I
trust that you continue your most interesting investigations on ants.

(PLATE: MR. A.R. WALLACE, 1878. From a photograph by Maull & Fox.)


(389/1. Published in "Life and Letters," III., page 230.)

(389/2. The following five letters refer to Mr. Wallace's "Geographical
Distribution of Animals," 1876.)

[Hopedene] (389/3. Mr. Hensleigh Wedgwood's house in Surrey.), June 5th,

I must have the pleasure of expressing to you my unbounded admiration of
your book (389/4. "Geographical Distribution," 1876.), though I have read
only to page 184--my object having been to do as little as possible while
resting. I feel sure that you have laid a broad and safe foundation for
all future work on Distribution. How interesting it will be to see
hereafter plants treated in strict relation to your views; and then all
insects, pulmonate molluscs and fresh-water fishes, in greater detail than
I suppose you have given to these lower animals. The point which has
interested me most, but I do not say the most valuable point, is your
protest against sinking imaginary continents in a quite reckless manner, as
was stated by Forbes, followed, alas, by Hooker, and caricatured by
Wollaston and [Andrew] Murray! By the way, the main impression that the
latter author has left on my mind is his utter want of all scientific
judgment. I have lifted up my voice against the above view with no avail,
but I have no doubt that you will succeed, owing to your new arguments and
the coloured chart. Of a special value, as it seems to me, is the
conclusion that we must determine the areas, chiefly by the nature of the
mammals. When I worked many years ago on this subject, I doubted much
whether the now-called Palaearctic and Nearctic regions ought to be
separated; and I determined if I made another region that it should be
Madagascar. I have, therefore, been able to appreciate your evidence on
these points. What progress Palaeontology has made during the last twenty
years! but if it advances at the same rate in the future, our views on the
migration and birthplace of the various groups will, I fear, be greatly
altered. I cannot feel quite easy about the Glacial period, and the
extinction of large mammals, but I must hope that you are right. I think
you will have to modify your belief about the difficulty of dispersal of
land molluscs; I was interrupted when beginning to experimentise on the
just hatched young adhering to the feet of ground-roosting birds. I differ
on one other point--viz. in the belief that there must have existed a
Tertiary Antarctic continent, from which various forms radiated to the
southern extremities of our present continents. But I could go on
scribbling forever. You have written, as I believe, a grand and memorable
work, which will last for years as the foundation for all future treatises
on Geographical Distribution.

P.S.--You have paid me the highest conceivable compliment, by what you say
of your work in relation to my chapters on distribution in the "Origin,"
and I heartily thank you for it.

The Dell, Grays, Essex, June 7th, 1876.

Many thanks for your very kind letter. So few people will read my book at
all regularly, that a criticism from one who does so will be very welcome.
If, as I suppose, it is only to page 184 of Volume I. that you have read,
you cannot yet quite see my conclusions on the points you refer to (land
molluscs and Antarctic continent). My own conclusion fluctuated during the
progress of the book, and I have, I know, occasionally used expressions
(the relics of earlier ideas) which are not quite consistent with what I
say further on. I am positively against any Southern continent as uniting
South America with Australia or New Zealand, as you will see at Volume I.,
pages 398-403, and 459-66. My general conclusions as to distribution of
land mollusca are at Volume II., pages 522-9. (390/1. "Geographical
Distribution" II., pages 524, 525. Mr. Wallace points out that "hardly a
small island on the globe but has some land-shells peculiar to it"--and he
goes so far as to say that probably air-breathing mollusca have been
chiefly distributed by air- or water-carriage, rather than by voluntary
dispersal on the land.) When you have read these passages, and looked at
the general facts which lead to them, I shall be glad to hear if you still
differ from me.

Though, of course, present results as to the origin and migrations of
genera of mammals will have to be modified owing to new discoveries, I
cannot help thinking that much will remain unaffected, because in all
geographical and geological discoveries the great outlines are soon
reached, the details alone remain to be modified. I also think much of the
geological evidence is now so accordant with, and explanatory of,
Geographical Distribution, that it is prima facie correct in outline.
Nevertheless, such vast masses of new facts will come out in the next few
years that I quite dread the labour of incorporating them in a new edition.

I hope your health is improved; and when, quite at your leisure, you have
waded through my book, I trust you will again let me have a few lines of
friendly criticism and advice.

Down, June 17th, 1876.

I have now finished the whole of Volume I., with the same interest and
admiration as before; and I am convinced that my judgment was right and
that it is a memorable book, the basis of all future work on the subject.
I have nothing particular to say, but perhaps you would like to hear my
impressions on two or three points. Nothing has struck me more than the
admirable and convincing manner in which you treat Java. To allude to a
very trifling point, it is capital about the unadorned head of the Argus-
pheasant. (391/1. See "Descent of Man," Edition I., pages 90 and 143, for
drawings of the Argus pheasant and its markings. The ocelli on the wing
feathers were favourite objects of Mr. Darwin, and sometimes formed the
subject of the little lectures which on rare occasions he would give to a
visitor interested in Natural History. In Mr. Wallace's book the meaning
of the ocelli comes in by the way, in the explanation of Plate IX., "A
Malayan Forest with some of its peculiar Birds." Mr. Wallace (volume i.,
page 340) points out that the head of the Argus pheasant is, during the
display of the wings, concealed from the view of a spectator in front, and
this accounts for the absence of bright colour on the head--a most unusual
point in a pheasant. The case is described as a "remarkable confirmation
of Mr. Darwin's views, that gaily coloured plumes are developed in the male
bird for the purpose of attractive display." For the difference of opinion
between the two naturalists on the broad question of coloration see "Life
and Letters," III., page 123. See Letters 440-453.) How plain a thing is,
when it is once pointed out! What a wonderful case is that of Celebes: I
am glad that you have slightly modified your views with respect to Africa.
(391/2. "I think this must refer to the following passage in 'Geog. Dist.
of Animals,' Volume I., pages 286-7. 'At this period (Miocene) Madagascar
was no doubt united with Africa, and helped to form a great southern
continent which must at one time have extended eastward as far as Southern
India and Ceylon; and over the whole of this the lemurine type no doubt
prevailed.' At the time this was written I had not paid so much attention
to islands, and in my "Island Life" I have given ample reasons for my
belief that the evidence of extinct animals does not require any direct
connection between Southern India and Africa."--Note by Mr. Wallace.) And
this leads me to say that I cannot swallow the so-called continent of
Lemuria--i.e., the direct connection of Africa and Ceylon. (391/3. See
"Geographical Distribution," I., page 76. The name Lemuria was proposed by
Mr. Sclater for an imaginary submerged continent extending from Madagascar
to Ceylon and Sumatra. Mr. Wallace points out that if we confine ourselves
to facts Lemuria is reduced to Madagascar, which he makes a subdivision of
the Ethiopian Region.) The facts do not seem to me many and strong enough
to justify so immense a change of level. Moreover, Mauritius and the other
islands appear to me oceanic in character. But do not suppose that I place
my judgment on this subject on a level with yours. A wonderfully good
paper was published about a year ago on India, in the "Geological Journal,"
I think by Blanford. (391/4. H.F. Blanford "On the Age and Correlations
of the Plant-bearing Series of India and the Former Existence of an Indo-
Oceanic Continent" ("Quart. Journ. Geol. Soc." XXXI., 1875, page 519). The
name Gondwana-Land was subsequently suggested by Professor Suess for this
Indo-Oceanic continent. Since the publication of Blanford's paper, much
literature has appeared dealing with the evidence furnished by fossil
plants, etc., in favour of the existence of a vast southern continent.)
Ramsay agreed with me that it was one of the best published for a long
time. The author shows that India has been a continent with enormous
fresh-water lakes, from the Permian period to the present day. If I
remember right, he believes in a former connection with S. Africa.

I am sure that I read, some twenty to thirty years ago in a French journal,
an account of teeth of Mastodon found in Timor; but the statement may have
been an error. (391/5. In a letter to Falconer (Letter 155), January 5th,
1863, Darwin refers to the supposed occurrence of Mastodon as having been
"smashed" by Falconer.)

With respect to what you say about the colonising of New Zealand, I
somewhere have an account of a frog frozen in the ice of a Swiss glacier,
and which revived when thawed. I may add that there is an Indian toad
which can resist salt-water and haunts the seaside. Nothing ever
astonished me more than the case of the Galaxias; but it does not seem
known whether it may not be a migratory fish like the salmon. (391/6. The
only genus of the Galaxidae, a family of fresh-water fishes occurring in
New Zealand, Tasmania, and Tierra del Fuego, ranging north as far as
Queensland and Chile (Wallace's "Geographical Distribution," II., page

Down, June 25th, 1876.

I have been able to read rather more quickly of late, and have finished
your book. I have not much to say. Your careful account of the temperate
parts of South America interested me much, and all the more from knowing
something of the country. I like also much the general remarks towards the
end of the volume on the land molluscs. Now for a few criticisms.

Page 122. (392/1. The pages refer to Volume II. of Wallace's
"Geographical Distribution.")--I am surprised at your saying that "during
the whole Tertiary period North America was zoologically far more strongly
contrasted with South America than it is now." But we know hardly anything
of the latter except during the Pliocene period; and then the mastodon,
horse, several great edentata, etc., etc., were common to the north and
south. If you are right, I erred greatly in my "Journal," where I insisted
on the former close connection between the two.

Page 252 and elsewhere.--I agree thoroughly with the general principle that
a great area with many competing forms is necessary for much and high
development; but do you not extend this principle too far--I should say
much too far, considering how often several species of the same genus have
been developed on very small islands?

Page 265.--You say that the Sittidae extend to Madagascar, but there is no
number in the tabular heading. [The number (4) was erroneously omitted.--

Page 359.--Rhinochetus is entered in the tabular heading under No. 3 of the
neotropical subregions. [An error: should have been the Australian.--

Reviewers think it necessary to find some fault; and if I were to review
you, the sole point which I should blame is your not giving very numerous
references. These would save whoever follows you great labour.
Occasionally I wished myself to know the authority for certain statements,
and whether you or somebody else had originated certain subordinate views.
Take the case of a man who had collected largely on some island, for
instance St. Helena, and who wished to work out the geographical relations
of his collections: he would, I think, feel very blank at not finding in
your work precise references to all that had been written on St. Helena. I
hope you will not think me a confoundedly disagreeable fellow.

I may mention a capital essay which I received a few months ago from Axel
Blytt (392/2. Axel Blytt, "Essay on the Immigration of the Norwegian
Flora." Christiania, 1876. See Letter 387.) on the distribution of the
plants of Scandinavia; showing the high probability of there having been
secular periods alternately wet and dry, and of the important part which
they have played in distribution.

I wrote to Forel (392/3. See Letter 388.), who is always at work on ants,
and told him your views about the dispersal of the blind coleoptera, and
asked him to observe.

I spoke to Hooker about your book, and feel sure that he would like nothing
better than to consider the distribution of plants in relation to your
views; but he seemed to doubt whether he should ever have time.

And now I have done my jottings, and once again congratulate you on having
brought out so grand a work. I have been a little disappointed at the
review in "Nature." (392/4. June 22nd, 1876, pages 165 et seq.)

Rosehill, Dorking, July 23rd, 1876.

I should have replied sooner to your last kind and interesting letters, but
they reached me in the midst of my packing previous to removal here, and I
have only just now got my books and papers in a get-at-able state.

And first, many thanks for your close observation in detecting the two
absurd mistakes in the tabular headings.

As to the former greater distinction of the North and South American
faunas, I think I am right. The edentata being proved (as I hold) to have
been mere temporary migrants into North America in the post-Pliocene epoch,
form no part of its Tertiary fauna. Yet in South America they were so
enormously developed in the Pliocene epoch that we know, if there is any
such thing as evolution, etc., that strange ancestral forms must have
preceded them in Miocene times.

Mastodon, on the other hand, represented by one or two species only,
appears to have been a late immigrant into South America from the north.

The immense development of ungulates (in varied families, genera, and
species) in North America during the whole Tertiary epoch is, however, the
great feature which assimilates it to Europe, and contrasts it with South
America. True camels, hosts of hog-like animals, true rhinoceroses, and
hosts of ancestral horses, all bring the North American [fauna] much nearer
to the Old World than it is now. Even the horse, represented in all South
America by Equus only, was probably a temporary immigrant from the north.

As to extending too far the principle (yours) of the necessity of
comparatively large areas for the development of varied faunas, I may have
done so, but I think not. There is, I think, every probability that most
islands, etc., where a varied fauna now exists, have been once more
extensive--eg., New Zealand, Madagascar: where there is no such evidence
(e.g., Galapagos), the fauna is very restricted.

Lastly, as to want of references: I confess the justice of your criticism;
but I am dreadfully unsystematic. It is my first large work involving much
of the labour of others. I began with the intention of writing a
comparatively short sketch, enlarged it, and added to it bit by bit;
remodelled the tables, the headings, and almost everything else, more than
once, and got my materials in such confusion that it is a wonder it has not
turned out far more crooked and confused than it is. I, no doubt, ought to
have given references; but in many cases I found the information so small
and scattered, and so much had to be combined and condensed from
conflicting authorities, that I hardly knew how to refer to them or where
to leave off. Had I referred to all authors consulted for every fact, I
should have greatly increased the bulk of the book, while a large portion
of the references would be valueless in a few years, owing to later and
better authorities. My experience of referring to references has generally
been most unsatisfactory. One finds, nine times out of ten, the fact is
stated, and nothing more; or a reference to some third work not at hand!

I wish I could get into the habit of giving chapter and verse for every
fact and extract; but I am too lazy, and generally in a hurry, having to
consult books against time, when in London for a day.

However, I will try to do something to mend this matter, should I have to
prepare another edition.

I return you Forel's letter. It does not advance the question much;
neither do I think it likely that even the complete observation he thinks
necessary would be of much use, because it may well be that the ova, or
larvae, or imagos of the beetles are not carried systematically by the
ants, but only occasionally, owing to some exceptional circumstances. This
might produce a great effect in distribution, yet be so rare as never to
come under observation.

Several of your remarks in previous letters I shall carefully consider. I
know that, compared with the extent of the subject, my book is in many
parts crude and ill-considered; but I thought, and still think, it better
to make some generalisations wherever possible, as I am not at all afraid
of having to alter my views in many points of detail. I was so overwhelmed
with zoological details, that I never went through the Geological Society's
"Journal" as I ought to have done, and as I mean to do before writing more
on the subject.


(394/1. "Written in acknowledgment of a copy of a paper (published by me
in the "Proceedings of the Zoological Society") on the Hemiptera of St.
Helena, but discussing the origin of the whole fauna and flora of that

Down, September 23rd. [1878].

I have now read your paper, and I hope that you will not think me
presumptuous in writing another line to say how excellent it seems to me.
I believe that you have largely solved the problem of the affinities of the
inhabitants of this most interesting little island, and this is a
delightful triumph.

Down, July 22nd [1879].

I have just read Ball's Essay. (395/1. The late John Ball's lecture "On
the Origin of the Flora of the Alps" in the "Proceedings of the R. Geogr.
Soc." 1879. Ball argues (page 18) that "during ancient Palaeozoic times,
before the deposition of the Coal-measures, the atmosphere contained twenty
times as much carbonic acid gas and considerably less oxygen than it does
at present." He further assumes that in such an atmosphere the percentage
of CO2 in the higher mountains would be excessively different from that at
the sea-level, and appends the result of calculations which gives the
amount of CO2 at the sea-level as 100 per 10,000 by weight, at a height of
10,000 feet as 12.5 per 10,000. Darwin understands him to mean that the
Vascular Cryptogams and Gymnosperms could stand the sea-level atmosphere,
whereas the Angiosperms would only be able to exist in the higher regions
where the percentage of CO2 was small. It is not clear to us that Ball
relies so largely on the condition of the atmosphere as regards CO2. If he
does he is clearly in error, for everything we know of assimilation points
to the conclusion that 100 per 10,000 (1 per cent.) is by no means a
hurtful amount of CO2, and that it would lead to an especially vigorous
assimilation. Mountain plants would be more likely to descend to the
plains to share in the rich feast than ascend to higher regions to avoid
it. Ball draws attention to the imperfection of our plant records as
regards the floras of mountain regions. It is, he thinks, conceivable that
there existed a vegetation on the Carboniferous mountains of which no
traces have been preserved in the rocks. See "Fossil Plants as Tests of
Climate," page 40, A.C. Seward, 1892.

Since the first part of this note was written, a paper has been read (May
29th, 1902) by Dr. H.T. Brown and Mr. F. Escombe, before the Royal Society
on "The Influence of varying amounts of Carbon Dioxide in the Air on the
Photosynthetic Process of Leaves, and on the Mode of Growth of Plants."
The author's experiments included the cultivation of several dicotyledonous
plants in an atmosphere containing in one case 180 to 200 times the normal
amount of CO2, and in another between three and four times the normal
amount. The general results were practically identical in the two sets of
experiments. "All the species of flowering plants, which have been the
subject of experiment, appear to be accurately 'tuned' to an atmospheric
environment of three parts of CO2 per 10,000, and the response which they
make to slight increases in this amount are in a direction altogether
unfavourable to their growth and reproduction." The assimilation of carbon
increases with the increase in the partial pressure of the CO2. But there
seems to be a disturbance in metabolism, and the plants fail to take
advantage of the increased supply of CO2. The authors say:--"All we are
justified in concluding is, that if such atmospheric variations have
occurred since the advent of flowering plants, they must have taken place
so slowly as never to outrun the possible adaptation of the plants to their
changing conditions."

Prof. Farmer and Mr. S.E. Chandler gave an account, at the same meeting of
the Royal Society, of their work "On the Influence of an Excess of Carbon
Dioxide in the Air on the Form and Internal Structure of Plants." The
results obtained were described as differing in a remarkable way from those
previously recorded by Teodoresco ("Rev. Gen. Botanique," II., 1899

It is hoped that Dr. Horace Brown and Mr. Escombe will extend their
experiments to Vascular Cryptogams, and thus obtain evidence bearing more
directly upon the question of an increased amount of CO2 in the atmosphere
of the Coal-period forests.) It is pretty bold. The rapid development as
far as we can judge of all the higher plants within recent geological times
is an abominable mystery. Certainly it would be a great step if we could
believe that the higher plants at first could live only at a high level;
but until it is experimentally [proved] that Cycadeae, ferns, etc., can
withstand much more carbonic acid than the higher plants, the hypothesis
seems to me far too rash. Saporta believes that there was an astonishingly
rapid development of the high plants, as soon [as] flower-frequenting
insects were developed and favoured intercrossing. I should like to see
this whole problem solved. I have fancied that perhaps there was during
long ages a small isolated continent in the S. Hemisphere which served as
the birthplace of the higher plants--but this is a wretchedly poor
conjecture. It is odd that Ball does not allude to the obvious fact that
there must have been alpine plants before the Glacial period, many of which
would have returned to the mountains after the Glacial period, when the
climate again became warm. I always accounted to myself in this manner for
the gentians, etc.

Ball ought also to have considered the alpine insects common to the Arctic
regions. I do not know how it may be with you, but my faith in the glacial
migration is not at all shaken.


(396/1. This letter is in reply to Mr. Darwin's criticisms on Mr.
Wallace's "Island Life," 1880.)

Pen-y-Bryn, St. Peter's Road, Croydon, November 8th, 1880.

Many thanks for your kind remarks and notes on my book. Several of the
latter will be of use to me if I have to prepare a second edition, which I
am not so sure of as you seem to be.

1. In your remark as to the doubtfulness of paucity of fossils being due
to coldness of water, I think you overlook that I am speaking only of water
in the latitude of the Alps, in Miocene and Eocene times, when icebergs and
glaciers temporarily descended into an otherwise warm sea; my theory being
that there was no Glacial epoch at that time, but merely a local and
temporary descent of the snow-line and glaciers owing to high excentricity
and winter in aphelion.

2. I cannot see the difficulty about the cessation of the Glacial period.

Between the Miocene and the Pleistocene periods geographical changes
occurred which rendered a true Glacial period possible with high
excentricity. When the high excentricity passed away the Glacial epoch
also passed away in the temperate zone; but it persists in the arctic zone,
where, during the Miocene, there were mild climates, and this is due to the
persistence of the changed geographical conditions. The present arctic
climate is itself a comparatively new and abnormal state of things, due to
geographical modification.

As to "epoch" and "period," I use them as synonyms to avoid repeating the
same word.

3. Rate of deposition and geological time. Here no doubt I may have gone
to an extreme, but my "28 million years" may be anything under 100
millions, as I state. There is an enormous difference between mean and
maximum denudation and deposition. In the case of the great faults the
upheaval along a given line would itself facilitate the denudation (whether
sub-aerial or marine) of the upheaved portion at a rate perhaps a hundred
times above the average, just as valleys have been denuded perhaps a
hundred times faster than plains and plateaux. So local subsidence might
itself lead to very rapid deposition. Suppose a portion of the Gulf of
Mexico, near the mouths of the Mississippi, were to subside for a few
thousand years, it might receive the greater portion of the sediment from
the whole Mississippi valley, and thus form strata at a very rapid rate.

4. You quote the Pampas thistles, etc., against my statement of the
importance of preoccupation. But I am referring especially to St. Helena,
and to plants naturally introduced from the adjacent continents. Surely if
a certain number of African plants reached the island, and became modified
into a complete adaptation to its climatic conditions, they would hardly be
expelled by other African plants arriving subsequently. They might be so,
conceivably, but it does not seem probable. The cases of the Pampas, New
Zealand, Tahiti, etc., are very different, where highly developed
aggressive plants have been artificially introduced. Under nature it is
these very aggressive species that would first reach any island in their
vicinity, and, being adapted to the island and colonising it thoroughly,
would then hold their own against other plants from the same country,
mostly less aggressive in character.

I have not explained this so fully as I should have done in the book. Your
criticism is therefore useful.

5. My Chapter XXIII. is no doubt very speculative, and I cannot wonder at
your hesitating at accepting my views. To me, however, your theory of
hosts of existing species migrating over the tropical lowlands from the N.
temperate to the S. temperate zone appears more speculative and more
improbable. For where could the rich lowland equatorial flora have existed
during a period of general refrigeration sufficient for this? and what
became of the wonderfully rich Cape flora, which, if the temperature of
tropical Africa had been so recently lowered, would certainly have spread
northwards, and on the return of the heat could hardly have been driven
back into the sharply defined and very restricted area in which it now

As to the migration of plants from mountain to mountain not being so
probable as to remote islands, I think that is fully counterbalanced by two

a. The area and abundance of the mountain stations along such a range as
the Andes are immensely greater than those of the islands in the N.
Atlantic, for example.

b. The temporary occupation of mountain stations by migrating plants
(which I think I have shown to be probable) renders time a much more
important element in increasing the number and variety of the plants so
dispersed than in the case of islands, where the flora soon acquires a
fixed and endemic character, and where the number of species is necessarily

No doubt direct evidence of seeds being carried great distances through the
air is wanted, but I am afraid can hardly be obtained. Yet I feel the
greatest confidence that they are so carried. Take, for instance, the two
peculiar orchids of the Azores (Habenaria sp.) What other mode of transit
is conceivable? The whole subject is one of great difficulty, but I hope
my chapter may call attention to a hitherto neglected factor in the
distribution of plants.

Your references to the Mauritius literature are very interesting, and will
be useful to me; and I again thank you for your valuable remarks.


(397/1. The following letters were written to Sir J.D. Hooker when he was
preparing his Address as President of the Geographical Section of the
British Association at its fiftieth meeting, at York. The second letter
(August 12th) refers to an earlier letter of August 6th, published in "Life
and Letters," III., page 246.)

4, Bryanston Street, W., Saturday, 26th [February, 1881].

I should think that you might make a very interesting address on
Geographical Distribution. Could you give a little history of the subject.
I, for one, should like to read such history in petto; but I can see one
very great difficulty--that you yourself ought to figure most prominently
in it; and this you would not do, for you are just the man to treat
yourself in a dishonourable manner. I should very much like to see you
discuss some of Wallace's views, especially his ignoring the all-powerful
effects of the Glacial period with respect to alpine plants. (397/2.
"Having been kindly permitted by Mr. Francis Darwin to read this letter, I
wish to explain that the above statement applies only to my rejection of
Darwin's view that the presence of arctic and north temperate plants in the
SOUTHERN HEMISPHERE was brought about by the lowering of the temperature of
the tropical regions during the Glacial period, so that even 'the lowlands
of these great continents were everywhere tenanted under the equator by a
considerable number of temperate forms ("Origin of Species," Edition VI.,
page 338). My own views are fully explained in Chapter XXIII. of my
"Island Life," published in 1880. I quite accept all that Darwin, Hooker,
and Asa Gray have written about the effect of the Glacial epoch in bringing
about the present distribution of alpine and arctic plants in the NORTHERN
HEMISPHERE."--Note by Mr. Wallace.) I do not know what you think, but it
appears to me that he exaggerates enormously the influence of debacles or
slips and new surface of soil being exposed for the reception of wind-blown
seeds. What kinds of seeds have the plants which are common to the distant
mountain-summits in Africa? Wallace lately wrote to me about the mountain
plants of Madagascar being the same with those on mountains in Africa, and
seemed to think it proved dispersal by the wind, without apparently having
inquired what sorts of seeds the plants bore. (397/3. The affinity with
the flora of the Eastern African islands was long ago pointed out by Sir
J.D. Hooker, "Linn. Soc. Journal," VI., 1861, page 3. Speaking of the
plants of Clarence Peak in Fernando Po, he says, "The next affinity is with
Mauritius, Bourbon, and Madagascar: of the whole 76 species, 16 inhabit
these places and 8 more are closely allied to plants from there. Three
temperate species are peculiar to Clarence Peak and the East African
islands..." The facts to which Mr. Wallace called Darwin's attention are
given by Mr. J.G. Baker in "Nature," December 9th, 1880, page 125. He
mentions the Madagascar Viola, which occurs elsewhere only at 7,000 feet in
the Cameroons, at 10,000 feet in Fernando Po and in the Abyssinian
mountains; and the same thing is true of the Madagascar Geranium. In Mr.
Wallace's letter to Darwin, dated January 1st, 1881, he evidently uses the
expression "passing through the air" in contradistinction to the migration
of a species by gradual extension of its area on land. "Through the air"
would moreover include occasional modes of transport other than simple
carriage by wind: e.g., the seeds might be carried by birds, either
attached to the feathers or to the mud on their feet, or in their crops or

I suppose it would be travelling too far (though for the geographical
section the discussion ought to be far-reaching), but I should like to see
the European or northern element in the Cape of Good Hope flora discussed.
I cannot swallow Wallace's view that European plants travelled down the
Andes, tenanted the hypothetical Antarctic continent (in which I quite
believe), and thence spread to South Australia and the Cape of Good Hope.

Moseley told me not long ago that he proposed to search at Kerguelen Land
the coal beds most carefully, and was absolutely forbidden to do so by Sir
W. Thomson, who said that he would undertake the work, and he never once
visited them. This puts me in a passion. I hope that you will keep to
your intention and make an address on distribution. Though I differ so
much from Wallace, his "Island Life" seems to me a wonderful book.

Farewell. I do hope that you may have a most prosperous journey. Give my
kindest remembrances to Asa Gray.

Down, August 12th, 1881.

...I think that I must have expressed myself badly about Humboldt. I
should have said that he was more remarkable for his astounding knowledge
than for originality. I have always looked at him as, in fact, the founder
of the geographical distribution of organisms. I thought that I had read
that extinct fossil plants belonging to Australian forms had lately been
found in Australia, and all such cases seem to me very interesting, as
bearing on development.

I have been so astonished at the apparently sudden coming in of the higher
phanerogams, that I have sometimes fancied that development might have
slowly gone on for an immense period in some isolated continent or large
island, perhaps near the South Pole. I poured out my idle thoughts in
writing, as if I had been talking with you.

No fact has so interested me for a heap of years as your case of the plants
on the equatorial mountains of Africa; and Wallace tells me that some one
(Baker?) has described analogous cases on the mountains of Madagascar
(398/1. See Letter 397, note.)...I think that you ought to allude to these

I most fully agree that no problem is more interesting than that of the
temperate forms in the southern hemisphere, common to the north. I
remember writing about this after Wallace's book appeared, and hoping that
you would take it up. The frequency with which the drainage from the land
passes through mountain-chains seems to indicate some general law--viz.,
the successive formation of cracks and lines of elevation between the
nearest ocean and the already upraised land; but that is too big a subject
for a note.

I doubt whether any insects can be shown with any probability to have been
flower feeders before the middle of the Secondary period. Several of the
asserted cases have broken down.

Your long letter has stirred many pleasant memories of long past days, when
we had many a discussion and many a good fight.

Down, August 21st, 1881.

I cannot aid you much, or at all. I should think that no one could have
thought on the modification of species without thinking of representative
species. But I feel sure that no discussion of any importance had been
published on this subject before the "Origin," for if I had known of it I
should assuredly have alluded to it in the "Origin," as I wished to gain
support from all quarters. I did not then know of Von Buch's view (alluded
to in my Historical Introduction in all the later editions). Von Buch
published his "Isles Canaries" in 1836, and he here briefly argues that
plants spread over a continent and vary, and the varieties in time come to
be species. He also argues that closely allied species have been thus
formed in the SEPARATE valleys of the Canary Islands, but not on the upper
and open parts. I could lend you Von Buch's book, if you like. I have
just consulted the passage.

I have not Baer's papers; but, as far as I remember, the subject is not
fully discussed by him.

I quite agree about Wallace's position on the ocean and continent question.

To return to geographical distribution: As far as I know, no one ever
discussed the meaning of the relation between representative species before
I did, and, as I suppose, Wallace did in his paper before the Linnean
Society. Von Buch's is the nearest approach to such discussion known to


(400/1. The following letters are interesting not only for their own sake,
but because they tell the history of the last of Mr. Darwin's
publications--his letter to "Nature" on the "Dispersal of Freshwater
Bivalves," April 6th, 1882.)

Down, February 21st, 1882.

Your fact is an interesting one, and I am very much obliged to you for
communicating it to me. You speak a little doubtfully about the name of
the shell, and it would be indispensable to have this ascertained with
certainty. Do you know any good conchologist in Northampton who could name
it? If so I should be obliged if you would inform me of the result.

Also the length and breadth of the shell, and how much of leg (which leg?)
of the Dytiscus [a large water-beetle] has been caught. If you cannot get
the shell named I could take it to the British Museum when I next go to
London; but this probably will not occur for about six weeks, and you may
object to lend the specimen for so long a time.

I am inclined to think that the case would be worth communicating to

P.S.--I suppose that the animal in the shell must have been alive when the
Dytiscus was captured, otherwise the adductor muscle of the shell would
have relaxed and the shell dropped off.

Down, February 25th, 1882.

I am much obliged for your clear and distinct answers to my questions. I
am sorry to trouble you, but there is one point which I do not fully
understand. Did the shell remain attached to the beetle's leg from the
18th to the 23rd, and was the beetle kept during this time in the air?

Do I understand rightly that after the shell had dropped off, both being in
water, that the beetle's antenna was again temporarily caught by the shell?

I presume that I may keep the specimen till I go to London, which will be
about the middle of next month.

I have placed the shell in fresh-water, to see if the valve will open, and
whether it is still alive, for this seems to me a very interesting point.
As the wretched beetle was still feebly alive, I have put it in a bottle
with chopped laurel leaves, that it may die an easy and quicker death. I
hope that I shall meet with your approval in doing so.

One of my sons tells me that on the coast of N. Wales the bare fishing
hooks often bring up young mussels which have seized hold of the points;
but I must make further enquiries on this head.

Down, March 23rd, 1882.

I have had a most unfortunate and extraordinary accident with your shell.
I sent it by post in a strong box to Mr. Gwyn Jeffreys to be named, and
heard two days afterwards that he had started for Italy. I then wrote to
the servant in charge of his house to open the parcel (within which was a
cover stamped and directed to myself) and return it to me. This servant, I
suppose, opened the box and dropped the glass tube on a stone floor, and
perhaps put his foot on it, for the tube and shell were broken into quite
small fragments. These were returned to me with no explanation, the box
being quite uninjured. I suppose you would not care for the fragments to
be returned or the Dytiscus; but if you wish for them they shall be
returned. I am very sorry, but it has not been my fault.

It seems to me almost useless to send the fragments of the shell to the
British Museum to be named, more especially as the umbo has been lost. It
is many years since I have looked at a fresh-water shell, but I should have
said that the shell was Cyclas cornea. (402/1. It was Cyclas cornea.) Is
Sphaenium corneum a synonym of Cyclas? Perhaps you could tell by looking
to Mr. G. Jeffreys' book. If so, may we venture to call it so, or shall I
put an (?) to the name?

As soon as I hear from you I will send my letter to "Nature." Do you take
in "Nature," or shall I send you a copy?


I. Descent of Man.--II. Sexual Selection.--III. Expression of the Emotions.

2.VIII.I. DESCENT OF MAN, 1860-1882.

Down, April 27th [1860].

I cannot explain why, but to me it would be an infinite satisfaction to
believe that mankind will progress to such a pitch that we should [look]
back at [ourselves] as mere Barbarians. I have received proof-sheets (with
a wonderfully nice letter) of very hostile review by Andrew Murray, read
before the Royal Society of Edinburgh. (403/1. "On Mr. Darwin's Theory of
the Origin of Species," by Andrew Murray. "Proc. Roy. Soc., Edinb." Volume
IV., pages 274-91, 1862. The review concludes with the following sentence:
"I have come to be of opinion that Mr. Darwin's theory is unsound, and that
I am to be spared any collision between my inclination and my convictions"
(referring to the writer's belief in Design).) But I am tired with
answering it. Indeed I have done nothing the whole day but answer letters.


(404/1. The following letter occurs in the "Memoir of Leonard Horner,
edited by his daughter Katherine M. Lyell," Volume II., page 300 (privately
printed, 1890).)

Down, March 20th [1861].

I am very much obliged for your Address (404/2. Mr. Horner's Anniversary
Address to the Geological Society ("Proc. Geol. Soc." XVII., 1861).) which
has interested me much...I thought that I had read up pretty well on the
antiquity of man; but you bring all the facts so well together in a
condensed focus, that the case seems much clearer to me. How curious about
the Bible! (404/3. At page lxviii. Mr. Horner points out that the
"chronology, given in the margin of our Bibles," i.e., the statement that
the world was created 4004 B.C., is the work of Archbishop Usher, and is in
no way binding on those who believe in the inspiration of Scripture. Mr.
Horner goes on (page lxx): "The retention of the marginal note in question
is by no means a matter of indifference; it is untrue, and therefore it is
mischievous." It is interesting that Archbishop Sumner and Dr. Dawes, Dean
of Hereford, wrote with approbation of Mr. Horner's views on Man. The
Archbishop says: "I have always considered the first verse of Genesis as
indicating, rather than denying, a PREADAMITE world" ("Memoir of Leonard
Horner, II., page 303).) I declare I had fancied that the date was somehow
in the Bible. You are coming out in a new light as a Biblical critic. I
must thank you for some remarks on the "Origin of Species" (404/4. Mr.
Horner (page xxxix) begins by disclaiming the qualifications of a competent
critic, and confines himself to general remarks on the philosophic candour
and freedom from dogmatism of the "Origin": he does, however, give an
opinion on the geological chapters IX. and X. As a general criticism he
quotes Mr. Huxley's article in the "Westminster Review," which may now be
read in "Collected Essays," II., page 22.) (though I suppose it is almost
as incorrect to do so as to thank a judge for a favourable verdict): what
you have said has pleased me extremely. I am the more pleased, as I would
rather have been well attacked than have been handled in the namby-pamby,
old-woman style of the cautious Oxford Professor. (404/5. This no doubt
refers to Professor Phillips' "Life on the Earth," 1860, a book founded on
the author's "Rede Lecture," given before the University of Cambridge.
Reference to this work will be found in "Life and Letters," II., pages 309,
358, 373.)


(405/1. Mr. Wallace was, we believe, the first to treat the evolution of
Man in any detail from the point of view of Natural Selection, namely, in a
paper in the "Anthropological Review and Journal of the Anthropological
Society," May 1864, page clviii. The deep interest with which Mr. Darwin
read his copy is graphically recorded in the continuous series of
pencil-marks along the margins of the pages. His views are fully given in
Letter 406. The phrase, "in this case it is too far," refers to Mr.
Wallace's habit of speaking of the theory of Natural Selection as due
entirely to Darwin.)

May 22nd 1864.

I have now read Wallace's paper on Man, and think it MOST striking and
original and forcible. I wish he had written Lyell's chapters on Man.
(405/2. See "Life and Letters," III., page 11 et seq. for Darwin's
disappointment over Lyell's treatment of the evolutionary question in his
"Antiquity of Man"; see also page 29 for Lyell's almost pathetic words
about his own position between the discarded faith of many years and the
new one not yet assimilated. See also Letters 132, 164, 170.) I quite
agree about his high-mindedness, and have long thought so; but in this case
it is too far, and I shall tell him so. I am not sure that I fully agree
with his views about Man, but there is no doubt, in my opinion, on the
remarkable genius shown by the paper. I agree, however, to the main new
leading idea.


(406/1. This letter was published in "Life and Letters," III., page 89.)

Down, [May] 28th [1864].

I am so much better that I have just finished a paper for the Linnean
Society (406/2. On the three forms, etc., of Lythrum.); but I am not yet
at all strong, I felt much disinclination to write, and therefore you must
forgive me for not having sooner thanked you for your paper on Man (406/3.
"Anthropological Review," May 1864.) received on the 11th. (406/4. Mr.
Wallace wrote, May 10th, 1864: "I send you now my little contribution to
the theory of the origin of man. I hope you will be able to agree with me.
If you are able [to write] I shall be glad to have your criticisms. I was
led to the subject by the necessity of explaining the vast mental and
cranial differences between man and the apes combined with such small
structural differences in other parts of the body,--and also by an
endeavour to account for the diversity of human races combined with man's
almost perfect stability of form during all historical epochs." But first
let me say that I have hardly ever in my life been more struck by any paper
than that on "Variation," etc., etc., in the "Reader." (406/5. "Reader,"
April 16th, 1864, an abstract of Mr. Wallace: "On the Phenomena of
Variation and Geographical Distribution as illustrated by the Papilionidae
of the Malayan Region." "Linn. Soc. Trans." XXV.) I feel sure that such
papers will do more for the spreading of our views on the modification of
species than any separate treatises on the simple subject itself. It is
really admirable; but you ought not in the Man paper to speak of the theory
as mine; it is just as much yours as mine. One correspondent has already
noticed to me your "high-minded" conduct on this head.

But now for your Man paper, about which I should like to write more than I
can. The great leading idea is quite new to me--viz. that during late ages
the mind will have been modified more than the body; yet I had got as far
as to see with you, that the struggle between the races of man depended
entirely on intellectual and moral qualities. The latter part of the paper
I can designate only as grand and most eloquently done. I have shown your
paper to two or three persons who have been here, and they have been
equally struck with it. I am not sure that I go with you on all minor
points: when reading Sir G. Grey's account of the constant battles of
Australian savages, I remember thinking that Natural Selection would come
in, and likewise with the Esquimaux, with whom the art of fishing and
managing canoes is said to be hereditary. I rather differ on the rank,
under a classificatory point of view, which you assign to man; I do not
think any character simply in excess ought ever to be used for the higher
divisions. Ants would not be separated from other hymenopterous insects,
however high the instinct of the one, and however low the instincts of the
other. With respect to the differences of race, a conjecture has occurred
to me that much may be due to the correlation of complexion (and
consequently hair) with constitution. Assume that a dusky individual best
escaped miasma, and you will readily see what I mean. I persuaded the
Director-General of the Medical Department of the Army to send printed
forms to the surgeons of all regiments in tropical countries to ascertain
this point, but I daresay I shall never get any returns. Secondly, I
suspect that a sort of sexual selection has been the most powerful means of
changing the races of man. I can show that the different races have a
widely different standard of beauty. Among savages the most powerful men
will have the pick of the women, and they will generally leave the most
descendants. I have collected a few notes on man, but I do not suppose I
shall ever use them. Do you intend to follow out your views? and if so,
would you like at some future time to have my few references and notes? I
am sure I hardly know whether they are of any value, and they are at
present in a state of chaos.

There is much more that I should like to write, but I have not strength.

P.S. Our aristocracy is handsomer (more hideous according to a Chinese or
Negro) than the middle classes, from [having the] pick of the women; but
oh, what a scheme is primogeniture for destroying Natural Selection! I
fear my letter will be barely intelligible to you.

5, Westbourne Grove Terrace, W., May 29th [1864].

You are always so ready to appreciate what others do, and especially to
overestimate my desultory efforts, that I cannot be surprised at your very
kind and flattering remarks on my papers. I am glad, however, that you
have made a few critical observations (and am only sorry that you were not
well enough to make more), as that enables me to say a few words in

My great fault is haste. An idea strikes me, I think over it for a few
days, and then write away with such illustrations as occur to me while
going on. I therefore look at the subject almost solely from one point of
view. Thus, in my paper on Man (406*/1. Published in the "Anthropological
Review," 1864.), I aim solely at showing that brutes are modified in a
great variety of ways by Natural Selection, but that in none of these
particular ways can Man be modified, because of the superiority of his
intellect. I therefore no doubt overlook a few smaller points in which
Natural Selection may still act on men and brutes alike. Colour is one of
them, and I have alluded to this in correlation to constitution, in an
abstract I have made at Sclater's request for the "Natural History Review."
(406*/2. "Nat. Hist. Review," 1864, page 328.) At the same time, there is
so much evidence of migrations and displacements of races of man, and so
many cases of peoples of distinct physical characters inhabiting the same
or similar regions, and also of races of uniform physical characters
inhabiting widely dissimilar regions,--that the external characteristics of
the chief races of man must, I think, be older than his present
geographical distribution, and the modifications produced by correlation to
favourable variations of constitution be only a secondary cause of external
modification. I hope you may get the returns from the Army. (406*/3.
Measurements taken of more than one million soldiers in the United States
showed that "local influences of some kind act directly on structure."--
"Descent of Man," 1901, page 45.) They would be very interesting, but I do
not expect the results would be favourable to your view.

With regard to the constant battles of savages leading to selection of
physical superiority, I think it would be very imperfect and subject to so
many exceptions and irregularities that it would produce no definite
result. For instance: the strongest and bravest men would lead, and
expose themselves most, and would therefore be most subject to wounds and
death. And the physical energy which led to any one tribe delighting in
war, might lead to its extermination, by inducing quarrels with all
surrounding tribes and leading them to combine against it. Again, superior
cunning, stealth, and swiftness of foot, or even better weapons, would
often lead to victory as well as mere physical strength. Moreover, this
kind of more or less perpetual war goes on amongst savage peoples. It
could lead, therefore, to no differential characters, but merely to the
keeping up of a certain average standard of bodily and mental health and

So with selection of variations adapted to special habits of life as
fishing, paddling, riding, climbing, etc., etc., in different races, no
doubt it must act to some extent, but will it be ever so rigid as to induce
a definite physical modification, and can we imagine it to have had any
part in producing the distinct races that now exist?

The sexual selection you allude to will also, I think, have been equally
uncertain in its results. In the very lowest tribes there is rarely much
polygamy, and women are more or less a matter of purchase. There is also
little difference of social condition, and I think it rarely happens that
any healthy and undeformed man remains without wife and children. I very
much doubt the often-repeated assertion that our aristocracy are more
beautiful than the middle classes. I allow that they present specimens of
the highest kind of beauty, but I doubt the average. I have noticed in
country places a greater average amount of good looks among the middle
classes, and besides we unavoidably combine in our idea of beauty,
intellectual expression, and refinement of manner, which often makes the
less appear the more beautiful. Mere physical beauty--i.e. a healthy and
regular development of the body and features approaching to the mean and
type of European man, I believe is quite as frequent in one class of
society as the other, and much more frequent in rural districts than in

With regard to the rank of man in zoological classification, I fear I have
not made myself intelligible. I never meant to adopt Owen's or any other
such views, but only to point out that from one point of view he was right.
I hold that a distinct family for Man, as Huxley allows, is all that can
possibly be given him zoologically. But at the same time, if my theory is
true, that while the animals which surrounded him have been undergoing
modification in all parts of their bodies to a generic or even family
degree of difference, he has been changing almost wholly in the brain and
head--then in geological antiquity the SPECIES man may be as old as many
mammalian families, and the origin of the FAMILY man may date back to a
period when some of the ORDERS first originated.

As to the theory of Natural Selection itself, I shall always maintain it to
be actually yours and yours only. You had worked it out in details I had
never thought of, years before I had a ray of light on the subject, and my
paper would never have convinced anybody or been noticed as more than an
ingenious speculation, whereas your book has revolutionised the study of
Natural History, and carried away captive the best men of the present age.
All the merit I claim is the having been the means of inducing you to write
and publish at once. I may possibly some day go a little more into this
subject (of Man), and if I do will accept the kind offer of your notes.

I am now, however, beginning to write the "Narrative of my Travels," which
will occupy me a long time, as I hate writing narrative, and after Bates'
brilliant success rather fear to fail.

I shall introduce a few chapters on Geographical Distribution and other
such topics. Sir C. Lyell, while agreeing with my main argument on Man,
thinks I am wrong in wanting to put him back into Miocene times, and thinks
I do not appreciate the immense interval even to the later Pliocene. But I
still maintain my view, which in fact is a logical result of my theory; for
if man originated in later Pliocene, when almost all mammalia were of
closely allied species to those now living, and many even identical, then
man has not been stationary in bodily structure while animals have been
varying, and my theory will be proved to be all wrong.

In Murchison's address to the Geographical Society, just delivered, he
points out Africa as being the oldest existing land. He says there is no
evidence of its having been ever submerged during the Tertiary epoch. Here
then is evidently the place to find early man. I hope something good may
be found in Borneo, and that the means may be found to explore the still
more promising regions of tropical Africa, for we can expect nothing of man
very early in Europe.

It has given me great pleasure to find that there are symptoms of
improvement in your health. I hope you will not exert yourself too soon or
write more than is quite agreeable to you. I think I made out every word
of your letter, though it was not always easy.

(406*/4. For Wallace's later views see Letter 408, note.)


(407/1. Sir William Turner is frequently referred to in the "Descent of
Man" as having supplied Mr. Darwin with information.)

Down, December 14th [1866].

Your kindness when I met you at the Royal Society makes me think that you
would grant me the favour of a little information, if in your power. I am
preparing a book on Domestic Animals, and as there has been so much
discussion on the bearing of such views as I hold on Man, I have some
thoughts of adding a chapter on this subject. The point on which I want
information is in regard to any part which may be fairly called rudimentary
in comparison with the same part in the Quadrumana or any other mammal.
Now the os coccyx is rudimentary as a tail, and I am anxious to hear about
its muscles. Mr. Flower found for me in some work that its one muscle
(with striae) was supposed only to bring this bone back to its proper
position after parturition. This seems to me hardly credible. He said he
had never particularly examined this part, and when I mentioned your name,
he said you were the most likely man to give me information.

Are there any traces of other muscles? It seems strange if there are none.
Do you know how the muscles are in this part in the anthropoid apes? The
muscles of the ear in man may, I suppose, in most cases be considered as
rudimentary; and so they seem to be in the anthropoids; at least, I am
assured in the Zoological Gardens they do not erect their ears. I gather
there are a good many muscles in various parts of the body which are in
this same state: could you specify any of the best cases? The mammae in
man are rudimentary. Are there any other glands or other organs which you
can think of? I know I have no right whatever to ask all these questions,
and can only say that I should be grateful for any information. If you
tell me anything about the os coccyx or other structures, I hope that you
will permit me to quote the statement on your authority, as that would add
so greatly to its value.

Pray excuse me for troubling you, and do not hurry yourself in the least in
answering me.

I do not know whether you would care to possess a copy, but I told my
publisher to send you a copy of the new edition of the "Origin" last month.

Down, February 1st [1867].

I thank you cordially for all your full information, and I regret much that
I have given you such great trouble at a period when your time is so much
occupied. But the facts were so valuable to me that I cannot pretend that
I am sorry that I did trouble you; and I am the less so, as from what you
say I hope you may be induced some time to write a full account of all
rudimentary structures in Man: it would be a very curious and interesting
memoir. I shall at present give only a brief abstract of the chief facts
which you have so very kindly communicated to me, and will not touch on
some of the doubtful points. I have received far more information than I
ventured to anticipate. There is one point which has occurred to me, but I
suspect there is nothing in it. If, however, there should be, perhaps you
will let me have a brief note from you, and if I do not hear I will
understand there is nothing in the notion. I have included the down on the
human body and the lanugo on the foetus as a rudimentary representation of
a hairy coat. (408/1. "Descent of Man" I., page 25; II., page 375.) I do
not know whether there is any direct functional connection between the
presence of hair and the panniculus carnosus (408/2. Professor Macalister
draws our attention to the fact that Mr. Darwin uses the term panniculus in
the generalised sense of any sheet of muscle acting on the skin.) (to put
the question under another point of view, is it the primary or aboriginal
function of the panniculus to move the dermal appendages or the skin
itself?); but both are superficial, and would perhaps together become
rudimentary. I was led to think of this by the places (as far as my
ignorance of anatomy has allowed me to judge) of the rudimentary muscular
fasciculi which you specify. Now, some persons can move the skin of their
hairy heads; and is this not effected by the panniculus? How is it with
the eyebrows? You specify the axillae and the front region of the chest
and lower part of scapulae: now, these are all hairy spots in man. On the
other hand, the neck, and as I suppose the covering of the gluteus medius,
are not hairy; so, as I said, I presume there is nothing in this notion.
If there were, the rudiments of the panniculus ought perhaps to occur more
plainly in man than in woman...

P.S.--If the skin on the head is moved by the panniculus, I think I ought
just to allude to it, as some men alone having power to move the skin shows
that the apparatus is generally rudimentary.

(408/3. In March 1869 Darwin wrote to Mr. Wallace: "I shall be intensely
curious to read the "Quarterly." I hope you have not murdered too
completely your own and my child." The reference is to Mr. Wallace's
review, in the April number of the "Quarterly," of Lyell's "Principles of
Geology" (tenth edition), and of the sixth edition of the "Elements of
Geology." Mr. Wallace points out that here for the first time Sir C. Lyell
gave up his opposition to evolution; and this leads Mr. Wallace to give a
short account of the views set forth in the "Origin of Species." In this
article Mr. Wallace makes a definite statement as to his views on the
evolution of man, which were opposed to those of Mr. Darwin. He upholds
the view that the brain of man, as well as the organs of speech, the hand
and the external form, could not have been evolved by Natural Selection
(the child he is supposed to murder). At page 391 he writes: "In the
brain of the lowest savages, and, as far as we know, of the prehistoric
races, we have an organ...little inferior in size and complexity to that of
the highest types...But the mental requirements of the lowest savages, such
as the Australians or the Andaman Islanders, are very little above those of
many animals...How, then, was an organ developed so far beyond the needs of
its possessor? Natural Selection could only have endowed the savage with a
brain a little superior to that of an ape, whereas he actually possesses
one but very little inferior to that of the average members of our learned
societies." This passage is marked in Mr. Darwin's copy with a triply
underlined "No," and with a shower of notes of exclamation. It was
probably the first occasion on which he realised the extent of this great
and striking divergence in opinion between himself and his colleague.

He had, however, some indication of it in Wallace's paper on Man,
"Anthropological Review," 1864. (See Letter 406). He wrote to Lyell, May
4th, 1869, "I was dreadfully disappointed about Man; it seems to me
incredibly strange." And to Mr. Wallace, April 14th, 1869, "If you had not
told me, I should have thought that [your remarks on Man] had been added by
some one else. As you expected, I differ grievously from you, and I am
very sorry for it."

Down, Thursday, February 21st [1868-70?].

I received the Jermyn Street programme, but have hardly yet considered it,
for I was all day on the sofa on Tuesday and Wednesday. Bad though I was,
I thought with constant pleasure of your very great kindness in offering to
read the proofs of my essay on man. I do not know whether I said anything
which might have appeared like a hint, but I assure you that such a thought
had never even momentarily passed through my mind. Your offer has just
made all the difference, that I can now write, whether or no my essay is
ever printed, with a feeling of satisfaction instead of vague dread.

Beg my colleague, Mrs. Huxley, not to forget the corrugator supercilii: it
will not be easy to catch the exact moment when the child is on the point
of crying, and is struggling against the wrinkling up [of] its little eyes;
for then I should expect the corrugator, from being little under the
command of the will, would come into play in checking or stopping the
wrinkling. An explosion of tears would tell nothing.

Down, December 23rd [1870?].

I have only read about fifty pages of your book (to the Judges) (410/1.
"Hereditary Genius: an Inquiry into its Laws and Consequences," by Francis
Galton, London, 1869. "The Judges of England between 1660 and 1865" is the
heading of a section of this work (page 55). See "Descent of Man" (1901),
page 41.), but I must exhale myself, else something will go wrong in my
inside. I do not think I ever in all my life read anything more
interesting and original. And how well and clearly you put every point!
George, who has finished the book, and who expressed himself just in the
same terms, tells me the earlier chapters are nothing in interest to the
later ones! It will take me some time to get to these later chapters, as
it is read aloud to me by my wife, who is also much interested. You have
made a convert of an opponent in one sense, for I have always maintained
that, excepting fools, men did not differ much in intellect, only in zeal
and hard work; and I still think [this] is an eminently important
difference. I congratulate you on producing what I am convinced will prove
a memorable work. I look forward with intense interest to each reading,
but it sets me thinking so much that I find it very hard work; but that is
wholly the fault of my brain, and not of your beautifully clear style.

March 21st [1871?].

Many thanks for your note. I am very glad indeed to read remarks made by a
man who possesses such varied and odd knowledge as you do, and who is so
acute a reasoner. I have no doubt that you will detect blunders of many
kinds in my book. (411/1. "The Descent of Man.") Your MS. on the
proportion of the sexes at birth seems to me extremely curious, and I hope
that some day you will publish it. It certainly appears that the males are
decreasing in the London districts, and a most strange fact it is. Mr.
Graham, however, I observe in a note enclosed, does not seem inclined to
admit your conclusion. I have never much considered the subject of the
causes of the proportion. When I reflected on queen bees producing only
males when not impregnated, whilst some other parthenogenetic insects
produced, as far as known, only females, the subject seemed to me
hopelessly obscure. It is, however, pretty clear that you have taken the
one path for its solution. I wished only to ascertain how far with various
animals the males exceeded the females, and I have given all the facts
which I could collect. As far as I know, no other data have been
published. The equality of the sexes with race-horses is surprising. My
remarks on mankind are quite superficial, and given merely as some sort of
standard for comparison with the lower animals. M. Thury is the writer who
makes the sex depend on the period of impregnation. His pamphlet was sent
me from Geneva. (411/2. "Memoire sur la loi de Production des Sexes," 2nd
edition, 1863 (a pamphlet published by Cherbuliez, Geneva).) I can lend it
you if you like. I subsequently read an account of experiments which
convinced me that M. Thury was in error; but I cannot remember what they
were, only the impression that I might safely banish this view from my
mind. Your remarks on the less ratio of males in illegitimate births
strikes me as the most doubtful point in your MS.--requiring two
assumptions, viz. that the fathers in such cases are relatively too young,
and that the result is the same as when the father is relatively too old.

My son, George, who is a mathematician, and who read your MS. with much
interest, has suggested, as telling in the right direction, but whether
sufficient is another question, that many more illegitimate children are
murdered and concealed shortly after birth, than in the case of legitimate
children; and as many more males than females die during the first few days
of life, the census of illegitimate children practically applies to an
older age than with legitimate children, and would thus slightly reduce the
excess of males. This might possibly be worth consideration. By a strange
coincidence a stranger writes to me this day, making the very same

I am quite delighted to hear that my book interests you enough to lead you
to read it with some care.

Down, January 4th, 1873.

Very many thanks for "Fraser" (412/1. "Hereditary Improvement," by Francis
Galton, "Fraser's Magazine," January 1873, page 116.): I have been greatly
interested by your article. The idea of castes being spontaneously formed
and leading to intermarriage (412/2. "My object is to build up, by the
mere process of extensive enquiry and publication of results, a sentiment
of caste among those who are naturally gifted, and to procure for them,
before the system has fairly taken root, such moderate social favours and
preference, no more no less, as would seem reasonable to those who were
justly informed of the precise measure of their importance to the nation"
(loc. cit., page 123).) is quite new to me, and I should suppose to others.
I am not, however, so hopeful as you. Your proposed Society (412/3. Mr.
Galton proposes that "Some society should undertake three scientific
services: the first, by means of a moderate number of influential local
agencies, to institute continuous enquiries into the facts of human
heredity; the second to be a centre of information on heredity for breeders
of animals and plants; and the third to discuss and classify the facts that
were collected" (loc. cit., page 124).) would have awfully laborious work,
and I doubt whether you could ever get efficient workers. As it is, there
is much concealment of insanity and wickedness in families; and there would
be more if there was a register. But the greatest difficulty, I think,
would be in deciding who deserved to be on the register. How few are above
mediocrity in health, strength, morals and intellect; and how difficult to
judge on these latter heads. As far as I see, within the same large
superior family, only a few of the children would deserve to be on the
register; and these would naturally stick to their own families, so that
the superior children of distinct families would have no good chance of
associating much and forming a caste. Though I see so much difficulty, the
object seems a grand one; and you have pointed out the sole feasible, yet I
fear utopian, plan of procedure in improving the human race. I should be
inclined to trust more (and this is part of your plan) to disseminating and
insisting on the importance of the all-important principle of inheritance.
I will make one or two minor criticisms. Is it not possible that the
inhabitants of malarious countries owe their degraded and miserable
appearance to the bad atmosphere, though this does not kill them, rather
than to "economy of structure"? I do not see that an orthognathous face
would cost more than a prognathous face; or a good morale than a bad one.
That is a fine simile (page 119) about the chip of a statue (412/4.
"...The life of the individual is treated as of absolutely no importance,
while the race is as everything; Nature being wholly careless of the former
except as a contributor to the maintenance and evolution of the latter.
Myriads of inchoate lives are produced in what, to our best judgment, seems
a wasteful and reckless manner, in order that a few selected specimens may
survive, and be the parents of the next generation. It is as though
individual lives were of no more consideration than are the senseless chips
which fall from the chisel of the artist who is elaborating some ideal form
from a rude block" (loc. cit., page 119).); but surely Nature does not more
carefully regard races than individuals, as (I believe I have misunderstood
what you mean) evidenced by the multitude of races and species which have
become extinct. Would it not be truer to say that Nature cares only for
the superior individuals and then makes her new and better races? But we
ought both to shudder in using so freely the word "Nature" (412/5. See
Letter 190, Volume I.) after what De Candolle has said. Again let me thank
you for the interest received in reading your essay.

Many thanks about the rabbits; your letter has been sent to Balfour: he is
a very clever young man, and I believe owes his cleverness to Salisbury
blood. This letter will not be worth your deciphering. I have almost
finished Greg's "Enigmas." (412/6. "The Enigmas of Life," 1872.) It is
grand poetry--but too Utopian and too full of faith for me; so that I have
been rather disappointed. What do you think about it? He must be a
delightful man.

I doubt whether you have made clear how the families on the Register are to
be kept pure or superior, and how they are to be in course of time still
further improved.

Down, July 3rd, 1873.

(413/1. In June, 1873, Professor Max Muller sent to Mr. Darwin a copy of
the sixth edition of his "Lectures on the Science of Language" (413/2. A
reference to the first edition occurs in "Life and Letters," II., page
390.), with a letter concluding with these words: "I venture to send you
my three lectures, trusting that, though I differ from some of your
conclusions, you will believe me to be one of your diligent readers and
sincere admirers.")

I am much obliged for your kind note and present of your lectures. I am
extremely glad to have received them from you, and I had intended ordering

I feel quite sure from what I have read in your works that you would never
say anything of an honest adversary to which he would have any just right
to object; and as for myself, you have often spoken highly of me--perhaps
more highly than I deserve.

As far as language is concerned I am not worthy to be your adversary, as I
know extremely little about it, and that little learnt from very few books.
I should have been glad to have avoided the whole subject, but was
compelled to take it up as well as I could. He who is fully convinced, as
I am, that man is descended from some lower animal, is almost forced to
believe a priori that articulate language has been developed from
inarticulate cries (413/3. "Descent of Man" (1901), page 133.); and he is
therefore hardly a fair judge of the arguments opposed to this belief.

(413/4. In October, 1875, Mr. Darwin again wrote cordially to Professor
Max Muller on receipt of a pamphlet entitled "In Self-Defence" (413/5.
Printed in "Chips from a German Workshop," Volume IV., 1875, page 473.),
which is a reply to Professor Whitney's "Darwinism and Language" in the
"North American Review," July 1874. This essay had been brought before the
"general reader" in England by an article of Mr. G. Darwin's in the
"Contemporary Review," November, 1874, page 894, entitled, "Professor
Whitney on the Origin of Language." The article was followed by "My reply
to Mr. Darwin," contributed by Professor Muller to the "Contemporary
Review," January, 1875, page 305.)

British Association, Bristol, August 30th, 1875.

(414/1. In the first edition of the "Descent of Man" Mr. Darwin wrote:
"It is a more curious fact that savages did not formerly waste away, as Mr.
Bagehot has remarked, before the classical nations, as they now do before
modern civilised nations...(414/2. Bagehot, "Physics and Politics,"
"Fortnightly Review," April, 1868, page 455.) In the second edition (page
183) the statement remains, but a mass of evidence (pages 183-92) is added,
to which reference occurs in the reply to the following letter.)

At pages 4-5 of the enclosed Address (414/3. "British Association
Reports," 1875, page 142.) you will find that I have controverted Mr.
Bagehot's view as to the extinction of the barbarians in the times of
classical antiquity, as also the view of Poppig as to there being some
occult influence exercised by civilisation to the disadvantage of savagery
when the two come into contact.

I write to say that I took up this subject without any wish to impugn any
views of yours as such, but with the desire of having my say upon certain
anti-sanitarian transactions and malfeasance of which I had had a painful

On reading however what I said, and had written somewhat hastily, it has
struck me that what I have said might bear the former interpretation in the
eyes of persons who might not read other papers of mine, and indeed other
parts of the same Address, in which my adhesion, whatever it is worth, to
your views in general is plainly enough implied. I have ventured to write
this explanation to you for several reasons.

Bassett, Southampton, September 2nd [1875].

I am much obliged to you for having sent me your Address, which has
interested me greatly. I quite subscribe to what you say about Mr.
Bagehot's striking remark, and wish I had not quoted it. I can perceive no
sort of reflection or blame on anything which I have written, and I know
well that I deserve many a good slap on the face. The decrease of savage
populations interests me much, and I should like you some time to look at a
discussion on this subject which I have introduced in the second edition of
the "Descent of Man," and which you can find (for I have no copy here) in
the list of additions. The facts have convinced me that lessened fertility
and the poor constitution of the children is one chief cause of such
decrease; and that the case is strictly parallel to the sterility of many
wild animals when made captive, the civilisation of savages and the
captivity of wild animals leading to the same result.

Down, June 30th, 1877.

I have been much interested by your able argument against the belief that
the sense of colour has been recently acquired by man. (416/1. See
"Kosmos," June 1877, page 264, a review of Dr. Hugo Magnus' "Die
Geschichtliche Entwickelung des Farbensinnes," 1877. The first part is
chiefly an account of the author's views; Dr. Krause's argument begins at
page 269. The interest felt by Mr. Darwin is recorded by the numerous
pencil-marks on the margin of his copy.) The following observation bears
on this subject.

I attended carefully to the mental development of my young children, and
with two, or as I believe three of them, soon after they had come to the
age when they knew the names of all common objects, I was startled by
observing that they seemed quite incapable of affixing the right names to
the colours in coloured engravings, although I tried repeatedly to teach
them. I distinctly remember declaring that they were colour-blind, but
this afterwards proved a groundless fear.

On communicating this fact to another person he told me that he had
observed a nearly similar case. Therefore the difficulty which young
children experience either in distinguishing, or more probably in naming
colours, seems to deserve further investigation. I will add that it
formerly appeared to me that the gustatory sense, at least in the case of
my own infants, and very young children, differed from that of grown-up
persons. This was shown by their not disliking rhubarb mixed with a little
sugar and milk, which is to us abominably nauseous; and in their strong
taste for the sourest and most austere fruits, such as unripe gooseberries
and crabapples.

(PLATE: G.J. ROMANES, 1891. Elliott & Fry, photo. Walker and Cockerell,
ph. sc.)

[Barlaston], August 20th, 1878.

(417/1. Part of this letter (here omitted) is published in "Life and
Letters," III., page 225, and the whole in the "Life and Letters of G.J.
Romanes," page 74. The lecture referred to was on animal intelligence, and
was given at the Dublin meeting of the British Association.)

...The sole fault which I find with your lecture is that it is too short,
and this is a rare fault. It strikes me as admirably clear and
interesting. I meant to have remonstrated that you had not discussed
sufficiently the necessity of signs for the formation of abstract ideas of
any complexity, and then I came on the discussion on deaf mutes. This
latter seems to me one of the richest of all the mines, and is worth
working carefully for years, and very deeply. I should like to read whole
chapters on this one head, and others on the minds of the higher idiots.
Nothing can be better, as it seems to me, than your several lines or
sources of evidence, and the manner in which you have arranged the whole
subject. Your book will assuredly be worth years of hard labour; and stick
to your subject. By the way, I was pleased at your discussing the
selection of varying instincts or mental tendencies; for I have often been
disappointed by no one having ever noticed this notion.

I have just finished "La Psychologie, son Present et son Avenir," 1876, by
Delboeuf (a mathematician and physicist of Belgium) in about a hundred
pages. It has interested me a good deal, but why I hardly know; it is
rather like Herbert Spencer. If you do not know it, and would care to see
it, send me a postcard.

Thank Heaven, we return home on Thursday, and I shall be able to go on with
my humdrum work, and that makes me forget my daily discomfort.

Have you ever thought of keeping a young monkey, so as to observe its mind?
At a house where we have been staying there were Sir A. and Lady Hobhouse,
not long ago returned from India, and she and he kept [a] young monkey and
told me some curious particulars. One was that her monkey was very fond of
looking through her eyeglass at objects, and moved the glass nearer and
further so as to vary the focus. This struck me, as Frank's son, nearly
two years old (and we think much of his intellect!!) is very fond of
looking through my pocket lens, and I have quite in vain endeavoured to
teach him not to put the glass close down on the object, but he always will
do so. Therefore I conclude that a child under two years is inferior in
intellect to a monkey.

Once again I heartily congratulate you on your well-earned present, and I
feel assured, grand future success.

(417/2. Later in the year Mr. Darwin wrote: "I am delighted to hear that
you mean to work the comparative Psychology well. I thought your letter to
the "Times" very good indeed. (417/3. Romanes wrote to the "Times" August
28th, 1878, expressing his views regarding the distinction between man and
the lower animals, in reply to criticisms contained in a leading article in
the "Times" of August 23rd on his lecture at the Dublin meeting of the
British Association.) Bartlett, at the Zoological Gardens, I feel sure,
would advise you infinitely better about hardiness, intellect, price, etc.,
of monkey than F. Buckland; but with him it must be viva voce.

"Frank says you ought to keep a idiot, a deaf mute, a monkey, and a baby in
your house.")

Down, November 15th, 1878.

(418/1. This letter has been published in Clapperton's "Scientific
Meliorism," 1885, page 340, together with Mr. Gaskell's letter of November
13th (page 337). Mr. Gaskell's laws are given in his letter of November
13th, 1878. They are:--

I. The Organological Law:
Natural Selection, or the Survival of the Fittest.

II. The Sociological Law:
Sympathetic Selection, or Indiscriminate Survival.

III. The Moral Law:
Social Selection, or the Birth of the Fittest.)

Your letter seems to me very interesting and clearly expressed, and I hope
that you are in the right. Your second law appears to be largely acted on
in all civilised countries, and I just alluded to it in my remarks to the
effect (as far as I remember) that the evil which would follow by checking
benevolence and sympathy in not fostering the weak and diseased would be
greater than by allowing them to survive and then to procreate.

With regard to your third law, I do not know whether you have read an
article (I forget when published) by F. Galton, in which he proposes
certificates of health, etc., for marriage, and that the best should be
matched. I have lately been led to reflect a little, (for, now that I am
growing old, my work has become [word indecipherable] special) on the
artificial checks, but doubt greatly whether such would be advantageous to
the world at large at present, however it may be in the distant future.
Suppose that such checks had been in action during the last two or three
centuries, or even for a shorter time in Britain, what a difference it
would have made in the world, when we consider America, Australia, New
Zealand, and S. Africa! No words can exaggerate the importance, in my
opinion, of our colonisation for the future history of the world.

If it were universally known that the birth of children could be prevented,
and this were not thought immoral by married persons, would there not be
great danger of extreme profligacy amongst unmarried women, and might we
not become like the "arreoi" societies in the Pacific? In the course of a
century France will tell us the result in many ways, and we can already see
that the French nation does not spread or increase much.

I am glad that you intend to continue your investigations, and I hope
ultimately may publish on the subject.

Down, January 13th, 1879.

I am much obliged for your note and for the essay which you have sent me.
I am a poor german scholar, and your german is difficult; but I think that
I understand your meaning, and hope at some future time, when more at
leisure, to recur to your essay. As far as I can judge, you have made a
great advance in many ways in the subject; and I will send your paper to
Mr. Edmund Gurney (The late Edmund Gurney, author of "The Power of Sound,"
1880.), who has written on and is much interested in the origin of the
taste for music. In reading your essay, it occurred to me that facility in
the utterance of prolonged sounds (I do not think that you allude to this
point) may possibly come into play in rendering them musical; for I have
heard it stated that those who vary their voices much, and use cadences in
long continued speaking, feel less fatigued than those who speak on the
same note.

Down, February 5th, 1880.

(420/1. Romanes was at work on what ultimately came to be a book on animal
intelligence. Romanes's reply to this letter is given in his "Life," page
95. The table referred to is published as a frontispiece to his "Mental
Evolution in Animals," 1885.)

As I feared, I cannot be of the least use to you. I could not venture to
say anything about babies without reading my Expression book and paper on
Infants, or about animals without reading the "Descent of Man" and
referring to my notes; and it is a great wrench to my mind to change from
one subject to another.

I will, however, hazard one or two remarks. Firstly, I should have thought
that the word "love" (not sexual passion), as shown very low in the scale,
to offspring and apparently to comrades, ought to have come in more
prominently in your table than appears to be the case. Secondly, if you
give any instance of the appreciation of different stimulants by plants,
there is a much better case than that given by you--namely, that of the
glands of Drosera, which can be touched roughly two or three times and do
not transmit any effect, but do so if pressed by a weight of 1/78000 grain
("Insectivorous Plants" 263). On the other hand, the filament of Dionoea
may be quietly loaded with a much greater weight, while a touch by a hair
causes the lobes to close instantly. This has always seemed to me a
marvellous fact. Thirdly, I have been accustomed to look at the coming in
of the sense of pleasure and pain as one of the most important steps in the
development of mind, and I should think it ought to be prominent in your
table. The sort of progress which I have imagined is that a stimulus
produced some effect at the point affected, and that the effect radiated at
first in all directions, and then that certain definite advantageous lines
of transmission were acquired, inducing definite reaction in certain lines.
Such transmission afterwards became associated in some unknown way with
pleasure or pain. These sensations led at first to all sorts of violent
action, such as the wriggling of a worm, which was of some use. All the
organs of sense would be at the same time excited. Afterwards definite
lines of action would be found to be the most useful, and so would be
practised. But it is of no use my giving you my crude notions.

Down, May 22nd, 1880.

(421/1. Mr. Preston wrote (May 20th, 1880) to the effect that
"self-interest as a motive for conduct is a thing to be commended--and it
certainly [is] I think...the only conceivable rational motive of conduct:
and always is the tacitly recognised motive in all rational actions." Mr.
Preston does not, of course, commend selfishness, which is not true

There seem to be two ways of looking at the case given by Darwin. The man
who knows that he is risking his life,--realising that the personal
satisfaction that may follow is not worth the risk--is surely admirable
from the strength of character that leads him to follow the social instinct
against his purely personal inclination. But the man who blindly obeys the
social instinct is a more useful member of a social community. He will act
with courage where even the strong man will fail.)

Your letter appears to me an interesting and valuable one; but I have now
been working for some years exclusively on the physiology of plants, and
all other subjects have gone out of my head, and it fatigues me much to try
and bring them back again into my head. I am, moreover, at present very
busy, as I leave home for a fortnight's rest at the beginning of next week.
My conviction as yet remains unchanged, that a man who (for instance) jumps
into a river to save a life without a second's reflection (either from an
innate tendency or from one gained by habit) is deservedly more honoured
than a man who acts deliberately and is conscious, for however short a
time, that the risk and sacrifice give him some inward satisfaction.

You are of course familiar with Herbert Spencer's writings on Ethics.

(422/1. The observations to which the following letters refer were
continued by Mr. Wallis, who gave an account of his work in an interesting
paper in the "Proceedings of the Zoological Society," March 2nd, 1897. The
results on the whole confirm the belief that traces of an ancestral pointed
ear exist in man.)

Down, March 22nd, 1881.

I am very much obliged for your courteous and kind note. The fact which
you communicate is quite new to me, and as I was laughed at about the tips
to human ears, I should like to publish in "Nature" some time your fact.
But I must first consult Eschricht, and see whether he notices this fact in
his curious paper on the lanugo on human embryos; and secondly I ought to
look to monkeys and other animals which have tufted ears, and observe how
the hair grows. This I shall not be able to do for some months, as I shall
not be in London until the autumn so as to go to the Zoological Gardens.
But in order that I may not hereafter throw away time, will you be so kind
as to inform me whether I may publish your observation if on further search
it seems desirable?

Down, March 31st, 1881.

I am much obliged for your interesting letter. I am glad to hear that you
are looking to other ears, and will visit the Zoological Gardens. Under
these circumstances it would be incomparably better (as more authentic) if
you would publish a notice of your observations in "Nature" or some
scientific journal. Would it not be well to confine your attention to
infants, as more likely to retain any primordial character, and offering
less difficulty in observing. I think, though, it would be worth while to
observe whether there is any relation (though probably none) between much
hairiness on the ears of an infant and the presence of the "tip" on the
folded margin. Could you not get an accurate sketch of the direction of
the hair of the tip of an ear?

The fact which you communicate about the goat-sucker is very curious.
About the difference in the power of flight in Dorkings, etc., may it not
be due merely to greater weight of body in the adults?

I am so old that I am not likely ever again to write on general and
difficult points in the theory of Evolution.

I shall use what little strength is left me for more confined and easy


(Mrs. Emily Talbot was secretary of the Education Department of the
American Social Science Association, Boston, Mass. A circular and register
was issued by the Department, and answers to various questions were asked
for. See "Nature," April 28th, page 617, 1881. The above letter was
published in "The Field Naturalist," Manchester, 1883, page 5, edited by
Mr. W.E. Axon, to whom we are indebted for a copy.)

Down, July 19th [1881?]

In response to your wish, I have much pleasure in expressing the interest
which I feel in your proposed investigation on the mental and bodily
development of infants. Very little is at present accurately known on this
subject, and I believe that isolated observations will add but little to
our knowledge, whereas tabulated results from a very large number of
observations, systematically made, would probably throw much light on the
sequence and period of development of the several faculties. This
knowledge would probably give a foundation for some improvement in our
education of young children, and would show us whether the system ought to
be followed in all cases.

I will venture to specify a few points of inquiry which, as it seems to me,
possess some scientific interest. For instance, does the education of the
parents influence the mental powers of their children at any age, either at
a very early or somewhat more advanced stage? This could perhaps be
learned by schoolmasters and mistresses if a large number of children were
first classed according to age and their mental attainments, and afterwards
in accordance with the education of their parents, as far as this could be
discovered. As observation is one of the earliest faculties developed in
young children, and as this power would probably be exercised in an equal
degree by the children of educated and uneducated persons, it seems not
impossible that any transmitted effect from education could be displayed
only at a somewhat advanced age. It would be desirable to test
statistically, in a similar manner, the truth of the oft-repeated statement
that coloured children at first learn as quickly as white children, but
that they afterwards fall off in progress. If it could be proved that
education acts not only on the individual, but, by transmission, on the
race, this would be a great encouragement to all working on this
all-important subject. It is well known that children sometimes exhibit,
at a very early age, strong special tastes, for which no cause can be
assigned, although occasionally they may be accounted for by reversion to
the taste or occupation of some progenitor; and it would be interesting to
learn how far such early tastes are persistent and influence the future
career of the individual. In some instances such tastes die away without
apparently leaving any after effect, but it would be desirable to know how
far this is commonly the case, as we should then know whether it were
important to direct as far as this is possible the early tastes of our
children. It may be more beneficial that a child should follow
energetically some pursuit, of however trifling a nature, and thus acquire
perseverance, than that he should be turned from it because of no future
advantage to him. I will mention one other small point of inquiry in
relation to very young children, which may possibly prove important with
respect to the origin of language; but it could be investigated only by
persons possessing an accurate musical ear. Children, even before they can
articulate, express some of their feelings and desires by noises uttered in
different notes. For instance, they make an interrogative noise, and
others of assent and dissent, in different tones; and it would, I think, be
worth while to ascertain whether there is any uniformity in different
children in the pitch of their voices under various frames of mind.

I fear that this letter can be of no use to you, but it will serve to show
my sympathy and good wishes in your researches.


Down, February 11th [1866].

I am much obliged to you for your kindness in sending me an abstract of
your paper on beauty. (425/1. A newspaper report of a communication to
the "Dumfries Antiquarian and Natural History Society.") In my opinion you
take quite a correct view of the subject. It is clear that Dr. Dickson has
either never seen my book, or overlooked the discussion on sexual
selection. If you have any precise facts on birds' "courtesy towards their
own image in mirror or picture," I should very much like to hear them.
Butterflies offer an excellent instance of beauty being displayed in
conspicuous parts; for those kinds which habitually display the underside
of the wing have this side gaudily coloured, and this is not so in the
reverse case. I daresay you will know that the males of many foreign
butterflies are much more brilliantly coloured than the females, as in the
case of birds. I can adduce good evidence from two large classes of facts
(too large to specify) that flowers have become beautiful to make them
conspicuous to insects. (425/2. This letter is published in "A Country
Schoolmaster, James Shaw." Edited by Robert Wallace, Edinburgh, 1899.)

(425/3. Mr. Darwin wrote again to Mr. Shaw in April, 1866:--)

I am much obliged for your kind letter and all the great trouble which you
have taken in sending to all the various and interesting facts on birds
admiring themselves. I am very glad to hear of these facts. I have just
finished writing and adding to a new edition of the "Origin," and in this I
have given, without going into details (so that I shall not be able to use
your facts), some remarks on the subject of beauty.

Down, February 16th [1867?]

I want to beg two favours of you. I wish to ascertain whether the Bower-
Bird discriminates colours. (426/1. Mr. Bartlett does not seem to have
supplied any information on the point in question. The evidence for the
Bower-Bird's taste in colour is in "Descent of Man," II., page 112.) Will
you have all the coloured worsted removed from the cage and bower, and then
put all in a row, at some distance from bower, the enclosed coloured
worsted, and mark whether the bird AT FIRST makes any selection. Each
packet contains an equal quantity; the packets had better be separate, and
each thread put separate, but close together; perhaps it would be fairest
if the several colours were put alternately--one thread of bright scarlet,
one thread of brown, etc., etc. There are six colours. Will you have the
kindness to tell me whether the birds prefer one colour to another?

Secondly, I very much want several heads of the fancy and long-domesticated
rabbits, to measure the capacity of skull. I want only small kinds, such
as Himalaya, small Angora, Silver Grey, or any small-sized rabbit which has
long been domesticated. The Silver Grey from warrens would be of little
use. The animals must be adult, and the smaller the breed the better. Now
when any one dies would you send me the carcase named; if the skin is of
any value it might be skinned, but it would be rather better with skin, and
I could make a present to any keeper to whom the skin is a perquisite.
This would be of great assistance to me, if you would have the kindness
thus to aid me.


(427/1. We are not aware that the experiment here suggested has ever been
carried out.)

Down, March 5th [1867].

I write on the bare and very improbable chance of your being able to try,
or get some trustworthy person to try, the following little experiment.
But I may first state, as showing what I want, that it has been stated that
if two long feathers in the tail of the male Widow-Bird at the Cape of Good
Hope are pulled out, no female will pair with him.

Now, where two or three common cocks are kept, I want to know, if the tail
sickle-feathers and saddle-feathers of one which had succeeded in getting
wives were cut and mutilated and his beauty spoiled, whether he would
continue to be successful in getting wives. This might be tried with
drakes or peacocks, but no one would be willing to spoil for a season his
peacocks. I have no strength or opportunity of watching my own poultry,
otherwise I would try it. I would very gladly repay all expenses of loss
of value of the poultry, etc. But, as I said, I have written on the most
improbable chance of your interesting any one to make the trial, or having
time and inclination yourself to make it. Another, and perhaps better,
mode of making the trial would be to turn down to some hens two or three
cocks, one being injured in its plumage.

I am glad to say that I have begun correcting proofs. (427/2. "The
Variation of Animals and Plants.") I hope that you received safely the
skulls which you so kindly lent me.

Down, March 30th [1867].

I am much obliged for your note, and shall be truly obliged if you will
insert any question on the subject. That is a capital remark of yours
about the trimmed game cocks, and shall be quoted by me. (428/1. "Descent
of Man," Edition I., Volume II., page 117. "Mr. Tegetmeier is convinced
that a game cock, though disfigured by being dubbed with his hackles
trimmed, would be accepted as readily as a male retaining all his natural
ornaments.") Nevertheless I am still inclined from many facts strongly to
believe that the beauty of the male bird determines the choice of the
female with wild birds, however it may be under domestication. Sir R.
Heron has described how one pied peacock was extra attentive to the hens.
This is a subject which I must take up as soon as my present book is done.

I shall be most particularly obliged to you if you will dye with magenta a
pigeon or two. (428/2. "Mr. Tegetmeier, at my request, stained some of
his birds with magenta, but they were not much noticed by the others."--
"Descent of Man" (1901), page 637.) Would it not be better to dye the tail
alone and crown of head, so as not to make too great difference? I shall
be very curious to hear how an entirely crimson pigeon will be received by
the others as well as his mate.

P.S.--Perhaps the best experiment, for my purpose, would be to colour a
young unpaired male and turn him with other pigeons, and observe whether he
was longer or quicker than usual in mating.

Down, April 29th [1867].

I have been greatly interested by your letter, but your view is not new to
me. (429/1. We have not been able to find Mr. Wallace's letter to which
this is a reply. It evidently refers to Mr. Wallace's belief in the
paramount importance of protection in the evolution of colour. This is
clear from the P.S. to the present letter and from the passages in the
"Origin" referred to. The first reference, Edition IV., page 240, is as
follows: "We can sometimes plainly see the proximate cause of the
transmission of ornaments to the males alone; for a pea-hen with the long
tail of the male bird would be badly fitted to sit on her eggs, and a coal-
black female capercailzie would be far more conspicuous on her nest, and
more exposed to danger, than in her present modest attire." The passages
in Edition I. (pages 89, 101) do not directly bear on the question of
protection.) If you will look at page 240 of the fourth edition of the
"Origin" you will find it very briefly given with two extreme examples of
the peacock and black grouse. A more general statement is given at page
101, or at page 89 of the first edition, for I have long entertained this
view, though I have never had space to develop it. But I had not
sufficient knowledge to generalise as far as you do about colouring and
nesting. In your paper perhaps you will just allude to my scanty remark in
the fourth edition, because in my Essay on Man I intend to discuss the
whole subject of sexual selection, explaining as I believe it does much
with respect to man. I have collected all my old notes, and partly written
my discussion, and it would be flat work for me to give the leading idea as
exclusively from you. But, as I am sure from your greater knowledge of
Ornithology and Entomology that you will write a much better discussion
than I could, your paper will be of great use to me. Nevertheless I must
discuss the subject fully in my Essay on Man. When we met at the
Zoological Society, and I asked you about the sexual differences in
kingfishers, I had this subject in view; as I had when I suggested to Bates
the difficulty about gaudy caterpillars, which you have so admirably (as I
believe it will prove) explained. (429/2. See a letter of February 26th,
1867, to Mr. Wallace, "Life and Letters" III., page 94.) I have got one
capital case (genus forgotten) of a [Australian] bird in which the female
has long tail-plumes, and which consequently builds a different nest from
all her allies. (429/3. Menura superba: see "Descent of Man" (1901),
page 687. Rhynchoea, mentioned a line or two lower down, is discussed in
the "Descent," page 727. The female is more brightly coloured than the
male, and has a convoluted trachea, elsewhere a masculine character. There
seems some reason to suppose that "the male undertakes the duty of
incubation.") With respect to certain female birds being more brightly
coloured than the males, and the latter incubating, I have gone a little
into the subject, and cannot say that I am fully satisfied. I remember
mentioning to you the case of Rhynchoea, but its nesting seems unknown. In
some other cases the difference in brightness seemed to me hardly
sufficiently accounted for by the principle of protection. At the Falkland
Islands there is a carrion hawk in which the female (as I ascertained by
dissection) is the brightest coloured, and I doubt whether protection will
here apply; but I wrote several months ago to the Falklands to make
enquiries. The conclusion to which I have been leaning is that in some of
these abnormal cases the colour happened to vary in the female alone, and
was transmitted to females alone, and that her variations have been
selected through the admiration of the male.

It is a very interesting subject, but I shall not be able to go on with it
for the next five or six months, as I am fully employed in correcting dull
proof-sheets. When I return to the work I shall find it much better done
by you than I could have succeeded in doing.

It is curious how we hit on the same ideas. I have endeavoured to show in
my MS. discussion that nearly the same principles account for young birds
not being gaily coloured in many cases, but this is too complex a point for
a note.

On reading over your letter again, and on further reflection, I do not
think (as far as I remember my words) that I expressed myself nearly
strongly enough on the value and beauty of your generalisation (429/4. See
Letter 203, Volume I.), viz., that all birds in which the female is
conspicuously or brightly coloured build in holes or under domes. I
thought that this was the explanation in many, perhaps most cases, but do
not think I should ever have extended my view to your generalisation.
Forgive me troubling you with this P.S.

Down, May 5th [1867].

The offer of your valuable notes is most generous, but it would vex me to
take so much from you, as it is certain that you could work up the subject
very much better than I could. Therefore I earnestly, and without any
reservation, hope that you will proceed with your paper, so that I return
your notes. You seem already to have well investigated the subject. I
confess on receiving your note that I felt rather flat at my recent work
being almost thrown away, but I did not intend to show this feeling. As a
proof how little advance I had made on the subject, I may mention that
though I had been collecting facts on the colouring, and other sexual
differences in mammals, your explanation with respect to the females had
not occurred to me. I am surprised at my own stupidity, but I have long
recognised how much clearer and deeper your insight into matters is than
mine. I do not know how far you have attended to the laws of inheritance,
so what follows may be obvious to you. I have begun my discussion on
sexual selection by showing that new characters often appear in one sex and
are transmitted to that sex alone, and that from some unknown cause such
characters apparently appear oftener in the male than in the female.
Secondly, characters may be developed and be confined to the male, and long
afterwards be transferred to the female. Thirdly, characters may arise in
either sex and be transmitted to both sexes, either in an equal or unequal
degree. In this latter case I have supposed that the survival of the
fittest has come into play with female birds and kept the female
dull-coloured. With respect to the absence of spurs in the female
gallinaceous birds, I presume that they would be in the way during
incubation; at least I have got the case of a German breed of fowls in
which the hens were spurred, and were found to disturb and break their eggs
much. With respect to the females of deer not having horns, I presume it
is to save the loss of organised matter. In your note you speak of sexual
selection and protection as sufficient to account for the colouring of all
animals, but it seems to me doubtful how far this will come into play with
some of the lower animals, such as sea anemones, some corals, etc., etc.
On the other hand Hackel (430/1. See "Descent of Man" (1901) page 402.)
has recently well shown that the transparency and absence of colour in the
lower oceanic animals, belonging to the most different classes, may be well
accounted for on the principle of protection.

Some time or other I should like much to know where your paper on the nests
of birds has appeared, and I shall be extremely anxious to read your paper
in the "Westminster Review." (430/2. "Westminster Review," July, 1867.)
Your paper on the sexual colouring of birds will, I have no doubt, be very
striking. Forgive me, if you can, for a touch of illiberality about your

March 19th, 1868.

(431/1. "The Variation of Animals and Plants" having been published on
January 30th, 1868, Mr. Darwin notes in his diary that on February 4th he
"Began on Man and Sexual Selection." He had already (in 1864 and 1867)
corresponded with Mr. Wallace on these questions--see for instance the
"Life and Letters," III., page 89; but, owing to various interruptions,
serious work on the subject did not begin until 1869. The following
quotations show the line of work undertaken early in 1868.

Mr. Wallace wrote (March 19th, 1868): "I am glad you have got good
materials on sexual selection. It is no doubt a difficult subject. One
difficulty to me is, that I do not see how the constant MINUTE variations,
which are sufficient for Natural Selection to work with, could be SEXUALLY
selected. We seem to require a series of bold and abrupt variations. How
can we imagine that an inch in the tail of the peacock, or 1/4-inch in that
of the Bird of Paradise, would be noticed and preferred by the female.")

In regard to sexual selection. A girl sees a handsome man, and without
observing whether his nose or whiskers are the tenth of an inch longer or
shorter than in some other man, admires his appearance and says she will
marry him. So, I suppose, with the pea-hen; and the tail has been
increased in length merely by, on the whole, presenting a more gorgeous
appearance. J. Jenner Weir, however, has given me some facts showing that
birds apparently admire details of plumage.

March 28th [1868].

I am particularly obliged to you for your observations on the stridulation
of the two sexes of Lamellicorns. (432/1. We are unable to find any
mention of F. Muller's observations on this point; but the reference is
clearly to Darwin's observations on Necrophorus and Pelobius, in which the
stridulating rasp was bigger in the males in the first individuals
examined, but not so in succeeding specimens. "Descent of Man," Edition
II., Volume I., page 382.) I begin to fear that I am completely in error
owing to that common cause, viz. mistaking at first individual variability
for sexual difference.

I go on working at sexual selection, and, though never idle, I am able to
do so little work each day that I make very slow progress. I knew from
Azara about the young of the tapir being striped, and about young deer
being spotted (432/2. Fritz Muller's views are discussed in the "Descent
of Man," Edition II., Volume II., page 305.); I have often reflected on
this subject, and know not what to conclude about the loss of the stripes
and spots. From the geographical distribution of the striped and unstriped
species of Equus there seems to be something very mysterious about the loss
of stripes; and I cannot persuade myself that the common ass has lost its
stripes owing to being rendered more conspicuous from having stripes and
thus exposed to danger.


(433/1. Mr. John Jenner Weir, to whom the following letters are addressed,
is frequently quoted in the "Descent of Man" as having supplied Mr. Darwin
with information on a variety of subjects.)

Down, February 27th [1868].

I must thank you for your paper on apterous lepidoptera (433/2. Published
by the West Kent Natural History, Microscopical and Photographic Society,
Greenwich, 1867. Mr. Weir's paper seems chiefly to have interested Mr.
Darwin as affording a good case of gradation in the degree of degradation
of the wings in various species.), which has interested me exceedingly, and
likewise for the very honourable mention which you make of my name. It is
almost a pity that your paper was not published in some Journal in which it
would have had a wider distribution. It contained much that was new to me.
I think the part about the relation of the wings and spiracles and tracheae
might have been made a little clearer. Incidentally, you have done me a
good service by reminding me of the rudimentary spurs on the legs of the
partridge, for I am now writing on what I have called sexual selection. I
believe that I am not mistaken in thinking that you have attended much to
birds in confinement, as well as to insects. If you could call to mind any
facts bearing on this subject, with birds, insects, or any animals--such as
the selection by a female of any particular male--or conversely of a
particular female by a male, or on the rivalry between males, or on the
allurement of the females by the males, or any such facts, I should be most
grateful for the information, if you would have the kindness to communicate

P.S.--I may give as instance of [this] class of facts, that Barrow asserts
that a male Emberiza (?) at the Cape has immensely long tail-feathers
during the breeding season (433/3. Barrow describes the long tail feathers
of Emberiza longicauda as enduring "but the season of love." "An Account
of Travels into the Interior of Southern Africa": London, 1801, Volume I.,
page 244.); and that if these are cut off, he has no chance of getting a
wife. I have always felt an intense wish to make analogous trials, but
have never had an opportunity, and it is not likely that you or any one
would be willing to try so troublesome an experiment. Colouring or
staining the fine red breast of a bullfinch with some innocuous matter into
a dingy tint would be an analogous case, and then putting him and ordinary
males with a female. A friend promised, but failed, to try a converse
experiment with white pigeons--viz., to stain their tails and wings with
magenta or other colours, and then observe what effect such a prodigious
alteration would have on their courtship. (433/4. See Letter 428.) It
would be a fairer trial to cut off the eyes of the tail-feathers of male
peacocks; but who would sacrifice the beauty of their bird for a whole
season to please a mere naturalist?

Down, February 29th [1868].

I have hardly ever received a note which has interested me more than your
last; and this is no exaggeration. I had a few cases of birds perceiving
slight changes in the dress of their owners, but your facts are of tenfold
value. I shall certainly make use of them, and need not say how much
obliged I should be for any others about which you feel confident.

Do you know of any birds besides some of the gallinaceae which are
polygamous? Do you know of any birds besides pigeons, and, as it is said,
the raven, which pair for their whole lives?

Many years ago I visited your brother, who showed me his pigeons and gave
me some valuable information. Could you persuade him (but I fear he would
think it high treason) to stain a male pigeon some brilliant colour, and
observe whether it excited in the other pigeons, especially the females,
admiration or contempt?

For the chance of your liking to have a copy and being able to find some
parts which would interest you, I have directed Mr. Murray to send you my
recent book on "Variation under Domestication."

P.S.--I have somewhere safe references to cases of magpies, of which one of
a pair has been repeatedly (I think seven times) killed, and yet another
mate was always immediately found. (434/1. On this subject see "Descent
of Man," Edition I., Volume II., page 104, where Mr. Weir's observations
were made use of. This statement is quoted from Jenner ("Phil. Trans."
1824) in the "Descent of Man" (1901), page 620.) A gamekeeper told me
yesterday of analogous case. This perplexes me much. Are there many
unmarried birds? I can hardly believe it. Or will one of a pair, of which
the nest has been robbed, or which are barren, always desert his or her
mate for a strange mate with the attraction of a nest, and in one instance
with young birds in the nest? The gamekeeper said during breeding season
he had never observed a single or unpaired partridge. How can the sexes be
so equally matched?

P.S. 2nd.--I fear you will find me a great bore, but I will be as
reasonable as can be expected in plundering one so rich as you.

P.S. 3rd.--I have just received a letter from Dr. Wallace (434/2. See
"Descent of Man," Edition I., Volume I., pages 386-401, where Dr. Wallace's
observations are quoted.), of Colchester, about the proportional numbers of
the two sexes in Bombyx; and in this note, apropos to an incidental remark
of mine, he stoutly maintains that female lepidoptera never notice the
colours or appearance of the male, but always receive the first male which
comes; and this appears very probable. He says he has often seen fine
females receive old battered and pale-tinted males. I shall have to admit
this very great objection to sexual selection in insects. His observations
no doubt apply to English lepidoptera, in most of which the sexes are
alike. The brimstone or orange-tip would be good to observe in this
respect, but it is hopelessly difficult. I think I have often seen several
males following one female; and what decides which male shall succeed? How
is this about several males; is it not so?

6, Queen Anne Street, Cavendish Square, W. [March 6th, 1868].

I have come here for a few weeks, for a little change and rest. Just as I
was leaving home I received your first note, and yesterday a second; and
both are most interesting and valuable to me. That is a very curious
observation about the goldfinch's beak (435/1. "Descent of Man," Edition
I., Volume I., page 39. Mr. Weir is quoted as saying that the birdcatchers
can distinguish the males of the goldfinch, Carduelis elegans, by their
"slightly longer beaks."), but one would hardly like to trust it without
measurement or comparison of the beaks of several male and female birds;
for I do not understand that you yourself assert that the beak of the male
is sensibly longer than that of the female. If you come across any acute
birdcatchers (I do not mean to ask you to go after them), I wish you would
ask what is their impression on the relative numbers of the sexes of any
birds which they habitually catch, and whether some years males are more
numerous and some years females. I see that I must trust to analogy (an
unsafe support) for sexual selection in regard to colour in butterflies.
You speak of the brimstone butterfly and genus Edusa (435/2. Colias
Edusa.) (I forget what this is, and have no books here, unless it is
Colias) not opening their wings. In one of my notes to Mr. Stainton I
asked him (but he could or did not answer) whether butterflies such as the
Fritillaries, with wings bright beneath and above, opened and shut their
wings more than Vanessae, most of which, I think, are obscure on the under
surface. That is a most curious observation about the red underwing moth
and the robin (435/3. "Descent of Man," Edition I., Volume I., page 395.
Mr. Weir describes the pursuit of a red-underwing, Triphoena pronuba, by a
robin which was attracted by the bright colour of the moth, and constantly
missed the insect by breaking pieces off the wing instead of seizing the
body. Mr. Wallace's facts are given on the same page.), and strongly
supports a suggestion (which I thought hardly credible) of A.R. Wallace,
viz. that the immense wings of some exotic lepidoptera served as a
protection from difficulty of birds seizing them. I will probably quote
your case.

No doubt Dr. Hooker collected the Kerguelen moth, for I remember he told me
of the case when I suggested in the "Origin," the explanation of the
coleoptera of Madeira being apterous; but he did not know what had become
of the specimens.

I am quite delighted to hear that you are observing coloured birds (435/4.
"Descent of Man," Edition I., Volume II., page 110.), though the
probability, I suppose, will be that no sure result will be gained. I am
accustomed with my numerous experiments with plants to be well satisfied if
I get any good result in one case out of five.

You will not be able to read all my book--too much detail. Some of the
chapters in the second volume are curious, I think. If any man wants to
gain a good opinion of his fellow-men, he ought to do what I am doing,
pester them with letters.

4, Chester Place, Regent's Park, N.W., March 13th [1868].

You make a very great mistake when you speak of "the risk of your notes
boring me." They are of the utmost value to me, and I am sure I shall
never be tired of receiving them; but I must not be unreasonable. I shall
give almost all the facts which you have mentioned in your two last notes,
as well as in the previous ones; and my only difficulty will be not to give
too much and weary my readers. Your last note is especially valuable about
birds displaying the beautiful parts of their plumage. Audubon (436/1. In
his "Ornithological Biography," 5 volumes, Edinburgh, 1831-49.) gives a
good many facts about the antics of birds during courtship, but nothing
nearly so much to the purpose as yours. I shall never be able to resist
giving the whole substance of your last note. It is quite a new light to
me, except with the peacock and Bird of Paradise. I must now look to
turkey's wings; but I do not think that their wings are beautiful when
opened during courtship. Its tail is finely banded. How about the drake
and Gallus bankiva? I forget how their wings look when expanded. Your
facts are all the more valuable as I now clearly see that for butterflies I
must trust to analogy altogether in regard to sexual selection. But I
think I shall make out a strong case (as far as the rather deceitful guide
of analogy will serve) in the sexes of butterflies being alike or differing
greatly--in moths which do not display the lower surface of their wings not
having them gaudily coloured, etc., etc.--nocturnal moths, etc.--and in
some male insects fighting for the females, and attracting them by music.

My discussion on sexual selection will be a curious one--a mere dovetailing
of information derived from you, Bates, Wallace, etc., etc., etc.

We remain at above address all this month, and then return home. In the
summer, could I persuade you to pay us a visit of a day or two, and I would
try and get Bates and some others to come down? But my health is so
precarious, I can ask no one who will not allow me the privilege of a poor
old invalid; for talking, I find by long and dear-bought experience, tries
my head more than anything, and I am utterly incapable of talking more than
half an hour, except on rare occasions.

I fear this note is very badly written; but I was very ill all yesterday,
and my hand shakes to-day.

4, Chester Place, Regent's Park, N.W., March 22nd [1868].

I hope that you will not think me ungrateful that I have not sooner
answered your note of the 16th; but in fact I have been overwhelmed both
with calls and letters; and, alas! one visit to the British Museum of an
hour or hour and a half does for me for the whole day.

I was particularly glad to hear your and your brother's statement about the
"gay" deceiver-pigeons. (437/1. Some cock pigeons "called by our English
fanciers gay birds are so successful in their gallantries that, as Mr. H.
Weir informs me, they must be shut up, on account of the mischief which
they cause.") I did not at all know that certain birds could win the
affections of the females more than other males, except, indeed, in the
case of the peacock. Conversely, Mr. Hewitt, I remember, states that in
making hybrids the cock pheasant would prefer certain hen fowls and
strongly dislike others. I will write to Mr. H. in a few days, and ask him
whether he has observed anything of this kind with pure unions of fowls,
ducks, etc. I had utterly forgotten the case of the ruff (437/2. The
ruff, Machetes pugnax, was believed by Montague to be polygamous. "Descent
of Man," Edition I., Volume I., page 270.), but now I remember having heard
that it was polygamous; but polygamy with birds, at least, does not seem
common enough to have played an important part. So little is known of
habits of foreign birds: Wallace does not even know whether Birds of
Paradise are polygamous. Have you been a large collector of caterpillars?
I believe so. I inferred from a letter from Dr. Wallace, of Colchester,
that he would account for Mr. Stainton and others rearing more female than
male by their having collected the larger and finer caterpillars. But I
misunderstood him, and he maintains that collectors take all caterpillars,
large and small, for that they collect the caterpillars alone of the rarer
moths or butterflies. What think you? I hear from Professor Canestrini
(437/3. See "Descent of Man" (1901), page 385.) in Italy that females are
born in considerable excess with Bombyx mori, and in greater excess of late
years than formerly! Quatrefages writes to me that he believes they are
equal in France. So that the farther I go the deeper I sink into the mire.
With cordial thanks for your most valuable letters.

We remain here till April 1st, and then hurrah for home and quiet work.

4, Chester Place, N.W., March 27th [1868].

I hardly know which of your three last letters has interested me most.
What splendid work I shall have hereafter in selecting and arranging all
your facts. Your last letter is most curious--all about the bird-catchers
--and interested us all. I suppose the male chaffinch in "pegging"
approaches the captive singing-bird, from rivalry or jealousy--if I am
wrong please tell me; otherwise I will assume so. Can you form any theory
about all the many cases which you have given me, and others which have
been published, of when one [of a] pair is killed, another soon appearing?
Your fact about the bullfinches in your garden is most curious on this
head. (438/1. Mr. Weir stated that at Blackheath he never saw or heard a
wild bullfinch, yet when one of his caged males died, a wild one in the
course of a few days generally came and perched near the widowed female,
whose call-note is not loud. "Descent of Man" (1901), page 623.) Are
there everywhere many unpaired birds? What can the explanation be?

Mr. Gould assures me that all the nightingales which first come over are
males, and he believes this is so with other migratory birds. But this
does not agree with what the bird-catchers say about the common linnet,
which I suppose migrates within the limits of England.

Many thanks for very curious case of Pavo nigripennis. (438/2. See
"Animals and Plants," Edition II., Volume I., page 306.) I am very glad to
get additional evidence. I have sent your fact to be inserted, if not too
late, in four foreign editions which are now printing. I am delighted to
hear that you approve of my book; I thought every mortal man would find the
details very tedious, and have often repented of giving so many. You will
find pangenesis stiff reading, and I fear will shake your head in
disapproval. Wallace sticks up for the great god Pan like a man.

The fertility of hybrid canaries would be a fine subject for careful

Down, April 4th [1868].

I read over your last ten (!) letters this morning, and made an index of
their contents for easy reference; and what a mine of wealth you have
bestowed on me. I am glad you will publish yourself on gay-coloured
caterpillars and birds (439/1. See "Descent of Man," Edition I., Volume
I., page 417, where Mr. Weir's experiments are given; they were made to
test Mr. Wallace's theory that caterpillars, which are protected against
birds by an unpleasant taste, have been rendered conspicuous, so that they
are easily recognised. They thus escape being pecked or tasted, which to
soft-skinned animals would be as fatal as being devoured. See Mr. Jenner
Weir's papers, "Transact. Entomolog. Soc." 1869, page 2; 1870, page 337.
In regard to one of these papers Mr. Darwin wrote (May 13th, 1869): "Your
verification of Wallace's suggestion seems to me to amount to quite a
discovery."); it seems to me much the best plan; therefore, I will not
forward your letter to Mr. Wallace. I was much in the Zoological Gardens
during my month in London, and picked up what scraps of knowledge I could.
Without my having mentioned your most interesting observations on the
display of the Fringillidae (439/2. "Descent of Man" (1901), page 738.),
Mr. Bartlett told me how the Gold Pheasant erects his collar and turns from
side to side, displaying it to the hen. He has offered to give me notes on
the display of all Gallinaceae with which he is acquainted; but he is so
busy a man that I rather doubt whether he will ever do so.

I received about a week ago a remarkably kind letter from your brother, and
I am sorry to hear that he suffers much in health. He gave me some fine
facts about a Dun Hen Carrier which would never pair with a bird of any
other colour. He told me, also, of some one at Lewes who paints his dog!
and will inquire about it. By the way, Mr. Trimen tells me that as a boy
he used to paint butterflies, and that they long haunted the same place,
but he made no further observations on them. As far as colour is
concerned, I see I shall have to trust to mere inference from the males
displaying their plumage, and other analogous facts. I shall get no direct
evidence of the preference of the hens. Mr. Hewitt, of Birmingham, tells
me that the common hen prefers a salacious cock, but is quite indifferent
to colour.

Will you consider and kindly give me your opinion on the two following
points. Do very vigorous and well-nourished hens receive the male earlier
in the spring than weaker or poorer hens? I suppose that they do.
Secondly, do you suppose that the birds which pair first in the season have
any advantage in rearing numerous and healthy offspring over those which
pair later in the season? With respect to the mysterious cases of which
you have given me so many, in addition to those previously collected, of
when one bird of a pair is shot another immediately supplying its place, I
was drawing to the conclusion that there must be in each district several
unpaired birds; yet this seems very improbable. You allude, also, to the
unknown causes which keep down the numbers of birds; and often and often
have I marvelled over this subject with respect to many animals.


(440/1. The following refers to Mr. Wallace's article "A Theory of Birds'
Nests," in Andrew Murray's "Journal of Travel," Volume I., page 73. He
here treats in fuller detail the view already published in the "Westminster
Review," July 1867, page 38. The rule which Mr. Wallace believes, with
very few exceptions, to hold good is, "that when both sexes are of
strikingly gay and conspicuous colours, the nest is...such as to conceal
the sitting bird; while, whenever there is a striking contrast of colours,
the male being gay and conspicuous, the female dull and obscure, the nest
is open, and the sitting bird exposed to view." At this time Mr. Wallace
allowed considerably more influence to sexual selection (in combination
with the need of protection) than in his later writings. The following
extract from a letter from Mr. Wallace to Darwin (July 23rd, 1877) fixes
the period at which the change in his views occurred: "I am almost afraid
to tell you that in going over the subject of the colours of animals, etc.,
etc., for a small volume of essays, etc., I am preparing, I have come to
conclusions directly opposed to voluntary sexual selection, and believe
that I can explain (in a general way) all the phenomena of sexual ornaments
and colours by laws of development aided by simple 'Natural Selection.'"
He finally rejected Mr. Darwin's theory that colours "have been developed
by the preference of the females, the more ornamented males becoming the
parents of each successive generation." "Darwinism," 1889, page 285. See
also Letters 442, 443, 449, 450, etc.)

Down, April 15th, [1868].

I have been deeply interested by your admirable article on birds' nests. I
am delighted to see that we really differ very little,--not more than two
men almost always will. You do not lay much or any stress on new
characters spontaneously appearing in one sex (generally the male), and
being transmitted exclusively, or more commonly only in excess, to that
sex. I, on the other hand, formerly paid far too little attention to
protection. I had only a glimpse of the truth; but even now I do not go
quite as far as you. I cannot avoid thinking rather more than you do about
the exceptions in nesting to the rule, especially the partial exceptions,
i.e., when there is some little difference between the sexes in species
which build concealed nests. I am not quite satisfied about the incubating
males; there is so little difference in conspicuousness between the sexes.
I wish with all my heart I could go the whole length with you. You seem to
think that male birds probably select the most beautiful females; I must
feel some doubt on this head, for I can find no evidence of it. Though I
am writing so carping a note, I admire the article thoroughly.

And now I want to ask a question. When female butterflies are more
brilliant than their males you believe that they have in most cases, or in
all cases, been rendered brilliant so as to mimic some other species, and
thus escape danger. But can you account for the males not having been
rendered equally brilliant and equally protected? (440/2. See Wallace in
the "Westminster Review," July, 1867, page 37, on the protection to the
female insect afforded by its resemblance either to an inanimate object or
to another insect protected by its unpalatableness. The cases are
discussed in relation to the much greater importance (to the species as a
whole) of the preservation of the female insect with her load of eggs than
the male who may safely be sacrificed after pairing. See Letter 189,
note.) Although it may be most for the welfare of the species that the
female should be protected, yet it would be some advantage, certainly no
disadvantage, for the unfortunate male to enjoy an equal immunity from
danger. For my part, I should say that the female alone had happened to
vary in the right manner, and that the beneficial variations had been
transmitted to the same sex alone. Believing in this, I can see no
improbability (but from analogy of domestic animals a strong probability)
that variations leading to beauty must often have occurred in the males
alone, and been transmitted to that sex alone. Thus I should account in
many cases for the greater beauty of the male over the female, without the
need of the protective principle. I should be grateful for an answer on
the point.

Down, April 18th [1868].

You see that I have taken you at your word, and have not (owing to heaps of
stupid letters) earlier noticed your three last letters, which as usual are
rich in facts. Your letters make almost a little volume on my table. I
daresay you hardly knew yourself how much curious information was lying in
your mind till I began the severe pumping process. The case of the
starling married thrice in one day is capital, and beats the case of the
magpies of which one was shot seven times consecutively. A gamekeeper here
tells me that he has repeatedly shot one of a pair of jays, and it has
always been immediately replaced. I begin to think that the pairing of
birds must be as delicate and tedious an operation as the pairing of young
gentlemen and ladies. If I can convince myself that there are habitually
many unpaired birds, it will be a great aid to me in sexual selection,
about which I have lately had many troubles, and am therefore rejoiced to
hear in your last note that your faith keeps staunch. That is a curious
fact about the bullfinches all appearing to listen to the German singer
(441/1. See Letter 445, note.); and this leads me to ask how much faith
may I put in the statement that male birds will sing in rivalry until they
injure themselves. Yarrell formerly told me that they would sometimes even
sing themselves to death. I am sorry to hear that the painted bullfinch
turns out to be a female; though she has done us a good turn in exhibiting
her jealousy, of which I had no idea.

Thank you for telling me about the wildness of the hybrid canaries:
nothing has hardly ever surprised me more than the many cases of reversion
from crossing. Do you not think it a very curious subject? I have not
heard from Mr. Bartlett about the Gallinaceae, and I daresay I never shall.
He told me about the Tragopan, and he is positive that the blue wattle
becomes gorged with blood, and not air.

Returning to the first of the last three letters. It is most curious the
number of persons of the name of Jenner who have had a strong taste for
Natural History. It is a pity you cannot trace your connection with the
great Jenner, for a duke might be proud of his blood.

I heard lately from Professor Rolleston of the inherited effects of an
injury in the same eye. Is the scar on your son's leg on the same side and
on exactly the same spot where you were wounded? And did the wound
suppurate, or heal by the first intention? I cannot persuade myself of the
truth of the common belief of the influence of the mother's imagination on
the child. A point just occurs to me (though it does not at present
concern me) about birds' nests. Have you read Wallace's recent articles?
(441/2. A full discussion of Mr. Wallace's views is given in "Descent of
Man," Edition I., Volume II., Chapter XV. Briefly, Mr. Wallace's point is
that the dull colour of the female bird is protective by rendering her
inconspicuous during incubation. Thus the relatively bright colour of the
male would not simply depend on sexual selection, but also on the hen being
"saved, through Natural Selection, from acquiring the conspicuous colours
of the male" (loc. cit., page 155).) I always distrust myself when I
differ from him; but I cannot admit that birds learn to make their nests
from having seen them whilst young. I must think it as true an instinct as
that which leads a caterpillar to suspend its cocoon in a particular
manner. Have you had any experience of birds hatched under a foster-mother
making their nests in the proper manner? I cannot thank you enough for all
your kindness.


(442/1. Dr. Clifford Allbutt's view probably had reference to the fact
that the sperm-cell goes, or is carried, to the germ-cell, never vice
versa. In this letter Darwin gives the reason for the "law" referred to.
Mr. A.R. Wallace has been good enough to give us the following note:--"It
was at this time that my paper on 'Protective Resemblance' first appeared
in the 'Westminster Review,' in which I adduced the greater, or rather, the
more continuous, importance of the female (in the lower animals) for the
race, and my 'Theory of Birds' Nests' ('Journal of Travel and Natural
History,' No. 2) in which I applied this to the usually dull colours of
female butterflies and birds. It is to these articles as well as to my
letters that Darwin chiefly refers."--Note by Mr. Wallace, May 27th, 1902.)

Down, April 30th [1868].

Your letter, like so many previous ones, has interested me much. Dr.
Allbutt's view occurred to me some time ago, and I have written a short
discussion on it. It is, I think, a remarkable law, to which I have found
no exception. The foundation lies in the fact that in many cases the eggs
or seeds require nourishment and protection by the mother-form for some
time after impregnation. Hence the spermatozoa and antherozoids travel in
the lower aquatic animals and plants to the female, and pollen is borne to
the female organ. As organisms rise in the scale it seems natural that the
male should carry the spermatozoa to the female in his own body. As the
male is the searcher, he has required and gained more eager passions than
the female; and, very differently from you, I look at this as one great
difficulty in believing that the males select the more attractive females;
as far as I can discover, they are always ready to seize on any female, and
sometimes on many females. Nothing would please me more than to find
evidence of males selecting the more attractive females. I have for months
been trying to persuade myself of this. There is the case of man in favour
of this belief, and I know in hybrid unions of males preferring particular
females, but, alas, not guided by colour. Perhaps I may get more evidence
as I wade through my twenty years' mass of notes.

I am not shaken about the female protected butterflies. I will grant (only
for argument) that the life of the male is of very little value,--I will
grant that the males do not vary, yet why has not the protective beauty of
the female been transferred by inheritance to the male? The beauty would
be a gain to the male, as far as we can see, as a protection; and I cannot
believe that it would be repulsive to the female as she became beautiful.
But we shall never convince each other. I sometimes marvel how truth
progresses, so difficult is it for one man to convince another, unless his
mind is vacant. Nevertheless, I myself to a certain extent contradict my
own remark, for I believe far more in the importance of protection than I
did before reading your articles.

I do not think you lay nearly stress enough in your articles on what you
admit in your letters: viz., "there seems to be some production of
vividness...of colour in the male independent of protection." This I am
making a chief point; and have come to your conclusion so far that I
believe that intense colouring in the female sex is often checked by being

That is an excellent remark of yours about no known case of male alone
assuming protective colours; but in the cases in which protection has been
gained by dull colours, I presume that sexual selection would interfere
with the male losing his beauty. If the male alone had acquired beauty as
a protection, it would be most readily overlooked, as males are so often
more beautiful than their females. Moreover, I grant that the life of the
male is somewhat less precious, and thus there would be less rigorous
selection with the male, so he would be less likely to be made beautiful
through Natural Selection for protection. (442/2. This does not apply to
sexual selection, for the greater the excess of males, and the less
precious their lives, so much the better for sexual selection. [Note in
original.]) But it seems to me a good argument, and very good if it could
be thoroughly established. I do not know whether you will care to read
this scrawl.

Down, May 5th [1868?].

I am afraid I have caused you a great deal of trouble in writing to me at
such length. I am glad to say that I agree almost entirely with your
summary, except that I should put sexual selection as an equal, or perhaps
as even a more important agent in giving colour than Natural Selection for
protection. As I get on in my work I hope to get clearer and more decided
ideas. Working up from the bottom of the scale, I have as yet only got to
fishes. What I rather object to in your articles is that I do not think
any one would infer from them that you place sexual selection even as high
as No. 4 in your summary. It was very natural that you should give only a
line to sexual selection in the summary to the "Westminster Review," but
the result at first to my mind was that you attributed hardly anything to
its power. In your penultimate note you say "in the great mass of cases in
which there is great differentiation of colour between the sexes, I believe
it is due almost wholly to the need of protection to the female." Now,
looking to the whole animal kingdom, I can at present by no means admit
this view; but pray do not suppose that because I differ to a certain
extent, I do not thoroughly admire your several papers and your admirable
generalisation on birds' nests. With respect to this latter point,
however, although, following you, I suspect that I shall ultimately look at
the whole case from a rather different point of view.

You ask what I think about the gay-coloured females of Pieris. (443/1.
See "Westminster Review," July, 1867, page 37; also Letter 440.) I believe
I quite follow you in believing that the colours are wholly due to mimicry;
and I further believe that the male is not brilliant from not having
received through inheritance colour from the female, and from not himself
having varied; in short, that he has not been influenced by selection.

I can make no answer with respect to the elephants. With respect to the
female reindeer, I have hitherto looked at the horns simply as the
consequence of inheritance not having been limited by sex.

Your idea about colour being concentrated in the smaller males seems good,
and I presume that you will not object to my giving it as your suggestion.

Down, May 7th [1868].

I have now to thank you for no less than four letters! You are so kind
that I will not apologise for the trouble I cause you; but it has lately
occurred to me that you ought to publish a paper or book on the habits of
the birds which you have so carefully observed. But should you do this, I
do not think that my giving some of the facts for a special object would
much injure the novelty of your work. There is such a multitude of points
in these last letters that I hardly know what to touch upon. Thanks about
the instinct of nidification, and for your answers on many points. I am
glad to hear reports about the ferocious female bullfinch. I hope you will
have another try in colouring males. I have now finished lepidoptera, and
have used your facts about caterpillars, and as a caution the case of the
yellow-underwings. I have now begun on fishes, and by comparing different
classes of facts my views are getting a little more decided. In about a
fortnight or three weeks I shall come to birds, and then I dare say that I
shall be extra troublesome. I will now enclose a few queries for the mere
chance of your being able to answer some of them, and I think it will save
you trouble if I write them on a separate slip, and then you can sometimes
answer by a mere "no" or "yes."

Your last letter on male pigeons and linnets has interested me much, for
the precise facts which you have given me on display are of the utmost
value for my work. I have written to Mr. Bartlett on Gallinaceae, but I
dare say I shall not get an answer. I had heard before, but am glad to
have confirmation about the ruffs being the most numerous. I am greatly
obliged to your brother for sending out circulars. I have not heard from
him as yet. I want to ask him whether he has ever observed when several
male pigeons are courting one female that the latter decides with which
male she will pair. The story about the black mark on the lambs must be a
hoax. The inaccuracy of many persons is wonderful. I should like to tell
you a story, but it is too long, about beans growing on the wrong side of
the pod during certain years.


Does any female bird regularly sing?

Do you know any case of both sexes, more especially of the female, [being]
more brightly coloured whilst young than when come to maturity and fit to
breed? An imaginary instance would be if the female kingfisher (or male)
became dull coloured when adult.

Do you know whether the male and female wild canary bird differ in plumage
(though I believe I could find this out for myself), and do any of the
domestic breeds differ sexually?

Do you know any gallinaceous bird in which the female has well developed

It is very odd that my memory should fail me, but I cannot remember
whether, in accordance with your views, the wing of Gallus bankiva (or
Game-Cock, which is so like the wild) is ornamental when he opens and
scrapes it before the female. I fear it is not; but though I have often
looked at wing of the wild and tame bird, I cannot call to mind the exact
colours. What a number of points you have attended to; I did not know that
you were a horticulturist. I have often marvelled at the different growth
of the flowering and creeping branches of the ivy; but had no idea that
they kept their character when propagated by cuttings. There is a S.
American genus (name forgotten just now) which differs in an analogous
manner but even greater degree, but it is difficult to cultivate in our
hot-house. I have tried and failed.

Down, May 30th [1868].

I am glad to hear your opinion on the nest-making instinct, for I am Tory
enough not to like to give up all old beliefs. Wallace's view (445/1. See
Letter 440, etc.) is also opposed to a great mass of analogical facts. The
cases which you mention of suddenly reacquired wildness seem curious. I
have also to thank you for a previous valuable letter. With respect to
spurs on female Gallinaceae, I applied to Mr. Blyth, who has wonderful
systematic knowledge, and he tells me that the female Pavo muticus and
Fire-back pheasants are spurred. From various interruptions I get on very
slowly with my Bird MS., but have already often and often referred to your
volume of letters, and have used various facts, and shall use many more.
And now I am ashamed to say that I have more questions to ask; but I
forget--you told me not to apologise.

1. In your letter of April 14th you mention the case of about twenty birds
which seemed to listen with much interest to an excellent piping bullfinch.
(445/2. Quoted in the "Descent of Man" (1901), page 564. "A bullfinch
which had been taught to pipe a German waltz...when this bird was first
introduced into a room where other birds were kept and he began to sing,
all the others, consisting of about twenty linnets and canaries, ranged
themselves on the nearest side of their cages, and listened with the
greatest interest to the new performer.") What kind of birds were these

2. Is it true, as often stated, that a bird reared by foster-parents, and
who has never heard the song of its own species, imitates to a certain
extent the song of the species which it may be in the habit of hearing?

Now for a more troublesome point. I find it very necessary to make out
relation of immature plumage to adult plumage, both when the sexes differ
and are alike in the adult state. Therefore, I want much to learn about
the first plumage (answering, for instance, to the speckled state of the
robin before it acquires the red breast) of the several varieties of the
canary. Can you help me? What is the character or colour of the first
plumage of bright yellow or mealy canaries which breed true to these tints?
So with the mottled-brown canaries, for I believe that there are breeds
which always come brown and mottled. Lastly, in the "prize-canaries,"
which have black wing- and tail-feathers during their first (?) plumage,
what colours are the wings and tails after the first (?) moult or when
adult? I should be particularly glad to learn this. Heaven have mercy on
you, for it is clear that I have none. I am going to investigate this same
point with all the breeds of fowls, as Mr. Tegetmeier will procure for me
young birds, about two months old, of all the breeds.

In the course of this next month I hope you will come down here on the
Saturday and stay over the Sunday. Some months ago Mr. Bates said he would
pay me a visit during June, and I have thought it would be pleasanter for
you to come here when I can get him, so that you would have a companion if
I get knocked up, as is sadly too often my bad habit and great misfortune.

Did you ever hear of the existence of any sub-breed of the canary in which
the male differs in plumage from the female?

Down, June 3rd [1868].

Your letter of April 22nd has much interested me. I am delighted that you
approve of my book, for I value your opinion more than that of almost any
one. I have yet hopes that you will think well of pangenesis. I feel sure
that our minds are somewhat alike, and I find it a great relief to have
some definite, though hypothetical view, when I reflect on the wonderful
transformations of animals, the re-growth of parts, and especially the
direct action of pollen on the mother form, etc. It often appears to me
almost certain that the characters of the parents are "photographed" on the
child, only by means of material atoms derived from each cell in both
parents, and developed in the child. I am sorry about the mistake in
regard to Leptotes. (446/1. See "Animals and Plants," Edition I., Volume
II., page 134, where it is stated that Oncidium is fertile with Leptotes, a
mistake corrected in the 2nd edition.) I daresay it was my fault, yet I
took pains to avoid such blunders. Many thanks for all the curious facts
about the unequal number of the sexes in crustacea, but the more I
investigate this subject the deeper I sink in doubt and difficulty.
Thanks, also, for the confirmation of the rivalry of Cicadae. (446/2. See
"Descent of Man," Edition I., Volume I., page 351, for F. Muller's
observations; and for a reference to Landois' paper.) I have often
reflected with surprise on the diversity of the means for producing music
with insects, and still more with birds. We thus get a high idea of the
importance of song in the animal kingdom. Please to tell me where I can
find any account of the auditory organs in the orthoptera? Your facts are
quite new to me. Scudder has described an annectant insect in Devonian
strata, furnished with a stridulating apparatus. (446/3. The insect is no
doubt Xenoneura antiquorum, from the Devonian rocks of New Brunswick.
Scudder compared a peculiar feature in the wing of this species to the
stridulating apparatus of the Locustariae, but afterwards stated that he
had been led astray in his original description, and that there was no
evidence in support of the comparison with a stridulating organ. See the
"Devonian Insects of New Brunswick," reprinted in S.H. Scudder's "Fossil
Insects of N. America," Volume I., page 179, New York, 1890.) I believe he
is to be trusted, and if so the apparatus is of astonishing antiquity.
After reading Landois' paper I have been working at the stridulating organ
in the lamellicorn beetles, in expectation of finding it sexual, but I have
only found it as yet in two cases, and in these it was equally developed in
both sexes. I wish you would look at any of your common lamellicorns and
take hold of both males and females and observe whether they make the
squeaking or grating noise equally. If they do not, you could perhaps send
me a male and female in a light little box. How curious it is that there
should be a special organ for an object apparently so unimportant as
squeaking. Here is another point: have you any Toucans? if so, ask any
trustworthy hunter whether the beaks of the males, or of both sexes, are
more brightly coloured during the breeding season than at other times of
the year? I have also to thank you for a previous letter of April 3rd,
with some interesting facts on the variation of maize, the sterility of
Bignonia and on conspicuous seeds. Heaven knows whether I shall ever live
to make use of half the valuable facts which you have communicated to me...

Down, June 18th [1868].

Many thanks. I am glad that you mentioned the linnet, for I had much
difficulty in persuading myself that the crimson breast could be due to
change in the old feathers, as the books say. I am glad to hear of the
retribution of the wicked old she-bullfinch. You remember telling me how
many Weirs and Jenners have been naturalists; now this morning I have been
putting together all my references about one bird of a pair being killed,
and a new mate being soon found; you, Jenner Weir, have given me some most
striking cases with starlings; Dr. Jenner gives the most curious case of
all in "Philosophical Transactions" (447/1. "Phil. Trans." 1824.), and a
Mr. Weir gives the next most striking in Macgillivray. (447/2.
Macgillivray's "History of British Birds," Volume I., page 570. See
"Descent of Man" (1901), page 621.) Now, is this not odd? Pray remember
how very glad we shall be to see you here whenever you can come.

Did some ancient progenitor of the Weirs and Jenners puzzle his brains
about the mating of birds, and has the question become indelibly fixed in
all your minds?

August 19th [1868].

I had become, before my nine weeks' horrid interruption of all work,
extremely interested in sexual selection, and was making fair progress. In
truth it has vexed me much to find that the farther I get on the more I
differ from you about the females being dull-coloured for protection. I
can now hardly express myself as strongly, even, as in the "Origin." This
has much decreased the pleasure of my work. In the course of September, if
I can get at all stronger, I hope to get Mr. J. Jenner Weir (who has been
wonderfully kind in giving me information) to pay me a visit, and I will
then write for the chance of your being able to come, and I hope bring with
you Mrs. Wallace. If I could get several of you together it would be less
dull for you, for of late I have found it impossible to talk with any human
being for more than half an hour, except on extraordinary good days.

(448/1. On September 16th Darwin wrote to Wallace on the same subject:--)

You will be pleased to hear that I am undergoing severe distress about
protection and sexual selection; this morning I oscillated with joy towards
you; this evening I have swung back to the old position, out of which I
fear I shall never get.


(449/1. From "Life and Letters," Volume III., page 123.)

Down, September 23rd [1868].

I am very much obliged for all your trouble in writing me your long letter,
which I will keep by me and ponder over. To answer it would require at
least 200 folio pages! If you could see how often I have rewritten some
pages you would know how anxious I am to arrive as near as I can to the
truth. I lay great stress on what I know takes place under domestication;
I think we start with different fundamental notions on inheritance. I find
it is most difficult, but not, I think, impossible to see how, for
instance, a few red feathers appearing on the head of a male bird, and
which are at first transmitted to both sexes, would come to be transmitted
to males alone. It is not enough that females should be produced from the
males with red feathers, which should be destitute of red feathers; but
these females must have a latent tendency to produce such feathers,
otherwise they would cause deterioration in the red head-feathers of their
male offspring. Such latent tendency would be shown by their producing the
red feathers when old, or diseased in their ovaria. But I have no
difficulty in making the whole head red if the few red feathers in the male
from the first tended to be sexually transmitted. I am quite willing to
admit that the female may have been modified, either at the same time or
subsequently, for protection by the accumulation of variations limited in
their transmission to the female sex. I owe to your writings the
consideration of this latter point. But I cannot yet persuade myself that
females alone have often been modified for protection. Should you grudge
the trouble briefly to tell me, whether you believe that the plainer head
and less bright colours of female chaffinch, the less red on the head and
less clean colours of female goldfinch, the much less red on the breast of
the female bullfinch, the paler crest of golden-crested wren, etc., have
been acquired by them for protection? I cannot think so, any more than I
can that the considerable differences between female and male
house-sparrow, or much greater brightness of male Parus caeruleus (both of
which build under cover) than of female Parus, are related to protection.
I even misdoubt much whether the less blackness of female blackbird is for

Again, can you give me reasons for believing that the moderate differences
between the female pheasant, the female Gallus bankiva, the female of black
grouse, the pea-hen, the female partridge, have all special references to
protection under slightly different conditions? I, of course, admit that
they are all protected by dull colours, derived, as I think, from some
dull-ground progenitor; and I account partly for their difference by
partial transference of colour from the male, and by other means too long
to specify; but I earnestly wish to see reason to believe that each is
specially adapted for concealment to its environment.

I grieve to differ from you, and it actually terrifies me and makes me
constantly distrust myself. I fear we shall never quite understand each
other. I value the cases of bright-coloured, incubating male fisher, and
brilliant female butterflies, solely as showing that one sex may be made
brilliant without any necessary transference of beauty to the other sex;
for in these cases I cannot suppose that beauty in the other sex was
checked by selection.

I fear this letter will trouble you to read it. A very short answer about
your belief in regard to the female finches and Gallinaceae would suffice.

9, St. Mark's Crescent, N.W., September 27th, 1868.

Your view seems to be that variations occurring in one sex are transmitted
either to that sex exclusively or to both sexes equally, or more rarely
partially transferred. But we have every gradation of sexual colours, from
total dissimilarity to perfect identity. If this is explained solely by
the laws of inheritance, then the colours of one or other sex will be
always (in relation to the environment) a matter of chance. I cannot think
this. I think selection more powerful than laws of inheritance, of which
it makes use, as shown by cases of two, three or four forms of female
butterflies, all of which have, I have little doubt, been specialised for

To answer your first question is most difficult, if not impossible, because
we have no sufficient evidence in individual cases of slight sexual
difference, to determine whether the male alone has acquired his superior
brightness by sexual selection, or the female been made duller by need of
protection, or whether the two causes have acted. Many of the sexual
differences of existing species may be inherited differences from parent
forms, which existed under different conditions and had greater or less
need of protection.

I think I admitted before, the general tendency (probably) of males to
acquire brighter tints. Yet this cannot be universal, for many female
birds and quadrupeds have equally bright tints.

To your second question I can reply more decidedly. I do think the females
of the Gallinaceae you mention have been modified or been prevented from
acquiring the brighter plumage of the male, by need of protection. I know
that the Gallus bankiva frequents drier and more open situations than the
pea-hen of Java, which is found among grassy and leafy vegetation,
corresponding with the colours of the two. So the Argus pheasant, male and
female, are, I feel sure, protected by their tints corresponding to the
dead leaves of the lofty forest in which they dwell, and the female of the
gorgeous fire-back pheasant Lophura viellottii is of a very similar rich
brown colour.

I do not, however, at all think the question can be settled by individual
cases, but by only large masses of facts. The colours of the mass of
female birds seem to me strictly analogous to the colours of both sexes of
snipes, woodcocks, plovers, etc., which are undoubtedly protective.

Now, supposing, on your view, that the colours of a male bird become more
and more brilliant by sexual selection, and a good deal of that colour is
transmitted to the female till it becomes positively injurious to her
during incubation, and the race is in danger of extinction; do you not
think that all the females who had acquired less of the male's bright
colours, or who themselves varied in a protective direction, would be
preserved, and that thus a good protective colouring would soon be

If you admit that this could occur, and can show no good reason why it
should not often occur, then we no longer differ, for this is the main
point of my view.

Have you ever thought of the red wax-tips of the Bombycilla beautifully
imitating the red fructification of lichens used in the nest, and therefore
the FEMALES have it too? Yet this is a very sexual-looking character.

If sexes have been differentiated entirely by sexual selection the females
can have no relation to environment. But in groups when both sexes require
protection during feeding or repose, as snipes, woodcock, ptarmigan, desert
birds and animals, green forest birds, etc., arctic birds of prey, and
animals, then both sexes are modified for protection. Why should that
power entirely cease to act when sexual differentiation exists and when the
female requires protection, and why should the colour of so many FEMALE
BIRDS seem to be protective, if it has not been made protective by

It is contrary to the principles of "Origin of Species," that colour should
have been produced in both sexes by sexual selection and never have been
modified to bring the female into harmony with the environment. "Sexual
selection is less rigorous than Natural Selection," and will therefore be
subordinate to it.

I think the case of female Pieris pyrrha proves that females alone can be
greatly modified for protection. (450/1. My latest views on this subject,
with many new facts and arguments, will be found in the later editions of
my "Darwinism," Chapter X. (A.R.W.))


(451/1. On October 4th, 1868, Mr. Wallace wrote again on the same subject
without adding anything of importance to his arguments of September 27th.
We give his final remarks:--)

October 4th, 1868.

I am sorry to find that our difference of opinion on this point is a source
of anxiety to you. Pray do not let it be so. The truth will come out at
last, and our difference may be the means of setting others to work who may
set us both right. After all, this question is only an episode (though an
important one) in the great question of the "Origin of Species," and
whether you or I are right will not at all affect the main doctrine--that
is one comfort.

I hope you will publish your treatise on "Sexual Selection" as a separate
book as soon as possible; and then, while you are going on with your other
work, there will no doubt be found some one to battle with me over your
facts on this hard problem.

Down, October 6th [1868].

Your letter is very valuable to me, and in every way very kind. I will not
inflict a long answer, but only answer your queries. There are breeds
(viz. Hamburg) in which both sexes differ much from each other and from
both sexes of Gallus bankiva; and both sexes are kept constant by
selection. The comb of the Spanish male has been ordered to be upright,
and that of Spanish female to lop over, and this has been effected. There
are sub-breeds of game fowl, with females very distinct and males almost
identical; but this, apparently, is the result of spontaneous variation,
without special selection. I am very glad to hear of case of female Birds
of Paradise.

I have never in the least doubted possibility of modifying female birds
alone for protection, and I have long believed it for butterflies. I have
wanted only evidence for the female alone of birds having had their colour
modified for protection. But then I believe that the variations by which a
female bird or butterfly could get or has got protective colouring have
probably from the first been variations limited in their transmission to
the female sex. And so with the variations of the male: when the male is
more beautiful than the female, I believe the variations were sexually
limited in their transmission to the males.

Down, October 31st, 1868.

(453/1. A short account of the Periodical Cicada (C. septendecim) is given
by Dr. Sharp in the Cambridge Natural History, Insects II., page 570. We
are indebted to Dr. Sharp for calling our attention to Mr. C.L. Marlatt's
full account of the insect in "Bulletin No. 14 [NS.] of the U.S. Department
of Agriculture," 1898. The Cicada lives for long periods underground as
larva and pupa, so that swarms of the adults of one race (septendecim)
appear at intervals of 17 years, while those of the southern form or race
(tredecim) appear at intervals of 13 years. This fact was first made out
by Phares in 1845, but was overlooked or forgotten, and was only re-
discovered by Walsh and Riley in 1868, who published a joint paper in the
"American Entomologist," Volume I., page 63. Walsh appears to have adhered
to the view that the 13- and 17-year forms are distinct species, though, as
we gather from Marlatt's paper (page 14), he published a letter to Mr.
Darwin in which he speaks of the 13-year form as an incipient species; see
"Index to Missouri Entomolog. Reports Bull. 6," U.S.E.C., page 58 (as given
by Marlatt). With regard to the cause of the difference in period of the
two forms, Marlatt (pages 15, 16) refers doubtfully to difference of
temperature as the determining factor. Experiments have been instituted by
moving 17-year eggs to the south, and vice versa with 13-year eggs. The
results were, however, not known at the time of publication of Marlatt's

I am very much obliged for the extracts about the "drumming," which will be
of real use to me.

I do not at all know what to think of your extraordinary case of the
Cicadas. Professor Asa Gray and Dr. Hooker were staying here, and I told
them of the facts. They thought that the 13-year and the 17-year forms
ought not to be ranked as distinct species, unless other differences
besides the period of development could be discovered. They thought the
mere rarity of variability in such a point was not sufficient, and I think
I concur with them. The fact of both the forms presenting the same case of
dimorphism is very curious. I have long wished that some one would dissect
the forms of the male stag-beetle with smaller mandibles, and see if they
were well developed, i.e., whether there was an abundance of spermatozoa;
and the same observations ought, I think, to be made on the rarer form of
your Cicada. Could you not get some observer, such as Dr. Hartman (453/2.
Mr. Walsh sent Mr. Darwin an extract from Dr. Hartman's "Journal of the
doings of a Cicada septendecim," in which the females are described as
flocking round the drumming males. "Descent of Man" (1901), page 433.), to
note whether the females flocked in equal numbers to the "drumming" of the
rarer form as to the common form? You have a very curious and perplexing
subject of investigation, and I wish you success in your work.

Down, June 15th [1869?].

You must not suppose from my delay that I have not been much interested by
your long letter. I write now merely to thank you, and just to say that
probably you are right on all the points you touch on, except, as I think,
about sexual selection, which I will not give up. My belief in it,
however, is contingent on my general belief in sexual selection. It is an
awful stretcher to believe that a peacock's tail was thus formed; but,
believing it, I believe in the same principle somewhat modified applied to

Down, February 13th [N.D.]

I wrote a little time ago asking you an odd question about elephants, and
now I am going to ask you an odder. I hope that you will not think me an
intolerable bore. It is most improbable that you could get me an answer,
but I ask on mere chance. Macacus silenus (455/1. Macacus silenus L., an
Indian ape.) has a great mane of hair round neck, and passing into large
whiskers and beard. Now what I want most especially to know is whether
these monkeys, when they fight in confinement (and I have seen it stated
that they are sometimes kept in confinement), are protected from bites by
this mane and beard. Any one who watched them fighting would, I think, be
able to judge on this head. My object is to find out with various animals
how far the mane is of any use, or a mere ornament. Is the male Macacus
silenus furnished with longer hair than the female about the neck and face?
As I said, it is a hundred or a thousand to one against your finding out
any one who has kept these monkeys in confinement.

Down, August 28th [1870].

I have to thank you very sincerely for two letters: one of April 25th,
containing a very curious account of the structure and morphology of
Bonatea. I feel that it is quite a sin that your letters should not all be
published! but, in truth, I have no spare strength to undertake any extra
work, which, though slight, would follow from seeing your letters in
English through the press--not but that you write almost as clearly as any
Englishman. This same letter also contained some seeds for Mr. Farrer,
which he was very glad to receive.

Your second letter, of July 5th, was chiefly devoted to mimicry in
lepidoptera: many of your remarks seem to me so good, that I have
forwarded your letter to Mr. Bates; but he is out of London having his
summer holiday, and I have not yet heard from him. Your remark about
imitators and imitated being of such different sizes, and the lower surface
of the wings not being altered in colour, strike me as the most curious
points. I should not be at all surprised if your suggestion about sexual
selection were to prove true; but it seems rather too speculative to be
introduced in my book, more especially as my book is already far too
speculative. The very same difficulty about brightly coloured caterpillars
had occurred to me, and you will see in my book what, I believe, is the
true explanation from Wallace. The same view probably applies in part to
gaudy butterflies. My MS. is sent to the printers, and, I suppose, will be
published in about three months: of course I will send you a copy. By the
way, I settled with Murray recently with respect to your book (456/1. The
translation of "Fur Darwin," published in 1869.), and had to pay him only
21 pounds 2 shillings 3 pence, which I consider a very small price for the
dissemination of your views; he has 547 copies as yet unsold. This most
terrible war will stop all science in France and Germany for a long time.
I have heard from nobody in Germany, and know not whether your brother,
Hackel, Gegenbaur, Victor Carus, or my other friends are serving in the
army. Dohrn has joined a cavalry regiment. I have not yet met a soul in
England who does not rejoice in the splendid triumph of Germany over France
(456/2. See Letter 239, Volume I.): it is a most just retribution against
that vainglorious, war-liking nation. As the posts are all in confusion, I
will not send this letter through France. The Editor has sent me duplicate
copies of the "Revue des Cours Scientifiques," which contain several
articles about my views; so I send you copies for the chance of your liking
to see them.

Holly House, Barking, E., January 27th, 1871.

Many thanks for your first volume (457/1. "The Descent of Man".), which I
have just finished reading through with the greatest pleasure and interest;
and I have also to thank you for the great tenderness with which you have
treated me and my heresies.

On the subject of "sexual selection" and "protection," you do not yet
convince me that I am wrong; but I expect your heaviest artillery will be
brought up in your second volume, and I may have to capitulate. You seem,
however, to have somewhat misunderstood my exact meaning, and I do not
think the difference between us is quite so great as you seem to think it.
There are a number of passages in which you argue against the view that the
female has in any large number of cases been "specially modified" for
protection, or that colour has generally been obtained by either sex for
purposes of protection. But my view is, as I thought I had made it clear,
that the female has (in most cases) been simply prevented from acquiring
the gay tints of the male (even when there was a tendency for her to
inherit it), because it was hurtful; and that, when protection is not
needed, gay colours are so generally acquired by both sexes as to show that
inheritance by both sexes of colour variations is the most usual, when not
prevented from acting by Natural Selection. The colour itself may be
acquired either by sexual selection or by other unknown causes.

There are, however, difficulties in the very wide application you give to
sexual selection which at present stagger me, though no one was or is more
ready than myself to admit the perfect truth of the principle or the
immense importance and great variety of its applications.

Your chapters on "Man" are of intense interest--but as touching my special
heresy, not as yet altogether convincing, though, of course, I fully agree
with every word and every argument which goes to prove the "evolution" or
"development" of man out of a lower form. My ONLY difficulties are, as to
whether you have accounted for EVERY STEP of the development by ascertained

I feel sure that the book will keep up and increase your high reputation,
and be immensely successful, as it deserves to be...

Down, March 13th, 1871.

(458/1. We are indebted to Mr. Murdoch for a draft of his letter dated
March 10th, 1871. It is too long to be quoted at length; the following
citations give some idea of its contents: "In your 'Descent of Man,' in
treating of the external differences between males and females of the same
variety, have you attached sufficient importance to the different amount
and kind of energy expended by them in reproduction?" Mr. Murdoch sums up:
"Is it wrong, then, to suppose that extra growth, complicated structure,
and activity in one sex exist as escape-valves for surplus vigour, rather
than to please or fight with, though they may serve these purposes and be
modified by them?")

I am much obliged for your valuable letter. I am strongly inclined to
think that I have made a great and complete oversight with respect to the
subject which you discuss. I am the more surprised at this, as I remember
reflecting on some points which ought to have led me to your conclusion.
By an odd chance I received the day before yesterday a letter from Mr.
Lowne (author of an excellent book on the anatomy of the Blow-fly) (458/2.
"The Anatomy and Physiology of the Blow-fly (Musca vomitaria L.)," by B.T.
Lowne. London, 1870.) with a discussion very nearly to the same effect as
yours. His conclusions were drawn from studying male insects with great
horns, mandibles, etc. He informs me that his paper on this subject will
soon be published in the "Transact. Entomolog. Society." (458/3.
"Observations on Immature Sexuality and Alternate Generation in Insects."
By B.T. Lowne. "Trans. Entomolog. Soc." 1871 [Read March 6th, 1871]. "I
believe that certain cutaneous appendages, as the gigantic mandibles and
thoracic horns of many males, are complemental to the sexual organs; that,
in point of fact, they are produced by the excess of nutriment in the male,
which in the female would go to form the generative organs and ova" (loc.
cit., page 197).) I am inclined to look at your and Mr. Lowne's view as
specially valuable from probably throwing light on the greater variability
of male than female animals, which manifestly has much bearing on sexual
selection. I will keep your remarks in mind whenever a new edition of my
book is demanded.


(459/1. The following letter refers to two letters to Mr. Darwin, in which
Mr. Fraser pointed out that illustrations of the theory of Sexual Selection
might be found amongst British butterflies and moths. Mr. Fraser, in
explanation of the letters, writes: "As an altogether unknown and far from
experienced naturalist, I feared to send my letters for publication
without, in the first place, obtaining Mr. Darwin's approval." The
information was published in "Nature," Volume III., April 20th, 1871, page
489. The article was referred to in the second edition of the "Descent of
Man" (1874), pages 312, 316, 319. Mr. Fraser adds: "This is only another
illustration of Mr. Darwin's great conscientiousness in acknowledging
suggestions received by him from the most humble sources." (Letter from
Mr. Fraser to F. Darwin, March 21, 1888.)

Down, April 14th [1871].

I am very much obliged for your letter and the interesting facts which it
contains, and which are new to me. But I am at present so much engaged
with other subjects that I cannot fully consider them; and, even if I had
time, I do not suppose that I should have anything to say worth printing in
a scientific journal. It would obviously be absurd in me to allow a mere
note of thanks from me to be printed. Whenever I have to bring out a
corrected edition of my book I will well consider your remarks (which I
hope that you will send to "Nature"), but the difficulty will be that my
friends tell me that I have already introduced too many facts, and that I
ought to prune rather than to introduce more.

Down, December 3rd, 1871.

I am much obliged to you for having sent me your two interesting papers,
and for the kind writing on the cover. I am very glad to have my error
corrected about the protective colouring of shells. (460/1. "On Adaptive
Coloration of the Mollusca," "Boston Society of Natural History Proc."
Volume XIV., April 5th, 1871. Mr. Morse quotes from the "Descent of Man,"
I., page 316, a passage to the effect that the colours of the mollusca do
not in general appear to be protective. Mr. Morse goes on to give
instances of protective coloration.) It is no excuse for my broad
statement, but I had in my mind the species which are brightly or
beautifully coloured, and I can as yet hardly think that the colouring in
such cases is protective.

Down, February 29th, 1872.

I am rejoiced to hear that your eyesight is somewhat better; but I fear
that work with the microscope is still out of your power. I have often
thought with sincere sympathy how much you must have suffered from your
grand line of embryological research having been stopped. It was very good
of you to use your eyes in writing to me. I have just received your essay
(461/1. "Ueber der Einfluss der Isolirung auf die Artbildung": Leipzig,
1872.); but as I am now staying in London for the sake of rest, and as
German is at all times very difficult to me, I shall not be able to read
your essay for some little time. I am, however, very curious to learn what
you have to say on isolation and on periods of variation. I thought much
about isolation when I wrote in Chapter IV. on the circumstances favourable
to Natural Selection. No doubt there remains an immense deal of work to do
on "Artbildung." I have only opened a path for others to enter, and in the
course of time to make a broad and clear high-road. I am especially glad
that you are turning your attention to sexual selection. I have in this
country hardly found any naturalists who agree with me on this subject,
even to a moderate extent. They think it absurd that a female bird should
be able to appreciate the splendid plumage of the male; but it would take
much to persuade me that the peacock does not spread his gorgeous tail in
the presence of the female in order to fascinate or excite her. The case,
no doubt, is much more difficult with insects. I fear that you will find
it difficult to experiment on diurnal lepidoptera in confinement, for I
have never heard of any of these breeding in this state. (461/2. We are
indebted to Mr. Bateson for the following note: "This belief does not seem
to be well founded, for since Darwin's time several species of Rhopalocera
(e.g. Pieris, Pararge, Caenonympha) have been successfully bred in
confinement without any special difficulty; and by the use of large cages
members even of strong-flying genera, such as Vanessa, have been induced to
breed.") I was extremely pleased at hearing from Fritz Muller that he
liked my chapter on lepidoptera in the "Descent of Man" more than any other
part, excepting the chapter on morals.

Down [May, 1872].

I have now read with the greatest interest your essay, which contains a
vast amount of matter quite new to me. (462/1. "Anwendung der
Darwin'schen Lehre auf Bienen," "Verhandl. d. naturhist. Vereins fur
preuss. Rheinld. u. Westf." 1872. References to Muller's paper occur in
the second edition of the "Descent of Man.") I really have no criticisms
or suggestions to offer. The perfection of the gradation in the character
of bees, especially in such important parts as the mouth-organs, was
altogether unknown to me. You bring out all such facts very clearly by
your comparison with the corresponding organs in the allied hymenoptera.
How very curious is the case of bees and wasps having acquired,
independently of inheritance from a common source, the habit of building
hexagonal cells and of producing sterile workers! But I have been most
interested by your discussion on secondary sexual differences; I do not
suppose so full an account of such differences in any other group of
animals has ever been published. It delights me to find that we have
independently arrived at almost exactly the same conclusion with respect to
the more important points deserving investigation in relation to sexual
selection. For instance, the relative number of the two sexes, the earlier
emergence of the males, the laws of inheritance, etc. What an admirable
illustration you give of the transference of characters acquired by one
sex--namely, that of the male of Bombus possessing the pollen-collecting
apparatus. Many of your facts about the differences between male and
female bees are surprisingly parallel with those which occur with birds.
The reading your essay has given me great confidence in the efficacy of
sexual selection, and I wanted some encouragement, as extremely few
naturalists in England seem inclined to believe in it. I am, however, glad
to find that Prof. Weismann has some faith in this principle.

The males of Bombus follow one remarkable habit, which I think it would
interest you to investigate this coming summer, and no one could do it
better than you. (462/2. Mr. Darwin's observations on this curious
subject were sent to Hermann Muller, and after his death were translated
and published in Krause's "Gesammelte kleinere Schriften von Charles
Darwin," 1887, page 84. The male bees had certain regular lines of flight
at Down, as from the end of the kitchen garden to the corner of the "sand-
walk," and certain regular "buzzing places" where they stopped on the wing
for a moment or two. Mr. Darwin's children remember vividly the pleasure
of helping in the investigation of this habit.) I have therefore enclosed
a briefly and roughly drawn-up account of this habit. Should you succeed
in making any observations on this subject, and if you would like to use in
any way my MS. you are perfectly welcome. I could, should you hereafter
wish to make any use of the facts, give them in rather fuller detail; but I
think that I have given enough.

I hope that you may long have health, leisure, and inclination to do much
more work as excellent as your recent essay.

2.VIII.III. EXPRESSION, 1868-1874.

Down, January 30th [1868].

I am very much obliged for your answers, though few in number (October
5th), about expression. I was especially glad to hear about shrugging the
shoulders. You say that an old negro woman, when expressing astonishment,
wonderfully resembled a Cebus when astonished; but are you sure that the
Cebus opened its mouth? I ask because the Chimpanzee does not open its
mouth when astonished, or when listening. (463/1. Darwin in the
"Expression of the Emotions," adheres to this statement as being true of
monkeys in general.) Please have the kindness to remember that I am very
anxious to know whether any monkey, when screaming violently, partially or
wholly closes its eyes.


(464/1. The late Sir W. Bowman, the well-known surgeon, supplied a good
deal of information of value to Darwin in regard to the expression of the
emotions. The gorging of the eyes with blood during screaming is an
important factor in the physiology of weeping, and indirectly in the
obliquity of the eyebrows--a characteristic expression of suffering. See
"Expression of the Emotions," pages 160 and 192.)

Down, March 30th [1868].

I called at your house about three weeks since, and heard that you were
away for the whole month, which I much regretted, as I wished to have had
the pleasure of seeing you, of asking you a question, and of thanking you
for your kindness to my son George. You did not quite understand the last
note which I wrote to you--viz., about Bell's precise statement that the
conjunctiva of an infant or young child becomes gorged with blood when the
eyes are forcibly opened during a screaming fit. (464/2. Sir C. Bell's
statement in his "Anatomy of Expression" (1844, page 106) is quoted in the
"Expression of the Emotions," page 158.) I have carefully kept your
previous note, in which you spoke doubtfully about Bell's statement. I
intended in my former note only to express a wish that if, during your
professional work, you were led to open the eyelids of a screaming child,
you would specially observe this point about the eye showing signs of
becoming gorged with blood, which interests me extremely. Could you ask
any one to observe this for me in an eye-dispensary or hospital? But I now
have to beg you kindly to consider one other question at any time when you
have half an hour's leisure.

When a man coughs violently from choking or retches violently, even when he
yawns, and when he laughs violently, tears come into the eyes. Now, in all
these cases I observe that the orbicularis muscle is more or less
spasmodically contracted, as also in the crying of a child. So, again,
when the muscles of the abdomen contract violently in a propelling manner,
and the breath is, I think, always held, as during the evacuation of a very
costive man, and as (I hear) with a woman during severe labour-pains, the
orbicularis contracts, and tears come into the eyes. Sir J.E. Tennant
states that tears roll down the cheeks of elephants when screaming and
trumpeting at first being captured; accordingly I went to the Zoological
Gardens, and the keeper made two elephants trumpet, and when they did this
violently the orbicularis was invariably plainly contracted. Hence I am
led to conclude that there must be some relation between the contraction of
this muscle and the secretion of tears. Can you tell me what this relation
is? Does the orbicularis press against, and so directly stimulate, the
lachrymal gland? As a slight blow on the eye causes, by reflex action, a
copious effusion of tears, can the slight spasmodic contraction of the
orbicularis act like a blow? This seems hardly possible. Does the same
nerve which runs to the orbicularis send off fibrils to the lachrymal
glands; and if so, when the order goes for the muscle to contract, is
nervous force sent sympathetically at the same time to the glands? (464/3.
See "Expression of the Emotions," page 169.)

I should be extremely much obliged if you [would] have the kindness to give
me your opinion on this point.


(465/1. Mr. Darwin was indebted to Sir W. Bowman for an introduction to
Professor Donders, whose work on Sir Charles Bell's views is quoted in the
"Expression of the Emotions," pages 160-62.)

Down, June 3rd [1870?].

I do not know how to thank you enough for the very great trouble which you
have taken in writing at such length, and for your kind expressions towards
me. I am particularly obliged for the abstract with respect to Sir C.
Bell's views (465/2. See "Expression of the Emotions," pages 158 et seq.:
Sir Charles Bell's view is that adopted by Darwin--viz. that the
contraction of the muscles round the eyes counteracts the gorging of the
parts during screaming, etc. The essay of Donders is, no doubt, "On the
Action of the Eyelids in Determination of Blood from Expiratory Effort" in
Beale's "Archives of Medicine," Volume V., 1870, page 20, which is a
translation of the original in Dutch.), as I shall now proceed with some
confidence; but I am intensely curious to read your essay in full when
translated and published, as I hope, in the "Dublin Journal," as you speak
of the weak point in the case--viz., that injuries are not known to follow
from the gorging of the eye with blood. I may mention that my son and his
friend at a military academy tell me that when they perform certain feats
with their heads downwards their faces become purple and veins distended,
and that they then feel an uncomfortable sensation in their eyes; but that
as it is necessary for them to see, they cannot protect their eyes by
closing the eyelids. The companions of one young man, who naturally has
very prominent eyes, used to laugh at him when performing such feats, and
declare that some day both eyes would start out of his head.

Your essay on the physiological and anatomical relations between the
contraction of the orbicular muscles and the secretion of tears is
wonderfully clear, and has interested me greatly. I had not thought about
irritating substances getting into the nose during vomiting; but my clear
impression is that mere retching causes tears. I will, however, try to get
this point ascertained. When I reflect that in vomiting (subject to the
above doubt), in violent coughing from choking, in yawning, violent
laughter, in the violent downward action of the abdominal muscle...and in
your very curious case of the spasms (465/3. In some cases a slight touch
to the eye causes spasms of the orbicularis muscle, which may continue for
so long as an hour, being accompanied by a flow of tears. See "Expression
of the Emotions," page 166.)--that in all these cases the orbicular muscles
are strongly and unconsciously contracted, and that at the same time tears
often certainly flow, I must think that there is a connection of some kind
between these phenomena; but you have clearly shown me that the nature of
the relation is at present quite obscure.

6, Queen Anne Street, W., December 19th [1870?].

I was with Mr. Wood this morning, and he expressed himself strongly about
your and your daughter's kindness in aiding him. He much wants assistance
on another point, and if you would aid him, you would greatly oblige me.
You know well the appearance of a dog when approaching another dog with
hostile intentions, before they come close together. The dog walks very
stiffly, with tail rigid and upright, hair on back erected, ears pointed
and eyes directed forwards. When the dog attacks the other, down go the
ears, and the canines are uncovered. Now, could you anyhow arrange so that
one of your dogs could see a strange dog from a little distance, so that
Mr. Wood could sketch the former attitude, viz., of the stiff gesture with
erected hair and erected ears. (466/1. In Chapter II. of the "Expression
of the Emotions" there are sketches of dogs in illustration of the
"Principle of Antithesis," drawn by Mr. Riviere and by Mr. A. May (figures
5-8). Mr. T.W. Wood supplied similar drawings of a cat (figures 9, 10),
also a sketch of the head of a snarling dog (figure 14).) And then he
could afterwards sketch the same dog, when fondled by his master and
wagging his tail with drooping ears. These two sketches I want much, and
it would be a great favour to Mr. Wood, and myself, if you could aid him.

P.S.--When a horse is turned out into a field he trots with high, elastic
steps, and carries his tail aloft. Even when a cow frisks about she throws
up her tail. I have seen a drawing of an elephant, apparently trotting
with high steps, and with the tail erect. When the elephants in the garden
are turned out and are excited so as to move quickly, do they carry their
tails aloft? How is this with the rhinoceros? Do not trouble yourself to
answer this, but I shall be in London in a couple of months, and then
perhaps you will be able to answer this trifling question. Or, if you
write about wolves and jackals turning round, you can tell me about the
tails of elephants, or of any other animals. (466/2. In the "Expression
of the Emotions," page 44, reference is made under the head of "Associated
habitual movements in the lower animals," to dogs and other animals turning
round and round and scratching the ground with their fore-paws when they
wish to go to sleep on a carpet, or other similar surface.)

Down, January 5th, [1871?]

Many thanks about Limulus. I am going to ask another favour, but I do not
want to trouble you to answer it by letter. When the Callithrix sciureus
screams violently, does it wrinkle up the skin round the eyes like a baby
always does? (467/1. "Humboldt also asserts that the eyes of the
Callithrix sciureus 'instantly fill with tears when it is seized with
fear'; but when this pretty little monkey in the Zoological Gardens was
teased, so as to cry out loudly, this did not occur. I do not, however,
wish to throw the least doubt on the accuracy of Humboldt's statement."
("The Expression of the Emotions in Man and Animals," 1872, page 137.)
When thus screaming do the eyes become suffused with moisture? Will you
ask Sutton to observe carefully? (467/2. One of the keepers who made many
observations on monkeys for Mr. Darwin.) Could you make it scream without
hurting it much? I should be truly obliged some time for this information,
when in spring I come to the Gardens.

Down, March 7th [1871].

I wrote to Tyndall, but had no clear answer, and have now written to him
again about odours. (468/1. Dr. Ogle's work on the Sense of Smell
("Medico-Chirurgical Trans." LIII., page 268) is referred to in the
"Expression of the Emotions," page 256.) I write now to ask you to be so
kind (if there is no objection) to tell me the circumstances under which
you saw a man arrested for murder. (468/2. Given in the "Expression of
the Emotions," page 294.) I say in my notes made from your conversation:
utmost horror--extreme pallor--mouth relaxed and open--general prostration
--perspiration--muscle of face contracted--hair observed on account of
having been dyed, and apparently not erected. Secondly, may I quote you
that you have often (?) seen persons (young or old? men or women?) who,
evincing no great fear, were about to undergo severe operation under
chloroform, showing resignation by (alternately?) folding one open hand
over the other on the lower part of chest (whilst recumbent?)--I know this
expression, and think I ought to notice it. Could you look out for an
additional instance?

I fear you will think me very troublesome, especially when I remind you
(not that I am in a hurry) about the Eustachian tube.

Down, June 14th [1870].

As usual, I am going to beg for information. Can you tell me whether any
Fringillidae or Sylviadae erect their feathers when frightened or enraged?
(469/1. See "Expression of the Emotions," page 99.) I want to show that
this expression is common to all or most of the families of birds. I know
of this only in the fowl, swan, tropic-bird, owl, ruff and reeve, and
cuckoo. I fancy that I remember having seen nestling birds erect their
feathers greatly when looking into nests, as is said to be the case with
young cuckoos. I should much like to know whether nestlings do really thus
erect their feathers. I am now at work on expression in animals of all
kinds, and birds; and if you have any hints I should be very glad for them,
and you have a rich wealth of facts of all kinds. Any cases like the
following: the sheldrake pats or dances on the tidal sands to make the
sea-worms come out; and when Mr. St. John's tame sheldrakes came to ask for
their dinners they used to pat the ground, and this I should call an
expression of hunger and impatience. How about the Quagga case? (469/2.
See Letter 235, Volume I.)

I am working away as hard as I can on my book; but good heavens, how slow
my progress is.

Down, March 18th, 1871.

Very many thanks for your kind letter. I have been interested by what you
tell me about your views published in 1848, and I wish I could read your
essay. It is clear to me that you were as near as possible in preceding me
on the subject of Natural Selection.

You will find very little that is new to you in my last book; whatever
merit it may possess consists in the grouping of the facts and in
deductions from them. I am now at work on my essay on Expression. My last
book fatigued me much, and I have had much correspondence, otherwise I
should have written to you long ago, as I often intended to tell you in how
high a degree your essay published in Beale's Archives interested me.
(470/1. Beale's "Archives of Medicine," Volume V., 1870.) I have heard
others express their admiration at the complete manner in which you have
treated the subject. Your confirmation of Sir C. Bell's rather loose
statement has been of paramount importance for my work. (470/2. On the
contraction of the muscles surrounding the eye. See "Expression of the
Emotions," page 158. See Letters 464, 465.) You told me that I might make
further enquiries from you.

When a person is lost in meditation his eyes often appear as if fixed on a
distant object (470/3. The appearance is due to divergence of the lines of
vision produced by muscular relaxation. See "Expression of the Emotions,"
Edition II., page 239.), and the lower eyelids may be seen to contract and
become wrinkled. I suppose the idea is quite fanciful, but as you say that
the eyeball advances in adaptation for vision for close objects, would the
eyeball have to be pushed backwards in adaptation for distant objects?
(470/4. Darwin seems to have misunderstood a remark of Donders.) If so,
can the wrinkling of the lower eyelids, which has often perplexed me, act
in pushing back the eyeball?

But, as I have said, I daresay this is quite fanciful. Gratiolet says that
the pupil contracts in rage, and dilates enormously in terror. (470/5.
See "Expression of the Emotions," Edition II., page 321.) I have not found
this great anatomist quite trustworthy on such points, and am making
enquiries on this subject. But I am inclined to believe him, as the old
Scotch anatomist Munro says, that the iris of parrots contracts and dilates
under passions, independently of the amount of light. Can you give any
explanation of this statement? When the heart beats hard and quick, and
the head becomes somewhat congested with blood in any illness, does the
pupil contract? Does the pupil dilate in incipient faintness, or in utter
prostration, as when after a severe race a man is pallid, bathed in
perspiration, with all his muscles quivering? Or in extreme prostration
from any illness?

Down, March 28th [1871].

I am much obliged for your kind note, and especially for your offer of
sending me some time corrections, for which I shall be truly grateful. I
know that there are many blunders to which I am very liable. There is a
terrible one confusing the supra-condyloid foramen with another one.
(471/1. In the first edition of the "Descent of Man," I., page 28, in
quoting Mr. Busk "On the Caves of Gibraltar," Mr. Darwin confuses together
the inter-condyloid foramen in the humerus with the supra-condyloid
foramen. His attention was called to the mistake by Sir William Turner, to
whom he had been previously indebted for other information on the anatomy
of man. The error is one, as Sir William Turner points out in a letter,
"which might easily arise where the writer is not minutely acquainted with
human anatomy." In speaking of his correspondence with Darwin, Sir William
remarks on a characteristic of Darwin's method of asking for information,
namely, his care in avoiding leading questions.) This, however, I have
corrected in all the copies struck off after the first lot of 2500. I
daresay there will be a new edition in the course of nine months or a year,
and this I will correct as well as I can. As yet the publishers have kept
up type, and grumble dreadfully if I make heavy corrections. I am very far
from surprised that "you have not committed yourself to full acceptation"
of the evolution of man. Difficulties and objections there undoubtedly
are, enough and to spare, to stagger any cautious man who has much
knowledge like yourself.

I am now at work at my hobby-horse essay on Expression, and I have been
reading some old notes of yours. In one you say it is easy to see that the
spines of the hedgehog are moved by the voluntary panniculus. Now, can you
tell me whether each spine has likewise an oblique unstriped or striped
muscle, as figured by Lister? (472/2. "Expression of the Emotions," page
101.) Do you know whether the tail-coverts of peacock or tail of turkey
are erected by unstriped or striped muscles, and whether these are
homologous with the panniculus or with the single oblique unstriped muscles
going to each separate hair in man and many animals? I wrote some time ago
to Kolliker to ask this question (and in relation to quills of porcupine),
and I received a long and interesting letter, but he could not answer these
questions. If I do not receive any answer (for I know how busy you must
be), I will understand you cannot aid me.

I heard yesterday that Paget was very ill; I hope this is not true. What a
loss he would be; he is so charming a man.

P.S.--As I am writing I will trouble you with one other question. Have you
seen anything or read of any facts which could induce you to think that the
mind being intently and long directed to any portion of the skin (or,
indeed, any organ) would influence the action of the capillaries, causing
them either to contract or dilate? Any information on this head would be
of great value to me, as bearing on blushing.

If I remember right, Paget seems to be a great believer in the influence of
the mind in the nutrition of parts, and even in causing disease. It is
awfully audacious on my part, but I remember thinking (with respect to the
latter assertion on disease) when I read the passage that it seemed rather
fanciful, though I should like to believe in it. Sir H. Holland alludes to
this subject of the influence of the mind on local circulation frequently,
but gives no clear evidence. (472/3. Ibid., pages 339 et seq.)

Down, March 29th [1871].

Forgive me for troubling you with one line. Since writing my P.S. I have
read the part on the influence of the nervous system on the nutrition of
parts in your last edition of Paget's "Lectures." (472/1. "Lectures on
Surgical Pathology," Edition III., revised by Professor Turner, 1870.) I
had not read before this part in this edition, and I see how foolish I was.
But still, I should be extremely grateful for any hint or evidence of the
influence of mental attention on the capillary or local circulation of the
skin, or of any part to which the mind may be intently and long directed.
For instance, if thinking intently about a local eruption on the skin (not
on the face, for shame might possibly intervene) caused it temporarily to
redden, or thinking of a tumour caused it to throb, independently of
increased heart action.


(473/1. Dr. Airy had written to Mr. Darwin on April 3rd:--

"With regard to the loss of voluntary movement of the ears in man and
monkey, may I ask if you do not think it might have been caused, as it is
certainly compensated, by the facility and quickness in turning the head,
possessed by them in virtue of their more erect stature, and the freedom of
the atlanto-axial articulation? (in birds the same end is gained by the
length and flexibility of the neck.) The importance, in case of danger, of
bringing the eyes to help the ears would call for a quick turn of the head
whenever a new sound was heard, and so would tend to make superfluous any
special means of moving the ears, except in the case of quadrupeds and the
like, that have great trouble (comparatively speaking) in making a
horizontal turn of the head--can only do it by a slow bend of the whole
neck." (473/2. We are indebted to Dr. Airy for furnishing us with a copy
of his letter to Mr. Darwin, the original of which had been mislaid.)

Down, April 5th [1871].

I am greatly obliged for your letter. Your idea about the easy turning of
the head instead of the ears themselves strikes me as very good, and quite
new to me, and I will keep it in mind; but I fear that there are some cases
opposed to the notion.

If I remember right the hedgehog has very human ears, but birds support
your view, though lizards are opposed to it.

Several persons have pointed out my error about the platysma. (473/3. The
error in question occurs on page 19 of the "Descent of Man," Edition I.,
where it is stated that the Platysma myoides cannot be voluntarily brought
into action. In the "Expression of the Emotions" Darwin remarks that this
muscle is sometimes said not to be under voluntary control, and he shows
that this is not universally true.) Nor can I remember how I was misled.
I find I can act on this muscle myself, now that I know the corners of the
mouth have to be drawn back. I know of the case of a man who can act on
this muscle on one side, but not on the other; yet he asserts positively
that both contract when he is startled. And this leads me to ask you to be
so kind as to observe, if any opportunity should occur, whether the
platysma contracts during extreme terror, as before an operation; and
secondly, whether it contracts during a shivering fit. Several persons are
observing for me, but I receive most discordant results.

I beg you to present my most respectful and kind compliments to your
honoured father [Sir G.B. Airy].


(474/1. Mr. Galton had written on November 7th, 1872, offering to send to
various parts of Africa Darwin's printed list of questions intended to
guide observers on expression. Mr. Galton goes on: "You do not, I think,
mention in "Expression" what I thought was universal among blubbering
children (when not trying to see if harm or help was coming out of the
corner of one eye) of pressing the knuckles against the eyeballs, thereby
reinforcing the orbicularis.")

Down, November 8th [1872].

Many thanks for your note and offer to send out the queries; but my career
is so nearly closed that I do not think it worth while. What little more I
can do shall be chiefly new work. I ought to have thought of crying
children rubbing their eyes with their knuckles, but I did not think of it,
and cannot explain it. As far as my memory serves, they do not do so
whilst roaring, in which case compression would be of use. I think it is
at the close of the crying fit, as if they wished to stop their eyes
crying, or possibly to relieve the irritation from the salt tears. I wish
I knew more about the knuckles and crying.

What a tremendous stir-up your excellent article on prayer has made in
England and America! (474/2. The article entitled "Statistical Inquiries
into the Efficacy of Prayer" appeared in the "Fortnightly Review," 1872.
In Mr. Francis Galton's book on "Enquiries into Human Faculty and its
Development," London, 1883, a section (pages 277-94) is devoted to a
discussion on the "Objective Efficacy of Prayer.")


(475/1. We have no means of knowing whether the observations suggested in
the following letter were made--if not, the suggestion is worthy of

Down, December 21st, 1872.

You will have received some little time ago my book on Expression, in
writing which I was so deeply indebted to your kindness. I want now to beg
a favour of you, if you have the means to grant it. A clergyman, the head
of an institution for the blind in England (475/2. The Rev. R.H. Blair,
Principal of the Worcester College: "Expression of the Emotions," Edition
II., page 237.), has been observing the expression of those born blind, and
he informs me that they never or very rarely frown. He kept a record of
several cases, but at last observed a frown on two of the children who he
thought never frowned; and then in a foolish manner tore up his notes, and
did not write to me until my book was published. He may be a bad observer
and altogether mistaken, but I think it would be worth while to ascertain
whether those born blind, when young, and whilst screaming violently,
contract the muscles round the eyes like ordinary infants. And secondly,
whether in after years they rarely or never frown. If it should prove true
that infants born blind do not contract their orbicular muscles whilst
screaming (though I can hardly believe it) it would be interesting to know
whether they shed tears as copiously as other children. The nature of the
affection which causes blindness may possibly influence the contraction of
the muscles, but on all such points you will judge infinitely better than I
can. Perhaps you could get some trustworthy superintendent of an asylum
for the blind to attend to this subject. I am sure that you will forgive
me asking this favour.

Down, December 22nd, 1872.

I have now finished your book, and have read it with great interest.
(476/1. "Influence of the Mind upon the Body. Designed to elucidate the
Power of the Imagination." 1872.)

Many of your cases are very striking. As I felt sure would be the case, I
have learnt much from it; and I should have modified several passages in my
book on Expression, if I had had the advantage of reading your work before
my publication. I always felt, and said so a year ago to Professor
Donders, that I had not sufficient knowledge of Physiology to treat my
subject in a proper way.

With many thanks for the interest which I have felt in reading your work...

Down, January 10th [1873].

I have read your Review with much interest, and I thank you sincerely for
the very kind spirit in which it is written. I cannot say that I am
convinced by your criticisms. (477/1. "Quarterly Journal of Science,"
January, 1873, page 116: "I can hardly believe that when a cat, lying on a
shawl or other soft material, pats or pounds it with its feet, or sometimes
sucks a piece of it, it is the persistence of the habit of pressing the
mammary glands and sucking during kittenhood." Mr. Wallace goes on to say
that infantine habits are generally completely lost in adult life, and that
it seems unlikely that they should persist in a few isolated instances.)
If you have ever actually observed a kitten sucking and pounding, with
extended toes, its mother, and then seen the same kitten when a little
older doing the same thing on a soft shawl, and ultimately an old cat (as I
have seen), and do not admit that it is identically the same action, I am
astonished. With respect to the decapitated frog, I have always heard of
Pfluger as a most trustworthy observer. (477/2. Mr. Wallace speaks of "a
readiness to accept the most marvellous conclusions or interpretations of
physiologists on what seem very insufficient grounds," and he goes on to
assert that the frog experiment is either incorrectly recorded or else that
it "demonstrates volition, and not reflex action.") If, indeed, any one
knows a frog's habits so well as to say that it never rubs off a bit of
leaf or other object which may stick to its thigh, in the same manner as it
did the acid, your objection would be valid. Some of Flourens'
experiments, in which he removed the cerebral hemispheres from a pigeon,
indicate that acts apparently performed consciously can be done without
consciousness. I presume through the force of habit, in which case it
would appear that intellectual power is not brought into play. Several
persons have made suggestions and objections as yours about the hands being
held up in astonishment; if there was any straining of the muscles, as with
protruded arms under fright, I would agree; as it is I must keep to my old
opinion, and I dare say you will say that I am an obstinate old blockhead.
(477/3. The raising of the hands in surprise is explained ("Expression of
Emotions," Edition I., page 287) on the doctrine of antithesis as being the
opposite of listlessness. Mr. Wallace's view (given in the 2nd edition of
"Expression of the Emotions," page 300) is that the gesture is appropriate
to sudden defence or to the giving of aid to another person.)

The book has sold wonderfully; 9,000 copies have now been printed.

Down, September 21st, 1874.

I have read your long letter with the greatest interest, and it was
extremely kind of you to take such great trouble. Now that you call my
attention to the fact, I well know the appearance of persons moving the
head from side to side when critically viewing any object; and I am almost
sure that I have seen the same gesture in an affected person when speaking
in exaggerated terms of some beautiful object not present. I should think
your explanation of this gesture was the true one. But there seems to me a
rather wide difference between inclining or moving the head laterally, and
moving it in the same plane, as we do in negation, and, as you truly add,
in disapprobation. It may, however, be that these two movements of the
head have been confounded by travellers when speaking of the Turks.
Perhaps Prof. Lowell would remember whether the movement was identically
the same. Your remarks on the effects of viewing a sunset, etc., with the
head inverted are very curious. (478/1. The letter dated September 3rd,
1874, is published in Mr. Thayer's "Letters" of Chauncey Wright, privately
printed, Cambridge, Mass., 1878. Wright quotes Mr. Sophocles, a native of
Greece, at the time Professor of Modern and Ancient Greek at Harvard
University, to the effect that the Turks do not express affirmation by a
shake of the head, but by a bow or grave nod, negation being expressed by a
backward nod. From the striking effect produced by looking at a landscape
with the head inverted, or by looking at its reflection, Chauncey Wright
was led to the lateral movement of the head, which is characteristic of
critical inspection--eg. of a picture. He thinks that in this way a
gesture of deliberative assent arose which may have been confused with our
ordinary sign of negation. He thus attempts to account for the
contradictions between Lieber's statement that a Turk or Greek expresses
"yes" by a shake of the head, and the opposite opinion of Prof. Sophocles,
and lastly, Mr. Lowell's assertion that in Italy our negative shake of the
head is used in affirmation (see "Expression of the Emotions," Edition II.,
page 289).) We have a looking-glass in the drawing-room opposite the
flower-garden, and I have often been struck how extremely pretty and
strange the flower garden and surrounding bushes appear when thus viewed.
Your letter will be very useful to me for a new edition of my Expression
book; but this will not be for a long time, if ever, as the publisher was
misled by the very large sale at first, and printed far too many copies.

I daresay you intend to publish your views in some essay, and I think you
ought to do so, for you might make an interesting and instructive

I have been half killing myself of late with microscopical work on plants.
I begin to think that they are more wonderful than animals.

P.S., January 29th, 1875.--You will see that by a stupid mistake in the
address this letter has just been returned to me. It is by no means worth
forwarding, but I cannot bear that you should think me so ungracious and
ungrateful as not to have thanked you for your long letter.

As I forget whether "Cambridge" is sufficient address, I will send this
through Asa Gray.

(PLATE: CHARLES LYELL. Engraved by G.I. (J). Stodart from a photograph.)

CHAPTER 2.IX. GEOLOGY, 1840-1882.

I. Vulcanicity and Earth-movements.--II. Ice-action.--III. The Parallel
Roads of Glen Roy.--IV. Coral Reefs, Fossil and Recent.--V. Cleavage and
Foliation.--VI. Age of the World.--VII. Geological Action of Earthworms.
--VIII. Miscellaneous.


12, Upper Gower Street, Thursday [March] 20th [1840].

I much regret that I am unable to give you any information of the kind you
desire. You must have misunderstood Mr. Lyell concerning the object of my
paper. (479/1. "On the Connexion of certain Volcanic Phenomena, and on
the Formation of Mountain-chains and the Effects of Continental
Elevations." "Trans. Geol. Soc." Volume V., 1840, pages 601-32 [March 7th,
1838].) It is an account of the shock of February, 1835, in Chile, which
is particularly interesting, as it ties most closely together volcanic
eruptions and continental elevations. In that paper I notice a very
remarkable coincidence in volcanic eruptions in S. America at very distant
places. I have also drawn up some short tables showing, as it appears to
me, that there are periods of unusually great volcanic activity affecting
large portions of S. America. I have no record of any coincidences between
shocks there and in Europe. Humboldt, by his table in the "Pers.
Narrative" (Volume IV., page 36, English Translation), seems to consider
the elevation of Sabrina off the Azores as connected with S. American
subterranean activity: this connection appears to be exceedingly vague. I
have during the past year seen it stated that a severe shock in the
northern parts of S. America coincided with one in Kamstchatka. Believing,
then, that such coincidences are purely accidental, I neglected to take a
note of the reference; but I believe the statement was somewhere in
"L'Institut" for 1839. (479/2. "L'Institut, Journal General des Societes
et Travaux Scientifiques de la France et de l'Etranger," Tome VIII. page
412, Paris, 1840. In a note on some earthquakes in the province Maurienne
it is stated that they occurred during a change in the weather, and at
times when a south wind followed a north wind, etc.) I was myself anxious
to see the list of the 1200 shocks alluded to by you, but I have not been
able to find out that the list has been published. With respect to any
coincidences you may discover between shocks in S. America and Europe, let
me venture to suggest to you that it is probably a quite accurate statement
that scarcely one hour in the year elapses in S. America without an
accompanying shock in some part of that large continent. There are many
regions in which earthquakes take place every three and four days; and
after the severer shocks the ground trembles almost half-hourly for months.
If, therefore, you had a list of the earthquakes of two or three of these
districts, it is almost certain that some of them would coincide with those
in Scotland, without any other connection than mere chance.

My paper will be published immediately in the "Geological Transactions,"
and I will do myself the pleasure of sending you a copy in the course of
(as I hope) a week or ten days. A large part of it is theoretical, and
will be of little interest to you; but the account of the Concepcion shock
of 1835 will, I think, be worth your perusal. I have understood from Mr.
Lyell that you believe in some connection between the state of the weather
and earthquakes. Under the very peculiar climate of Northern Chile, the
belief of the inhabitants in such connection can hardly, in my opinion, be
founded in error. It must possibly be worth your while to turn to pages
430-433 in my "Journal of Researches during the Voyage of the 'Beagle',"
where I have stated this circumstance. (479/3. "Journal of Researches
into the Natural History and Geology of the Countries visited during the
Voyage of H.M.S. 'Beagle' round the World." London, 1870, page 351.) On
the hypothesis of the crust of the earth resting on fluid matter, would the
influence of the moon (as indexed by the tides) affect the periods of the
shocks, when the force which causes them is just balanced by the resistance
of the solid crust? The fact you mention of the coincidence between the
earthquakes of Calabria and Scotland appears most curious. Your paper will
possess a high degree of interest to all geologists. I fancied that such
uniformity of action, as seems here indicated, was probably confined to
large continents, such as the Americas. How interesting a record of
volcanic phenomena in Iceland would be, now that you are collecting
accounts of every slight trembling in Scotland. I am astonished at their
frequency in that quiet country, as any one would have called it. I wish
it had been in my power to have contributed in any way to your researches
on this most interesting subject.

Down, August 29th [1844].

I am greatly obliged for your kind note, and much pleased with its
contents. If one-third of what you say be really true, and not the verdict
of a partial judge (as from pleasant experience I much suspect), then
should I be thoroughly well contented with my small volume which, small as
it is, cost me much time. (480/1. "Geological Observations on the
Volcanic Islands visited during the Voyage of H.M.S. 'Beagle'": London,
1844. A French translation has been made by Professor Renard of Ghent, and
published by Reinwald of Paris in 1902.) The pleasure of observation amply
repays itself: not so that of composition; and it requires the hope of
some small degree of utility in the end to make up for the drudgery of
altering bad English into sometimes a little better and sometimes worse.
With respect to craters of elevation (480/2. "Geological Observations,"
pages 93-6.), I had no sooner printed off the few pages on that subject
than I wished the whole erased. I utterly disbelieve in Von Buch and de
Beaumont's views; but on the other hand, in the case of the Mauritius and
St. Jago, I cannot, perhaps unphilosophically, persuade myself that they
are merely the basal fragments of ordinary volcanoes; and therefore I
thought I would suggest the notion of a slow circumferential elevation, the
central part being left unelevated, owing to the force from below being
spent and [relieved?] in eruptions. On this view, I do not consider these
so-called craters of elevation as formed by the ejection of ashes, lava,
etc., etc., but by a peculiar kind of elevation acting round and modified
by a volcanic orifice. I wish I had left it all out; I trust that there
are in other parts of the volume more facts and less theory. The more I
reflect on volcanoes, the more I appreciate the importance of E. de
Beaumont's measurements (480/3. Elie de Beaumont's views are discussed by
Sir Charles Lyell both in the "Principles of Geology" (Edition X., 1867,
Volume I. pages 633 et seq.) and in the "Elements of Geology" (Edition
III., 1878, pages 495, 496). See also Darwin's "Geological Observations,"
Edition II., 1876, page 107.) (even if one does not believe them
implicitly) of the natural inclination of lava-streams, and even more the
importance of his view of the dikes, or unfilled fissures, in every
volcanic mountain, being the proofs and measures of the stretching and
consequent elevation which all such mountains must have undergone. I
believe he thus unintentionally explains most of his cases of lava-streams
being inclined at a greater angle than that at which they could have

But excuse this lengthy note, and once more let me thank you for the
pleasure and encouragement you have given me--which, together with Lyell's
never-failing kindness, will help me on with South America, and, as my
books will not sell, I sometimes want such aid. I have been lately reading
with care A. d'Orbigny's work on South America (480/4. "Voyage dans
l'Amerique Meridionale--execute pendant les annees 1826-33": six volumes,
Paris, 1835-43.), and I cannot say how forcibly impressed I am with the
infinite superiority of the Lyellian school of Geology over the
continental. I always feel as if my books came half out of Lyell's brain,
and that I never acknowledge this sufficiently; nor do I know how I can
without saying so in so many words--for I have always thought that the
great merit of the "Principles" was that it altered the whole tone of one's
mind, and therefore that, when seeing a thing never seen by Lyell, one yet
saw it partially through his eyes--it would have been in some respects
better if I had done this less: but again excuse my long, and perhaps you
will think presumptuous, discussion. Enclosed is a note from Emma to Mrs.
Horner, to beg you, if you can, to give us the great pleasure of seeing you
here. We are necessarily dull here, and can offer no amusements; but the
weather is delightful, and if you could see how brightly the sun now shines
you would be tempted to come. Pray remember me most kindly to all your
family, and beg of them to accept our proposal, and give us the pleasure of
seeing them.

Down, [September, 1844].

I was glad to get your note, and wanted to hear about your work. I have
been looking to see it advertised; it has been a long task. I had, before
your return from Scotland, determined to come up and see you; but as I had
nothing else to do in town, my courage has gradually eased off, more
especially as I have not been very well lately. We get so many invitations
here that we are grown quite dissipated, but my stomach has stood it so ill
that we are going to have a month's holidays, and go nowhere.

The subject which I was most anxious to talk over with you I have settled,
and having written sixty pages of my "S. American Geology," I am in pretty
good heart, and am determined to have very little theory and only short
descriptions. The two first chapters will, I think, be pretty good, on the
great gravel terraces and plains of Patagonia and Chili and Peru.

I am astonished and grieved over D'Orbigny's nonsense of sudden elevations.
(481/1. D'Orbigny's views are referred to by Lyell in chapter vii. of the
"Principles," Volume I. page 131. "This mud [i.e. the Pampean mud]
contains in it recent species of shells, some of them proper to brackish
water, and is believed by Mr. Darwin to be an estuary or delta deposit.
M.A. D'Orbigny, however, has advanced an hypothesis...that the agitation
and displacement of the waters of the ocean, caused by the elevation of the
Andes, gave rise to a deluge, of which this Pampean mud, which reaches
sometimes the height of 12,000 feet, is the result and monument.") I must
give you one of his cases: He finds an old beach 600 feet above sea. He
finds STILL ATTACHED to the rocks at 300 feet six species of truly littoral
shells. He finds at 20 to 30 feet above sea an immense accumulation of
chiefly littoral shells. He argues the whole 600 feet uplifted at one
blow, because the attached shells at 300 feet have not been displaced.
Therefore when the sea formed a beach at 600 feet the present littoral
shells were attached to rocks at 300 feet depth, and these same shells were
accumulating by thousands at 600 feet.

Hear this, oh Forbes. Is it not monstrous for a professed conchologist?
This is a fair specimen of his reasoning.

One of his arguments against the Pampas being a slow deposit, is that
mammifers are very seldom washed by rivers into the sea!

Because at 12,000 feet he finds the same kind of clay with that of the
Pampas he never doubts that it is contemporaneous with the Pampas
[debacle?] which accompanied the right royal salute of every volcano in the
Cordillera. What a pity these Frenchmen do not catch hold of a comet, and
return to the good old geological dramas of Burnett and Whiston. I shall
keep out of controversy, and just give my own facts. It is enough to
disgust one with Geology; though I have been much pleased with the frank,
decided, though courteous manner with which D'Orbigny disputes my
conclusions, given, unfortunately, without facts, and sometimes rashly, in
my journal.

Enough of S. America. I wish you would ask Mr. Horner (for I forgot to do
so, and am unwilling to trouble him again) whether he thinks there is too
much detail (quite independent of the merits of the book) in my volcanic
volume; as to know this would be of some real use to me. You could tell me
when we meet after York, when I will come to town. I had intended being at
York, but my courage has failed. I should much like to hear your lecture,
but still more to read it, as I think reading is always better than

I am very glad you talk of a visit to us in the autumn if you can spare the
time. I shall be truly glad to see Mrs. Lyell and yourself here; but I
have scruples in asking any one--you know how dull we are here. Young
Hooker (481/2. Sir J.D. Hooker.) talks of coming; I wish he might meet
you,--he appears to me a most engaging young man.

I have been delighted with Prescott, of which I have read Volume I. at your
recommendation; I have just been a good deal interested with W. Taylor's
(of Norwich) "Life and Correspondence."

On your return from York I shall expect a great supply of Geological

[October 3rd, 1846.]

I have been much interested with Ramsay, but have no particular suggestions
to offer (482/1. "On the Denudation of South Wales and the Adjacent
Counties of England." A.C. Ramsay, "Mem. Geol. Survey Great Britain,"
Volume I., London, 1846.); I agree with all your remarks made the other
day. My final impression is that the only argument against him is to tell
him to read and re-read the "Principles," and if not then convinced to send
him to Pluto. Not but what he has well read the "Principles!" and largely
profited thereby. I know not how carefully you have read this paper, but I
think you did not mention to me that he does (page 327) (482/2. Ramsay
refers the great outlines of the country to the action of the sea in
Tertiary times. In speaking of the denudation of the coast, he says:
"Taking UNLIMITED time into account, we can conceive that any extent of
land might be so destroyed...If to this be added an EXCEEDINGLY SLOW
DEPRESSION of the land and sea bottom, the wasting process would be
materially assisted by this depression" (loc. cit., page 327).) believe
that the main part of his great denudation was effected during a vast
(almost gratuitously assumed) slow Tertiary subsidence and subsequent
Tertiary oscillating slow elevation. So our high cliff argument is
inapplicable. He seems to think his great subsidence only FAVOURABLE for
great denudation. I believe from the general nature of the off-shore sea's
bottoms that it is almost necessary; do look at two pages--page 25 of my S.
American volume--on this subject. (482/3. "Geological Observations on S.
America," 1846, page 25. "When viewing the sea-worn cliffs of Patagonia,
in some parts between 800 and 900 feet in height, and formed of horizontal
Tertiary strata, which must once have extended far seaward...a difficulty
often occurred to me, namely, how the strata could possibly have been
removed by the action of the sea at a considerable depth beneath its
surface." The cliffs of St. Helena are referred to in illustration of the
same problem; speaking of these, Darwin adds: "Now, if we had any reason
to suppose that St. Helena had, during a long period, gone on slowly
subsiding, every difficulty would be removed...I am much inclined to
suspect that we shall hereafter find in all such cases that the land with
the adjoining bed of the sea has in truth subsided..." (loc. cit., pages

The foundation of his views, viz., of one great sudden upheaval, strikes me
as threefold. First, to account for the great dislocations. This strikes
me as the odder, as he admits that a little northwards there were many and
some violent dislocations at many periods during the accumulation of the
Palaeozoic series. If you argue against him, allude to the cool assumption
that petty forces are conflicting: look at volcanoes; look at recurrent
similar earthquakes at same spots; look at repeatedly injected intrusive
masses. In my paper on Volcanic Phenomena in the "Geol. Transactions."
(482/4. "On the Connection of certain Volcanic Phenomena, and on the
Formation of Mountain-chains and the Effects of Continental Elevations."
"Geol. Soc. Proc." Volume II., pages 654-60, 1838; "Trans. Geol. Soc."
Volume V., pages 601-32, 1842. [Read March 7th, 1838.]) I have argued
(and Lonsdale thought well of the argument, in favour, as he remarked, of
your original doctrine) that if Hopkins' views are correct, viz., that
mountain chains are subordinate consequences to changes of level in mass,
then, as we have evidence of such horizontal movements in mass having been
slow, the foundation of mountain chains (differing from volcanoes only in
matter being injected instead of ejected) must have been slow.

Secondly, Ramsay has been influenced, I think, by his Alpine insects; but
he is wrong in thinking that there is any necessary connection of tropics
and large insects--videlicet--Galapagos Arch., under the equator. Small
insects swarm in all parts of tropics, though accompanied generally with
large ones.

Thirdly, he appears influenced by the absence of newer deposits on the old
area, blinded by the supposed necessity of sediment accumulating somewhere
near (as no doubt is true) and being PRESERVED--an example, as I think, of
the common error which I wrote to you about. The preservation of
sedimentary deposits being, as I do not doubt, the exception when they are
accumulated during periods of elevation or of stationary level, and
therefore the preservation of newer deposits would not be probable,
according to your view that Ramsay's great Palaeozoic masses were denuded,
whilst slowly rising. Do pray look at end of Chapter II., at what little I
have said on this subject in my S. American volume. (482/5. The second
chapter of the "Geological Observations" concludes with a Summary on the
Recent Elevations of the West Coast of South America, (page 53).)

I do not think you can safely argue that the whole surface was probably
denuded at same time to the level of the lateral patches of Magnesian

The latter part of the paper strikes me as good, but obvious.

I shall send him my S. American volume for it is curious on how many
similar points we enter, and I modestly hope it may be a half-oz. weight
towards his conversion to better views. If he would but reject his great
sudden elevations, how sound and good he would be. I doubt whether this
letter will be worth the reading.

Down [September 4th, 1849].

It was very good of you to write me so long a letter, which has interested
me much. I should have answered it sooner, but I have not been very well
for the few last days. Your letter has also flattered me much in many
points. I am very glad you have been thinking over the relation of
subsidence and the accumulation of deposits; it has to me removed many
great difficulties; please to observe that I have carefully abstained from
saying that sediment is not deposited during periods of elevation, but only
that it is not accumulated to sufficient thickness to withstand subsequent
beach action; on both coasts of S. America the amount of sediment
deposited, worn away, and redeposited, oftentimes must have been enormous,
but still there have been no wide formations produced: just read my
discussion (page 135 of my S. American book (483/1. See Letter 556, note.
The discussion referred to ("Geological Observations on South America,"
1846) deals with the causes of the absence of recent conchiferous deposits
on the coasts of South America.)) again with this in your mind. I never
thought of your difficulty (i.e. in relation to this discussion) of where
was the land whence the three miles of S. Wales strata were derived!
(483/2. In his classical paper "On the Denudation of South Wales and the
Adjacent Counties of England" ("Mem. Geol. Survey," Volume I., page 297,
1846), Ramsay estimates the thickness of certain Palaeozoic formations in
South Wales, and calculates the cubic contents of the strata in the area
they now occupy together with the amount removed by denudation; and he goes
on to say that it is evident that the quantity of matter employed to form
these strata was many times greater than the entire amount of solid land
they now represent above the waves. "To form, therefore, so great a
thickness, a mass of matter of nearly equal cubic contents must have been
worn by the waves and the outpourings of rivers from neighbouring lands, of
which perhaps no original trace now remains" (page 334.)) Do you not think
that it may be explained by a form of elevation which I have always
suspected to have been very common (and, indeed, had once intended getting
all facts together), viz. thus?--

(Figure 1. A line drawing of ocean bottom subsiding beside mountains and
continent rising.)

The frequency of a DEEP ocean close to a rising continent bordered with
mountains, seems to indicate these opposite movements of rising and sinking
CLOSE TOGETHER; this would easily explain the S. Wales and Eocene cases. I
will only add that I should think there would be a little more sediment
produced during subsidence than during elevation, from the resulting
outline of coast, after long period of rise. There are many points in my
volume which I should like to have discussed with you, but I will not
plague you: I should like to hear whether you think there is anything in
my conjecture on Craters of Elevation (483/3. In the "Geological
Observations on Volcanic Islands," 1844, pages 93-6, Darwin speaks of St.
Helena, St. Jago and Mauritius as being bounded by a ring of basaltic
mountains which he regards as "Craters of Elevation." While unable to
accept the theory of Elie de Beaumont and attribute their formation to a
dome-shaped elevation and consequent arching of the strata, he recognises a
"very great difficulty in admitting that these basaltic mountains are
merely the basal fragments of great volcanoes, of which the summits have
been either blown off, or, more probably, swallowed by subsidence." An
explanation of the origin and structure of these volcanic islands is
suggested which would keep them in the class of "Craters of Elevation," but
which assumes a slow elevation, during which the central hollow or platform
having been formed "not by the arching of the surface, but simply by that
part having been upraised to a less height."); I cannot possibly believe
that Saint Jago or Mauritius are the basal fragments of ordinary volcanoes;
I would sooner even admit E. de Beaumont's views than that--much as I would
sooner in my own mind in all cases follow you. Just look at page 232 in my
"S. America" for a trifling point, which, however, I remember to this day
relieved my mind of a considerable difficulty. (483/4. This probably
refers to a paragraph (page 232) "On the Eruptive Sources of the
Porphyritic Claystone and Greenstone Lavas." The opinion is put forward
that "the difficulty of tracing the streams of porphyries to their ancient
and doubtless numerous eruptive sources, may be partly explained by the
very general disturbance which the Cordillera in most parts has suffered";
but, Darwin adds, "a more specific cause may be that 'the original points
of eruption tend to become the points of injection'...On this view of there
being a tendency in the old points of eruption to become the points of
subsequent injection and disturbance, and consequently of denudation, it
ceases to be surprising that the streams of lava in the porphyritic
claystone conglomerate formation, and in other analogous cases, should most
rarely be traceable to their actual sources." The latter part of this
letter is published in "Life and Letters," I., pages 377, 378.) I remember
being struck with your discussion on the Mississippi beds in relation to
Pampas, but I should wish to read them over again; I have, however, re-lent
your work to Mrs. Rich, who, like all whom I have met, has been much
interested by it. I will stop about my own Geology. But I see I must
mention that Scrope did suggest (and I have alluded to him, page 118
(483/5. "Geological Observations," Edition II., 1876. Chapter VI. opens
with a discussion "On the Separation of the Constituent Minerals of Lava,
according to their Specific Gravities." Mr. Darwin calls attention to the
fact that Mr. P. Scrope had speculated on the subject of the separation of
the trachytic and basaltic series of lavas (page 113).), but without
distinct reference and I fear not sufficiently, though I utterly forgot
what he wrote) the separation of basalt and trachyte; but he does not
appear to have thought about the crystals, which I believe to be the
keystone of the phenomenon. I cannot but think this separation of the
molten elements has played a great part in the metamorphic rocks: how else
could the basaltic dykes have come in the great granitic districts such as
those of Brazil? What a wonderful book for labour is d'Archiac!...(483/6.
Possibly this refers to d'Archiac's "Histoire des Progres de la Geologie,"

Down, Wednesday night [1849?].

I am going to beg a very very great favour of you: it is to translate one
page (and the title) of either Danish or Swedish or some such language. I
know not to whom else to apply, and I am quite dreadfully interested about
the barnacles therein described. Does Lyell know Loven, or his address and
title? for I must write to him. If Lyell knows him I would use his name as
introduction; Loven I know by name as a first-rate naturalist.

Accidentally I forgot to give you the "Footsteps," which I now return,
having ordered a copy for myself.

I sincerely hope the "Craters of Denudation" prosper; I pin my faith to
this view. (484/1. "On Craters of Denudation, with Observations on the
Structure and Growth of Volcanic Cones." "Proc. Geol. Soc." Volume VI.,
1850, pages 207-34. In a letter to Bunbury (January 17th, 1850) Lyell
wrote:..."Darwin adopts my views as to Mauritius, St. Jago, and so-called
elevation craters, which he has examined, and was puzzled with."--"Life of
Sir Charles Lyell," Volume II., page 158.)

Please tell Sir C. Lyell that outside the crater-like mountains at St.
Jago, even throughout a distance of two or three miles, there has been much
denudation of the older volcanic rocks contemporaneous with those of the
ring of mountains. (484/2. The island of St. Jago, one of the Cape de
Verde group, is fully described in the "Volcanic Islands," Chapter 1.)

I hope that you will not find the page troublesome, and that you will
forgive me asking you.

[November 6th, 1849].

I have been deeply interested in your letter, and so far, at least, worthy
of the time it must have cost you to write it. I have not much to say. I
look at the whole question as settled. Santorin is splendid! it is
conclusive! it is perfect! (485/1. "The Gulf of Santorin, in the Grecian
Archipelago, has been for two thousand years a scene of active volcanic
operations. The largest of the three outer islands of the groups (to which
the general name of Santorin is given) is called Thera (or sometimes
Santorin), and forms more than two-thirds of the circuit of the Gulf"
("Principles of Geology," Volume II., Edition X., London, 1868, page 65).
Lyell attributed "the moderate slope of the beds in their having
originally descended the inclined flanks of a large volcanic cone..."; he
refuted the theory of "Elevation Craters" by Leopold von Buch, which
explained the slope of the rocks in a volcanic mountain by assuming that
the inclined beds had been originally horizontal and subsequently tilted by
an explosion.) You have read Dufrenoy in a hurry, I think, and added to
the difficulty--it is the whole hill or "colline" which is composed of tuff
with cross-stratification; the central boss or "monticule" is simply
trachyte. Now, I have described one tuff crater at Galapagos (page 108)
(485/2. The pages refer to Darwin's "Geological Observations on the
Volcanic Islands, etc." 1844.) which has broken through a great solid sheet
of basalt: why should not an irregular mass of trachyte have been left in
the middle after the explosion and emission of mud which produced the
overlying tuff? Or, again, I see no difficulty in a mass of trachyte being
exposed by subsequent dislocations and bared or cleaned by rain. At
Ascension (page 40), subsequent to the last great aeriform explosion, which
has covered the country with fragments, there have been dislocations and a
large circular subsidence...Do not quote Banks' case (485/3. This refers
to Banks' Cove: see "Volcanic Islands," page 107.) (for there has been
some denudation there), but the "elliptic one" (page 105), which is 1,500
yards (three-quarters of a nautical mile) in internal diameter...and is the
very one the inclination of whose mud stream on tuff strata I measured
(before I had ever heard the name Dufrenoy) and found varying from 25 to 30
deg. Albemarle Island, instead of being a crater of elevation, as Von Buch
foolishly guessed, is formed of four great subaerial basaltic volcanoes
(page 103), of one of which you might like to know the external diameter of
the summit or crater was above three nautical miles. There are no "craters
of denudation" at Galapagos. (485/4. See Lyell "On Craters of Denudation,
with Observations on the Structure and Growth of Volcanic Cones," "Quart.
Journ. Geol. Soc." Volume VI., 1850, page 207.)

I hope you will allude to Mauritius. I think this is the instance on the
largest scale of any known, though imperfectly known.

If I were you I would give up consistency (or, at most, only allude in note
to your old edition) and bring out the Craters of Denudation as a new view,
which it essentially is. You cannot, I think, give it prominence as a
novelty and yet keep to consistency and passages in old editions. I should
grudge this new view being smothered in your address, and should like to
see a separate paper. The one great channel to Santorin and Palma, etc.,
etc., is just like the one main channel being kept open in atolls and
encircling barrier reefs, and on the same principle of water being driven
in through several shallow breaches.

I of course utterly reprobate my wild notion of circular elevation; it is a
satisfaction to me to think that I perceived there was a screw loose in the
old view, and, so far, I think I was of some service to you.

Depend on it, you have for ever smashed, crushed, and abolished craters of
elevation. There must be craters of engulfment, and of explosion (mere
modifications of craters of eruption), but craters of denudation are the
ones which have given rise to all the discussions.

Pray give my best thanks to Lady Lyell for her translation, which was as
clear as daylight to me, including "leglessness."


Down [November 20th, 1849].

I remembered the passage in E. de B. [Elie de Beaumont] and have now re-
read it. I have always and do still entirely disbelieve it; in such a
wonderful case he ought to have hammered every inch of rock up to actual
junction; he describes no details of junction, and if I were in your place
I would absolutely dispute the fact of junction (or articulation as he
oddly calls it) on such evidence. I go farther than you; I do not believe
in the world there is or has been a junction between a dike and stream of
lava of exact shape of either (1) or (2) Figure 2].

(Figures 2, 3 and 4.)

If dike gave immediate origin to volcanic vent we should have craters of
[an] elliptic shape [Figure 3]. I believe that when the molten rock in a
dike comes near to the surface, some one two or three points will always
certainly chance to afford an easier passage upward to the actual surface
than along the whole line, and therefore that the dike will be connected
(if the whole were bared and dissected) with the vent by a column or cone
(see my elegant drawing) of lava [Figure 4]. I do not doubt that the dikes
are thus indirectly connected with eruptive vents. E. de B. seems to have
observed many of his T; now without he supposes the whole line of fissure
or dike to have poured out lava (which implies, as above remarked, craters
of an elliptic or almost linear shape) on both sides, how extraordinarily
improbable it is, that there should have been in a single line of section
so many intersections of points eruption; he must, I think, make his
orifices of eruption almost linear or, if not so, astonishingly numerous.
One must refer to what one has seen oneself: do pray, when you go home,
look at the section of a minute cone of eruption at the Galapagos, page 109
(486/1. "Geological Observations on Volcanic Islands." London, 1890, page
238.), which is the most perfect natural dissection of a crater which I
have ever heard of, and the drawing of which you may, I assure you, trust;
here the arching over of the streams as they were poured out over the lip
of the crater was evident, and are now thus seen united to the central
irregular column. Again, at St. Jago I saw some horizontal sections of the
bases of small craters, and the sources or feeders were circular. I really
cannot entertain a doubt that E. de B. is grossly wrong, and that you are
right in your view; but without most distinct evidence I will never admit
that a dike joins on rectangularly to a stream of lava. Your argument
about the perpendicularity of the dike strikes me as good.

The map of Etna, which I have been just looking at, looks like a sudden
falling in, does it not? I am not much surprised at the linear vent in
Santorin (this linear tendency ought to be difficult to a circular-crater-
of-elevation-believer), I think Abich (486/2. "Geologische Beobachtungen
uber die vulkanischen Erscheinungen und Bildungen in Unter- und Mittel-
Italien." Braunschweig, 1841.) describes having seen the same actual thing
forming within the crater of Vesuvius. In such cases what outline do you
give to the upper surface of the lava in the dike connecting them? Surely
it would be very irregular and would send up irregular cones or columns as
in my above splendid drawing.

At the Royal on Friday, after more doubt and misgiving than I almost ever
felt, I voted to recommend Forbes for Royal Medal, and that view was
carried, Sedgwick taking the lead.

I am glad to hear that all your party are pretty well. I know from
experience what you must have gone through. From old age with suffering
death must be to all a happy release. (486/3. This seems to refer to the
death of Sir Charles Lyell's father, which occurred on November 8th, 1849.)

I saw Dan Sharpe the other day, and he told me he had been working at the
mica schist (i.e. not gneiss) in Scotland, and that he was quite convinced
my view was right. You are wrong and a heretic on this point, I know well.

Down, March 4th [1850].

(487/1. The paper was sent in MS., and seems not to have been published.
Mr. Woodd was connected by marriage with Mr. Darwin's cousin, the late Rev.
W. Darwin Fox. It was perhaps in consequence of this that Mr. Darwin
proposed Mr. Woodd for the Geological Society.)

I have read over your paper with attention; but first let me thank you for
your very kind expressions towards myself. I really feel hardly competent
to discuss the questions raised by your paper; I feel the want of
mathematical mechanics. All such problems strike me as awfully
complicated; we do not even know what effect great pressure has on
retarding liquefaction by heat, nor, I apprehend, on expansion. The chief
objection which strikes me is a doubt whether a mass of strata, when
heated, and therefore in some slight degree at least softened, would bow
outwards like a bar of metal. Consider of how many subordinate layers each
great mass would be composed, and the mineralogical changes in any length
of any one stratum: I should have thought that the strata would in every
case have crumpled up, and we know how commonly in metamorphic strata,
which have undergone heat, the subordinate layers are wavy and sinuous,
which has always been attributed to their expansion whilst heated.

Before rocks are dried and quarried, manifold facts show how extremely
flexible they are even when not at all heated. Without the bowing out and
subsequent filling in of the roof of the cavity, if I understand you, there
would be no subsidence. Of course the crumpling up of the strata would
thicken them, and I see with you that this might compress the underlying
fluidified rock, which in its turn might escape by a volcano or raise a
weaker part of the earth's crust; but I am too ignorant to have any opinion
whether force would be easily propagated through a viscid mass like molten
rock; or whether such viscid mass would not act in some degree like sand
and refuse to transmit pressure, as in the old experiment of trying to
burst a piece of paper tied over the end of a tube with a stick, an inch or
two of sand being only interposed. I have always myself felt the greatest
difficulty in believing in waves of heat coming first to this and then to
that quarter of the world: I suspect that heat plays quite a subordinate
part in the upward and downward movements of the earth's crust; though of
course it must swell the strata where first affected. I can understand Sir
J. Herschel's manner of bringing heat to unheated strata--namely, by
covering them up by a mile or so of new strata, and then the heat would
travel into the lower ones. But who can tell what effect this mile or two
of new sedimentary strata would have from mere gravity on the level of the
supporting surface? Of course such considerations do not render less true
that the expansion of the strata by heat would have some effect on the
level of the surface; but they show us how awfully complicated the
phenomenon is. All young geologists have a great turn for speculation; I
have burned my fingers pretty sharply in that way, and am now perhaps
become over-cautious; and feel inclined to cavil at speculation when the
direct and immediate effect of a cause in question cannot be shown. How
neatly you draw your diagrams; I wish you would turn your attention to real
sections of the earth's crust, and then speculate to your heart's content
on them; I can have no doubt that speculative men, with a curb on, make far
the best observers. I sincerely wish I could have made any remarks of more
interest to you, and more directly bearing on your paper; but the subject
strikes me as too difficult and complicated. With every good wish that you
may go on with your geological studies, speculations, and especially

Down, March 24th [1853].

I have often puzzled over Dana's case, in itself and in relation to the
trains of S. American volcanoes of different heights in action at the same
time (page 605, Volume V. "Geological Transactions." (488/1. "On the
Connection of certain Volcanic Phenomena in South America, and on the
Formation of Mountain Chains and Volcanoes, as the Effect of the same Power
by which Continents are Elevated" ("Trans. Geol. Soc." Volume V., page 601,
1840). On page 605 Darwin records instances of the simultaneous activity
after an earthquake of several volcanoes in the Cordillera.)) I can throw
no light on the subject. I presume you remember that Hopkins (488/2. See
"Report on the Geological Theories of Elevation and Earthquakes," by W.
Hopkins, "Brit. Assoc. Rep." 1847, page 34.) in some one (I forget which)
of his papers discusses such cases, and urgently wishes the height of the
fluid lava was known in adjoining volcanoes when in contemporaneous action;
he argues vehemently against (as far as I remember) volcanoes in action of
different heights being connected with one common source of liquefied rock.
If lava was as fluid as water, the case would indeed be hopeless; and I
fancy we should be led to look at the deep-seated rock as solid though
intensely hot, and becoming fluid as soon as a crack lessened the tension
of the super-incumbent strata. But don't you think that viscid lava might
be very slow in communicating its pressure equally in all directions? I
remember thinking strongly that Dana's case within the one crater of
Kilauea proved too much; it really seems monstrous to suppose that the lava
within the same crater is not connected at no very great depth.

When one reflects on (and still better sees) the enormous masses of lava
apparently shot miles high up, like cannon-balls, the force seems out of
all proportion to the mere gravity of the liquefied lava; I should think
that a channel a little straightly or more open would determine the line of
explosion, like the mouth of a cannon compared to the touch-hole. If a
high-pressure boiler was cracked across, no one would think for a moment
that the quantity of water and steam expelled at different points depended
on the less or greater height of the water within the boiler above these
points, but on the size of the crack at these points; and steam and water
might be driven out both at top and bottom. May not a volcano be likened
to a protruding and cracked portion on a vast natural high-pressure boiler,
formed by the surrounding area of country? In fact, I think my simile
would be truer if the difference consisted only in the cracked case of the
boiler being much thicker in some parts than in others, and therefore
having to expel a greater thickness or depth of water in the thicker cracks
or parts--a difference of course absolutely as nothing.

I have seen an old boiler in action, with steam and drops of water spurting
out of some of the rivet-holes. No one would think whether the rivet-holes
passed through a greater or less thickness of iron, or were connected with
the water higher or lower within the boiler, so small would the gravity be
compared with the force of the steam. If the boiler had been not heated,
then of course there would be a great difference whether the rivet-holes
entered the water high or low, so that there was greater or less pressure
of gravity. How to close my volcanic rivet-holes I don't know.

I do not know whether you will understand what I am driving at, and it will
not signify much whether you do or not. I remember in old days (I may
mention the subject as we are on it) often wishing I could get you to look
at continental elevations as THE phenomenon, and volcanic outbursts and
tilting up of mountain chains as connected, but quite secondary, phenomena.
I became deeply impressed with the truth of this view in S. America, and I
do not think you hold it, or if so make it clear: the same explanation,
whatever it may be, which will account for the whole coast of Chili rising,
will and must apply to the volcanic action of the Cordillera, though
modified no doubt by the liquefied rock coming to the surface and reaching
water, and so [being] rendered explosive. To me it appears that this ought
to be borne in mind in your present subject of discussion. I have written
at too great length; and have amused myself if I have done you no good--so

Down, July 5th [1856].

I am very much obliged for your long letter, which has interested me much;
but before coming to the volcanic cosmogony I must say that I cannot gather
your verdict as judge and jury (and not as advocate) on the continental
extensions of late authors (489/1. See "Life and Letters," II., page 74;
Letter to Lyell, June 25th, 1856: also letters in the sections of the
present work devoted to Evolution and Geographical Distribution.), which I
must grapple with, and which as yet strikes me as quite unphilosophical,
inasmuch as such extensions must be applied to every oceanic island, if to
any one, as to Madeira; and this I cannot admit, seeing that the skeletons,
at least, of our continents are ancient, and seeing the geological nature
of the oceanic islands themselves. Do aid me with your judgment: if I
could honestly admit these great [extensions], they would do me good

With respect to active volcanic areas being rising areas, which looks so
pretty on the coral maps, I have formerly felt "uncomfortable" on exactly
the same grounds with you, viz. maritime position of volcanoes; and still
more from the immense thicknesses of Silurian, etc., volcanic strata, which
thicknesses at first impress the mind with the idea of subsidence. If this
could be proved, the theory would be smashed; but in deep oceans, though
the bottom were rising, great thicknesses of submarine lava might
accumulate. But I found, after writing Coral Book, cases in my notes of
submarine vesicular lava-streams in the upper masses of the Cordillera,
formed, as I believe, during subsidence, which staggered me greatly. With
respect to the maritime position of volcanoes, I have long been coming to
the conclusion that there must be some law causing areas of elevation
(consequently of land) and of subsidence to be parallel (as if balancing
each other) and closely approximate; I think this from the form of
continents with a deep ocean on one side, from coral map, and especially
from conversations with you on immense subsidences of the Carboniferous and
[other] periods, and yet with continued great supply of sediment. If this
be so, such areas, with opposite movements, would probably be separated by
sets of parallel cracks, and would be the seat of volcanoes and tilts, and
consequently volcanoes and mountains would be apt to be maritime; but why
volcanoes should cling to the rising edge of the cracks I cannot
conjecture. That areas with extinct volcanic archipelagoes may subside to
any extent I do not doubt.

Your view of the bottom of Atlantic long sinking with continued volcanic
outbursts and local elevations at Madeira, Canaries, etc., grates (but of
course I do not know how complex the phenomena are which are thus
explained) against my judgment; my general ideas strongly lead me to
believe in elevatory movements being widely extended. One ought, I think,
never to forget that when a volcano is in action we have distinct proof of
an action from within outwards. Nor should we forget, as I believe follows
from Hopkins (489/2. "Researches in Physical Geology," W. Hopkins, "Trans.
Phil. Soc. Cambridge," Volume VI., 1838. See also "Report on the
Geological Theories of Elevation and Earthquakes," W. Hopkins, "Brit.
Assoc. Rep." page 33, 1847 (Oxford meeting).), and as I have insisted in my
Earthquake paper, that volcanoes and mountain chains are mere accidents
resulting from the elevation of an area, and as mountain chains are
generally long, so should I view areas of elevation as generally large.
(489/3. "On the Connexion of certain Volcanic Phenomena in S. America, and
on the Formation of Mountain Chains and Volcanoes, as the Effect of the
same Power by which Continents are Elevated," "Trans. Geol. Soc." Volume
V., page 601, 1840. "Bearing in mind Mr. Hopkins' demonstration, if there
be considerable elevation there must be fissures, and, if fissures, almost
certainly unequal upheaval, or subsequent sinking down, the argument may be
finally thus put: mountain chains are the effects of continental
elevations; continental elevations and the eruptive force of volcanoes are
due to one great motive, now in progressive action..." (loc. cit., page

Your old original view that great oceans must be sinking areas, from there
being causes making land and yet there being little land, has always struck
me till lately as very good. But in some degree this starts from the
assumption that within periods of which we know anything there was either a
continent in such areas, or at least a sea-bottom of not extreme depth.

King's Head Hotel, Sandown, Isle of Wight, July 18th [1858].

I write merely to thank you for the abstract of the Etna paper. (490/1.
"On the Structure of Lavas which have Consolidated on Steep Slopes, with
Remarks on the Mode of Origin of Mount Etna and on the Theory of 'Craters
of Elevation,'" by C. Lyell, "Phil. Trans. R. Soc." Volume CXLVIII., page
703, 1859.) It seems to me a very grand contribution to our volcanic
knowledge. Certainly I never expected to see E. de B.'s [Elie de Beaumont]
theory of slopes so completely upset. He must have picked out favourable
cases for measurement. And such an array of facts he gives! You have
scotched, and will see die, I now think, the Crater of Elevation theory.
But what vitality there is in a plausible theory! (490/2. The rest of
this letter is published in "Life and Letters," II., page 129.)

Down, November 25th [1860].

I have endeavoured to think over your discussion, but not with much
success. You will have to lay down, I think, very clearly, what foundation
you argue from--four parts (which seems to me exceedingly moderate on your
part) of Europe being now at rest, with one part undergoing movement. How
it is, that from this you can argue that the one part which is now moving
will have rested since the commencement of the Glacial period in the
proportion of four to one, I do not pretend to see with any clearness; but
does not your argument rest on the assumption that within a given period,
say two or three million years, the whole of Europe necessarily has to
undergo movement? This may be probable or not so, but it seems to me that
you must explain the foundation of your argument from space to time, which
at first, to me was very far from obvious. I can, of course, see that if
you can make out your argument satisfactorily to yourself and others it
would be most valuable. I can imagine some one saying that it is not fair
to argue that the great plains of Europe and the mountainous districts of
Scotland and Wales have been at all subjected to the same laws of movement.
Looking to the whole world, it has been my opinion, from the very size of
the continents and oceans, and especially from the enormous ranges of so
many mountain-chains (resulting from cracks which follow from vast areas of
elevation, as Hopkins argues (491/1. See "Report on the Geological
Theories of Elevation and Earthquakes." by William Hopkins. "Brit. Assoc.
Rep." 1847, pages 33-92; also the Anniversary Address to the Geological
Society by W. Hopkins in 1852 ("Quart. Journ. Geol. Soc." Volume VIII.); in
this Address, pages lxviii et seq.) reference is made to the theory of
elevation which rests on the supposition "of the simultaneous action of an
upheaving force at every point of the area over which the phenomena of
elevation preserve a certain character of continuity...The elevated
mass...becomes stretched, and is ultimately torn and fissured in those
directions in which the tendency thus to tear is greatest...It is thus that
the complex phenomena of elevation become referable to a general and simple
mechanical cause...")) and from other reasons, it has been my opinion that,
as a general rule, very large portions of the world have been
simultaneously affected by elevation or subsidence. I can see that this
does not apply so strongly to broken Europe, any more than to the Malay
Archipelago. Yet, had I been asked, I should have said that probably
nearly the whole of Europe was subjected during the Glacial period to
periods of elevation and of subsidence. It does not seem to me so certain
that the kinds of partial movement which we now see going on show us the
kind of movement which Europe has been subjected to since the commencement
of the Glacial period. These notions are at least possible, and would they
not vitiate your argument? Do you not rest on the belief that, as
Scandinavia and some few other parts are now rising, and a few others
sinking, and the remainder at rest, so it has been since the commencement
of the Glacial period? With my notions I should require this to be made
pretty probable before I could put much confidence in your calculations.
You have probably thought this all over, but I give you the reflections
which come across me, supposing for the moment that you took the
proportions of space at rest and in movement as plainly applicable to time.
I have no doubt that you have sufficient evidence that, at the commencement
of the Glacial period, the land in Scotland, Wales, etc., stood as high or
higher than at present, but I forget the proofs.

Having burnt my own fingers so consumedly with the Wealden, I am fearful
for you, but I well know how infinitely more cautious, prudent, and
far-seeing you are than I am; but for heaven's sake take care of your
fingers; to burn them severely, as I have done, is very unpleasant.

Your 2 1/2 feet for a century of elevation seems a very handsome allowance.
can D. Forbes really show the great elevation of Chili? I am astounded at
it, and I took some pains on the point.

I do not pretend to say that you may not be right to judge of the past
movements of Europe by those now and recently going on, yet it somehow
grates against my judgment,--perhaps only against my prejudices.

As a change from elevation to subsidence implies some great subterranean or
cosmical change, one may surely calculate on long intervals of rest
between. Though, if the cause of the change be ever proved to be
astronomical, even this might be doubtful.

P.S.--I do not know whether I have made clear what I think probable, or at
least possible: viz., that the greater part of Europe has at times been
elevated in some degree equably; at other times it has all subsided
equably; and at other times might all have been stationary; and at other
times it has been subjected to various unequal movements, up and down, as
at present.

Down, December 4th [1860].

It certainly seems to me safer to rely solely on the slowness of
ascertained up-and-down movement. But you could argue length of probable
time before the movement became reversed, as in your letter. And might you
not add that over the whole world it would probably be admitted that a
larger area is NOW at rest than in movement? and this I think would be a
tolerably good reason for supposing long intervals of rest. You might even
adduce Europe, only guarding yourself by saying that possibly (I will not
say probably, though my prejudices would lead me to say so) Europe may at
times have gone up and down all together. I forget whether in a former
letter you made a strong point of upward movement being always interrupted
by long periods of rest. After writing to you, out of curiosity I glanced
at the early chapters in my "Geology of South America," and the areas of
elevation on the E. and W. coasts are so vast, and proofs of many
successive periods of rest so striking, that the evidence becomes to my
mind striking. With regard to the astronomical causes of change: in
ancient days in the "Beagle" when I reflected on the repeated great
oscillations of level on the very same area, and when I looked at the
symmetry of mountain chains over such vast spaces, I used to conclude that
the day would come when the slow change of form in the semi-fluid matter
beneath the crust would be found to be the cause of volcanic action, and of
all changes of level. And the late discussion in the "Athenaeum" (492/1.
"On the Change of Climate in Different Regions of the Earth." Letters from
Sir Henry James, Col. R.E., "Athenaeum," August 25th, 1860, page 256;
September 15th, page 355; September 29th, page 415; October 13th, page 483.
Also letter from J. Beete Jukes, Local Director of the Geological Survey of
Ireland, loc. cit., September 8th, page 322; October 6th, page 451.), by
Sir H. James (though his letter seemed to me mighty poor, and what Jukes
wrote good), reminded me of this notion. In case astronomical agencies
should ever be proved or rendered probable, I imagine, as in nutation or
precession, that an upward movement or protrusion of fluidified matter
below might be immediately followed by movement of an opposite nature.
This is all that I meant.

I have not read Jamieson, or yet got the number. (492/2. Possibly William
Jameson, "Journey from Quito to Cayambe," "Geog. Soc. Journ." Volume XXXI.,
page 184, 1861.) I was very much struck with Forbes' explanation of
n[itrate] of soda beds and the saliferous crust, which I saw and examined
at Iquique. (492/3. "On the Geology of Bolivia and Southern Peru," by D.
Forbes, "Quart. Journ. Geol. Soc." Volume XVII., page 7, 1861. Mr. Forbes
attributes the formation of the saline deposits to lagoons of salt water,
the communication of which with the sea has been cut off by the rising of
the land (loc. cit., page 13).) I often speculated on the greater rise
inland of the Cordilleras, and could never satisfy myself...

I have not read Stur, and am awfully behindhand in many things...(492/4.
The end of this letter is published as a footnote in "Life and Letters,"
II., page 352.)

(FIGURE 5. Map of part of South America and the Galapagos Archipelago.)

Down, July 18th [1867].

(493/1. The first part of this letter is published in "Life and Letters,"
III., page 71.)

(493/2. Tahiti (Society Islands) is coloured blue in the map showing the
distribution of the different kinds of reefs in "The Structure and
Distribution of Coral Reefs," Edition III., 1889, page 185. The blue
colour indicates the existence of barrier reefs and atolls which, on
Darwin's theory, point to subsidence.)

Tahiti is, I believe, rightly coloured, for the reefs are so far from the
land, and the ocean so deep, that there must have been subsidence, though
not very recently. I looked carefully, and there is no evidence of recent
elevation. I quite agree with you versus Herschel on Volcanic Islands.
(493/3. Sir John Herschel suggested that the accumulation on the sea-floor
of sediment, derived from the waste of the island, presses down the bed of
the ocean, the continent being on the other hand relieved of pressure;
"this brings about a state of strain in the crust which will crack in its
weakest spot, the heavy side going down, and the light side rising." In
discussing this view Lyell writes ("Principles," Volume II. Edition X.,
page 229), "This hypothesis appears to me of very partial application, for
active volcanoes, even such as are on the borders of continents, are rarely
situated where great deltas have been forming, whether in Pliocene or
post-Tertiary times. The number, also, of active volcanoes in oceanic
islands is very great, not only in the Pacific, but equally in the
Atlantic, where no load of coral matter...can cause a partial weighting and
pressing down of a supposed flexible crust.") Would not the Atlantic and
Antarctic volcanoes be the best examples for you, as there then can be no
coral mud to depress the bottom? In my "Volcanic Islands," page 126, I
just suggest that volcanoes may occur so frequently in the oceanic areas as
the surface would be most likely to crack when first being elevated. I
find one remark, page 128 (493/4. "Volcanic Islands," page 128: "The
islands, moreover, of some of the small volcanic groups, which thus border
continents, are placed in lines related to those along which the adjoining
shores of the continents trend" [see Figure 5].), which seems to me worth
consideration--viz. the parallelism of the lines of eruption in volcanic
archipelagoes with the coast lines of the nearest continent, for this seems
to indicate a mechanical rather than a chemical connection in both cases,
i.e. the lines of disturbance and cracking. In my "South American
Geology," page 185 (493/5. "Geological Observations on South America,"
London, 1846, page 185.), I allude to the remarkable absence at present of
active volcanoes on the east side of the Cordillera in relation to the
absence of the sea on this side. Yet I must own I have long felt a little
sceptical on the proximity of water being the exciting cause. The one
volcano in the interior of Asia is said, I think, to be near great lakes;
but if lakes are so important, why are there not many other volcanoes
within other continents? I have always felt rather inclined to look at the
position of volcanoes on the borders of continents, as resulting from coast
lines being the lines of separation between areas of elevation and
subsidence. But it is useless in me troubling you with my old

March 22nd [1869].

(494/1. The following extract from a letter to Mr. Wallace refers to his
"Malay Archipelago," 1869.)

I have only one criticism of a general nature, and I am not sure that other
geologists would agree with me. You repeatedly speak as if the pouring out
of lava, etc., from volcanoes actually caused the subsidence of an
adjoining area. I quite agree that areas undergoing opposite movements are
somehow connected; but volcanic outbursts must, I think, be looked at as
mere accidents in the swelling up of a great dome or surface of plutonic
rocks, and there seems no more reason to conclude that such swelling or
elevation in mass is the cause of the subsidence, than that the subsidence
is the cause of the elevation, which latter view is indeed held by some
geologists. I have regretted to find so little about the habits of the
many animals which you have seen.

Down, May 20th, 1869.

I have been much pleased to hear that you have been looking at my S.
American book (495/1. "Geological Observations on South America," London,
1846.), which I thought was as completely dead and gone as any pre-Cambrian
fossil. You are right in supposing that my memory about American geology
has grown very hazy. I remember, however, a paper on the Cordillera by D.
Forbes (495/2. "Geology of Bolivia and South Peru," by Forbes, "Quart.
Journ. Geol. Soc." Volume XVII., pages 7-62, 1861. Forbes admits that
there is "the fullest evidence of elevation of the Chile coast since the
arrival of the Spaniards. North of Arica, if we accept the evidence of M.
d'Orbigny and others, the proof of elevation is much more decided; and
consequently it may be possible that here, as is the case about Lima,
according to Darwin, the elevation may have taken place irregularly in
places..." (loc. cit., page 11).), with splendid sections, which I saw in
MS., but whether "referred" to me or lent to me I cannot remember. This
would be well worth your looking to, as I think he both supports and
criticises my views. In Ormerod's Index to the Journal (495/3.
"Classified Index to the Transactions, Proceedings and Quarterly Journal of
the Geological Society."), which I do not possess, you would, no doubt,
find a reference; but I think the sections would be worth borrowing from
Forbes. Domeyko (495/4. Reference is made by Forbes in his paper on
Bolivia and Peru to the work of Ignacio Domeyko on the geology of Chili.
Several papers by this author were published in the "Annales des Mines"
between 1840 and 1869, also in the "Comptes Rendus" of 1861, 1864, etc.)
has published in the "Comptes Rendus papers on Chili, but not, as far as I
can remember, on the structure of the mountains. Forbes, however, would
know. What you say about the plications being steepest in the central and
generally highest part of the range is conclusive to my mind that there has
been the chief axis of disturbance. The lateral thrusting has always
appeared to me fearfully perplexing. I remember formerly thinking that all
lateral flexures probably occurred deep beneath the surface, and have been
brought into view by an enormous superincumbent mass having been denuded.
If a large and deep box were filled with layers of damp paper or clay, and
a blunt wedge was slowly driven up from beneath, would not the layers above
it and on both sides become greatly convoluted, whilst those towards the
top would be only slightly arched? When I spoke of the Andes being
comparatively recent, I suppose that I referred to the absence of the older
formations. In looking to my volume, which I have not done for many years,
I came upon a passage (page 232) which would be worth your looking at, if
you have ever felt perplexed, as I often was, about the sources of volcanic
rocks in mountain chains. You have stirred up old memories, and at the
risk of being a bore I should like to call your attention to another point
which formerly perplexed me much--viz. the presence of basaltic dikes in
most great granitic areas. I cannot but think the explanation given at
page 123 of my "Volcanic Islands" is the true one. (495/5. On page 123 of
the "Geological Observations on the Volcanic Islands visited during the
Voyage of H.M.S. 'Beagle,'" 1844, Darwin quotes several instances of
greenstone and basaltic dikes intersecting granitic and allied metamorphic
rocks. He suggests that these dikes "have been formed by fissures
penetrating into partially cooled rocks of the granitic and metamorphic
series, and by their more fluid parts, consisting chiefly of hornblende
oozing out, and being sucked into such fissures.")

Down, March 21st, 1876.

The very kind expressions in your letter have gratified me deeply.

I quite forget what I said about my geological works, but the papers
referred to in your letter are the right ones. I enclose a list with those
which are certainly not worth translating marked with a red line; but
whether those which are not thus marked with a red line are worth
translation you will have to decide. I think much more highly of my book
on "Volcanic Islands" since Mr. Judd, by far the best judge on the subject
in England, has, as I hear, learnt much from it.

I think the short paper on the "formation of mould" is worth translating,
though, if I have time and strength, I hope to write another and longer
paper on the subject.

I can assure you that the idea of any one translating my books better than
you never even momentarily crossed my mind. I am glad that you can give a
fairly good account of your health, or at least that it is not worse.

London, December 9th, 1880.

I am sorry to say that I do not return home till the middle of next week,
and as I order no pamphlets to be forwarded to me by post, I cannot return
the "Geolog. Mag." until my return home, nor could my servants pick it out
of the multitude which come by the post. (497/1. Article on "Oceanic
Islands," by T. Mellard Reade, "Geol. Mag." Volume VIII., page 75, 1881.)

As I remarked in a letter to a friend, with whom I was discussing Wallace's
last book (497/2. Wallace's "Island Life," 1880.), the subject to which
you refer seems to me a most perplexing one. The fact which I pointed out
many years ago, that all oceanic islands are volcanic (except St. Paul's,
and now this is viewed by some as the nucleus of an ancient volcano), seems
to me a strong argument that no continent ever occupied the great oceans.
(497/3. "During my investigations on coral reefs I had occasion to consult
the works of many voyagers, and I was invariably struck with the fact that,
with rare exceptions, the innumerable islands scattered through the
Pacific, Indian, and Atlantic Oceans were composed either of volcanic or of
modern coral rocks" ("Geological Observations on Volcanic Islands, etc."
Edition II., 1876, page 140).) Then there comes the statement from the
"Challenger" that all sediment is deposited within one or two hundred miles
from the shores, though I should have thought this rather doubtful with
respect to great rivers like the Amazons.

The chalk formerly seemed to me the best case of an ocean having extended
where a continent now stands; but it seems that some good judges deny that
the chalk is an oceanic deposit. On the whole, I lean to the side that the
continents have since Cambrian times occupied approximately their present
positions. But, as I have said, the question seems a difficult one, and
the more it is discussed the better.

Down, January 1st, 1881.

I must write a line or two to thank you much for having written to me so
long a letter on coral reefs at a time when you must have been so busy. Is
it not difficult to avoid believing that the wonderful elevation in the
West Indies must have been accompanied by much subsidence, notwithstanding
the state of Florida? (498/1. The Florida reefs cannot be explained by
subsidence. Alexander Agassiz, who has described these reefs in detail
("Three Cruises of the U.S. Coast and Geodetic Survey Steamer 'Blake,'" 2
volumes, London, 1888), shows that the southern extremity of the peninsula
"is of comparatively recent growth, consisting of concentric barrier-reefs,
which have been gradually converted into land by the accumulation of
intervening mud-flats" (see also Appendix II., page 287, to Darwin's "Coral
Reefs," by T.G. Bonney, Edition III., 1889.)) When reflecting in old days
on the configuration of our continents, the position of mountain chains,
and especially on the long-continued supply of sediment over the same
areas, I used to think (as probably have many other persons) that areas of
elevation and subsidence must as a general rule be separated by a single
great line of fissure, or rather of several closely adjoining lines of
fissure. I mention this because, when looking within more recent times at
charts with the depths of the sea marked by different tints, there seems to
be some connection between the profound depths of the ocean and the trends
of the nearest, though distant, continents; and I have often wished that
some one like yourself, to whom the subject was familiar, would speculate
on it.

P.S.--I do hope that you will re-urge your views about the reappearance of
old characters (498/2. See "Life and Letters," III., pages 245, 246.),
for, as far as I can judge, the most important views are often neglected
unless they are urged and re-urged.

I am greatly indebted to you for sending me very many most valuable works
published at your institution.

2.IX.II. ICE-ACTION, 1841-1882.


Your extract has set me puzzling very much, and as I find I am better at
present for not going out, you must let me unload my mind on paper. I
thought everything so beautifully clear about glaciers, but now your case
and Agassiz's statement about the cavities in the rock formed by cascades
in the glaciers, shows me I don't understand their structure at all. I
wish out of pure curiosity I could make it out. (499/1. "Etudes sur les
Glaciers," by Louis Agassiz, 1840, contains a description of cascades (page
343), and "des cavites interieures" (page 348).)

If the glacier travelled on (and it certainly does travel on), and the
water kept cutting back over the edge of the ice, there would be a great
slit in front of the cascade; if the water did not cut back, the whole
hollow and cascade, as you say, must travel on; and do you suppose the next
season it falls down some crevice higher up? In any case, how in the name
of Heaven can it make a hollow in solid rock, which surely must be a work
of many years? I must point out another fact which Agassiz does not, as it
appears to me, leave very clear. He says all the blocks on the surface of
the glaciers are angular, and those in the moraines rounded, yet he says
the medial moraines whence the surface rocks come and are a part [of], are
only two lateral moraines united. Can he refer to terminal moraines alone
when he says fragments in moraines are rounded? What a capital book
Agassiz's is. In [reading] all the early part I gave up entirely the Jura
blocks, and was heartily ashamed of my appendix (499/2. "M. Agassiz has
lately written on the subject of the glaciers and boulders of the Alps. He
clearly proves, as it appears to me, that the presence of the boulders on
the Jura cannot be explained by any debacle, or by the power of ancient
glaciers driving before them moraines...M. Agassiz also denies that they
were transported by floating ice." ("Voyages of the 'Adventure' and
'Beagle,'" Volume III., 1839: "Journal and Remarks: Addenda," page 617.))
(and am so still of the manner in which I presumptuously speak of Agassiz),
but it seems by his own confession that ordinary glaciers could not have
transported the blocks there, and if an hypothesis is to be introduced the
sea is much simpler; floating ice seems to me to account for everything as
well as, and sometimes better than the solid glaciers. The hollows,
however, formed by the ice-cascades appear to me the strongest hostile
fact, though certainly, as you said, one sees hollow round cavities on
present rock-beaches.

I am glad to observe that Agassiz does not pretend that direction of
scratches is hostile to floating ice. By the way, how do you and Buckland
account for the "tails" of diluvium in Scotland? (499/3. Mr. Darwin
speaks of the tails of diluvium in Scotland extending from the protected
side of a hill, of which the opposite side, facing the direction from which
the ice came, is marked by grooves and striae (loc. cit., pages 622, 623).)
I thought in my appendix this made out the strongest argument for rocks
having been scratched by floating ice.

Some facts about boulders in Chiloe will, I think, in a very small degree
elucidate some parts of Jura case. What a grand new feature all this ice
work is in Geology! How old Hutton would have stared! (499/4. Sir
Charles Lyell speaks of the Huttonian theory as being characterised by "the
exclusion of all causes not supposed to belong to the present order of
Nature" (Lyell's "Principles," Edition XII., volume I., page 76, 1875).
Sir Archibald Geikie has recently edited the third volume of Hutton's
"Theory of the Earth," printed by the Geological Society, 1899. See also
"The Founders of Geology," by Sir Archibald Geikie; London, 1897.)

I ought to be ashamed of myself for scribbling on so. Talking of shame, I
have sent a copy of my "Journal" (499/5. "Journal and Remarks," 1832-36.
See note 2, page 148.) with very humble note to Agassiz, as an apology for
the tone I used, though I say, I daresay he has never seen my appendix, or
would care at all about it.

I did not suppose my note about Glen Roy could have been of any use to
you--I merely scribbled what came uppermost. I made one great oversight,
as you would perceive. I forgot the Glacier theory: if a glacier most
gradually disappeared from mouth of Spean Valley [this] would account for
buttresses of shingle below lowest shelf. The difficulty I put about the
ice-barrier of the middle Glen Roy shelf keeping so long at exactly same
level does certainly appear to me insuperable. (499/5. For a description
of the shelves or parallel roads in Glen Roy see Darwin's "Observations on
the Parallel Roads of Glen Roy, etc." "Phil. Trans. R. Soc." 1839, page
39; also Letter 517 et seq.)

What a wonderful fact this breakdown of old Niagara is. How it disturbs
the calculations about lengths of time before the river would have reached
the lakes.

I hope Mrs. Lyell will read this to you, then I shall trust for forgiveness
for having scribbled so much. I should have sent back Agassiz sooner, but
my servant has been very unwell. Emma is going on pretty well.

My paper on South American boulders and "till," which latter deposit is
perfectly characterised in Tierra del Fuego, is progressing rapidly.
(499/6. "On the Distribution of the Erratic Boulders and on the
Contemporaneous Unstratified Deposits of South America," "Trans. Geol.
Soc." Volume VI., page 415, 1842.)

I much like the term post-Pliocene, and will use it in my present paper
several times.

P.S.--I should have thought that the most obvious objection to the marine-
beach theory for Glen Roy would be the limited extension of the shelves.
Though certainly this is not a valid one, after an intermediate one, only
half a mile in length, and nowhere else appearing, even in the valley of
Glen Roy itself, has been shown to exist.


I had some talk with Murchison, who has been on a flying visit into Wales,
and he can see no traces of glaciers, but only of the trickling of water
and of the roots of the heath. It is enough to make an extraneous man
think Geology from beginning to end a work of imagination, and not founded
on observation. Lonsdale, I observe, pays Buckland and myself the
compliment of thinking Murchison not seeing as worth nothing; but I confess
I am astonished, so glaringly clear after two or three days did the
evidence appear to me. Have you seen last "New Edin. Phil. Journ.", it is
ice and glaciers almost from beginning to end. (500/1. "The Edinburgh New
Philosophical Journal," Volume XXXIII. (April-October), 1842, contains
papers by Sir G.S. Mackenzie, Prof. H.G. Brown, Jean de Charpentier,
Roderick Murchison, Louis Agassiz, all dealing with glaciers or ice; also
letters to the Editor relating to Prof. Forbes' account of his recent
observations on Glaciers, and a paper by Charles Darwin entitled "Notes on
the Effects produced by the Ancient Glaciers of Carnarvonshire, and on the
Boulders transported by Floating Ice.") Agassiz says he saw (and has laid
down) the two lowest terraces of Glen Roy in the valley of the Spean,
opposite mouth of Glen Roy itself, where no one else has seen them. (500/2.
"The Glacial Theory and its Recent Progress," by Louis Agassiz, loc. cit.,
page 216. Agassiz describes the parallel terraces on the flanks of Glen
Roy and Glen Spean (page 236), and expresses himself convinced "that the
Glacial theory alone satisfies all the exigencies of the phenomenon" of the
parallel roads.) I carefully examined that spot, owing to the sheep tracks
[being] nearly but not quite parallel to the terrace. So much, again, for
difference of observation. I do not pretend to say who is right.

Down, October 12th, 1849.

I was heartily glad to get your last letter; but on my life your thanks for
my very few and very dull letters quite scalded me. I have been very
indolent and selfish in not having oftener written to you and kept my ears
open for news which would have interested you; but I have not forgotten
you. Two days after receiving your letter, there was a short leading
notice about you in the "Gardeners' Chronicle" (501/1. The "Gardeners'
Chronicle," 1849, page 628.); in which it is said you have discovered a
noble crimson rose and thirty rhododendrons. I must heartily congratulate
you on these discoveries, which will interest the public; and I have no
doubt that you will have made plenty of most interesting botanical
observations. This last letter shall be put with all your others, which
are now safe together. I am very glad that you have got minute details
about the terraces in the valleys: your description sounds curiously like
the terraces in the Cordillera of Chili; these latter, however, are single
in each valley; but you will hereafter see a description of these terraces
in my "Geology of S. America." (501/2. "Geological Observations," pages
10 et passim.) At the end of your letter you speak about giving up
Geology, but you must not think of it; I am sure your observations will be
very interesting. Your account of the great dam in the Yangma valley is
most curious, and quite full; I find that I did not at all understand its
wonderful structure in your former letter. Your notion of glaciers pushing
detritus into deep fiords (and ice floating fragments on their channels),
is in many respects new to me; but I cannot help believing your dam is a
lateral moraine: I can hardly persuade myself that the remains of floating
ice action, at a period so immensely remote as when the Himalaya stood at a
low level in the sea, would now be distinguishable. (501/3. Hooker's
"Himalayan Journals," Volume II., page 121, 1854. In describing certain
deposits in the Lachoong valley, Hooker writes: "Glaciers might have
forced immense beds of gravel into positions that would dam up lakes
between the ice and the flanks of the valley" (page 121). In a footnote he
adds: "We are still very ignorant of many details of ice action, and
especially of the origin of many enormous deposits which are not true
moraines." Such deposits are referred to as occurring in the Yangma
valley.) Your not having found scored boulders and solid rocks is an
objection both to glaciers and floating ice; for it is certain that both
produce such. I believe no rocks escape scoring, polishing and
mammillation in the Alps, though some lose it easily when exposed. Are you
familiar with appearance of ice-action? If I understand rightly, you
object to the great dam having been produced by a glacier, owing to the
dryness of the lateral valley and general infrequency of glaciers in
Himalaya; but pray observe that we may fairly (from what we see in Europe)
assume that the climate was formerly colder in India, and when the land
stood at a lower height more snow might have fallen. Oddly enough, I am
now inclined to believe that I saw a gigantic moraine crossing a valley,
and formerly causing a lake above it in one of the great valleys (Valle del
Yeso) of the Cordillera: it is a mountain of detritus, which has puzzled
me. If you have any further opportunities, do look for scores on steep
faces of rock; and here and there remove turf or matted parts to have a
look. Again I beg, do not give up Geology:--I wish you had Agassiz's work
and plates on Glaciers. (501/4. "Etudes sur les Glaciers." L. Agassiz,
Neuchatel, 1840.) I am extremely sorry that the Rajah, ill luck to him,
has prevented your crossing to Thibet; but you seem to have seen most
interesting country: one is astonished to hear of Fuegian climate in
India. I heard from the Sabines that you were thinking of giving up
Borneo; I hope that this report may prove true.

Down, May 8th [1855].

The notion you refer to was published in the "Geological Journal" (502/1.
"on the Transportal of Erratic Boulders from a lower to a higher Level."
By C. Darwin.), Volume IV. (1848), page 315, with reference to all the
cases which I could collect of boulders apparently higher than the parent

The argument of probable proportion of rock dropped by sea ice compared to
land glaciers is new to me. I have often thought of the idea of the
viscosity and enormous momentum of great icebergs, and still think that the
notion I pointed out in appendix to Ramsay's paper is probable, and can
hardly help being applicable in some cases. (502/2. The paper by Ramsay
has no appendix; probably, therefore Mr. Darwin's notes were published
separately as a paper in the "Phil. Mag.") I wonder whether the "Phil.
Journal [Magazine?.]" would publish it, if I could get it from Ramsay or
the Geological Society. (502/3. "On the Power of Icebergs to make
rectilinear, uniformly-directed grooves across a Submarine Undulatory
Surface." By C. Darwin, "Phil. Mag." Volume X., page 96, 1855.) If you
chance to meet Ramsay will you ask him whether he has it? I think it would
perhaps be worth while just to call the N. American geologists' attention
to the idea; but it is not worth any trouble. I am tremendously busy with
all sorts of experiments. By the way, Hopkins at the Geological Society
seemed to admit some truth in the idea of scoring by (viscid) icebergs. If
the Geological Society takes so much [time] to judge of truth of notions,
as you were telling me in regard to Ramsay's Permian glaciers (502/4. "On
the Occurrence of angular, sub-angular, polished, and striated Fragments
and Boulders in the Permian Breccia of Shropshire, Worcestershire, etc.;
and on the Probable Existence of Glaciers and Icebergs in the Permian
Epoch." By A.C. Ramsay, "Quart. Journ. Geol. Soc." Volume XI., page 185,
1855.), it will be as injurious to progress as the French Institut.

Cliff Cottage, Bournemouth, [September] 21st [1862].

I am especially obliged to you for sending me Haast's communications.
(503/1. "Quart. Journ. Geol. Soc." Volume XXI., pages 130, 133, 1865;
Volume XXIII., page 342, 1867.) They are very interesting and grand about
glacial and drift or marine glacial. I see he alludes to the whole
southern hemisphere. I wonder whether he has read the "Origin."
Considering your facts on the Alpine plants of New Zealand and remarks, I
am particularly glad to hear of the geological evidence of glacial action.
I presume he is sure to collect and send over the mountain rat of which he
speaks. I long to know what it is. A frog and rat together would, to my
mind, prove former connection of New Zealand to some continent; for I can
hardly suppose that the Polynesians introduced the rat as game, though so
esteemed in the Friendly Islands. Ramsay sent me his paper (503/2. "On
the Glacial Origin of certain Lakes in Switzerland, etc." "Quart. Journ.
Geol. Soc." Volume XVIII., page 185, 1862.) and asked my opinion on it. I
agree with you and think highly of it. I cannot doubt that it is to a
large extent true; my only doubt is, that in a much disturbed country, I
should have thought that some depressions, and consequently lakes, would
almost certainly have been left. I suggested a careful consideration of
mountainous tropical countries such as Brazil, peninsula of India, etc.; if
lakes are there, [they are] very rare. I should fully subscribe to
Ramsay's views.

What presumption, as it seems to me, in the Council of Geological Society
that it hesitated to publish the paper.

We return home on the 30th. I have made up [my] mind, if I can keep up my
courage, to start on the Saturday for Cambridge, and stay the last few days
of the [British] Association there. I do so hope that you may be there

November 3rd [1864].

When I wrote to you I had not read Ramsay. (504/1. "On the Erosion of
Valleys and Lakes: a Reply to Sir Roderick Murchison's Anniversary Address
to the Geographical Society." "Phil. Mag." Volume XXVIII., page 293, 1864)
How capitally it is written! It seems that there is nothing for style like
a man's dander being put up. I think I agree largely with you about
denudation--but the rocky-lake-basin theory is the part which interests me
at present. It seems impossible to know how much to attribute to ice,
running water, and sea. I did not suppose that Ramsay would deny that
mountains had been thrown up irregularly, and that the depressions would
become valleys. The grandest valleys I ever saw were at Tahiti, and here I
do not believe ice has done anything; anyhow there were no erratics. I
said in my S. American Geology (504/2. "Finally, the conclusion at which I
have arrived with respect to the relative powers of rain, and sea-water on
the land is, that the latter is by far the most efficient agent, and that
its chief tendency is to widen the valleys, whilst torrents and rivers tend
to deepen them and to remove the wreck of the sea's destroying action"
("Geol. Observations," pages 66, 67).) that rivers deepen and the sea
widens valleys, and I am inclined largely to stick to this, adding ice to
water. I am sorry to hear that Tyndall has grown dogmatic. H. Wedgwood
was saying the other day that T.'s writings and speaking gave him the idea
of intense conceit. I hope it is not so, for he is a grand man of science.

...I have had a prospectus and letter from Andrew Murray (504/3. See
Volume II., Letters 379, 384, etc.) asking me for suggestions. I think
this almost shows he is not fit for the subject, as he gives me no idea
what his book will be, excepting that the printed paper shows that all
animals and all plants of all groups are to be treated of. Do you know
anything of his knowledge?

In about a fortnight I shall have finished, except concluding chapter, my
book on "Variation under Domestication"; (504/4. Published in 1868.) but
then I have got to go over the whole again, and this will take me very many
months. I am able to work about two hours daily.

Down [July, 1865].

I was glad to read your article on Glaciers, etc., in Yorkshire. You seem
to have been struck with what most deeply impressed me at Glen Roy (wrong
as I was on the whole subject)--viz. the marvellous manner in which every
detail of surface of land had been preserved for an enormous period. This
makes me a little sceptical whether Ramsay, Jukes, etc., are not a little
overdoing sub-aerial denudation.

In the same "Reader" (505/1. Sir J.D. Hooker wrote to Darwin, July 13th,
1865, from High Force Inn, Middleton, Teesdale: "I am studying the
moraines all day long with as much enthusiasm as I am capable of after
lying in bed till nine, eating heavy breakfasts, and looking forward to
dinner as the summum bonum of existence." The result of his work, under
the title "Moraines of the Tees Valley," appeared in the "Reader" (July
15th, 1865, page 71), of which Huxley was one of the managers or
committee-men, and Norman Lockyer was scientific editor ("Life and Letters
of T.H. Huxley," I., page 211). Hooker describes the moraines and other
evidence of glacial action in the upper part of the Tees valley, and speaks
of the effect of glaciers in determining the present physical features of
the country.) there was a striking article on English and Foreign Men of
Science (505/2. "British and Foreign Science," "The Reader," loc. cit.,
page 61. The writer of the article asserts the inferiority of English
scientific workers.), and I think unjust to England except in pure
Physiology; in biology Owen and R. Brown ought to save us, and in Geology
we are most rich.

It is curious how we are reading the same books. We intend to read Lecky
and certainly to re-read Buckle--which latter I admired greatly before. I
am heartily glad you like Lubbock's book so much. It made me grieve his
taking to politics, and though I grieve that he has lost his election, yet
I suppose, now that he is once bitten, he will never give up politics, and
science is done for. Many men can make fair M.P.'s; and how few can work
in science like him!

I have been reading a pamphlet by Verlot on "Variation of Flowers," which
seems to me very good; but I doubt whether it would be worth your reading.
it was published originally in the "Journal d'Hort.," and so perhaps you
have seen it. It is a very good plan this republishing separately for sake
of foreigners buying, and I wish I had tried to get permission of Linn.
Soc. for my Climbing paper, but it is now too late.

Do not forget that you have my paper on hybridism, by Max Wichura. (505/3.
Wichura, M.E., "L'Hybridisation dans le regne vegetal etudiee sur les
Saules," "Arch. Sci. Phys. Nat." XXIII., page 129, 1865.)

I hope you are returned to your work, refreshed like a giant by your huge
breakfasts. How unlucky you are about contagious complaints with your

I keep very weak, and had much sickness yesterday, but am stronger this

Can you remember how we ever first met? (505/4. See "Life and Letters,"
II., page 19.) It was in Park Street; but what brought us together? I
have been re-reading a few old letters of yours, and my heart is very warm
towards you.

Down, March 8th [1866].

(506/1. In a letter from Sir Joseph Hooker to Mr. Darwin on February 21st,
1866, the following passage occurs: "I wish I could explain to you my
crude notions as to the Glacial period and your position towards it. I
suppose I hold this doctrine: that there was a Glacial period, but that it
was not one of universal cold, because I think that the existing
distribution of glaciers is sufficiently demonstrative of the proposition
that by comparatively slight redispositions of sea and land, and perhaps
axis of globe, you may account for all the leading palaeontological
phenomena." This letter was sent by Mr. Darwin to Sir Charles Lyell, and
the latter, writing on March 1st, 1866, expresses his belief that "the
whole globe must at times have been superficially cooler. Still," he adds,
"during extreme excentricity the sun would make great efforts to compensate
in perihelion for the chill of a long winter in aphelion in one hemisphere,
and a cool summer in the other. I think you will turn out to be right in
regard to meridional lines of mountain-chains by which the migrations
across the equator took place while there was contemporaneous tropical heat
of certain lowlands, where plants requiring heat and moisture were saved
from extinction by the heat of the earth's surface, which was stored up in
perihelion, being prevented from radiating off freely into space by a
blanket of aqueous vapour caused by the melting of ice and snow. But
though I am inclined to profit by Croll's maximum excentricity for the
glacial period, I consider it quite subordinate to geographical causes or
the relative position of land and sea and the abnormal excess of land in
polar regions." In another letter (March 5th, 1866) Lyell writes: "In the
beginning of Hooker's letter to you he speaks hypothetically of a change in
the earth's axis as having possibly co-operated with redistribution of land
and sea in causing the cold of the Glacial period. Now, when we consider
how extremely modern, zoologically and botanically, the Glacial period is
proved to be, I am shocked at any one introducing, with what I may call so
much levity, so organic a change as a deviation in the axis of the
planet...' (see Lyell's "Principles," 1875, Chapter XIII.; also a letter to
Sir Joseph Hooker printed in the "Life of Sir Charles Lyell," Volume II.,
page 410.))

Many thanks for your interesting letter. From the serene elevation of my
old age I look down with amazement at your youth, vigour, and indomitable
energy. With respect to Hooker and the axis of the earth, I suspect he is
too much overworked to consider now any subject properly. His mind is so
acute and critical that I always expect to hear a torrent of objections to
anything proposed; but he is so candid that he often comes round in a year
or two. I have never thought on the causes of the Glacial period, for I
feel that the subject is beyond me; but though I hope you will own that I
have generally been a good and docile pupil to you, yet I must confess that
I cannot believe in change of land and water, being more than a subsidiary
agent. (506/2. In Chapter XI. of the "Origin," Edition V., 1869, page
451, Darwin discusses Croll's theory, and is clearly inclined to trust in
Croll's conclusion that "whenever the northern hemisphere passes through a
cold period the temperature of the southern hemisphere is actually
raised..." In Edition VI., page 336, he expresses his faith even more
strongly. Mr. Darwin apparently sent his MS. on the climate question,
which was no doubt prepared for a new edition of the "Origin," to Sir
Charles. The arrival of the MS. is acknowledged in a letter from Lyell on
March 10th, 1866 ("Life of Sir Charles Lyell," II., page 408), in which the
writer says that he is "more than ever convinced that geographical
changes...are the principal and not the subsidiary causes.") I have come
to this conclusion from reflecting on the geographical distribution of the
inhabitants of the sea on the opposite sides of our continents and of the
inhabitants of the continents themselves.

Down, September 8th [1866].

Many thanks for the pamphlet, which was returned this morning. I was very
glad to read it, though chiefly as a psychological curiosity. I quite
follow you in thinking Agassiz glacier-mad. (507/1. Agassiz's pamphlet,
("Geology of the Amazons") is referred to by Lyell in a letter written to
Bunbury in September, 1866 ("Life of Sir Charles Lyell," II., page 409):
"Agassiz has written an interesting paper on the 'Geology of the Amazons,'
but, I regret to say, he has gone wild about glaciers, and has actually
announced his opinion that the whole of the great valley, down to its mouth
in latitude 0 deg., was filled by ice..." Agassiz published a paper,
"Observations Geologiques faites dans la Vallee de l'Amazone," in the
"Comptes Rendus," Volume LXIV., page 1269, 1867. See also a letter
addressed to M. Marcou, published in the "Bull. Soc. Geol. France," Volume
XXIV., page 109, 1866.) His evidence reduces itself to supposed moraines,
which would be difficult to trace in a forest-clad country; and with
respect to boulders, these are not said to be angular, and their source
cannot be known in a country so imperfectly explored. When I was at Rio, I
was continually astonished at the depth (sometimes 100 feet) to which the
granitic rocks were decomposed in situ, and this soft matter would easily
give rise to great alluvial accumulations; I well remember finding it
difficult to draw a line between the alluvial matter and the softened rock
in situ. What a splendid imagination Agassiz has, and how energetic he is!
What capital work he would have done, if he had sucked in your "Principles"
with his mother's milk. It is wonderful that he should have written such
wild nonsense about the valley of the Amazon; yet not so wonderful when one
remembers that he once maintained before the British Association that the
chalk was all deposited at once.

With respect to the insects of Chili, I knew only from Bates that the
species of Carabus showed no special affinity to northern species; from the
great difference of climate and vegetation I should not have expected that
many insects would have shown such affinity. It is more remarkable that
the birds on the broad and lofty Cordillera of Tropical S. America show no
affinity with European species. The little power of diffusion with birds
has often struck me as a most singular fact--even more singular than the
great power of diffusion with plants. Remember that we hope to see you in
the autumn.

P.S.--There is a capital paper in the September number of "Annals and
Magazine," translated from Pictet and Humbert, on Fossil Fish of Lebanon,
but you will, I daresay, have received the original. (507/2. "Recent
Researches on the Fossil Fishes of Mount Lebanon," "Ann. Mag. Nat. Hist."
Volume XVIII., page 237, 1866.) It is capital in relation to modification
of species; I would not wish for more confirmatory facts, though there is
no direct allusion to the modification of species. Hooker, by the way,
gave an admirable lecture at Nottingham; I read it in MS., or rather, heard
it. I am glad it will be published, for it was capital. (507/3. Sir
Joseph Hooker delivered a lecture at the Nottingham meeting of the British
Association (1866) on "Insular Floras," published in the "Gardeners'
Chronicle," 1867. See Letters 366-377, etc.)

Sunday morning.

P.S.--I have just received a letter from Asa Gray with the following
passage, so that, according to this, I am the chief cause of Agassiz's
absurd views:--

"Agassiz is back (I have not seen him), and he went at once down to the
National Academy of Sciences, from which I sedulously keep away, and, I
hear, proved to them that the Glacial period covered the whole continent of
America with unbroken ice, and closed with a significant gesture and the
remark: 'So here is the end of the Darwin theory.' How do you like that?

"I said last winter that Agassiz was bent on covering the whole continent
with ice, and that the motive of the discovery he was sure to make was to
make sure that there should be no coming down of any terrestrial life from
Tertiary or post-Tertiary period to ours. You cannot deny that he has done
his work effectually in a truly imperial way."

Down, July 14th, 1868.

Mr. Agassiz's book has been read aloud to me, and I am wonderfully
perplexed what to think about his precise statements of the existence of
glaciers in the Ceara Mountains, and about the drift formation near Rio.
(508/1. "Sur la Geologie de l'Amazone," by MM. Agassiz and Continho,
"Bull. Soc. Geol. France," Volume XXV., page 685, 1868. See also "A
Journey in Brazil," by Professor and Mrs. Louis Agassiz, Boston, 1868.)
There is a sad want of details. Thus he never mentions whether any of the
blocks are angular, nor whether the embedded rounded boulders, which cannot
all be disintegrated, are scored. Yet how can so experienced an observer
as A. be deceived about lateral and terminal moraines? If there really
were glaciers in the Ceara Mountains, it seems to me one of the most
important facts in the history of the inorganic and organic world ever
observed. Whether true or not, it will be widely believed, and until
finally decided will greatly interfere with future progress on many points.
I have made these remarks in the hope that you will coincide. If so, do
you think it would be possible to persuade some known man, such as Ramsay,
or, what would be far better, some two men, to go out for a summer trip,
which would be in many respects delightful, for the sole object of
observing these phenomena in the Ceara Mountains, and if possible also near
Rio? I would gladly put my name down for 50 pounds in aid of the expense
of travelling. Do turn this over in your mind. I am so very sorry not to
have seen you this summer, but for the last three weeks I have been good
for nothing, and have had to stop almost all work. I hope we may meet in
the autumn.

Down, November 24th, 1868.

I have read with the greatest interest the last paper which you have kindly
sent me. (509/1. Croll discussed the power of icebergs as grinding and
striating agents in the latter part of a paper ("On Geological Time, and
the probable Dates of the Glacial and the Upper Miocene Period") published
in the "Philosophical Magazine," Volume XXXV., page 363, 1868, Volume
XXXVI., pages 141, 362, 1868. His conclusion was that the advocates of the
Iceberg theory had formed "too extravagant notions regarding the potency of
floating ice as a striating agent.") If we are to admit that all the
scored rocks throughout the more level parts of the United States result
from true glacier action, it is a most wonderful conclusion, and you
certainly make out a very strong case; so I suppose I must give up one more
cherished belief. But my object in writing is to trespass on your kindness
and ask a question, which I daresay I could answer for myself by reading
more carefully, as I hope hereafter to do, all your papers; but I shall
feel much more confidence in a brief reply from you. Am I right in
supposing that you believe that the glacial periods have always occurred
alternately in the northern and southern hemispheres, so that the erratic
deposits which I have described in the southern parts of America, and the
glacial work in New Zealand, could not have been simultaneous with our
Glacial period? From the glacial deposits occurring all round the northern
hemisphere, and from such deposits appearing in S. America to be as recent
as in the north, and lastly, from there being some evidence of the former
lower descent of glaciers all along the Cordilleras, I inferred that the
whole world was at this period cooler. It did not appear to me justifiable
without distinct evidence to suppose that the N. and S. glacial deposits
belonged to distinct epochs, though it would have been an immense relief to
my mind if I could have assumed that this had been the case. Secondly, do
you believe that during the Glacial period in one hemisphere the opposite
hemisphere actually becomes warmer, or does it merely retain the same
temperature as before? I do not ask these questions out of mere curiosity;
but I have to prepare a new edition of my "Origin of Species," and am
anxious to say a few words on this subject on your authority. I hope that
you will excuse my troubling you.

Down, January 31st, 1869.

To-morrow I will return registered your book, which I have kept so long. I
am most sincerely obliged for its loan, and especially for the MS., without
which I should have been afraid of making mistakes. If you require it, the
MS. shall be returned. Your results have been of more use to me than, I
think, any other set of papers which I can remember. Sir C. Lyell, who is
staying here, is very unwilling to admit the greater warmth of the S.
hemisphere during the Glacial period in the N.; but, as I have told him,
this conclusion which you have arrived at from physical considerations,
explains so well whole classes of facts in distribution, that I must
joyfully accept it; indeed, I go so far as to think that your conclusion is
strengthened by the facts in distribution. Your discussion on the flowing
of the great ice-cap southward is most interesting. I suppose that you
have read Mr. Moseley's recent discussion on the force of gravity being
quite insufficient to account for the downward movement of glaciers (510/1.
Canon Henry Moseley, "On the Mechanical Impossibility of the Descent of
Glaciers by their Weight only." "Proc. R. Soc." Volume XVII., page 202,
1869; "Phil. Mag." Volume XXXVII., page 229, 1869.): if he is right, do
you not think that the unknown force may make more intelligible the
extension of the great northern ice-cap? Notwithstanding your excellent
remarks on the work which can be effected within the million years (510/2.
In his paper "On Geological Time, and the probable Date of the Glacial and
the Upper Miocene Period" ("Phil. Mag." Volume XXXV., page 363, 1868),
Croll endeavours to convey to the mind some idea of what a million years
really is: "Take a narrow strip of paper, an inch broad or more, and 83
feet 4 inches in length, and stretch it along the wall of a large hall, or
round the walls of an apartment somewhat over 20 feet square. Recall to
memory the days of your boyhood, so as to get some adequate conception of
what a period of a hundred years is. Then mark off from one of the ends of
the strip one-tenth of an inch. The one-tenth of an inch will then
represent a hundred years, and the entire length of the strip a million of
years" (loc. cit., page 375).), I am greatly troubled at the short duration
of the world according to Sir W. Thomson (510/3. In a paper communicated
to the Royal Society of Edinburgh, Lord Kelvin (then Sir William Thomson)
stated his belief that the age of our planet must be more than twenty
millions of years, but not more than four hundred millions of years
("Trans. R. Soc. Edinb." Volume XXIII., page 157, 1861, "On the Secular
Cooling of the Earth."). This subject has been recently dealt with by Sir
Archibald Geikie in his address as President of the Geological Section of
the British Association, 1899 ("Brit. Assoc. Report," Dover Meeting, 1899,
page 718).), for I require for my theoretical views a very long period
BEFORE the Cambrian formation. If it would not trouble you, I should like
to hear what you think of Lyell's remark on the magnetic force which comes
from the sun to the earth: might not this penetrate the crust of the earth
and then be converted into heat? This would give a somewhat longer time
during which the crust might have been solid; and this is the argument on
which Sir W. Thomson seems chiefly to rest. You seem to argue chiefly on
the expenditure of energy of all kinds by the sun, and in this respect
Lyell's remark would have no bearing.

My new edition of the "Origin" (510/4. Fifth edition, May, 1869.) will be
published, I suppose, in about two months, and for the chance of your
liking to have a copy I will send one.

P.S.--I wish that you would turn your astronomical knowledge to the
consideration whether the form of the globe does not become periodically
slightly changed, so as to account for the many repeated ups and downs of
the surface in all parts of the world. I have always thought that some
cosmical cause would some day be discovered.

Down, July 12th [1872].

I have been glad to see the enclosed and return it. It seems to me very
cool in Agassiz to doubt the recent upheaval of Patagonia, without having
visited any part; and he entirely misrepresents me in saying that I infer
upheaval from the form of the land, as I trusted entirely to shells
embedded and on the surface. It is simply monstrous to suppose that the
terraces stretching on a dead level for leagues along the coast, and miles
in breadth, and covered with beds of stratified gravel, 10 to 30 feet in
thickness, are due to subaerial denudation.

As for the pond of salt-water twice or thrice the density of sea-water, and
nearly dry, containing sea-shells in the same relative proportions as on
the adjoining coast, it almost passes my belief. Could there have been a
lively midshipman on board, who in the morning stocked the pool from the
adjoining coast?

As for glaciation, I will not venture to express any opinion, for when in
S. America I knew nothing about glaciers, and perhaps attributed much to
icebergs which ought to be attributed to glaciers. On the other hand,
Agassiz seems to me mad about glaciers, and apparently never thinks of
drift ice.

I did see one clear case of former great extension of a glacier in T. del


(512/1. The following letter was in reply to a request from Prof. James
Geikie for permission to publish Mr. Darwin's views, communicated in a
previous letter (November 1876), on the vertical position of stones in
gravelly drift near Southampton. Prof. Geikie wrote (July 15th, 1880):
"You may remember that you attributed the peculiar position of those stones
to differential movements in the drift itself arising from the slow melting
of beds of frozen snow interstratified into the gravels...I have found this
explanation of great service even in Scotland, and from what I have seen of
the drift-gravels in various parts of southern England and northern France,
I am inclined to think that it has a wide application.")

Down, July 19th, 1880.

Your letter has pleased me very much, and I truly feel it an honour that
anything which I wrote on the drift, etc., should have been of the least
use or interest to you. Pray make any use of my letter (512/2. Professor
James Geikie quotes the letter in "Prehistoric Europe," London, 1881 (page
141). Practically the whole of it is given in the "Life and Letters,"
III., page 213.): I forget whether it was written carefully or clearly, so
pray touch up any passages that you may think fit to quote.

All that I have seen since near Southampton and elsewhere has strengthened
my notion. Here I live on a chalk platform gently sloping down from the
edge of the escarptment to the south (512/3. Id est, sloping down from the
escarpment which is to the south.) (which is about 800 feet in height) to
beneath the Tertiary beds to the north. The (512/4. From here to the end
of the paragraph is quoted by Prof. Geikie, loc. cit., page 142.) beds of
the large and broad valleys (and only of these) are covered with an immense
mass of closely packed broken and angular flints; in which mass the skull
of the musk-ox [musk-sheep] and woolly elephant have been found. This
great accumulation of unworn flints must therefore have been made when the
climate was cold, and I believe it can be accounted for by the larger
valleys having been filled up to a great depth during a large part of the
year with drifted frozen snow, over which rubbish from the upper parts of
the platforms was washed by the summer rains, sometimes along one line and
sometimes along another, or in channels cut through the snow all along the
main course of the broad valleys.

I suppose that I formerly mentioned to you the frequent upright position of
elongated flints in the red clayey residue over the chalk, which residue
gradually subsides into the troughs and pipes corroded in the solid chalk.
This letter is very untidy, but I am tired.

P.S. Several palaeolithic celts have recently been found in the great
angular gravel-bed near Southampton in several places.

Down, November 13th, 1880.

Your discovery is a very interesting one, and I congratulate you on it.
(513/1. "On the Precise Mode of Accumulation and Derivation of the Moel-
Tryfan Shelly Deposits; on the Discovery of Similar High-level Deposits
along the Eastern Slopes of the Welsh Mountains; and on the Existence of
Drift-Zones, showing probable Variations in the Rate of Submergence." By
D. Mackintosh, "Quart. Journ. Geol. Soc." Volume XXXVII., pages 351-69,
1881. [Read April 27th, 1881.]) I failed to find shells on Moel Tryfan,
but was interested by finding ("Philosoph. Mag." 3rd series, Volume XXI.,
page 184) shattered rocks (513/2. In reviewing the work by previous
writers on the Moel-Tryfan deposits, Mackintosh refers to Darwin's "very
suggestive description of the Moel-Tryfan deposits...Under the drift he saw
that the surface of the slate, TO A DEPTH OF SEVERAL FEET, HAD BEEN
slate, which Mackintosh regarded as "the most interesting of the Moel-
Tryfan phenomena," had not previously been regarded as "sufficiently
striking to arrest attention" by any geologist except Darwin. The
Pleistocene gravel and sand containing marine shells on Moel-Tryfan, about
five miles south-east of Caernarvon, have been the subject of considerable
controversy. By some geologists the drift deposits have been regarded as
evidence of a great submergence in post-Pliocene times, while others have
explained their occurrence at a height of 1300 feet by assuming that the
gravel and sand had been thrust uphill by an advancing ice-sheet. (See
H.B. Woodward, "Geology of England and Wales," Edition II., 1887, pages
491, 492.) Darwin attributed the shattering and contorting of the slates
below the drift to "icebergs grating over the surface.") and far-distant
rounded boulders, which I attributed to the violent impact of icebergs or
coast-ice. I can offer no opinion on whether the more recent changes of
level in England were or were not accompanied by earthquakes. It does not
seem to me a correct expression (which you use probably from haste in your
note) to speak of elevations or depressions as caused by earthquakes: I
suppose that every one admits that an earthquake is merely the vibration
from the fractured crust when it yields to an upward or downward force. I
must confess that of late years I have often begun to suspect (especially
when I think of the step-like plains of Patagonia, the heights of which
were measured by me) that many of the changes of level in the land are due
to changes of level in the sea. (513/3. This view is an agreement with
the theory recently put forward by Suess in his "Antlitz der Erde" (Prag
and Leipzig, 1885). Suess believes that "the local invasions and
transgressions of the continental areas by the sea" are due to "secular
movements of the hydrosphere itself." (See J. Geikie, F.R.S., Presidential
Address before Section E at the Edinburgh Meeting of the British
Association, "Annual Report," page 794.) I suppose that there can be no
doubt that when there was much ice piled up in the Arctic regions the sea
would be attracted to them, and the land on the temperate regions would
thus appear to have risen. There would also be some lowering of the sea by
evaporation and the fixing of the water as ice near the Pole.

I shall read your paper with much interest when published.

Down, December 13th, 1880.

You must allow me the pleasure of thanking you for the great interest with
which I have read your "Prehistoric Europe." (514/1. "Prehistoric Europe:
a Geological Sketch," London, 1881.) Nothing has struck me more than the
accumulated evidence of interglacial periods, and assuredly the
establishment of such periods is of paramount importance for understanding
all the later changes of the earth's surface. Reading your book has
brought vividly before my mind the state of knowledge, or rather ignorance,
half a century ago, when all superficial matter was classed as diluvium,
and not considered worthy of the attention of a geologist. If you can
spare the time (though I ask out of mere idle curiosity) I should like to
hear what you think of Mr. Mackintosh's paper, illustrated by a little map
with lines showing the courses or sources of the erratic boulders over the
midland counties of England. (514/2. "Results of a Systematic Survey, in
1878, of the Directions and Limits of Dispersion, Mode of Occurrence, and
Relation to Drift-Deposits of the Erratic Blocks or Boulders of the West of
England and East of Wales, including a Revision of Many Years' Previous
Observations," D. Mackintosh, "Quart. Journ. Geol. Soc." Volume XXXV., page
425, 1879.) It is a little suspicious their ending rather abruptly near
Wolverhampton, yet I must think that they were transported by floating ice.
Fifty years ago I knew Shropshire well, and cannot remember anything like
till, but abundance of gravel and sand beds, with recent marine shells. A
great boulder (514/3. Mackintosh alludes (loc. cit., page 442) to felstone
boulders around Ashley Heath, the highest ground between the Pennine and
Welsh Hills north of the Wrekin; also to a boulder on the summit of the
eminence (774 feet above sea-level), "probably the same as that noticed
many years ago by Mr. Darwin." In a later paper, "On the Correlation of
the Drift-Deposits of the North-West of England with those of the Midland
and Eastern Counties" ("Quart. Journ. Geol. Soc." Volume XXXVI., page 178,
1880) Mackintosh mentions a letter received from Darwin, "who was the first
to elucidate the boulder-transporting agency of floating ice," containing
an account of the great Ashley Heath boulder, which he was the first to
discover and expose, as to find that the block rested on fragments of
New Red Sandstone, one of which was split into two and deeply scored...The
facts mentioned in the letter from Mr. Darwin would seem to show that the
boulder must have fallen through water from floating ice with a force
sufficient to split the underlying lump of sandstone, but not sufficient to
crush it.") which I had undermined on the summit of Ashley Heath, 720 (?)
feet above the sea, rested on clean blocks of the underlying red sandstone.
I was also greatly interested by your long discussion on the Loss (514/4.
For an account of the Loss of German geologists--"a fine-grained, more or
less homogeneous, consistent, non-plastic loam, consisting of an intimate
admixture of clay and carbonate of lime," see J. Geikie, loc. cit., page
144 et seq.); but I do not feel satisfied that all has been made out about
it. I saw much brick-earth near Southampton in some manner connected with
the angular gravel, but had not strength enough to make out relations. It
might be worth your while to bear in mind the possibility of fine sediment
washed over and interstratified with thick beds of frozen snow, and
therefore ultimately dropped irrespective of the present contour of the

I remember as a boy that it was said that the floods of the Severn were
more muddy when the floods were caused by melting snow than from the
heaviest rains; but why this should be I cannot see.

Another subject has interested me much--viz. the sliding and travelling of
angular debris. Ever since seeing the "streams of stones" at the Falkland
Islands (514/5. "Geological Observations on South America" (1846), page 19
et seq.), I have felt uneasy in my mind on this subject. I wish Mr. Kerr's
notion could be fully elucidated about frozen snow. Some one ought to
observe the movements of the fields of snow which supply the glaciers in

Yours is a grand book, and I thank you heartily for the instruction and
pleasure which it has given me.

For heaven's sake forgive the untidiness of this whole note.

LETTER 515. TO JOHN LUBBOCK [Lord Avebury].
Down, November 6th, 1881.

If I had written your Address (515/1. Address delivered by Lord Avebury as
President of the British Association at York in 1881. Dr. Hicks is
mentioned as having classed the pre-Cambrian strata in "four great groups
of immense thickness and implying a great lapse of time" and giving no
evidence of life. Hicks' third formation was named by him the Arvonian
("Quart. Journ. Geol. Soc." Volume XXXVII., 1881, Proc., page 55.) (but
this requires a fearful stretch of imagination on my part) I should not
alter what I had said about Hicks. You have the support of the President
[of the] Geological Society (515/2. Robert Etheridge.), and I think that
Hicks is more likely to be right than X. The latter seems to me to belong
to the class of objectors general. If Hicks should be hereafter proved to
be wrong about this third formation, it would signify very little to you.

I forget whether you go as far as to support Ramsay about lakes as large as
the Italian ones: if so, I would myself modify the passage a little, for
these great lakes have always made me tremble for Ramsay, yet some of the
American geologists support him about the still larger N. American lakes.
I have always believed in the main in Ramsay's views from the date of
publication, and argued the point with Lyell, and am convinced that it is a
very interesting step in Geology, and that you were quite right to allude
to it. (515/3. "Glacial Origin of Lakes in Switzerland, Black Forest,
etc." ("Quart. Journ. Geol. Soc." Volume XVIII., pages 185-204, 1862).
Sir John Lubbock (Lord Avebury) gives a brief statement of Ramsay's views
concerning the origin of lakes (Presidential Address, Brit. Assoc. 1881,
page 22): "Prof. Ramsay divides lakes into three classes: (1) Those which
are due to irregular accumulations of drift, and which are generally quite
shallow; (2) those which are formed by moraines; and (3) those which occupy
true basins scooped by glaciers out of the solid rocks. To the latter
class belong, in his opinion, most of the great Swiss and Italian
lakes...Professor Ramsay's theory seems, therefore, to account for a large
number of interesting facts." Sir Archibald Geikie has given a good
summary of Ramsay's theory in his "Memoir of Sir Andrew Crombie Ramsay,"
page 361, London, 1895.)

Down, February 28th, 1882.

I have read professor Geikie's essay, and it certainly appears to me that
he underrated the importance of floating ice. (516/1. "The Intercrossing
of Erratics in Glacial Deposits," by James Geikie, "Scottish Naturalist,"
1881.) Memory extending back for half a century is worth a little, but I
can remember nothing in Shropshire like till or ground moraine, yet I can
distinctly remember the appearance of many sand and gravel beds--in some of
which I found marine shells. I think it would be well worth your while to
insist (but perhaps you have done so) on the absence of till, if absent in
the Western Counties, where you find many erratic boulders.

I was pleased to read the last sentence in Geikie's essay about the value
of your work. (516/2. The concluding paragraph reads as follows: "I
cannot conclude this paper without expressing my admiration for the long-
continued and successful labours of the well-known geologist whose views I
have been controverting. Although I entered my protest against his iceberg
hypothesis, and have freely criticised his theoretical opinions, I most
willingly admit that the results of his unwearied devotion to the study of
those interesting phenomena with which he is so familiar have laid all his
fellow-workers under a debt of gratitude." Mr. Darwin used to speak with
admiration of Mackintosh's work, carried on as it was under considerable

With respect to the main purport of your note, I hardly know what to say.
Though no evidence worth anything has as yet, in my opinion, been advanced
in favour of a living being, being developed from inorganic matter, yet I
cannot avoid believing the possibility of this will be proved some day in
accordance with the law of continuity. I remember the time, above fifty
years ago, when it was said that no substance found in a living plant or
animal could be produced without the aid of vital forces. As far as
external form is concerned, Eozoon shows how difficult it is to distinguish
between organised and inorganised bodies. If it is ever found that life
can originate on this world, the vital phenomena will come under some
general law of nature. Whether the existence of a conscious God can be
proved from the existence of the so-called laws of nature (i.e., fixed
sequence of events) is a perplexing subject, on which I have often thought,
but cannot see my way clearly. If you have not read W. Graham's "Creed of
Science," (516/3. "The Creed of Science: Religious, Moral, and Social,"
London, 1881.), it would, I think, interest you, and he supports the view
which you are inclined to uphold.


(517/1. In the bare hilly country of Lochaber, in the Scotch Highlands,
the slopes of the mountains overlooking the vale of Glen Roy are marked by
narrow terraces or parallel roads, which sweep round the shoulders of the
hills with "undeviating horizontality." These roads are described by Sir
Archibald Geikie as having long been "a subject of wonderment and legendary
story among the Highlanders, and for so many years a source of sore
perplexity among men of science." (517/2. "The Scenery of Scotland,"
1887, page 266.) In Glen Roy itself there are three distinct shelves or
terraces, and the mountain sides of the valley of the Spean and other glens
bear traces of these horizontal "roads."

The first important papers dealing with the origin of this striking
physical feature were those of MacCulloch (517/3. "Trans. Geol. Soc."
Volume IV., page 314, 1817.) and Sir Thomas Lauder Dick (517/4. "Trans. R.
Soc. Edinb." Volume IX., page 1, 1823.), in which the writers concluded
that the roads were the shore-lines of lakes which once filled the Lochaber
valleys. Towards the end of June 1838 Mr. Darwin devoted "eight good days"
(517/5. "Life and Letters," I., page 290.) to the examination of the
Lochaber district, and in the following year he communicated a paper to the
Royal Society of London, in which he attributed their origin to the action
of the sea, and regarded them as old sea beaches which had been raised to
their present level by a gradual elevation of the Lochaber district.

In 1840 Louis Agassiz and Buckland (517/6. "Edinb. New Phil. Journal,"
Volume XXXIII., page 236, 1842.) proposed the glacier-ice theory; they
described the valleys as having been filled with lakes dammed back by
glaciers which formed bars across the valleys of Glen Roy, Glen Spean, and
the other glens in which the hill-sides bear traces of old lake-margins.
Agassiz wrote in 1842: "When I visited the parallel roads of Glen Roy with
Dr. Buckland we were convinced that the glacial theory alone satisfied all
the exigencies of the phenomenon." (517/7. Ibid., page 236.)

Mr. David Milne (afterwards Milne-Home) (517/8. "Trans. R. Soc. Edinb."
Volume XVI., page 395, 1847.) in 1847 upheld the view that the ledges
represent the shore-lines of lakes which were imprisoned in the valleys by
dams of detrital material left in the glens during a submergence of 3,000
feet, at the close of the Glacial period. Chambers, in his "Ancient Sea
Margins" (1848), expressed himself in agreement with Mr. Darwin's marine
theory. The Agassiz-Buckland theory was supported by Mr. Jamieson (517/9.
"Quart. Journ. Geol. Soc." Volume XIX., page 235, 1863.), who brought
forward additional evidence in favour of the glacial barriers. Sir Charles
Lyell at first (517/10. "Elements of Geology," Edition II., 1841.)
accepted the explanation given by Mr. Darwin, but afterwards (517/11.
"Antiquity of Man," 1863, pages 252 et seq.) came to the conclusion that
the terrace-lines represent the beaches of glacial lakes. In a paper
published in 1878 (517/12. "Phil. Trans. R. Soc." 1879, page 663.), Prof.
Prestwich stated his acceptance of the lake theory of MacCulloch and Sir T.
Lauder Dick and of the glacial theory of Agassiz, but differed from these
authors in respect of the age of the lakes and the manner of formation of
the roads.

The view that has now gained general acceptance is that the parallel roads
of Glen Roy represent the shores of a lake "that came into being with the
growth of the glaciers and vanished as these melted away." (517/13. Sir
Archibald Geikie, loc. cit., page 269.)

Mr. Darwin became a convert to the glacier theory after the publication of
Mr. Jamieson's paper. He speaks of his own paper as "a great failure"; he
argued in favour of sea action as the cause of the terraces "because no
other explanation was possible under our then state of knowledge."
Convinced of his mistake, Darwin looked upon his error as "a good lesson
never to trust in science to the principle of exclusion." (517/14. "Life
and Letters," I., page 69.)

[March 9th, 1841.]

I have just received your note. It is the greatest pleasure to me to write
or talk Geology with you...

I think I have thought over the whole case without prejudice, and remain
firmly convinced they [the parallel roads] are marine beaches. My
principal reason for doing so is what I have urged in my paper (517/15.
"Observations on the Parallel Roads of Glen Roy, and of other parts of
Lochaber in Scotland, with an attempt to prove that they are of Marine
Origin." "Phil. Trans. R. Soc." 1839, page 39.), the buttress-like
accumulations of stratified shingle on sides of valley, especially those
just below the lowest shelf in Spean Valley.

2nd. I can hardly conceive the extension of the glaciers in front of the
valley of Kilfinnin, where I found a new road--where the sides of Great
Glen are not very lofty.

3rd. The flat watersheds which I describe in places where there are no
roads, as well as those connected with "roads." These remain unexplained.

I might continue to add many other such reasons, all of which, however, I
daresay would appear trifling to any one who had not visited the district.
With respect to equable elevation, it cannot be a valid objection to any
one who thinks of Scandinavia or the Pampas. With respect to the glacier
theory, the greatest objection appears to me the following, though possibly
not a sound one. The water has beyond doubt remained very long at the
levels of each shelf--this is unequivocally shown by the depth of the notch
or beach formed in many places in the hard mica-slate, and the large
accumulations or buttresses of well-rounded pebbles at certain spots on the
level of old beaches. (The time must have been immense, if formed by lakes
without tides.) During the existence of the lakes their drainage must have
been at the head of the valleys, and has given the flat appearance of the
watersheds. All this is very clear for four of the shelves (viz., upper
and lower in Glen Roy, the 800-foot one in Glen Spean, and the one in
Kilfinnin), and explains the coincidence of "roads" with the watersheds
more simply than my view, and as simply as the common lake theory. But how
was the Glen Roy lake drained when the water stood at level of the middle
"road"? It must (for there is no other exit whatever) have been drained
over the glacier. Now this shelf is full as narrow in a vertical line and
as deeply worn horizontally into the mountain side and with a large
accumulation of shingle (I can give cases) as the other shelves. We must,
therefore, on the glacier theory, suppose that the surface of the ice
remained at exactly the same level, not being worn down by the running
water, or the glacier moved by its own movement during the very long period
absolutely necessary for a quiet lake to form such a beach as this shelf
presents in its whole course. I do not know whether I have explained
myself clearly. I should like to know what you think of this difficulty.
I shall much like to talk over the Jura case with you. I am tired, so

Down [1846].

(518/1. It was agreed at the British Association meeting held at
Southampton in 1846 "That application be made to Her Majesty's Government
to direct that during the progress of the Ordnance Trigonometrical Surveys
in the North of Scotland, the so-called Parallel Roads of Glen Roy and the
adjoining country be accurately surveyed, with the view of determining
whether they are truly parallel and horizontal, the intervening distances,
and their elevations above the present sea-level" ("British Association
Report," 1846, page xix). The survey was undertaken by the Government
Ordnance Survey Office under Col. Sir Henry James, who published the
results in 1874 ("Notes on the Parallel Roads of Glen Roy"); the map on
which the details are given is sheet 63 (one-inch scale).)

In following your suggestion in drawing out something about Glen Roy for
the Geological Committee, I have been completely puzzled how to do it. I
have written down what I should say if I had to meet the head of the Survey
and wished to persuade him to undertake the task; but as I have written it,
it is too long, ill expressed, seems as if it came from nobody and was
going to nobody, and therefore I send it to you in despair, and beg you to
turn the subject in your mind. I feel a conviction if it goes through the
Geological part of Ordnance Survey it will be swamped, and as it is a case
for mere accurate measurements it might, I think without offence, go to the
head of the real Surveyors.

If Agassiz or Buckland are on the Committee they will sneer at the whole
thing and declare the beaches are those of a glacier-lake, than which I am
sure I could convince you that there never was a more futile theory.

I look forward to Southampton (518/2. The British Association meeting
(1846).) with much interest, and hope to hear to-morrow that the lodgings
are secured to us. You cannot think how thoroughly I enjoyed our
geological talks, and the pleasure of seeing Mrs. Horner and yourself here.
(518/3. This letter is published in the privately printed "Memoir of
Leonard Horner," II., page 103.)

[Here follows Darwin's Memorandum.]

The Parallel Roads of Glen Roy, in Scotland, have been the object of
repeated examination, but they have never hitherto been levelled with
sufficient accuracy. Sir T. Lauder Dick (518/4. "On the Parallel Roads of
Lochaber" (with map and plates), by Sir Thomas Lauder Dick, "Trans. R. Soc.
Edinb." Volume IX., page 1, 1823.) procured the assistance of an engineer
for this purpose, but owing to the want of a true ground-plan it was
impossible to ascertain their exact curvature, which, as far as could be
estimated, appeared equal to that of the surface of the sea. Considering
how very rarely the sea has left narrow and well-defined marks of its
action at any considerable height on the land, and more especially
considering the remarkable observations by M. Bravais (518/5. "On the
Lines of Ancient Level of the Sea in Finmark," by M. A. Bravais, translated
from "Voyages de la Commission Scientifique du Nord, etc."; "Quart. Journ.
Geol. Soc." Volume I., page 534, 1845.) on the ancient sea-beaches of
Scandinavia, showing the they are not strictly parallel to each other, and
that the movement has been greater nearer the mountains than on the coast,
it appears highly desirable that the roads of Glen Roy should be examined
with the utmost care during the execution of the Ordnance Survey of
Scotland. The best instruments and the most accurate measurements being
necessary for this end almost precludes the hope of its being ever
undertaken by private individuals; but by the means at the disposal of the
Ordnance, measurements would be easily made even more accurate than those
of M. Bravais. It would be desirable to take two lines of the greatest
possible length in the district, and at nearly right angles to each other,
and to level from the beach at one extremity to that at the other, so that
it might be ascertained whether the curvature does exactly correspond with
that of the globe, or, if not, what is the direction of the line of
greatest elevation. Much attention would be requisite in fixing on either
the upper or lower edge of the ancient beaches as the standard of
measurement, and in rendering this line conspicuous. The heights of the
three roads, one above the other and above the level of the sea, ought to
be accurately ascertained. Mr. Darwin observed one short beach-line north
of Glen Roy, and he has indicated, on the authority of Sir David Brewster,
others in the valley of the Spey. If these could be accurately connected,
by careful measurements of their absolute heights or by levelling, with
those of Glen Roy, it would make a most valuable addition to our knowledge
on this subject. Although the observations here specified would probably
be laborious, yet, considering how rarely such evidence is afforded in any
quarter of the world, it cannot be doubted that one of the most important
problems in Geology--namely, the exact manner in which the crust of the
earth rises in mass--would be much elucidated, and a great service done to
geological science.

St. Andrews, September 7th, 1847.

I have had a letter to-day from Mr. Charles Darwin, beseeching me to obtain
for him a copy of your paper on Glen Roy. (519/1. No doubt Mr. Milne's
paper "On the Parallel Roads of Lochaber," "Trans. R. Soc. Edinb." Volume
XVI., page 395, 1849. [Read March 1st and April 5th, 1847.]) I am sure
you will have pleasure in sending him one; his address is "Down,
Farnborough, Kent." I have again read over your paper carefully, and feel
assured that the careful collection and statement of facts which are found
in it must redound to your credit with all candid persons. The suspicions,
however, which I obtained some time ago as to land-straits and heights of
country being connected with sea-margins and their ordinary memorials still
possesses me, and I am looking forward to some means of further testing the
Glen Roy mystery. If my suspicion turn out true, I shall at once be
regretful on your account, and shall feel it as a great check and
admonition to myself not to be too confident about anything in science till
it has been proved over and over again. The ground hereabouts is now
getting clear of the crops; perhaps when I am in town a few days hence we
may be able to make some appointment for an examination of the beaches of
the district, my list of which has been greatly enlarged during the last
two months.

September 11th, 1847.

I hope you will read the first part of my paper before you go [to Glen
Roy], and attend to the manner in which the lines end in Glen Collarig. I
wish Mr. Milne had read it more carefully. He misunderstands me in several
respects, but [I] suppose it is my own fault, for my paper is most
tediously written. Mr. Milne fights me very pleasantly, and I plead guilty
to his rebuke about "demonstration." (520/1. See Letter 521, note.) I do
not know what you think; but Mr. Milne will think me as obstinate as a pig
when I say that I think any barriers of detritus at the mouth of Glen Roy,
Collarig and Glaster more utterly impossible than words can express. I
abide by all that I have written on that head. Conceive such a mass of
detritus having been removed, without great projections being left on each
side, in the very close proximity to every little delta preserved on the
lines of the shelves, even on the shelf 4, which now crosses with uniform
breadth the spot where the barrier stood, with the shelves dying gradually
out, etc. To my mind it is monstrous. Oddly enough, Mr. Milne's
description of the mouth of Loch Treig (I do not believe that valley has
been well examined in its upper end) leaves hardly a doubt that a glacier
descended from it, and, if the roads were formed by a lake of any kind, I
believe it must have been an ice-lake. I have given in detail to Lyell my
several reasons for not thinking ice-lakes probable (520/2. Mr. Darwin
gives some arguments against the glacier theory in the letter (517) to Sir
Charles Lyell; but the letter alluded to is no doubt the one written to
Lyell on "Wednesday, 8th" (Letter 522), in which the reasons are fully
stated.); but to my mind they are incomparably more probable than detritus
of rock-barriers. Have you ever attended to glacier action? After having
seen N. Wales, I can no more doubt the former existence of gigantic
glaciers than I can the sun in the heaven. I could distinguish in N. Wales
to a certain extent icebergs from glacier action (Lyell has shown that
icebergs at the present day score rocks), and I suspect that in Lochaber
the two actions are united, and that the scored rock on the watersheds,
when tideways, were rubbed and bumped by half-stranded icebergs. You will,
no doubt, attend to Glen Glaster. Mr. Milne, I think, does not mention
whether shelf 4 enters it, which I should like to know, and especially he
does not state whether rocks worn on their upper faces are found on the
whole 212 [feet] vertical course of this Glen down to near L. Loggan, or
whether only in the upper part; nor does he state whether these rocks are
scored, or polished, or moutonnees, or whether there are any "perched"
boulders there or elsewhere. I suspect it would be difficult to
distinguish between a river-bed and tidal channel. Mr. Milne's description
of the Pass of Mukkul, expanding to a width of several hundred yards 21
feet deep in the shoalest part, and with a worn islet in the middle, sounds
to me much more like a tidal channel than a river-bed. There must have
been, on the latter view, plenty of fresh water in those days. With
respect to the coincidence of the shelves with the now watersheds, Mr.
Milne only gives half of my explanation. Please read page 65 of my paper.
(520/3. "Observations on the Parallel Roads of Glen Roy, and of other
Parts of Lochaber in Scotland, with an Attempt to Prove that they are of
Marine Origin." "Phil. Trans. R. Soc." 1839, page 39. [Read February 7th,
1839.]) I allude only to the head of Glen Roy and Kilfinnin as silted up.
I did not know Mukkul Pass; and Glen Roy was so much covered up that I did
not search it well, as I was not able to walk very well. It has been an
old conjectural belief of mine that a rising surface becomes stationary,
not suddenly, but by the movement becoming very slow. Now, this would
greatly aid the tidal currents cutting down the passes between the
mountains just before, and to the level of, the stationary periods. The
currents in the fiords in T. del Fuego in a narrow crooked part are often
most violent; in other parts they seem to silt up.

Shall you do any levelling? I believe all the levelling has been [done] in
Glen Roy, nearly parallel to the Great Glen of Scotland. For inequalities
of elevation, the valley of the Spean, at right angles to the apparent axes
of elevation, would be the one to examine. If you go to the head of Glen
Roy, attend to the apparent shelf above the highest one in Glen Roy, lying
on the south side of Loch Spey, and therefore beyond the watershed of Glen
Roy. It would be a crucial case. I was too unwell on that day to examine
it carefully, and I had no levelling instruments. Do these fragments
coincide in level with Glen Gluoy shelf?

MacCulloch talks of one in Glen Turret above the shelf. I could not see
it. These would be important discoveries. But I will write no more, and
pray your forgiveness for this long, ill-written outpouring. I am very
glad you keep to your subject of the terraces. I have lately observed that
you have one great authority (C. Prevost), [not] that authority signifies a
[farthing?] on your side respecting your heretical and damnable doctrine of
the ocean falling. You see I am orthodox to the burning pitch.

Down, [September] 20th, [1847].

I am much obliged by your note. I returned from London on Saturday, and I
found then your memoir (521/1. "On the Parallel Roads of Lochaber, with
Remarks on the Change of Relative Levels of Sea and Land in Scotland, and
on the Detrital Deposits in that Country," "Trans. R. Soc. Edinb." Volume
XVI., page 395, 1849. [Read March 1st and April 5th, 1847.]), which I had
not then received, owing to the porter having been out when I last sent to
the Geological Society. I have read your paper with the greatest interest,
and have been much struck with the novelty and importance of many of your
facts. I beg to thank you for the courteous manner in which you combat me,
and I plead quite guilty to your rebuke about demonstration. (521/2. Mr.
Milne quotes a passage from Mr. Darwin's paper ("Phil. Trans. R. Soc."
1839, page 56), in which the latter speaks of the marine origin of the
parallel roads of Lochaber as appearing to him as having been demonstrated.
Mr. Milne adds: "I regret that Mr. Darwin should have expressed himself in
these very decided and confident terms, especially as his survey was
incomplete; for I venture to think that it can be satisfactorily
established that the parallel roads of Lochaber were formed by fresh-water
lakes" (Milne, loc. cit., page 400).) You have misunderstood my paper on a
few points, but I do not doubt that is owing to its being badly and
tediously written. You will, I fear, think me very obstinate when I say
that I am not in the least convinced about the barriers (521/3. Mr. Milne
believed that the lower parts of the valleys were filled with detritus,
which constituted barriers and thus dammed up the waters into lakes.):
they remain to me as improbable as ever. But the oddest result of your
paper on me (and I assure you, as far as I know myself, it is not
perversity) is that I am very much staggered in favour of the ice-lake
theory of Agassiz and Buckland (521/4. Agassiz and Buckland believed that
the lakes which formed the "roads" were confined by glaciers or moraines.
See "The Glacial Theory and its Recent Progress," by Louis Agassiz, "Edinb.
New Phil. Journ." Volume XXXIII., page 217, 1842 (with map).): until I
read your important discovery of the outlet in Glen Glaster I never thought
this theory at all tenable. (521/5. Mr. Milne discovered that the middle
shelf of Glen Roy, which Mr. Darwin stated was "not on a level with any
watershed" (Darwin, loc. cit., page 43), exactly coincided with a watershed
at the head of Glen Glaster (Milne, loc. cit., page 398).) Now it appears
to me that a very good case can be made in its favour. I am not, however,
as yet a believer in the ice-lake theory, but I tremble for the result. I
have had a good deal of talk with Mr. Lyell on the subject, and from his
advice I am going to send a letter to the "Scotsman," in which I give
briefly my present impression (though there is not space to argue with you
on such points as I think I could argue), and indicate what points strike
me as requiring further investigation with respect, chiefly, to the ice-
lake theory, so that you will not care about it...

P.S.--Some facts mentioned in my "Geology of S. America," page 24 (521/6.
The creeks which penetrate the western shores of Tierra del Fuego are
described as "almost invariably much shallower close to the open sea at
their mouths than inland...This shoalness of the sea-channels near their
entrances probably results from the quantity of sediment formed by the wear
and tear of the outer rocks exposed to the full force of the open sea. I
have no doubt that many lakes--for instance, in Scotland--which are very
deep within, and are separated from the sea apparently only by a tract of
detritus, were originally sea-channels, with banks of this nature near
their mouths, which have since been upheaved" ("Geol. Obs. S. America,"
page 24, footnote.), with regard to the shoaling of the deep fiords of T.
del Fuego near their mouths, and which I have remarked would tend, with a
little elevation, to convert such fiords into lakes with a great mound-like
barrier of detritus at their mouths, might, possibly, have been of use to
you with regard to the lakes of Glen Roy.

Down, Wednesday, 8th.

Many thanks for your paper. (522/1. "On the Ancient Glaciers of
Forfarshire." "Proc. Geol. Soc." Volume III., page 337, 1840.) I do
admire your zeal on a subject on which you are not immediately at work. I
will give my opinion as briefly as I can, and I have endeavoured my best to
be honest. Poor Mrs. Lyell will have, I foresee, a long letter to read
aloud, but I will try to write better than usual. Imprimis, it is
provoking that Mr. Milne (522/2. "On the Parallel Roads of Lochaber, etc."
"Trans. R. Soc. Edinb." Volume XVI., page 395, 1849. [Read March 1st and
April 5th, 1847.]) has read my paper (522/3. "Observations on the Parallel
Roads of Glen Roy, etc." "Phil. Trans. R. Soc." 1839, page 39. [Read
February 7th, 1839.].) with little attention, for he makes me say several
things which I do not believe--as, that the water sunk suddenly! (page 10),
that the Valley of Glen Roy, page 13, and Spean was filled up with detritus
to level of the lower shelf, against which there is, I conceive, good
evidence, etc., but I suppose it is the consequence of my paper being most
tediously written. He gives me a just snub for talking of demonstration,
and he fights me in a very pleasant manner. Now for business. I utterly
disbelieve in the barriers (522/4. See note, Letter 521.) for his lakes,
and think he has left that point exactly where it was in the time of
MacCulloch (522/5. "On the Parallel Roads of Glen Roy." "Geol. Trans."
Volume IV., page 314, 1817 (with several maps and sections).) and Dick.
(522/6. "On the Parallel Roads of Lochaber." "Trans. R. Soc. Edinb."
Volume IX., page 1, 1823.) Indeed, in showing that there is a passage at
Glen Glaster at the level of the intermediate shelf, he makes the
difficulty to my mind greater. (522/7. See Letter 521, note.) When I
think of the gradual manner in which the two upper terraces die out at Glen
Collarig and at the mouth of Glen Roy, the smooth rounded form of the hills
there, and the lower shelf retaining its usual width where the immense
barrier stood, I can deliberately repeat "that more convincing proofs of
the non-existence of the imaginary Loch Roy could scarcely have been
invented with full play given to the imagination," etc.: but I do not
adhere to this remark with such strength when applied to the glacier-lake
theory. Oddly, I was never at all staggered by this theory until now,
having read Mr. Milne's argument against it. I now can hardly doubt that a
great glacier did emerge from Loch Treig, and this by the ice itself (not
moraine) might have blocked up the three outlets from Glen Roy. I do not,
however, yet believe in the glacier theory, for reasons which I will
presently give.

There are three chief hostile considerations in Mr. Milne's paper. First,
the Glen [shelf?], not coinciding in height with the upper one [outlet?],
from observations giving 12 feet, 15 feet, 29 feet, 23 feet: if the latter
are correct the terrace must be quite independent, and the case is hostile;
but Mr. Milne shows that there is one in Glen Roy 14 feet below the upper
one, and a second one again (which I observed) beneath this, and then we
come to the proper second shelf. Hence there is no great improbability in
an independent shelf having been found in Glen Gluoy.

This leads me to Mr. Milne's second class of facts (obvious to every one),
namely the non-extension of the three shelves beyond Glen Roy; but I abide
by what I have written on that point, and repeat that if in Glen Roy, where
circumstances have been so favourable for the preservation or formation of
the terraces, a terrace could be formed quite plain for three-quarters of a
mile with hardly a trace elsewhere, we cannot argue, from the non-existence
of shelves, that water did not stand at the same levels in other valleys.
Feeling absolutely convinced that there was no barrier of detritus at the
mouth of Glen Roy, and pretty well convinced that there was none of ice,
the manner in which the terraces die out when entering Glen Spean, which
must have been a tideway, shows on what small circumstances the formation
of these shelves depended. With respect to the non-existence of shelves in
other parts of Scotland, Mr. Milne shows that many others do exist, and
their heights above the sea have not yet been carefully measured, nor have
even those of Glen Roy, which I suspect are all 100 feet too high.
Moreover, according to Bravais (522/8. "On the Lines of Ancient Level of
the Sea in Finmark." By A. Bravais, Member of the Scientific Commission of
the North. "Quart. Journ. Geol. Soc." Volume I., page 534, 1845 (a
translation).), we must not feel sure that either the absolute height or
the intermediate heights between the terraces would be at all the same at
distant points. In levelling the terraces in Lochaber, all, I believe,
have been taken in Glen Roy, nearly N. and S. There should be levels taken
at right angles to this line and to the Great Glen of Scotland or chief
line of elevation.

Thirdly, the nature of the outlets from the supposed lakes. This appears
to me the best and newest part of the paper. If Sir James Clark would like
to attend to any particular points, direct his attention to this:
especially to follow Glen Glaster from Glen Roy to L. Laggan. Mr. Milne
describes this as an old and great river-course with a fall of 212 feet.
He states that the rocks are smooth on upper face and rough on lower, but
he does not mention whether this character prevails throughout the whole
212 vertical feet--a most important consideration; nor does he state
whether these rocks are polished or scratched, as might have happened even
to a considerable depth beneath the water (Mem. great icebergs in narrow
fiords of T. del Fuego (522/9. In the "Voyage of the 'Beagle'" a
description is given of the falling of great masses of ice from the icy
cliffs of the glaciers with a crash that "reverberates like the broadside
of a man-of-war, through the lonely channels" which intersect the
coast-line of Tierra del Fuego. Loc. cit., page 246.)) by the action of
icebergs, for that icebergs transported boulders on to terraces, I have no
doubt. Mr. Milne's description of the outlets of his lake sound to me more
like tidal channels, nor does he give any arguments how such are to be
distinguished from old river-courses. I cannot believe in the body of
fresh water which must, on the lake theory, have flowed out of them. At
the Pass of Mukkul he states that the outlet is 70 feet wide and the rocky
bottom 21 feet below the level of the shelf, and that the gorge expands to
the eastwards into a broad channel of several hundred yards in width,
divided in the middle by what has formerly been a rocky islet, against
which the waters of this large river had chafed in issuing from the pass.
We know the size of the river at the present day which would flow out
through this pass, and it seems to me (and in the other given cases) to be
as inadequate; the whole seems to me far easier explained by a tideway than
by a formerly more humid climate.

With respect to the very remarkable coincidence between the shelves and the
outlets (rendered more remarkable by Mr. Milne's discovery of the outlet to
the intermediate shelf at Glen Glaster (522/10. See Letter 521, note.)),
Mr. Milne gives only half of my explanation; he alludes to (and disputes)
the smoothing and silting-up action, which I still believe in. I state:
If we consider what must take place during the gradual rise of a group of
islands, we shall have the currents endeavouring to cut down and deepen
some shallow parts in the channels as they are successively brought near
the surface, but tending from the opposition of tides to choke up others
with littoral deposits. During a long interval of rest, from the length of
time allowed to the above processes, the tendency would often prove
effective, both in forming, by accumulation of matter, isthmuses, and in
keeping open channels. Hence such isthmuses and channels just kept open
would oftener be formed at the level which the waters held at the interval
of rest, than at any other (page 65). I look at the Pass of Mukkul (21
feet deep, Milne) as a channel just kept open, and the head of Glen Roy
(where there is a great bay silted up) and of Kilfinnin (at both which
places there are level-topped mounds of detritus above the level of the
terraces) as instances of channels filled up at the stationary levels. I
have long thought it a probable conjecture that when a rising surface
becomes stationary it becomes so, not at once, but by the movements first
becoming very slow; this would greatly favour the cutting down many gaps in
the mountains to the level of the stationary periods.


If a glacialist admitted that the sea, before the formation of the
terraces, covered the country (which would account for land-straits above
level of terraces), and that the land gradually emerged, and if he supposed
his lakes were banked by ice alone, he would make out, in my opinion, the
best case against the marine origin of the terraces. From the scattered
boulders and till, you and I must look at it as certain that the sea did
cover the whole country, and I abide quite by my arguments from the
buttresses, etc., that water of some kind receded slowly from the valleys
of Lochaber (I presume Mr. Milne admits this). Now, I do not believe in
the ice-lake theory, from the following weak but accumulating reasons:
because, 1st, the receding water must have been that of a lake in Glen
Spean, and of the sea in the other valleys of Scotland, where I saw similar
buttresses at many levels; 2nd, because the outlets of the supposed lakes
as already stated seem, from Mr. Milne's statements, too much worn and too
large; 3rd, when the lake stood at the three-quarters of a mile shelf the
water from it must have flowed over ice itself for a very long time, and
kept at the same exact level: certainly this shelf required a long time
for its formation; 4th, I cannot believe a glacier would have blocked up
the short, very wide valley of Kilfinnin, the Great Glen of Scotland also
being very low there; 5th, the country at some places where Mr. Milne has
described terraces is not mountainous, and the number of ice-lakes appears
to me very improbable; 6th, I do not believe any lake could scoop the rocks
so much as they are at the entrance to Loch Treig or cut them off at the
head of Upper Glen Roy; 7th, the very gradual dying away of the terraces at
the mouth of Glen Roy does not look like a barrier of any kind; 8th, I
should have expected great terminal moraines across the mouth of Glen Roy,
Glen Collarig, and Glaster, at least at the bottom of the valleys. Such, I
feel pretty sure, do not exist.

I fear I must have wearied you with the length of this letter, which I have
not had time to arrange properly. I could argue at great length against
Mr. Milne's theory of barriers of detritus, though I could help him in one
way--viz., by the soundings which occur at the entrances of the deepest
fiords in T. del Fuego. I do not think he gives the smallest satisfaction
with respect to the successive and comparatively sudden breakage of his
many lakes.

Well, I enjoyed my trip to Glen Roy very much, but it was time thrown away.
I heartily wish you would go there; it should be some one who knows glacier
and iceberg action, and sea action well. I wish the Queen would command
you. I had intended being in London to-morrow, but one of my principal
plagues will, I believe, stop me; if I do I will assuredly call on you. I
have not yet read Mr. Milne on Elevation (522/11. "On a Remarkable
Oscillation of the Sea, observed at Various Places on the Coasts of Great
Britain in the First Week of July, 1843." "Trans. R. Soc. Edinb." Volume
XV., page 609, 1844.), so will keep his paper for a day or two.

P.S.--As you cannot want this letter, I wish you would return it to me, as
it will serve as a memorandum for me. Possibly I shall write to Mr.
Chambers, though I do not know whether he will care about what I think on
the subject. This letter is too long and ill-written for Sir J. Clark.

[October 4th, 1847.]

I enclose a letter from Chambers, which has pleased me very much (which
please return), but I cannot feel quite so sure as he does. If the
Lochaber and Tweed roads really turn out exactly on a level, the sea theory
is proved. What a magnificent proof of equality of elevation, which does
not surprise me much; but I fear I see cause of doubt, for as far as I
remember there are numerous terraces, near Galashiels, with small intervals
of height, so that the coincidence of height might be cooked. Chambers
does not seem aware of one very striking coincidence, viz., that I made by
careful measurement my Kilfinnin terrace 1202 feet above sea, and now Glen
Gluoy is 1203 feet, according to the recent more careful measurements.
Even Agassiz (523/1. "On the Glacial Theory," by Louis Agassiz, "Edinb.
New Phil. Journ." Volume XXXIII., page 217, 1842. The parallel terraces
are dealt with by Agassiz, pages 236 et seq.) would be puzzled to block up
Glen Gluoy and Kilfinnin by the same glacier, and then, moreover, the lake
would have two outlets. With respect to the middle terrace of Glen Roy--
seen by Chambers in the Spean (figured by Agassiz, and seen by myself but
not noticed, as I thought it might have been a sheep track)--it might yet
have been formed on the ice-lake theory by two independent glaciers going
across the Spean, but it is very improbable that two such immense ones
should not have been united into one. Chambers, unfortunately, does not
seem to have visited the head of the Spey, and I have written to propose
joining funds and sending some young surveyor there. If my letter is
published in the "Scotsman," how Buckland (523/2. Professor Buckland may
be described as joint author, with Agassiz, of the Glacier theory.), as I
have foreseen, will crow over me: he will tell me he always knew that I
was wrong, but now I shall have rather ridiculously to say, "but I am all
right again."

I have been a good deal interested in Miller (523/3. Hugh Miller's "First
Impressions of England and its People," London, 1847.), but I find it not
quick reading, and Emma has hardly begun it yet. I rather wish the scenic
descriptions were shorter, and that there was a little less geologic

Lyell's picture now hangs over my chimneypiece, and uncommonly glad I am to
have it, and thank you for it.

Down, September 6th [1861].

I think the enclosed is worth your reading. I am smashed to atoms about
Glen Roy. My paper was one long gigantic blunder from beginning to end.
Eheu! Eheu! (524/1. See "Life and Letters," I., pages 68, 69, also pages
290, 291.)

Down, September 22nd [1861].

I have read Mr. Jamieson's last letter, like the former ones, with very
great interest. (525/1. Mr. Jamieson visited Glen Roy in August 1861 and
in July 1862. His paper "On the Parallel Roads of Glen Roy, and their
Place in the History of the Glacial Period," was published in the
"Quarterly Journal of the Geological Society" in 1863, Volume XIX., page
235. His latest contribution to this subject was published in the
"Quarterly Journal," Volume XLVIII., page 5, 1892.) What a problem you
have in hand! It beats manufacturing new species all to bits. It would be
a great personal consolation to me if Mr. J. can admit the sloping Spean
terrace to be marine, and would remove one of my greatest difficulties--
viz. the vast contrast of Welsh and Lochaber valleys. But then, as far as
I dare trust my observations, the sloping terraces ran far up the Roy
valley, so as to reach not far below the lower shelf. If the sloping
fringes are marine and the shelves lacustrine, all I can say is that nature
has laid a shameful trap to catch an unwary wretch. I suppose that I have
underrated the power of lakes in producing pebbles; this, I think, ought to
be well looked to. I was much struck in Wales on carefully comparing the
glacial scratches under a lake (formed by a moraine and which must have
existed since the Glacial epoch) and above water, and I could perceive NO
difference. I believe I saw many such beds of good pebbles on level of
lower shelf, which at the time I could not believe could have been found on
shores of lake. The land-straits and little cliffs above them, to which I
referred, were quite above the highest shelf; they may be of much more
ancient date than the shelves. Some terrace-like fringes at head of the
Spey strike me as very suspicious. Mr. J. refers to absence of pebbles at
considerable heights: he must remember that every storm, every deer, every
hare which runs tends to roll pebbles down hill, and not one ever goes up
again. I may mention that I particularly alluded to this on S. Ventanao
(525/2. "Geolog. Obs. on South America," page 79. "On the flanks of the
mountains, at a height of 300 or 400 feet above the plain, there were a few
small patches of conglomerate and breccia, firmly cemented by ferruginous
matter to the abrupt and battered face of the quartz--traces being thus
exhibited of ancient sea-action.") in N. Patagonia, a great isolated rugged
quartz-mountain 3,000 feet high, and I could find not one pebble except on
one very small spot, where a ferruginous spring had firmly cemented a few
to the face of mountain. If the Lochaber lakes had been formed by an ice-
period posterior to the (marine?) sloping terraces in the Spean, would not
Mr. J. have noticed gigantic moraines across the valley opposite the
opening of Lake Treig? I go so far as not to like making the elevation of
the land in Wales and Scotland considerably different with respect to the
ice-period, and still more do I dislike it with respect to E. and W.
Scotland. But I may be prejudiced by having been so long accustomed to the
plains of Patagonia. But the equality of level (barring denudation) of
even the Secondary formations in Britain, after so many ups and downs,
always impresses my mind, that, except when the crust-cracks and mountains
are formed, movements of elevation and subsidence are generally very

But it is folly my scribbling thus. You have a grand problem, and heaven
help you and Mr. Jamieson through it. It is out of my line nowadays, and
above and beyond me.

Down, September 28th [1861].

It is, I believe, true that Glen Roy shelves (I remember your Indian
letter) were formed by glacial lakes. I persuaded Mr. Jamieson, an
excellent observer, to go and observe them; and this is his result. There
are some great difficulties to be explained, but I presume this will
ultimately be proved the truth...

Down, October 1st [1861].

Thank you for the most interesting correspondence. What a wonderful case
that of Bedford. (527/1. No doubt this refers to the discovery of flint
implements in the Valley of the Ouse, near Bedford, in 1861 (see Lyell's
"Antiquity of Man," pages 163 et seq., 1863.) I thought the problem
sufficiently perplexing before, but now it beats anything I ever heard of.
Far from being able to give any hypothesis for any part, I cannot get the
facts into my mind. What a capital observer and reasoner Mr. Jamieson is.
The only way that I can reconcile my memory of Lochaber with the state of
the Welsh valleys is by imagining a great barrier, formed by a terminal
moraine, at the mouth of the Spean, which the river had to cut slowly
through, as it drained the lowest lake after the Glacial period. This
would, I can suppose, account for the sloping terraces along the Spean. I
further presume that sharp transverse moraines would not be formed under
the waters of the lake, where the glacier came out of L. Treig and abutted
against the opposite side of the valley. A nice mess I made of Glen Roy!
I have no spare copy of my Welsh paper (527/2. "Notes on the Effects
produced by the Ancient Glaciers of Caernarvonshire, and on the Boulders
transported by Floating Ice," "Edinb. New Phil. Journ." Volume XXXIII.,
page 352, 1842.); it would do you no good to lend it. I suppose I thought
that there must have been floating ice on Moel Tryfan. I think it cannot
be disputed that the last event in N. Wales was land-glaciers. I could not
decide where the action of land-glaciers ceased and marine glacial action
commenced at the mouths of the valleys.

What a wonderful case the Bedford case. Does not the N. American view of
warmer or more equable period, after great Glacial period, become much more
probable in Europe?

But I am very poorly to-day, and very stupid, and hate everybody and
everything. One lives only to make blunders. I am going to write a little
book for Murray on Orchids (527/3. "On the Various Contrivances by which
Orchids are Fertilised by Insects," London, 1862.), and to-day I hate them
worse than everything. So farewell, in a sweet frame of mind.

Down, October 14th [1861].

I return Jamieson's capital letter. I have no comments, except to say that
he has removed all my difficulties, and that now and for evermore I give up
and abominate Glen Roy and all its belongings. It certainly is a splendid
case, and wonderful monument of the old Ice-period. You ought to give a
woodcut. How many have blundered over those horrid shelves!

That was a capital paper by Jamieson in the last "Geol. Journal." (528/1.
"On the Drift and Rolled Gravel of the North of Scotland," "Quart. Journ.
Geol. Soc." Volume XVI., page 347, 1860.) I was never before fully
convinced of the land glacialisation of Scotland before, though Chambers
tried hard to convince me.

I must say I differ rather about Ramsay's paper; perhaps he pushes it too
far. (528/2. "On the Glacial Origin of Certain Lakes, etc." "Quart.
Journ. Geol. Soc." Volume XVIII., page 185. See Letter 503.) It struck me
the more from remembering some years ago marvelling what could be the
meaning of such a multitude of lakes in Friesland and other northern
districts. Ramsay wrote to me, and I suggested that he ought to compare
mountainous tropical regions with northern regions. I could not remember
many lakes in any mountainous tropical country. When Tyndall talks of
every valley in Switzerland being formed by glaciers, he seems to forget
there are valleys in the tropics; and it is monstrous, in my opinion, the
accounting for the Glacial period in the Alps by greater height of
mountains, and their lessened height, if I understand, by glacial erosion.
"Ne sutor ultra crepidam," I think, applies in this case to him. I am hard
at work on "Variation under Domestication." (528/3. Published 1868.)

P.S.--I am rather overwhelmed with letters at present, and it has just
occurred to me that perhaps you will forward my note to Mr. Jamieson; as it
will show that I entirely yield. I do believe every word in my Glen Roy
paper is false.

Down, October 20th [1861].

Notwithstanding the orchids, I have been very glad to see Jamieson's
letter; no doubt, as he says, certainty will soon be reached.

With respect to the minor points of Glen Roy, I cannot feel easy with a
mere barrier of ice; there is so much sloping, stratified detritus in the
valleys. I remember that you somewhere have stated that a running stream
soon cuts deeply into a glacier. I have been hunting up all old references
and pamphlets, etc., on shelves in Scotland, and will send them off to Mr.
J., as they possibly may be of use to him if he continues the subject. The
Eildon Hills ought to be specially examined. Amongst MS. I came across a
very old letter from me to you, in which I say: "If a glacialist admitted
that the sea, before the formation of the shelves, covered the country
(which would account for the land-straits above the level of the shelves),
and if he admitted that the land gradually emerged, and if he supposed that
his lakes were banked up by ice alone, he would make out, in my opinion,
the best case against the marine origin of the shelves." (529/1. See
Letter 522.) This seems very much what you and Mr. J. have come to.

The whole glacial theory is really a magnificent subject.

Down, April 1st [1862].

I am not quite sure that I understand your difficulty, so I must give what
seems to me the explanation of the glacial lake theory at some little
length. You know that there is a rocky outlet at the level of all the
shelves. Please look at my map. (530/1. The map accompanying Mr.
Darwin's paper in the "Phil. Trans. R. Soc." 1839.) I suppose whole valley
of Glen Spean filled with ice; then water would escape from an outlet at
Loch Spey, and the highest shelf would be first formed. Secondly, ice
began to retreat, and water will flow for short time over its surface; but
as soon as it retreated from behind the hill marked Craig Dhu, where the
outlet on level of second shelf was discovered by Milne (530/2. See note,
Letter 521.), the water would flow from it and the second shelf would be
formed. This supposes that a vast barrier of ice still remains under Ben
Nevis, along all the lower part of the Spean. Lastly, I suppose the ice
disappeared everywhere along L. Loggan, L. Treig, and Glen Spean, except
close under Ben Nevis, where it still formed a barrier, the water flowing
out at level of lowest shelf by the Pass of Mukkul at head of L. Loggan.
This seems to me to account for everything. It presupposes that the
shelves were formed towards the close of the Glacial period. I come up to
London to read on Thursday a short paper at the Linnean Society. Shall I
call on Friday morning at 9.30 and sit half an hour with you? Pray have no
scruple to send a line to Queen Anne Street to say "No" if it will take
anything out of you. If I do not hear, I will come.

Down, January 3rd, 1880.

You are perfectly right. (531/1. Prof. Prestwich's paper on Glen Roy was
published in the "Phil. Trans. R. Soc." for 1879, page 663.) As soon as I
read Mr. Jamieson's article on the parallel roads, I gave up the ghost with
more sighs and groans than on almost any other occasion in my life.


Shrewsbury, Tuesday, 6th [July, 1841].

Your letter was forwarded me here. I was the more glad to receive it, as I
never dreamed of your being able to find time to write, now that you must
be so very busy; and I had nothing to tell you about myself, else I should
have written. I am pleased to hear how extensive and successful a trip you
appear to have made. You must have worked hard, and got your Silurian
subject well in your head, to have profited by so short an excursion. How
I should have enjoyed to have followed you about the coral-limestone. I
once was close to Wenlock (532/1. The Wenlock limestone (Silurian)
contains an abundance of corals. "The rock seems indeed to have been
formed in part by massive sheets and bunches of coral" (Geikie, "Text-book
of Geology," 1882, page 678.), something such as you describe, and made a
rough drawing, I remember, of the masses of coral. But the degree in which
the whole mass was regularly stratified, and the quantity of mud, made me
think that the reefs could never have been like those in the Pacific, but
that they most resembled those on the east coast of Africa, which seem
(from charts and descriptions) to confine extensive flats and mangrove
swamps with mud, or like some imperfect ones about the West India Islands,
within the reefs of which there are large swamps. All the reefs I have
myself seen could be associated only with nearly pure calcareous rocks. I
have received a description of a reef lying some way off the coast near
Belize (terra firma), where a thick bed of mud seems to have invaded and
covered a coral reef, leaving but very few islets yet free from it. But I
can give you no precise information without my notes (even if then) on
these heads...

Bermuda differs much from any other island I am acquainted with. At first
sight of a chart it resembles an atoll; but it differs from this structure
essentially in the gently shelving bottom of the sea all round to some
distance; in the absence of the defined circular reefs, and, as a
consequence, of the defined central pool or lagoon; and lastly, in the
height of the land. Bermuda seems to be an irregular, circular, flat bank,
encrusted with knolls and reefs of coral, with land formed on one side.
This land seems once to have been more extensive, as on some parts of the
bank farthest removed from the island there are little pinnacles of rock of
the same nature as that of the high larger islands. I cannot pretend to
form any precise notion how the foundation of so anomalous an island has
been produced, but its whole history must be very different from that of
the atolls of the Indian and Pacific oceans--though, as I have said, at
first glance of the charts there is a considerable resemblance.


Considering the probability of subsidence in the middle of the great oceans
being very slow; considering in how many spaces, both large ones and small
ones (within areas favourable to the growth of corals), reefs are absent,
which shows that their presence is determined by peculiar conditions;
considering the possible chance of subsidence being more rapid than the
upward growth of the reefs; considering that reefs not very rarely perish
(as I cannot doubt) on part, or round the whole, of some encircled islands
and atolls: considering these things, I admit as very improbable that the
polypifers should continue living on and above the same reef during a
subsidence of very many thousand feet; and therefore that they should form
masses of enormous thickness, say at most above 5,000 feet. (533/1.
"...As we know that some inorganic causes are highly injurious to the
growth of coral, it cannot be expected that during the round of change to
which earth, air, and water are exposed, the reef-building polypifers
should keep alive for perpetuity in any one place; and still less can this
be expected during the progressive which by our theory
these reefs and islands have been subjected, and are liable" ("The
Structure and Distribution of Coral Reefs," page 107: London, 1842).)
This admission, I believe, is in no way fatal to the theory, though it is
so to certain few passages in my book.

In the areas where the large groups of atolls stand, and where likewise a
few scattered atolls stand between such groups, I always imagined that
there must have been great tracts of land, and that on such large tracts
there must have been mountains of immense altitudes. But not, it appears
to me, that one is only justified in supposing that groups of islands stood
there. There are (as I believe) many considerable islands and groups of
islands (Galapagos Islands, Great Britain, Falkland Islands, Marianas, and,
I believe, Viti groups), and likewise the majority of single scattered
islands, all of which a subsidence between 4,000 and 5,000 feet would
entirely submerge or would leave only one or two summits above water, and
hence they would produce either groups of nothing but atolls, or of atolls
with one or two encircled islands. I am far from wishing to say that the
islands of the great oceans have not subsided, or may not continue to
subside, any number of feet, but if the average duration (from all causes
of destruction) of reefs on the same spot is limited, then after this limit
has elapsed the reefs would perish, and if the subsidence continued they
would be carried down; and if the group consisted only of atolls, only open
ocean would be left; if it consisted partly or wholly of encircled islands,
these would be left naked and reefless, but should the area again become
favourable for growth of reefs, new barrier-reefs might be formed round
them. As an illustration of this notion of a certain average duration of
reefs on the same spot, compared with the average rate of subsidence, we
may take the case of Tahiti, an island of 7,000 feet high. Now here the
present barrier-reefs would never be continued upwards into an atoll,
although, should the subsidence continue at a period long after the death
of the present reefs, new ones might be formed high up round its sides and
ultimately over it. The case resolves itself into: what is the ordinary
height of groups of islands, of the size of existing groups of atolls
(excepting as many of the highest islands as there now ordinarily occur
encircling barrier-reefs in the existing groups of atolls)? and likewise
what is the height of the single scattered islands standing between such
groups of islands? Subsidence sufficient to bury all these islands (with
the exception of as many of the highest as there are encircled islands in
the present groups of atolls) my theory absolutely requires, but no more.
To say what amount of subsidence would be required for this end, one ought
to know the height of all existing islands, both single ones and those in
groups, on the face of the globe--and, indeed, of half a dozen worlds like
ours. The reefs may be of much greater [thickness] than that just
sufficient on an average to bury groups of islands; and the probability of
the thickness being greater seems to resolve itself into the average rate
of subsidence allowing upward growth, and average duration of reefs on the
same spot. Who will say what this rate and what this duration is? but till
both are known, we cannot, I think, tell whether we ought to look for
upraised coral formations (putting on one side denudation) above the
unknown limit, say between 3,000 and 5,000 feet, necessary to submerge
groups of common islands. How wretchedly involved do these speculations

Down, January 29th, 1879.

I thank you cordially for the continuation of your fine work on the
Tyrolese Dolomites (534/1. "Dolomitriffe Sudtirols und Venetiens": Wien,
1878.), with its striking engravings and the maps, which are quite
wonderful from the amount of labour which they exhibit, and its extreme
difficulty. I well remember more than forty years ago examining a section
of Silurian limestone containing many corals, and thinking to myself that
it would be for ever impossible to discover whether the ancient corals had
formed atolls or barrier reefs; so you may well believe that your work will
interest me greatly as soon as I can find time to read it. I am much
obliged for your photograph, and from its appearance rejoice to see that
much more good work may be expected from you.

I enclose my own photograph, in case you should like to possess a copy.


(535/1. Part of this letter is published in "Life and Letters," III.,
pages 183, 184.)

Down, May 5th, 1881.

It was very good of you to write to me from Tortugas, as I always feel much
interested in hearing what you are about, and in reading your many
discoveries. It is a surprising fact that the peninsula of Florida should
have remained at the same level for the immense period requisite for the
accumulation of so vast a pile of debris. (535/2. Alexander Agassiz
published a paper on "The Tortugas and Florida Reefs" in the "Mem. Amer.
Acad. Arts and Sci." XI., page 107, 1885. See also his "Three Cruises of
the 'Blake,'" Volume I., 1888.)

You will have seen Mr. Murray's views on the formation of atolls and
barrier reefs. (535/3. "On the Structure and Origin of Coral Reefs and
Islands," "Proc. R. Soc. Edin." Volume X., page 505, 1880. Prof. Bonney
has given a summary of Sir John Murray's views in Appendix II. of the third
edition of Darwin's "Coral Reefs," 1889.) Before publishing my book, I
thought long over the same view, but only as far as ordinary marine
organisms are concerned, for at that time little was known of the multitude
of minute oceanic organisms. I rejected this view, as from the few
dredgings made in the 'Beagle' in the S. Temperate regions, I concluded
that shells, the smaller corals, etc., etc., decayed and were dissolved
when not protected by the deposition of sediment; and sediment could not
accumulate in the open ocean. Certainly shells, etc., were in several
cases completely rotten, and crumbled into mud between my fingers; but you
will know well whether this is in any degree common. I have expressly said
that a bank at the proper depth would give rise to an atoll, which could
not be distinguished from one formed during subsidence. I can, however,
hardly believe, in the former presence of as many banks (there having been
no subsidence) as there are atolls in the great oceans, within a reasonable
depth, on which minute oceanic organisms could have accumulated to the
thickness of many hundred feet. I think that it has been shown that the
oscillations from great waves extend down to a considerable depth, and if
so the oscillating water would tend to lift up (according to an old
doctrine propounded by Playfair) minute particles lying at the bottom, and
allow them to be slowly drifted away from the submarine bank by the
slightest current. Lastly, I cannot understand Mr. Murray, who admits that
small calcareous organisms are dissolved by the carbonic acid in the water
at great depths, and that coral reefs, etc., etc., are likewise dissolved
near the surface, but that this does not occur at intermediate depths,
where he believes that the minute oceanic calcareous organisms accumulate
until the bank reaches within the reef-building depth. But I suppose that
I must have misunderstood him.

Pray forgive me for troubling you at such a length, but it has occurred to
me that you might be disposed to give, after your wide experience, your
judgment. If I am wrong, the sooner I am knocked on the head and
annihilated so much the better. It still seems to me a marvellous thing
that there should not have been much and long-continued subsidence in the
beds of the great oceans. I wish that some doubly rich millionaire would
take it into his head to have borings made in some of the Pacific and
Indian atolls, and bring home cores for slicing from a depth of 500 or 600
feet. (535/4. In 1891 a Committee of the British Association was formed
for the investigation of an atoll by means of boring. The Royal Society
took up the scheme, and an expedition was sent to Funafuti, with Prof.
Sollas as leader. Another expedition left Sydney in 1897 under the
direction of Prof. Edgeworth David, and a deeper boring was made. The
Reports will be published in the "Philosophical Transactions," and will
contain Prof. David's notes upon the boring and the island generally, Dr.
Hinde's description of the microscopic structure of the cores and other
examinations of them, carried on at the Royal College of Science, South
Kensington. The boring reached a depth of 1114 feet; the cores were found
to consist entirely of reef-forming corals in situ and in fragments, with
foraminifera and calcareous algae; at the bottom there were no traces of
any other kind of rock. It seems, therefore, to us, that unless it can be
proved that reef-building corals began their work at depths of at least 180
fathoms--far below that hitherto assigned--the result gives the strongest
support to Darwin's theory of subsidence; the test which Darwin wished to
be applied has been fairly tried, and the verdict is entirely in his



(536/1. The following eight letters were written at a time when the
subjects of cleavage and foliation were already occupying the minds of
several geologists, including Sharpe, Sorby, Rogers, Haughton, Phillips,
and Tyndall. The paper by Sharpe referred to was published in 1847
("Quart. Journ. Geol. Soc." Volume III.), and his ideas were amplified in
two later papers (ibid., Volume V., 1849, and "Phil. Trans." 1852).
Darwin's own views, based on his observations during the "Beagle"
expedition, had appeared in Chapter XIII. of "South America" (1846) and in
the "Manual of Scientific Enquiry" (1849), but are perhaps nowhere so
clearly expressed as in this correspondence. His most important
contribution to the question was in establishing the fact that foliation is
often a part of the same process as cleavage, and is in nowise necessarily
connected with planes of stratification. Herein he was opposed to Lyell
and the other geologists of the day, but time has made good his position.
The postscript to Letter 542 is especially interesting. We are indebted to
Mr. Harker, of St. John's College, for this note.)

Down, August 23rd [1846?].

I must just send one line to thank you for your note, and to say how
heartily glad I am that you stick to the cleavage and foliation question.
Nothing will ever convince me that it is not a noble subject of
investigation, which will lead some day to great views. I think it quite
extraordinary how little the subject seems to interest British geologists.
You will, I think live to see the importance of your paper recognised.
(536/2. Probably the paper "On Slaty Cleavage." "Quart. Journ. Geol.
Soc." Volume III., page 74, 1847.) I had always thought that Studer was
one of the few geologists who had taken a correct and enlarged view on the

Down [November 1846].

I have been much interested with your letter, and am delighted that you
have thought my few remarks worth attention. My observations on foliation
are more deserving confidence than those on cleavage; for during my first
year in clay-slate countries, I was quite unaware of there being any
marked difference between cleavage and stratification; I well remember my
astonishment at coming to the conclusion that they were totally different
actions, and my delight at subsequently reading Sedgwick's views (537/1.
"Remarks on the Structure of Large Mineral Masses, and especially on the
Chemical Changes produced in the Aggregation of Stratified Rocks during
different periods after their Deposition." "Trans. Geol. Soc." Volume
III., page 461, 1835. In the section of this paper dealing with cleavage
(page 469) Prof. Sedgwick lays stress on the fact that "the cleavage is in
no instance parallel to the true beds."); hence at that time I was only
just getting out of a mist with respect to cleavage-laminae dipping inwards
on mountain flanks. I have certainly often observed it--so often that I
thought myself justified in propounding it as usual. I might perhaps have
been in some degree prejudiced by Von Buch's remarks, for which in those
days I had a somewhat greater deference than I now have. The Mount at M.
Video (page 146 of my book (537/2. "Geol. Obs. S. America." page 146. The
mount is described as consisting of hornblendic slate; "the laminae of the
slate on the north and south side near the summit dip inwards.")) is
certainly an instance of the cleavage-laminae of a hornblendic schist
dipping inwards on both sides, for I examined this hill carefully with
compass in hand and notebook. I entirely admit, however, that a conclusion
drawn from striking a rough balance in one's mind is worth nothing compared
with the evidence drawn from one continuous line of section. I read
Studer's paper carefully, and drew the conclusion stated from it; but I may
very likely be in an error. I only state that I have frequently seen
cleavage-laminae dipping inwards on mountain sides; that I cannot give up,
but I daresay a general extension of the rule (as might justly be inferred
from the manner of my statement) would be quite erroneous. Von Buch's
statement is in his "Travels in Norway" (537/3. "Travels through Norway
and Lapland during the years 1806-8": London, 1813.); I have unfortunately
lost the reference, and it is a high crime, I confess, even to refer to an
opinion without a precise reference. If you never read these travels they
might be worth skimming, chiefly as an amusement; and if you like and will
send me a line by the general post of Monday or Tuesday, I will either send
it up with Hopkins on Wednesday, or bring it myself to the Geological
Society. I am very glad you are going to read Hopkins (537/4. "Researches
in Physical Geology," by W. Hopkins. "Phil. Trans. R. Soc." 1839, page
381; ibid, 1842, page 43, etc.); his views appear to me eminently worth
well comprehending; false views and language appear to me to be almost
universally held by geologists on the formation of fissures, dikes and
mountain chains. If you would have the patience, I should be glad if you
would read in my "Volcanic Islands" from page 65, or even pages 54 to 72--
viz., on the lamination of volcanic rocks; I may add that I sent the series
of specimens there described to Professor Forbes of Edinburgh, and he
thought they bore out my views.

There is a short extract from Prof. Rogers (537/5. "On Cleavage of Slate-
strata." "Edinburgh New Phil. Journ." Volume XLI., page 422, 1846.) in the
last "Edinburgh New Phil. Journal," well worth your attention, on the
cleavage of the Appalachian chain, and which seems far more uniform in the
direction of dip than in any case which I have met with; the Rogers
doctrine of the ridge being thrown up by great waves I believe is
monstrous; but the manner in which the ridges have been thrown over (as if
by a lateral force acting on one side on a higher level than on the other)
is very curious, and he now states that the cleavage is parallel to the
axis-planes of these thrown-over ridges. Your case of the limestone beds
to my mind is the greatest difficulty on any mechanical doctrine; though I
did not expect ever to find actual displacement, as seems to be proved by
your shell evidence. I am extremely glad you have taken up this most
interesting subject in such a philosophical spirit; I have no doubt you
will do much in it; Sedgwick let a fine opportunity slip away. I hope you
will get out another section like that in your letter; these are the real
things wanted.

Down, [January 1847].

I am very much obliged for the MS., which I return. I do not quite
understand from your note whether you have struck out all on this point in
your paper: I much hope not; if you have, allow me to urge on you to
append a note, briefly stating the facts, and that you omitted them in your
paper from the observations not being finished.

I am strongly tempted to suspect that the cleavage planes will be proved by
you to have slided a little over each other, and to have been planes of
incipient tearing, to use Forbes' expression in ice; it will in that case
be beautifully analogical with my laminated lavas, and these in composition
are intimately connected with the metamorphic schists.

The beds without cleavage between those with cleavage do not weigh quite so
heavily on me as on you. You remember, of course, Sedgwick's facts of
limestone, and mine of sandstone, breaking in the line of cleavage,
transversely to the planes of deposition. If you look at cleavage as I do,
as the result of chemical action or crystalline forces, super-induced in
certain places by their mechanical state of tension, then it is not
surprising that some rocks should yield more or less readily to the
crystalline forces.

I think I shall write to Prof. Forbes (538/1. Prof. D. Forbes.) of
Edinburgh, with whom I corresponded on my laminated volcanic rocks, to call
his early attention to your paper.

Down, October 16th [1851].

I am very much obliged to you for telling me the results of your foliaceous
tour, and I am glad you are drawing up an account for the Royal Society.
(539/1. "On the Arrangement of the Foliation and Cleavage of the Rocks of
the North of Scotland." "Phil. Trans. R. Soc." 1852, page 445, with Plates
XXIII. and XXIV.) I hope you will have a good illustration or map of the
waving line of junction of the slate and schist with uniformly directed
cleavage and foliation. It strikes me as crucial. I remember longing for
an opportunity to observe this point. All that I say is that when slate
and the metamorphic schists occur in the same neighbourhood, the cleavage
and foliation are uniform: of this I have seen many cases, but I have
never observed slate overlying mica-slate. I have, however, observed many
cases of glossy clay-slate included within mica-schist and gneiss. All
your other observations on the order, etc., seem very interesting. From
conversations with Lyell, etc., I recommend you to describe in a little
detail the nature of the metamorphic schists; especially whether there are
quasi-substrata of different varieties of mica-slate or gneiss, etc.; and
whether you traced such quasi beds into the cleavage slate. I have not the
least doubt of such facts occurring, from what I have seen (and described
at M. Video) of portions of fine chloritic schists being entangled in the
midst of a gneiss district. Have you had any opportunity of tracing a bed
of marble? This, I think, from reasons given at page 166 of my "S.
America," would be very interesting. (539/2. "I have never had an
opportunity of tracing, for any distance, along the line both of strike
and dip, the so-called beds in the metamorphic schists, but I strongly
suspect that they would not be found to extend, with the same character,
very far in the line either of their dip or strike. Hence I am led to
believe that most of the so-called beds are of the nature of complex folia,
and have not been separately deposited. Of course, this view cannot be
extended to THICK masses included in the metamorphic series, which are of
totally different composition from the adjoining schists, and which are
far-extended, as is sometimes the case with quartz and marble; these must
generally be of the nature of true strata" ("Geological Observations," page
166).) A suspicion has sometimes occurred to me (I remember more
especially when tracing the clay-slate at the Cape of Good Hope turning
into true gneiss) that possibly all the metamorphic schists necessarily
once existed as clay-slate, and that the foliation did not arise or take
its direction in the metamorphic schists, but resulted simply from the pre-
existing cleavage. The so-called beds in the metamorphic schists, so
unlike common cleavage laminae, seems the best, or at least one argument
against such a suspicion. Yet I think it is a point deserving your notice.
Have you thought at all over Rogers' Law, as he reiterates it, of cleavage
being parallel to his axes-planes of elevation?

If you know beforehand, will you tell me when your paper is read, for the
chance of my being able to attend? I very seldom leave home, as I find
perfect quietude suits my health best.

(PLATE: CHARLES DARWIN, Cir. 1854. Maull & Fox, photo. Walker &
Cockerell, ph. sc.)

Down, January 10th, 1855.

I received your letter yesterday, but was unable to answer it, as I had to
go out at once on business of importance. I am very glad that you are
reconsidering the subject of foliation; I have just read over what I have
written on the subject, and admire it very much, and abide by it all.
(540/1. "Geological Observations on South America," Chapter VI., 1846.)
You will not readily believe how closely I attended to the subject, and in
how many and wide areas I verified my remarks. I see I have put pretty
strongly the mechanical view of origin; but I might even then, but was
afraid, have put my belief stronger. Unfortunately I have not D. Sharpe's
paper here to look over, but I think his chief points [are] (1) the
foliation forming great symmetrical curves, and (2) the proof from effects
of form of shell (540/2. This refers to the distortion of shells in
cleaved rocks.) of the mechanical action in cleaved rocks. The great
curvature would be, I think, a grand discovery of Sharpe's, but I confess
there is some want of minuteness in the statement of Sharpe which makes me
wish to see his facts confirmed. That the foliation and cleavage are parts
of curves I am quite prepared, from what I have seen, to believe; but the
simplicity and grandeur of Sharpe's curves rather stagger me. I feel
deeply convinced that when (and I and Sharpe have seen several most
striking and obvious examples) great neighbouring or alternating regions of
true metamorphic schists and clay-slate have their foliations and cleavage
parallel, there is no way of escaping the conclusion, that the layers of
pure quartz, feldspar, mica, chlorite, etc., etc., are due not to original
deposition, but to segregation; and this is I consider the point which I
have established. This is very odd, but I suspect that great metamorphic
areas are generally derived from the metamorphosis of clay-slate, and not
from alternating layers of ordinary sedimentary matter. I think you have
exactly put the chief difficulty in its strongest light--viz. what would be
the result of pure or nearly pure layers of very different mineralogical
composition being metamorphosed? I believe even such might be converted
into an ordinary varying mass of metamorphic schists. I am certain of the
correctness of my account of patches of chlorite schists enclosed in other
schist, and of enormous quartzose veins of segregation being absolutely
continuous and contemporaneous with the folia of quartz, and such, I think,
might be the result of the folia crossing a true stratum of quartz. I
think my description of the wonderful and beautiful laminated volcanic
rocks at Ascension would be worth your looking at. (540/3. "Geological
Observations on S. America," pages 166, 167; also "Geological Observations
on the Volcanic Islands," Chapter III. (Ascension), 1844.)

Down, January 14th [1855].

We were yesterday and the day before house-hunting, so I could not answer
your letter. I hope we have succeeded in a house, after infinite trouble,
but am not sure, in York Place, Baker Street.

I do not doubt that I either read or heard from Sharpe about the Grampians;
otherwise from my own old suspicion I should not have inserted the passage
in the manual.

The laminated rocks at Ascension are described at page 54. (541/1.
"Volcanic Islands," page 54. "Singular laminated beds alternating with and
passing into obsidian.")

As far as my experience has gone, I should speak only of clay-slate being
associated with mica-slate, for when near the metamorphic schists I have
found stratification so gone that I should not dare to speak of them as
overlying them. With respect to the difficulty of beds of quartz and
marble, this has for years startled me, and I have longed (since I have
felt its force) to have some opportunity of testing this point, for without
you are sure that the beds of quartz dip, as well as strike, parallel to
the foliation, the case is only just like true strata of sandstone included
in clay-slate and striking parallel to the cleavage of the clay-slate, but
of course with different dip (excepting in those rare cases when cleavage
and stratification are parallel). Having this difficulty before my eyes, I
was much struck with MacCulloch's statement (page 166 of my "S. America")
about marble in the metamorphic series not forming true strata.


Your expectation of the metamorphic schists sending veins into neighbouring
rocks is quite new to me; but I much doubt whether you have any right to
assume fluidity from almost any amount of molecular change. I have seen in
fine volcanic sandstone clear evidence of all the calcareous matter
travelling at least 4 1/2 feet in distance to concretions on either hand
(page 113 of "S. America") (541/2. "Some of these concretions (flattened
spherical concretions composed of hard calcareous sandstone, containing a
few shells, occurring in a bed of sandstone) were 4 feet in diameter, and
in a horizontal line 9 feet apart, showing that the calcareous matter must
have been drawn to the centres of attraction from a distance of four feet
and a half on both sides" ("Geological Observations on S. America," page
113).) I have not examined carefully, from not soon enough seeing all the
difficulties; but I believe, from what I have seen, that the folia in the
metamorphic schists (I do not here refer to the so-called beds) are not of
great length, but thin out, and are succeeded by others; and the notion I
have of the molecular movements is shown in the indistinct sketch herewith
sent [Figure 6]. The quartz of the strata might here move into the
position of the folia without much more movement of molecules than in the
formation of concretions. I further suspect in such cases as this, when
there is a great original abundance of quartz, that great branching
contemporaneous veins of segregation (as sometimes called) of quartz would
be formed. I can only thus understand the relation which exists between
the distorted foliation (not appearing due to injection) and the presence
of such great veins.

I believe some gneiss, as the gneiss-granite of Humboldt, has been as fluid
as granite, but I do not believe that this is usually the case, from the
frequent alternations of glossy clay and chlorite slates, which we cannot
suppose to have been melted.

I am far from wishing to doubt that true sedimentary strata have been
converted into metamorphic schists: all I can say is, that in the three or
four great regions, where I could ascertain the relations of the
metamorphic schists to the neighbouring cleaved rocks, it was impossible
(as it appeared to me) to admit that the foliation was due to aqueous
deposition. Now that you intend agitating the subject, it will soon be
cleared up.

27, York Place, Baker Street [1855].

I have received your letter from Down, and I have been studying my S.
American book.

I ought to have stated [it] more clearly, but undoubtedly in W. Tierra del
Fuego, where clay-slate passes by alternation into a grand district of
mica-schist, and in the Chonos Islands and La Plata, where glossy slates
occur within the metamorphic schists, the foliation is parallel to the
cleavage--i.e. parallel in strike and dip; but here comes, I am sorry and
ashamed to say, a great hiatus in my reasoning. I have assumed that the
cleavage in these neighbouring or intercalated beds was (as in more distant
parts) distinct from stratification. If you choose to say that here the
cleavage was or might be parallel to true bedding, I cannot gainsay it, but
can only appeal to apparent similarity to the great areas of uniformity of
strike and high angle--all certainly unlike, as far as my experience goes,
to true stratification. I have long known how easily I overlook flaws in
my own reasoning, and this is a flagrant case. I have been amused to find,
for I had quite forgotten, how distinctly I give a suspicion (top of page
155) to the idea, before Sharpe, of cleavage (not foliation) being due to
the laminae forming parts of great curves. (542/1. "I suspect that the
varying and opposite dips (of the cleavage-planes) may possibly be
accounted for by the cleavage-laminae...being parts of large abrupt curves,
with their summits cut off and worn down" ("Geological Observations on S.
America," page 155). I well remember the fine section at the end of a
region where the cleavage (certainly cleavage) had been most uniform in
strike and most variable in dip.

I made with really great care (and in MS. in detail) observations on a case
which I believe is new, and bears on your view of metamorphosis (page 149,
at bottom). (Ibid., page 149.)


In a clay-slate porphyry region, where certain thin sedimentary layers of
tuff had by self-attraction shortened themselves into little curling
pieces, and then again into crystals of feldspar of large size, and which
consequently were all strictly parallel, the series was perfect and
beautiful. Apparently also the rounded grains of quartz had in other parts
aggregated themselves into crystalline nodules of quartz. [Figure 7.]

I have not been able to get Sorby yet, but shall not probably have anything
to write on it. I am delighted you have taken up the subject, even if I am
utterly floored.

P.S.--I have a presentiment it will turn out that when clay-slate has been
metamorphosed the foliation in the resultant schist has been due generally
(if not, as I think, always) to the cleavage, and this to a certain degree
will "save my bacon" (please look at my saving clause, page 167) (542/2.
"As in some cases it appears that where a fissile rock has been exposed to
partial metamorphic action (for instance, from the irruption of granite)
the foliation has supervened on the already existing cleavage-planes; so,
perhaps in some instances, the foliation of a rock may have been determined
by the original planes of deposition or of oblique current laminae. I
have, however, myself never seen such a case, and I must maintain that in
most extensive metamorphic areas the foliation is the extreme result of
that process, of which cleavage is the first effect" (Ibid., page 167).),
but [with] other rocks than that, stratification has been the ruling agent,
the strike, but not the dip, being in such cases parallel to any adjoining
clay-slate. If this be so, pre-existing planes of division, we must
suppose on my view of the cause, determining the lines of crystallisation
and segregation, and not planes of division produced for the first time
during the act of crystallisation, as in volcanic rocks. If this should
ever be proved, I shall not look back with utter shame at my work.

Down, September 8th [1856].

I got your letter of the 1st this morning, and a real good man you have
been to write. Of all the things I ever heard, Mrs. Hooker's pedestrian
feats beat them. My brother is quite right in his comparison of "as strong
as a woman," as a type of strength. Your letter, after what you have seen
in the Himalayas, etc., gives me a wonderful idea of the beauty of the
Alps. How I wish I was one-half or one-quarter as strong as Mrs. Hooker:
but that is a vain hope. You must have had some very interesting work with
glaciers, etc. When will the glacier structure and motion ever be settled!
When reading Tyndall's paper it seemed to me that movement in the particles
must come into play in his own doctrine of pressure; for he expressly
states that if there be pressure on all sides, there is no lamination. I
suppose I cannot have understood him, for I should have inferred from this
that there must have been movement parallel to planes of pressure. (543/1.
Prof. Tyndall had published papers "On Glaciers," and "On some Physical
Properties of Ice" ("Proc. R. Inst." 1854-58) before the date of this
letter. In 1856 he wrote a paper entitled "Observations on 'The Theory of
the Origin of Slaty Cleavage,' by H.C. Sorby." "Phil. Mag." XII., 1856,
page 129.)

Sorby read a paper to the Brit. Assoc., and he comes to the conclusion that
gneiss, etc., may be metamorphosed cleavage or strata; and I think he
admits much chemical segregation along the planes of division. (543/2.
"On the Microscopical Structure of Mica-schist:" "Brit. Ass. Rep." 1856,
page 78. See also Letters 540-542.) I quite subscribe to this view, and
should have been sorry to have been so utterly wrong, as I should have been
if foliation was identical with stratification.

I have been nowhere and seen no one, and really have no news of any kind to
tell you. I have been working away as usual, floating plants in salt water
inter alia, and confound them, they all sink pretty soon, but at very
different rates. Working hard at pigeons, etc., etc. By the way, I have
been astonished at the differences in the skeletons of domestic rabbits. I
showed some of the points to Waterhouse, and asked him whether he could
pretend that they were not as great as between species, and he answered,
"They are a great deal more." How very odd that no zoologist should ever
have thought it worth while to look to the real structure of varieties...

2.IX.VI. AGE OF THE WORLD, 1868-1877.

Down, September 19th, 1868.

I hope that you will allow me to thank you for sending me your papers in
the "Phil. Magazine." (544/1. Croll published several papers in the
"Philosophical Magazine" between 1864 and the date of this letter (1868).)
I have never, I think, in my life been so deeply interested by any
geological discussion. I now first begin to see what a million means, and
I feel quite ashamed of myself at the silly way in which I have spoken of
millions of years. I was formerly a great believer in the power of the sea
in denudation, and this was perhaps natural, as most of my geological work
was done near sea-coasts and on islands. But it is a consolation to me to
reflect that as soon as I read Mr. Whitaker's paper (544/2. "On Subaerial
Denudation," and "On Cliffs and Escarpments of the Chalk and Lower Tertiary
Beds," "Geol. Mag." Volume IV., page 447, 1867.) on the escarpments of
England, and Ramsay (544/3. "Quart. Journ. Geol. Soc." Volume XVIII., page
185, 1862. "On the Glacial Origin of certain Lakes in Switzerland, the
Black Forest, Great Britain, Sweden, North America, and elsewhere.') and
Jukes' papers (544/4. "Quart. Journ. Geol. Soc." Volume XVIII., page 378,
1862. "On the Mode of Formation of some River-Valleys in the South of
Ireland."), I gave up in my own mind the case; but I never fully realised
the truth until reading your papers just received. How often I have
speculated in vain on the origin of the valleys in the chalk platform round
this place, but now all is clear. I thank you cordially for having cleared
so much mist from before my eyes.

Down, February 9th, 1877.

I am much obliged for your kind note, and the present of your essay. I
have read it with great interest, and the results are certainly most
surprising. (545/1. Presidential Address delivered by T. Mellard Reade
before the Liverpool Geological Society ("Proc. Liverpool Geol. Soc."
Volume III., pt. iii., page 211, 1877). See also "Examination of a
Calculation of the Age of the Earth, based upon the hypothesis of the
Permanence of Oceans and Continents." "Geol. Mag." Volume X., page 309,
1883.) It appears to me almost monstrous that Professor Tait should say
that the duration of the world has not exceeded ten million years. (545/2.
"Lecture on Some Recent Advances in Physical Science," by P.G. Tait,
London, 1876.) The argument which seems the most weighty in favour of the
belief that no great number of millions of years have elapsed since the
world was inhabited by living creatures is the rate at which the
temperature of the crust increases, and I wish that I could see this
argument answered.

Down, August 9th, 1877.

I am much obliged for your essay, which I have read with the greatest
interest. With respect to the geological part, I have long wished to see
the evidence collected on the time required for denudation, and you have
done it admirably. (546/1. In a paper "On the Tidal Retardation Argument
for the Age of the Earth" ("Brit. Assoc. Report," 1876, page 88), Croll
reverts to the influence of subaerial denudation in altering the form of
the earth as an objection to the argument from tidal retardation. He had
previously dealt with this subject in "Climate and Time," Chapter XX.,
London, 1875.) I wish some one would in a like spirit compare the
thickness of sedimentary rocks with the quickest estimated rate of
deposition by a large river, and other such evidence. Your main argument
with respect to the sun seems to me very striking.

My son George desires me to thank you for his copy, and to say how much he
has been interested by it.


"My whole soul is absorbed with worms just at present." (From a letter to
Sir W. Thistleton-Dyer, November 26th, 1880.)

LETTER 547. TO T.H. FARRER (Lord Farrer).

(547/1. The five following letters, written shortly before and after the
publication of "The Formation of Vegetable Mould through the Action of
Worms," 1881, deal with questions connected with Mr. Darwin's work on the
habits and geological action of earthworms.)

Down, October 20th, 1880.

What a man you are to do thoroughly whatever you undertake to do! The
supply of specimens has been magnificent, and I have worked at them for a
day and a half. I find a very few well-rounded grains of brick in the
castings from over the gravel walk, and plenty over the hole in the field,
and over the Roman floor. (547/2. See "The Formation of Vegetable Mould,"
1881, pages 178 et seq. The Roman remains formed part of a villa
discovered at Abinger, Surrey. Excavations were carried out, under Lord
Farrer's direction, in a field adjoining the ground in which the Roman
villa was first found, and extended observations were made by Lord Farrer,
which led Mr. Darwin to conclude that a large part of the fine vegetable
mould covering the floor of the villa had been brought up from below by
worms.) You have done me the greatest possible service by making me more
cautious than I should otherwise have been--viz., by sending me the rubbish
from the road itself; in this rubbish I find very many particles, rounded
(I suppose) by having been crushed, angles knocked off, and somewhat rolled
about. But not a few of the particles may have passed through the bodies
of worms during the years since the road was laid down. I still think that
the fragments are ground in the gizzards of worms, which always contain
bits of stone; but I must try and get more evidence. I have to-day started
a pot with worms in very fine soil, with sharp fragments of hard tiles laid
on the surface, and hope to see in the course of time whether any of those
become rounded. I do not think that more specimens from Abinger would aid

Down, March 7th.

I was quite mistaken about the "Gardeners' Chronicle;" in my index there
are only the few enclosed and quite insignificant references having any
relation to the minds of animals. When I returned to my work, I found that
I had nearly completed my statement of facts about worms plugging up their
burrows with leaves (548/1. Chapter II., of "The Formation of Vegetable
Mould through the Action of Worms," 1881, contains a discussion on the
intelligence shown by worms in the manner of plugging up their burrows with
leaves (pages 78 et seq.).), etc., etc., so I waited until I had naturally
to draw up a few concluding remarks. I hope that it will not bore you to
read the few accompanying pages, and in the middle you will find a few
sentences with a sort of definition of, or rather discussion on,
intelligence. I am altogether dissatisfied with it. I tried to observe
what passed in my own mind when I did the work of a worm. If I come across
a professed metaphysician, I will ask him to give me a more technical
definition, with a few big words about the abstract, the concrete, the
absolute, and the infinite; but seriously, I should be grateful for any
suggestions, for it will hardly do to assume that every fool knows what
"intelligent" means. (548/2. "Mr. Romanes, who has specially studied the
minds of animals, believes that we can safely infer intelligence only when
we see an individual profiting by its own experience...Now, if worms try to
drag objects into their burrows, first in one way and then in another,
until they at last succeed, they profit, at least in each particular
instance, by experience" ("The Formation of Vegetable Mould," 1881, page
95).) You will understand that the MS. is only the first rough copy, and
will need much correction. Please return it, for I have no other copy--
only a few memoranda. When I think how it has bothered me to know what I
mean by "intelligent," I am sorry for you in your great work on the minds
of animals.

I daresay that I shall have to alter wholly the MS.

Down, March 8th [1881].

Very many thanks for your note. I have been observing the [worm] tracks on
my walks for several months, and they occur (or can be seen) only after
heavy rain. As I know that worms which are going to die (generally from
the parasitic larva of a fly) always come out of their burrows, I have
looked out during these months, and have usually found in the morning only
from one to three or four along the whole length of my walks. On the other
hand, I remember having in former years seen scores or hundreds of dead
worms after heavy rain. (549/1. "After heavy rain succeeding dry weather,
an astonishing number of dead worms may sometimes be seen lying on the
ground. Mr. Galton informs me that on one occasion (March, 1881), the dead
worms averaged one for every two-and-a-half paces in length on a walk in
Hyde Park, four paces in width" (loc. cit., page 14).) I cannot possibly
believe that worms are drowned in the course of even three or four days'
immersion; and I am inclined to conclude that the death of sickly (probably
with parasites) worms is thus hastened. I will add a few words to what I
have said about these tracks. Occasionally worms suffer from epidemics (of
what nature I know not) and die by the million on the surface of the
ground. Your ruby paper answers capitally, but I suspect that it is only
for dimming the light, and I know not how to illuminate worms by the same
intensity of light, and yet of a colour which permits the actinic rays to
pass. I have tried drawing triangles of damp paper through a small
cylindrical hole, as you suggested, and I can discover no source of error.
(549/2. Triangles of paper were used in experiments to test the
intelligence of worms (loc. cit., page 83).) Nevertheless, I am becoming
more doubtful about the intelligence of worms. The worst job is that they
will do their work in a slovenly manner when kept in pots (549/3. Loc.
cit., page 75.), and I am beyond measure perplexed to judge how far such
observations are trustworthy.


(550/1. Mr. Lankester had written October 11th, 1881, to thank Mr. Darwin
for the present of the Earthworm book. He asks whether Darwin knows of
"any experiments on the influence of sea-water on earthworms. I have
assumed that it is fatal to them. But there is a littoral species
(Pontodrilus of Perrier) found at Marseilles." Lankester adds, "It is a
great pleasure and source of pride to me to see my drawing of the
earthworm's alimentary canal figuring in your pages."

Down, October 13th [1881].

I have been much pleased and interested by your note. I never actually
tried sea-water, but I was very fond of angling when a boy, and as I could
not bear to see the worms wriggling on the hook, I dipped them always first
in salt water, and this killed them very quickly. I remember, though not
very distinctly, seeing several earthworms dead on the beach close to where
a little brook entered, and I assumed that they had been brought down by
the brook, killed by the sea-water, and cast on shore. With your skill and
great knowledge, I have no doubt that you will make out much new about the
anatomy of worms, whenever you take up the subject again.

Down, January, 12th, 1882.

I have been much interested by your letter, for which I thank you heartily.
There was not the least cause for you to apologise for not having written
sooner, for I attributed it to the right cause, i.e. your hands being full
of work.

Your statement about the quantity of nitrogen in the collected castings is
most curious, and much exceeds what I should have expected. In lately
reading one of your and Mr. Lawes' great papers in the "Philosophical
Transactions" (551/1. The first Report on "Agricultural, Botanical, and
Chemical Results of Experiments on the Mixed Herbage of Permanent
Grassland, conducted for many years in succession on the same land," was
published in the "Philosophical Transactions of the Royal Society" in 1880,
the second paper appeared in the "Phil. Trans." for 1882, and the third in
the "Phil. Trans." of 1900, Volume 192, page 139.) (the value and
importance of which cannot, in my opinion, be exaggerated) I was struck
with the similarity of your soil with that near here; and anything observed
here would apply to your land. Unfortunately I have never made deep
sections in this neighbourhood, so as to see how deep the worms burrow,
except in one spot, and here there had been left on the surface of the
chalk a little very fine ferruginous sand, probably of Tertiary age; into
this the worms had burrowed to a depth of 55 and 61 inches. I have never
seen here red castings on the surface, but it seems possible (from what I
have observed with reddish sand) that much of the red colour of the
underlying clay would be discharged in passing through the intestinal

Worms usually work near the surface, but I have noticed that at certain
seasons pale-coloured earth is brought up from beneath the outlying
blackish mould on my lawn; but from what depth I cannot say. That some
must be brought up from a depth of four or five or six feet is certain, as
the worms retire to this depth during very dry and very cold weather. As
worms devour greedily raw flesh and dead worms, they could devour dead
larvae, eggs, etc., etc., in the soil, and thus they might locally add to
the amount of nitrogen in the soil, though not of course if the whole
country is considered. I saw in your paper something about the difference
in the amount of nitrogen at different depths in the superficial mould, and
here worms may have played a part. I wish that the problem had been before
me when observing, as possibly I might have thrown some little light on it,
which would have pleased me greatly.


(552/1. The following four letters refer to questions connected with the
origin of coal.)

Down, May [1846].

I am delighted that you are in the field, geologising or palaeontologising.
I beg you to read the two Rogers' account of the Coal-fields of N. America;
in my opinion they are eminently instructive and suggestive. (552/1. "On
the Physical Structure of the Appalachian Chain," by W.B. and H.D. Rogers.
Boston, 1843. See also "Geology of Pennsylvania," by H.D. Rogers. 4
volumes. London and Philadelphia, 1843.) I can lend you their resume of
their own labours, and, indeed, I do not know that their work is yet
published in full. L. Horner gives a capital balance of difficulties on
the Coal-theory in his last Anniversary Address, which, if you have not
read, will, I think, interest you. (552/2. "Quart. Journ. Geol. Soc."
Volume II., 1846, page 170.) In a paper just read an author (552/3. "On
the Remarkable Fossil Trees lately discovered near St. Helen's." By E.W.
Binney. "Phil. Mag." Volume XXIV., page 165, 1844. On page 173 the author
writes: "The Stigmaria or Sigillaria, whichever name is to be retained...
was a tree that undoubtedly grew in water.") throws out the idea that the
Sigillaria was an aquatic plant (552/4. See "Life and Letters," I., pages
356 et seq.)--I suppose a Cycad-Conifer with the habits of the mangrove.
From simple geological reasoning I have for some time been led to suspect
that the great (and great and difficult it is) problem of the Coal would be
solved on the theory of the upright plants having been aquatic. But even
on such, I presume improbable notion, there are, as it strikes me, immense
difficulties, and none greater than the width of the coal-fields. On what
kind of coast or land could the plants have lived? It is a grand problem,
and I trust you will grapple with it. I shall like much to have some
discussion with you. When will you come here again? I am very sorry to
infer from your letter that your sister has been ill.

[June 2nd, 1847.]

I received your letter the other day, full of curious facts, almost all new
to me, on the coal-question. (553/1. Sir Joseph Hooker deals with the
formation of coal in his classical paper "On the Vegetation of the
Carboniferous Period, as compared with that of the Present Day." "Mem.
Geol. Surv. Great Britain," Volume II., pt. ii., 1848.) I will bring your
note to Oxford (553/2. The British Association met at Oxford in 1847.),
and then we will talk it over. I feel pretty sure that some of your purely
geological difficulties are easily solvable, and I can, I think, throw a
very little light on the shell difficulty. Pray put no stress in your mind
about the alternate, neatly divided, strata of sandstone and shale, etc. I
feel the same sort of interest in the coal question as a man does watching
two good players at play, he knowing little or nothing of the game. I
confess your last letter (and this you will think very strange) has almost
raised Binney's notion (an old, growing hobby-horse of mine) to the dignity
of an hypothesis (553/3. Binney suggested that the Coal-plants grew in
salt water. (See Letters 102, 552.) Recent investigations have shown that
several of the plants of the Coal period possessed certain anatomical
peculiarities, which indicate xerophytic characteristics, and lend support
to the view that some at least of the plants grew in seashore swamps.),
though very far yet below the promotion of being properly called a theory.

I will bring the remainder of my species-sketch to Oxford to go over your
remarks. I have lately been getting a good many rich facts. I saw the
poor old Dean of Manchester (553/4. Dean Herbert.) on Friday, and he
received me very kindly. He looked dreadfully ill, and about an hour
afterwards died! I am most sincerely sorry for it.

[May 12th, 1847.]

I cannot resist thanking you for your most kind note. Pray do not think
that I was annoyed by your letter. I perceived that you had been thinking
with animation, and accordingly expressed yourself strongly, and so I
understood it. Forefend me from a man who weighs every expression with
Scotch prudence. I heartily wish you all success in your noble problem,
and I shall be very curious to have some talk with you and hear your
ultimatum. (554/1. The above paragraph was published in "Life and
Letters," I., page 359.) I do really think, after Binney's pamphlet
(554/2. "On the Origin of Coal," "Mem. Lit. Phil. Soc." Manchester Volume
VIII., page 148, 1848.), it will be worth your while to array your facts
and ideas against an aquatic origin of the coal, though I do not know
whether you object to freshwater. I am sure I have read somewhere of the
cones of Lepidodendron being found round the stump of a tree, or am I
confusing something else? How interesting all rooted--better, it seems
from what you say, than upright--specimens become.

I wish Ehrenberg would undertake a microscopical hunt for infusoria in the
underclay and shales; it might reveal something. Would a comparison of the
ashes of terrestrial peat and coal give any clue? (554/3. In an article
by M. F. Rigaud on "La Formation de la Houille," published in the "Revue
Scientifique," Volume II., page 385, 1894, the author lays stress on the
absence of certain elements in the ash of coals, which ought to be present,
on the assumption that the carbon has been derived from plant tissues. If
coal consists of altered vegetable debris, we ought to find a certain
amount of alkalies and phosphoric acid in its ash. Had such substances
ever been present, it is difficult to understand how they could all have
been removed by the solvent action of water. (Rigaud's views are given at
greater length in an article on the "Structure and Formation of Coal,"
"Science Progress," Volume II., pages 355 and 431, 1895.)) Peat ashes are
good manure, and coal ashes, except mechanically, I believe are of little
use. Does this indicate that the soluble salts have been washed out? i.e.,
if they are NOT present. I go up to Geological Council to-day--so

(554/4. In a letter to Sir Joseph Hooker, October 6th, 1847, Mr. Darwin,
in referring to the origin of Coal, wrote: "...I sometimes think it could
not have been formed at all. Old Sir Anthony Carlisle once said to me
gravely that he supposed Megatherium and such cattle were just sent down
from heaven to see whether the earth would support them, and I suppose the
coal was rained down to puzzle mortals. You must work the coal well in

Down, May 22nd, 1860.

Lyell tells me that Binney has published in Proceedings of Manchester
Society a paper trying to show that Coal plants must have grown in very
marine marshes. (555/1. "On the Origin of Coal," by E.W. Binney, "Mem.
Lit. Phil. Soc. Manchester," Volume VIII., 1848, page 148. Binney examines
the evidence on which dry land has been inferred to exist during the
formation of the Coal Measures, and comes to the conclusion that the land
was covered by water, confirming Brongniart's opinion that Sigillaria was
an aquatic plant. He believes the Sigillaria "grew in water, on the
deposits where it is now discovered, and that it is the plant which in a
great measure contributed to the formation of our valuable beds of coal."
(Loc. cit., page 193.)) Do you remember how savage you were long years ago
at my broaching such a conjecture?

Down [1846?].

I am truly pleased at your approval of my book (556/1. "Geological
Observations on South America," London, 1846.): it was very kind of you
taking the trouble to tell me so. I long hesitated whether I would publish
it or not, and now that I have done so at a good cost of trouble, it is
indeed highly satisfactory to think that my labour has not been quite
thrown away.

I entirely acquiesce in your criticism on my calling the Pampean formation
"recent" (556/2. "We must, therefore, conclude that the Pampean formation
belongs, in the ordinary geological sense of the word, to the Recent
Period." ("Geol. Obs." page 101).); Pleistocene would have been far
better. I object, however, altogether on principle (whether I have always
followed my principle is another question) to designate any epoch after
man. It breaks through all principles of classification to take one
mammifer as an epoch. And this is presupposing we know something of the
introduction of man: how few years ago all beds earlier than the
Pleistocene were characterised as being before the monkey epoch. It
appears to me that it may often be convenient to speak of an Historical or
Human deposit in the same way as we speak of an Elephant bed, but that to
apply it to an epoch is unsound.

I have expressed myself very ill, and I am not very sure that my notions
are very clear on this subject, except that I know that I have often been
made wroth (even by Lyell) at the confidence with which people speak of the
introduction of man, as if they had seen him walk on the stage, and as if,
in a geological chronological sense, it was more important than the entry
of any other mammifer.

You ask me to do a most puzzling thing, to point out what is newest in my
volume, and I found myself incapable of doing almost the same for Lyell.
My mind goes from point to point without deciding: what has interested
oneself or given most trouble is, perhaps quite falsely, thought newest.
The elevation of the land is perhaps more carefully treated than any other
subject, but it cannot, of course, be called new. I have made out a sort
of index, which will not take you a couple of minutes to skim over, and
then you will perhaps judge what seems newest. The summary at the end of
the book would also serve same purpose.

I do not know where E. de B. [Elie de Beaumont] has lately put forth on the
recent elevation of the Cordillera. He "rapported" favourably on
d'Orbigny, who in late times fires off a most Royal salute; every volcano
bursting forth in the Andes at the same time with their elevation, the
debacle thus caused depositing all the Pampean mud and all the Patagonian
shingle! Is not this making Geology nice and simple for beginners?

We have been very sorry to hear of Bunbury's severe illness; I believe the
measles are often dangerous to grown-up people. I am very glad that your
last account was so much better.

I am astonished that you should have had the courage to go right through my
book. It is quite obvious that most geologists find it far easier to write
than to read a book.

Chapter I. and II.--Elevation of the land: equability on E. coast as shown
by terraces, page 19; length on W. coast, page 53; height at Valparaiso,
page 32; number of periods of rest at Coquimbo, page 49; elevation within
Human period near Lima greater than elsewhere observed; the discussion
(page 41) on non-horizontality of terraces perhaps one of newest features--
on formation of terraces rather newish.

Chapter III., page 65.--Argument of horizontal elevation of Cordillera I
believe new. I think the connection (page 54) between earthquake [shocks]
and insensible rising important.

Chapter IV.--The strangeness of the (Eocene) mammifers, co-existing with
recent shells.

Chapter V.--Curious pumiceous infusorial mudstone (page 118) of Patagonia;
climate of old Tertiary period, page 134. The subject which has been most
fertile in my mind is the discussion from page 135 to end of chapter on the
accumulation of fossiliferous deposits. (556/3. The last section of
Chapter V. treats of "the Absence of extensive modern Conchiferous Deposits
in South America; and on the contemporaneousness of the older Tertiary
Deposits at distant points being due to contemporaneous movements of
subsidence." Darwin expresses the view that "the earth's surface
oscillates up and down; and...during the elevatory movements there is but a
small chance of durable fossiliferous deposits accumulating" (loc. cit.,
page 139).)

Chapter VI.--Perhaps some facts on metamorphism, but chiefly on the layers
in mica-slate, etc., being analogous to cleavage.

Chapter VII.--The grand up-and-down movements (and vertical silicified
trees) in the Cordillera: see summary, page 204 and page 240. Origin of
the Claystone porphyry formation, page 170.

Chapter VIII., page 224.--Mixture of Cretaceous and Oolitic forms (page
226)--great subsidence. I think (page 232) there is some novelty in
discussion on axes of eruption and injection. (page 247) Continuous
volcanic action in the Cordillera. I think the concluding summary (page
237) would show what are the most salient features in the book.

Shrewsbury [August 10th, 1846].

I was delighted to receive your letter, which was forwarded here to me. I
am very glad to hear about the new edition of the "Principles," (557/1.
The seventh edition of the "Principles of Geology" was published in 1847.),
and I most heartily hope you may live to bring out half a dozen more
editions. There would not have been such books as d'Orbigny's S. American
Geology (557/2. "Voyage dans l'Amerique meridionale execute pendant les
Annees 1826-37." 6 volumes, Paris, 1835-43.) published, if there had been
seven editions of the "Principles" distributed in France. I am rather
sorry about the small type; but the first edition, my old true love, which
I never deserted for the later editions, was also in small type. I much
fear I shall not be able to give any assistance to Book III. (557/3. This
refers to Book III. of the "Principles"--"Changes of the Organic World now
in Progress.") I think I formerly gave my few criticisms, but I will read
it over again very soon (though I am striving to finish my S. American
Geology (557/4. "Geological Observations on South America" was published
in 1846.)) and see whether I can give you any references. I have been
thinking over the subject, and can remember no one book of consequence, as
all my materials (which are in an absolute chaos on separate bits of paper)
have been picked out of books not directly treating of the subjects you
have discussed, and which I hope some day to attempt; thus Hooker's
"Antarctic Flora" I have found eminently useful (557/5. "Botany of the
Antarctic Voyage of H.M.S. 'Erebus' and 'Terror' in the Years 1839-43." I.,
"Flora Antarctica." 2 volumes, London, 1844-47.), and yet I declare I do
not know what precise facts I could refer you to. Bronn's "Geschichte"
(557/6. "Naturgeschichte der drei Reiche." H.E. Bronn, Stuttgart, 1834-
49.) which you once borrowed) is the only systematic book I have met with
on such subjects; and there are no general views in such parts as I have
read, but an immense accumulation of references, very useful to follow up,
but not credible in themselves: thus he gives hybrids from ducks and fowls
just as readily as between fowls and pheasants! You can have it again if
you like. I have no doubt Forbes' essay, which is, I suppose, now fairly
out, will be very good under geographical head. (557/7. "On the
Connection between the Distribution of the existing Fauna and Flora of the
British Isles, and the Geological Changes which have affected their Area,
especially during the Epoch of the Northern Drift," by E. Forbes. "Memoirs
of Geological Survey," Volume I., page 336, 1846.) Kolreuter's German book
is excellent on hybrids, but it will cost you a good deal of time to work
out any conclusion from his numerous details. (557/8. Joseph Gottlieb
Kolreuter's "Vorlaufige Nachricht von eininigen das Geschlecht der Pflanzen
betreffenden Versuchen und Beobachtungen." Leipzig, 1761.) With respect
to variation I have found nothing--but minute details scattered over scores
of volumes. But I will look over Book III. again. What a quantity of work
you have in hand! I almost wish you could have finished America, and thus
have allowed yourself rather more time for the old "Principles"; and I am
quite surprised that you could possibly have worked your own new matter in
within six weeks. Your intention of being in Southampton will much
strengthen mine, and I shall be very glad to hear some of your American
Geology news.

Down, Sunday [January 1847].

Your most agreeable praise of my book is enough to turn my head; I am
really surprised at it, but shall swallow it with very much gusto...
(558/1. "Geological Observations in S. America," London, 1846.)

E. de Beaumont measured the inclination with a sextant and artificial
horizon, just as you take the height of the sun for latitude.

With respect to my Journal, I think the sketches in the second edition
(558/2. "Journal of Researches into the Natural History and Geology of the
Countries visited during the Voyage of H.M.S. 'Beagle.'" Edition II.
London, 1845.) are pretty accurate; but in the first they are not so, for I
foolishly trusted to my memory, and was much annoyed to find how hasty and
inaccurate many of my remarks were, when I went over my huge pile of
descriptions of each locality.

If ever you meet anyone circumstanced as I was, advise him not, on any
account, to give any sketches until his materials are fully worked out.

What labour you must be undergoing now; I have wondered at your patience in
having written to me two such long notes. How glad Mrs. Horner will be
when your address is completed. (558/3. Anniversary Address of the
President ("Quart. Journ. Geol. Soc." Volume III., page xxii, 1847).) I
must say that I am much pleased that you will notice my volume in your
address, for former Presidents took no notice of my two former volumes.

I am exceedingly glad that Bunbury is going on well.

Down, July 3rd [1849].

I don't know when I have read a book so interesting (559/1. "A Second
Visit to the United States of North America." 2 volumes, London, 1849.);
some of your stories are very rich. You ought to be made Minister of
Public Education--not but what I should think even that beneath the author
of the old "Principles." Your book must, I should think, do a great deal
of good and set people thinking. I quite agree with the "Athenaeum" that
you have shown how a man of science can bring his powers of observation to
social subjects. (559/2. "Sir Charles Lyell, besides the feelings of a
gentleman, seems to carry with him the best habits of scientific
observation into other strata than those of clay, into other 'formations'
than those of rock or river-margin." "The Athenaeum," June 23rd, 1849,
page 640.) You have made H. Wedgwood, heart and soul, an American; he
wishes the States would annex us, and was all day marvelling how anyone who
could pay his passage money was so foolish as to remain here.

Down, [December, 1849].

(560/1. In this letter Darwin criticises Dana's statements in his volume
on "Geology," forming Volume X. of the "Wilkes Exploring Expedition,"

...Dana is dreadfully hypothetical in many parts, and often as "d--d cocked
sure" as Macaulay. He writes however so lucidly that he is very
persuasive. I am more struck with his remarks on denudation than you seem
to be. I came to exactly the same conclusion in Tahiti, that the wonderful
valleys there (on the opposite extreme of the scale of wonder [to] the
valleys of New South Wales) were formed exclusively by fresh water. He
underrates the power of sea, no doubt, but read his remarks on valleys in
the Sandwich group. I came to the conclusion in S. America (page 67) that
the main effect of fresh water is to deepen valleys, and sea to widen them;
I now rather doubt whether in a valley or fiord...the sea would deepen the
rock at its head during the elevation of the land. I should like to tour
on the W. coast of Scotland, and attend to this. I forget how far
generally the shores of fiords (not straits) are cliff-formed. It is a
most interesting subject.

I return once again to Coral. I find he does not differ so much in detail
with me regarding areas of subsidence; his map is coloured on some quite
unintelligible principle, and he deduces subsidence from the vaguest
grounds, such as that the N. Marianne Islands must have subsided because
they are small, though long in volcanic action: and that the Marquesas
subsided because they are penetrated by deep bays, etc., etc. I utterly
disbelieve his statements that most of the atolls have been lately raised a
foot or two. He does not condescend to notice my explanation for such
appearances. He misrepresents me also when he states that I deduce,
without restriction, elevation from all fringing reefs, and even from
islands without any reefs! If his facts are true, it is very curious that
the atolls decrease in size in approaching the vast open ocean S. of the
Sandwich Islands. Dana puts me in a passion several times by disputing my
conclusions without condescending to allude to my reasons; thus, regarding
S. Lorenzo elevation, he is pleased to speak of my "characteristic
accuracy" (560/2. Dana's "Geology" (Wilkes expedition), page 590.), and
then gives difficulties (as if his own) when they are stated by me, and I
believe explained by me--whereas he only alludes to a few of the facts. So
in Australian valleys, he does not allude to my several reasons. But I am
forgetting myself and running on about what can only interest myself. He
strikes me as a very clever fellow; I wish he was not quite so grand a
generaliser. I see little of interest except on volcanic action and
denudation, and here and there scattered remarks; some of the later
chapters are very bald.

Down, December 5th, 1849.

I have not for some years been so much pleased as I have just been by
reading your most able discussion on coral reefs. I thank you most
sincerely for the very honourable mention you make of me. (561/1. "United
States Exploring Expedition during the Years 1839-42 under the Command of
Charles Wilkes, U.S.N." Volume X., "Geology," by J.D. Dana, 1849.) This
day I heard that the atlas has arrived, and this completes your munificent
present to me. I have not yet come to the chapter on subsidence, and in
that I fancy we shall disagree, but in the descriptive part our agreement
has been eminently satisfactory to me, and far more than I ever ventured to
anticipate. I consider that now the subsidence theory is established. I
have read about half through the descriptive part of the "Volcanic Geology"
(561/2. Part of Dana's "Geology" is devoted to volcanic action.) (last
night I ascended the peaks of Tahiti with you, and what I saw in my short
excursion was most vividly brought before me by your descriptions), and
have been most deeply interested by it. Your observations on the Sandwich
craters strike me as the most important and original of any that I have
read for a long time. Now that I have read yours, I believe I saw at the
Galapagos, at a distance, instances of those most curious fissures of
eruption. There are many points of resemblance between the Galapagos and
Sandwich Islands (even to the shape of the mound-like hills)--viz., in the
liquidity of the lavas, absence of scoriae, and tuff-craters. Many of your
scattered remarks on denudation have particularly interested me; but I see
that you attribute less to sea and more to running water than I have been
accustomed to do. After your remarks in your last very kind letter I could
not help skipping on to the Australian valleys (561/3. Ibid., pages 526 et
seq.: "The Formation of Valleys, etc., in New South Wales."), on which
your remarks strike me as exceedingly ingenious and novel, but they have
not converted me. I cannot conceive how the great lateral bays could have
been scooped out, and their sides rendered precipitous by running water. I
shall go on and read every word of your excellent volume.

If you look over my "Geological Instructions" you will be amused to see
that I urge attention to several points which you have elaborately
discussed. (561/4. "A Manual of Scientific Enquiry, prepared for the use
of Her Majesty's Navy, and adapted for Travellers in General." Edited by
Sir John F.W. Herschel, Bart. London, 1849 (Section VI., "Geology." By
Charles Darwin).) I lately read a paper of yours on Chambers' book, and
was interested by it. I really believe the facts of the order described by
Chambers, in S. America, which I have described in my Geolog. volume. This
leads me to ask you (as I cannot doubt that you will have much geological
weight in N. America) to look to a discussion at page 135 in that volume on
the importance of subsidence to the formation of deposits, which are to
last to a distant age. This view strikes me as of some importance.

When I meet a very good-natured man I have that degree of badness of
disposition in me that I always endeavour to take advantage of him;
therefore I am going to mention some desiderata, which if you can supply I
shall be very grateful, but if not no answer will be required.

Thank you for your "Conspectus Crust.," but I am sorry to say I am not
worthy of it, though I have always thought the Crustacea a beautiful
subject. (561/5. "Conspectus Crustaceorum in orbis terrarum
circumnavigatione, C. Wilkes duce, collectorum." Cambridge (U.S.A.),

[Down, March 9th, 1850.]

I am uncommonly much obliged to you for your address, which I had not
expected to see so soon, and which I have read with great interest.
(562/1. Anniversary Address of the President, "Quart. Journ. Geol. Soc."
Volume VI., page 32, 1850.) I do not know whether you spent much time over
it, but it strikes me as extra well arranged and written--done in the most
artistic manner, to use an expression which I particularly hate. Though I
am necessarily pretty well familiar with your ideas from your conversation
and books, yet the whole had an original freshness to me. I am glad that
you broke through the routine of the President's addresses, but I should be
sorry if others did. Your criticisms on Murchison were to me, and I think
would be to many, particularly acceptable. (562/2. In a paper "On the
Geological Structure of the Alps, etc." ("Quart. Journ. Geol. Soc." Volume
V., page 157, 1849) Murchison expressed his belief that the apparent
inversion of certain Tertiary strata along the flanks of the Alps afforded
"a clear demonstration of a sudden operation or catastrophe." It is this
view of paroxysmal energy that Lyell criticises in the address.) Capital,
that metaphor of the clock. (562/3. "In a word, the movement of the
inorganic world is obvious and palpable, and might be likened to the
minute-hand of a clock, the progress of which can be seen and heard,
whereas the fluctuations of the living creation are nearly invisible, and
resemble the motion of the hour-hand of a timepiece" (loc. cit., page
xlvi).) I shall next February be much interested by seeing your hour-hand
of the organic world going.

Many thanks for your kindness in taking the trouble to tell me of the
anniversary dinner. What a compliment that was which Lord Mahon paid me!
I never had so great a one. He must be as charming a man as his wife is a
woman, though I was formerly blind to his merit. Bunsen's speech must have
been very interesting and very useful, if any orthodox clergyman were
present. Your metaphor of the pebbles of pre-existing languages reminds me
that I heard Sir J. Herschel at the Cape say how he wished some one would
treat language as you had Geology, and study the existing causes of change,
and apply the deduction to old languages.

We are all pretty flourishing here, though I have been retrograding a
little, and I think I stand excitement and fatigue hardly better than in
old days, and this keeps me from coming to London. My cirripedial task is
an eternal one; I make no perceptible progress. I am sure that they belong
to the hour-hand, and I groan under my task.

April 23rd, 1855.

I have seen a good deal of French geologists and palaeontologists lately,
and there are many whom I should like to put on the R.S. Foreign List, such
as D'Archiac, Prevost, and others. But the man who has made the greatest
sacrifices and produced the greatest results, who has, in fact, added a new
period to the calendar, is Barrande.

The importance of his discoveries as they stand before the public fully
justify your choice of him; but what is unpublished, and which I have seen,
is, if possible, still more surprising. Thirty genera of gasteropods (150
species) and 150 species of lamellibranchiate bivalves in the Silurian!
All obtained by quarries opened solely by him for fossils. A man of very
moderate fortune spending nearly all his capital on geology, and with

E. Forbes' polarity doctrines are nearly overturned by the unpublished
discoveries of Barrande. (563/1. See note, Letter 41, Volume I.)

I have called Barrande's new period Cambrian (see "Manual," 5th edition),
and you will see why. I could not name it Protozoic, but had Barrande
called it Bohemian, I must have adopted that name. All the French will
rejoice if you confer an honour on Barrande. Dana is well worthy of being
a foreign member.

Should you succeed in making Barrande F.R.S., send me word.

June 5th [1857].

(564/1. The following, which bears on the subject of medals, forms part of
the long letter printed in the "Life and Letters," II., page 100.)

I do not quite agree with your estimate of Richardson's merits. Do, I beg
you (whenever you quietly see), talk with Lyell on Prestwich: if he agrees
with Hopkins, I am silenced; but as yet I must look at the correlation of
the Tertiaries as one of the highest and most frightfully difficult tasks a
man could set himself, and excellent work, as I believe, P. has done.
(564/2. Prof. Prestwich had published numerous papers dealing with
Tertiary Geology before 1857. The contributions referred to are probably
those "On the Correlation of the Lower Tertiaries of England with those of
France and Belgium," "Quart. Journ. Geol. Soc." Volume X., 1854, page 454;
and "On the Correlation of the Middle Eocene Tertiaries of England, France,
and Belgium," ibid., XII., 1856, page 390.) I confess I do not value
Hopkins' opinion on such a point. I confess I have never thought, as you
show ought to be done, on the future. I quite agree, under all
circumstances, with the propriety of Lindley. How strange no new
geologists are coming forward! Are there not lots of good young chemists
and astronomers or physicists? Fitton is the only old geologist left who
has done good work, except Sedgwick. Have you thought of him? He would be
a brilliant companion for Lindley. Only it would never do to give Lyell a
Copley and Sedgwick a Royal in the same year. It seems wrong that there
should be three Natural Science medals in the same year. Lindley,
Sedgwick, and Bunsen sounds well, and Lyell next year for the Copley.
(564/3. In 1857 a Royal medal was awarded to John Lindley; Lyell received
the Copley in 1858, and Bunsen in 1860.) You will see that I am
speculating as a mere idle amateur.

Down, May 27th [1856].

I am very much obliged to you for having taken the trouble to answer my
query so fully. I can now be at rest, for from what you say and from what
little I remember Forbes said, my point is unanswerable. The case of
Terebratula is to the point as far as it goes, and is negative. I have
already attempted to get a solution through geographical distribution by
Dr. Hooker's means, and he finds that the same genera which have very
variable species in Europe have other very variable species elsewhere.
This seems the general rule, but with some few exceptions. I see from the
several reasons which you assign, that there is no hope of comparing the
same genus at two different periods, and seeing whether the tendency to
vary is greater at one period in such genus than at another period. The
variability of certain genera or groups of species strikes me as a very odd
fact. (565/1. The late Dr. Neumayr has dealt, to some extent, with this
subject in "Die Stamme des Thierreichs," Volume I., Wien, 1889.)

I shall have no points, as far as I can remember, to suggest for your
reconsideration, but only some on which I shall have to beg for a little
further information. However, I feel inclined very much to dispute your
doctrine of islands being generally ancient in comparison, I presume, with
continents. I imagine you think that islands are generally remnants of old
continents, a doctrine which I feel strongly disposed to doubt. I believe
them generally rising points; you, it seems, think them sinking points.

Down, April 14th [1860].

Many thanks for your kind and pleasant letter. I have been much interested
by "Deep-sea Soundings,", and will return it by this post, or as soon as I
have copied a few sentences. (566/1. Specimens of the mud dredged by
H.M.S. "Cyclops" were sent to Huxley for examination, who gave a brief
account of them in Appendix A of Capt. Dayman's Report, 1858, under the
title "Deep-sea Soundings in the North Atlantic.") I think you said that
some one was investigating the soundings. I earnestly hope that you will
ask the some one to carefully observe whether any considerable number of
the calcareous organisms are more or less friable, or corroded, or scaling;
so that one might form some crude notion whether the deposition is so rapid
that the foraminifera are preserved from decay and thus are forming strata
at this profound depth. This is a subject which seems to me to have been
much neglected in examining soundings.

Bronn has sent me two copies of his Morphologische Studien uber die
Gestaltungsgesetze." (H.G. Bronn, "Morphologische Studien uber die
Gestaltungsgesetze der Naturkorper uberhaupt und der organischen
insbesondere": Leipzig, 1858.) It looks elementary. If you will write
you shall have the copy; if not I will give it to the Linnean Library.

I quite agree with the letter from Lyell that your extinguished theologians
lying about the cradle of each new science, etc., etc., is splendid.
(566/2. "Darwiniana, Collected Essays," Volume II., page 52.)

May 10th [1862 or later].

I have been in London, which has prevented my writing sooner. I am very
sorry to hear that you have been ill: if influenza, I can believe in any
degree of prostration of strength; if from over-work, for God's sake do not
be rash and foolish. You ask for criticisms; I have none to give, only
impressions. I fully agree with your "skimming-of-pot theory," and very
well you have put it. With respect [to] contemporaneity I nearly agree
with you, and if you will look to the d--d book, 3rd edition, page 349 you
will find nearly similar remarks. (567/1. "When the marine forms are
spoken of as having changed simultaneously throughout the world, it must
not be supposed that this expression relates to the same year, or to the
same century, or even that it has a very strict geological sense; for if
all the marine animals now living in Europe, and all those that lived in
Europe during the Pleistocene period (a very remote period as measured by
years, including the whole Glacial epoch), were compared with those now
existing in South America or in Australia, the most skilful naturalist
would hardly be able to say whether the present or the Pleistocene
inhabitants of Europe resembled most closely those of the Southern
hemisphere." "Origin," Edition VI., page 298. The passage in Edition
III., page 350, is substantially the same.) But at page 22 of your
Address, in my opinion you put your ideas too far. (567/2. Anniversary
Address to the Geological Society of London ("Quart. Journ. Geol. Soc."
Volume XVIII., page xl, 1862). As an illustration of the misleading use of
the term "contemporaneous" as employed by geologists, Huxley gives the
following illustration: "Now suppose that, a million or two of years
hence, when Britain has made another dip beneath the sea and has come up
again, some geologist applies this doctrine [i.e., the doctrine of the
Contemporaneity of the European and of the North American Silurians: proof
of contemporaneity is considered to be established by the occurrence of 60
per cent. of species in common], in comparing the strata laid bare by the
upheaval of the bottom, say, of St. George's Channel with what may then
remain of the Suffolk Crag. Reasoning in the same way, he will at once
decide the Suffolk Crag and the St. George's Channel beds to be
contemporaneous; although we happen to know that a vast period...of
time...separates the two" (loc. cit., page xlv). This address is
republished in the "Collected Essays," Volume VIII.; the above passage is
at page 284.) I cannot think that future geologists would rank the Suffolk
and St. George's strata as contemporaneous, but as successive sub-stages;
they rank N. America and British stages as contemporaneous, notwithstanding
a percentage of different species (which they, I presume, would account for
by geographical difference) owing to the parallel succession of the forms
in both countries. For terrestrial productions I grant that great errors
may creep in (567/3. Darwin supposes that terrestrial productions have
probably not changed to the same extent as marine organisms. "If the
Megatherium, Mylodon...had been brought to Europe from La Plata, without
any information in regard to their geological position, no one would have
suspected that they had co-existed with sea shells all still living"
("Origin," Edition VI., page 298).); but I should require strong evidence
before believing that, in countries at all well-known, so-called Silurian,
Devonian, and Carboniferous strata could be contemporaneous. You seem to
me on the third point, viz., on non-advancement of organisation, to have
made a very strong case. I have not knowledge or presumption enough to
criticise what you say. I have said what I could at page 363 of "Origin."
It seems to me that the whole case may be looked at from several points of
view. I can add only one miserable little special case of advancement in
cirripedes. The suspicion crosses me that if you endeavoured your best you
would say more on the other side. Do you know well Bronn in his last
Entwickelung (or some such word) on this subject? it seemed to me very well
done. (567/4. Probably "Untersuchungen uber die Entwickelungsgesetze der
organischen Welt wahrend der Bildungszeit unserer Erdoberflache,"
Stuttgart, 1858. Translated by W.S. Dallas in the "Ann. and Mag. Nat.
Hist." Volume IV., page 81.) I hope before you publish again you will read
him again, to consider the case as if you were a judge in a court of
appeal; it is a very important subject. I can say nothing against your
side, but I have an "inner consciousness" (a highly philosophical style of
arguing!) that something could be said against you; for I cannot help
hoping that you are not quite as right as you seem to be. Finally, I
cannot tell why, but when I finished your Address I felt convinced that
many would infer that you were dead against change of species, but I
clearly saw that you were not. I am not very well, so good-night, and
excuse this horrid letter.

Down, June 30th [1866].

I have heard from Sulivan (who, poor fellow, gives a very bad account of
his own health) about the fossils (568/1. In a letter to Huxley (June 4th,
1866) Darwin wrote: "Admiral Sulivan several years ago discovered an
astonishingly rich accumulation of fossil bones not far from the Straits
[of Magellan]...During many years it has seemed to me extremely desirable
that these should be collected; and here is an excellent opportunity.")...
The place is Gallegos, on the S. coast of Patagonia. Sulivan says that in
the course of two or three days all the boats in the ship could be filled
twice over; but to get good specimens out of the hardish rock two or three
weeks would be requisite. It would be a grand haul for Palaeontology. I
have been thinking over your lecture. (568/2. A lecture on "Insular
Floras" given at the British Association meeting at Nottingham, August
27th, 1866, published in the "Gard. Chron." 1867.) Will it not be possible
to give enlarged drawings of some leading forms of trees? You will, of
course, have a large map, and George tells me that he saw at Sir H. James',
at Southampton, a map of the world on a new principle, as seen from within,
so that almost 4/5ths of the globe was shown at once on a large scale.
Would it not be worth while to borrow one of these from Sir H. James as a
curiosity to hang up?

Remember you are to come here before Nottingham. I have almost finished
the last number of H. Spencer, and am astonished at its prodigality of
original thought. But the reflection constantly recurred to me that each
suggestion, to be of real value to science, would require years of work.
It is also very unsatisfactory, the impossibility of conjecturing where
direct action of external circumstances begins and ends--as he candidly
owns in discussing the production of woody tissue in the trunks of trees on
the one hand, and on the other in spines and the shells of nuts. I shall
like to hear what you think of this number when we meet.

Down, November 17th, 1868.

On my return home after a short absence I found your note of Nov. 9th, and
your magnificent work on the fossil animals of Attica. (569/1. The
"Geologie de l'Attique," 2 volumes 4to, 1862-7, is the only work of
Gaudry's of this date in Mr. Darwin's library.) I assure you that I feel
very grateful for your generosity, and for the honour which you have thus
conferred on me. I know well, from what I have already read of extracts,
that I shall find your work a perfect mine of wealth. One long passage
which Sir C. Lyell quotes from you in the 10th and last edition of the
"Principles of Geology" is one of the most striking which I have ever read
on the affiliation of species. (569/2. The quotation in Lyell's
"Principles," Edition X., Volume II., page 484, is from M. Gaudry's
"Animaux Fossiles de Pikermi," 1866, page 34:--

"In how different a light does the question of the nature of species now
present itself to us from that in which it appeared only twenty years ago,
before we had studied the fossil remains of Greece and the allied forms of
other countries. How clearly do these fossil relics point to the idea that
species, genera, families, and orders now so distinct have had common
ancestors. The more we advance and fill up the gaps, the more we feel
persuaded that the remaining voids exist rather in our knowledge than in
nature. A few blows of the pickaxe at the foot of the Pyrenees, of the
Himalaya, of Mount Pentelicus in Greece, a few diggings in the sandpits of
Eppelsheim, or in the Mauvaises Terres of Nebraska, have revealed to us the
closest connecting links between forms which seemed before so widely
separated. How much closer will these links be drawn when Palaeontology
shall have escaped from its cradle!")


(570/1. In May, 1870, Darwin "went to the Bull Hotel, Cambridge, to see
the boys, and for a little rest and enjoyment." (570/2. See "Life and
Letters," III., 125.) The following letter was received after his return
to Down.)

Trinity College, Cambridge, May 30th, 1870.

My dear Darwin,

Your very kind letter surprised me. Not that I was surprised at the
pleasant and very welcome feeling with which it was written. But I could
not make out what I had done to deserve the praise of "extraordinary
kindness to yourself and family." I would most willingly have done my best
to promote the objects of your visit, but you gave me no opportunity of
doing so. I was truly grieved to find that my joy at seeing you again was
almost too robust for your state of nerves, and that my society, after a
little while, became oppressive to you. But I do trust that your Cambridge
visit has done you no constitutional harm; nay, rather that it has done you
some good. I only speak honest truth when I say that I was overflowing
with joy when I saw you, and saw you in the midst of a dear family party,
and solaced at every turn by the loving care of a dear wife and daughters.
How different from my position--that of a very old man, living in cheerless
solitude! May god help and cheer you all with the comfort of hopeful
hearts--you and your wife, and your sons and daughters!

You were talking about my style of writing,--I send you my last specimen,
and it will probably continue to be my last. It is the continuation of a
former pamphlet of which I have not one spare copy. I do not ask you to
read it. It is addressed to the old people in my native Dale of Dent, on
the outskirts of Westmorland. While standing at the door of the old
vicarage, I can see down the valley the Lake mountains--Hill Bell at the
head of Windermere, about twenty miles off. On Thursday next (D.V.) I am
to start for Dent, which I have not visited for full two years. Two years
ago I could walk three or four miles with comfort. Now, alas! I can only
hobble about on my stick.

I remain your true-hearted old friend
A. Sedgwick.

Down, September 3rd [1874].

Many thanks for your very kind and interesting letter. I was glad to hear
at Southampton from Miss Heathcote a good account of your health and

With respect to the great subject to which you refer in your P.S., I always
try to banish it from my mind as insoluble; but if I were circumstanced as
you are, no doubt it would recur in the dead of the night with painful
force. Many persons seem to make themselves quite easy about immortality
(571/1. See "Life and Letters," I., page 312.) and the existence of a
personal God, by intuition; and I suppose that I must differ from such
persons, for I do not feel any innate conviction on any such points.

We returned home about ten days ago from Southampton, and I enjoyed my
holiday, which did me much good. But already I am much fatigued by
microscope and experimental work with insect-eating plants.

When at Southampton I was greatly interested by looking at the odd gravel
deposits near at hand, and speculating about their formation. You once
told me something about them, but I forget what; and I think that Prestwich
has written on the superficial deposits on the south coasts, and I must
find out his paper and read it. (571/2. Prof. Prestwich contributed
several papers to the Geological Society on the Superficial Deposits of the
South of England.)

From what I have seen of Mr. Judd's papers I have thought that he would
rank amongst the few leading British geologists.


(572/1. The following letter was written before Mr. Darwin knew that Sir
Charles Lyell was to be buried in Westminster Abbey, a memorial which
thoroughly satisfied him. See "Life and Letters," III., 197.)

Down, February 23rd, 1875.

I have just heard from Miss Buckley of Lyell's death. I have long felt
opposed to the present rage for testimonials; but when I think how Lyell
revolutionised Geology, and aided in the progress of so many other branches
of science, I wish that something could be done in his honour. On the
other hand it seems to me that a poor testimonial would be worse than none;
and testimonials seem to succeed only when a man has been known and loved
by many persons, as in the case of Falconer and Forbes. Now, I doubt
whether of late years any large number of scientific men did feel much
attachment towards Lyell; but on this head I am very ill fitted to judge.
I should like to hear some time what you think, and if anything is proposed
I should particularly wish to join in it. We have both lost as good and as
true a friend as ever lived.


(573/1. This letter shows the difficulty which the inscription for Sir
Charles Lyell's memorial gave his friends. The existing inscription is,
"Charles Lyell...Author of 'The Principles of Geology'...Throughout a long
and laborious life he sought the means of deciphering the fragmentary
records of the Earth's history in the patient investigation of the present
order of Nature, enlarging the boundaries of knowledge, and leaving on
Scientific thought an enduring influence..."

Down, June 21st [1876].

I am sorry for you about the inscription, which has almost burst me. We
think there are too many plurals in yours, and when read aloud it hisses
like a goose. I think the omission of some words makes it much stronger.
"World" (573/2. The suggested sentence runs: "he gave to the world the
results of his labour, etc.") is much stronger and truer than "public." As
Lyell wrote various other books and memoirs, I have some little doubt about
the "Principles of Geology." People here do not like your "enduring
value": it sounds almost an anticlimax. They do not much like my "last
(or endure) as long as science lasts." If one reads a sentence often
enough, it always becomes odious.

God help you.

Down, March 8th [1875].

I thank you for your very kind and deeply interesting letter of March 1st,
received yesterday, and for the present of your work, which no doubt I
shall soon receive from Dr. Hooker. (574/1. "Flora Fossilis Arctica,"
Volume III., 1874, sent by Prof. Heer through Sir Joseph Hooker.) The
sudden appearance of so many Dicotyledons in the Upper Chalk appears to me
a most perplexing phenomenon to all who believe in any form of evolution,
especially to those who believe in extremely gradual evolution, to which
view I know that you are strongly opposed. (574/2. The volume referred to
contains a paper on the Cretaceous Flora of the Arctic Zone (Spitzbergen
and Greenland), in which several dicotyledonous plants are described. In a
letter written by Heer to Darwin the author speaks of a species of poplar
which he describes as the oldest Dicotyledon so far recorded.) The
presence of even one true Angiosperm in the Lower Chalk makes me inclined
to conjecture that plants of this great division must have been largely
developed in some isolated area, whence owing to geographical changes, they
at last succeeded in escaping, and spread quickly over the world. (574/3.
No satisfactory evidence has so far been brought forward of the occurrence
of fossil Angiosperms in pre-Cretaceous rocks. The origin of the
Monocotyledons and Dicotyledons remains one of the most difficult and
attractive problems of Palaeobotany.) (574/4. See Letters 395, 398.) But
I fully admit that this case is a great difficulty in the views which I
hold. Many as have been the wonderful discoveries in Geology during the
last half-century, I think none have exceeded in interest your results with
respect to the plants which formerly existed in the Arctic regions. How I
wish that similar collections could be made in the Southern hemisphere, for
instance in Kerguelen's Land.

The death of Sir C. Lyell is a great loss to science, but I do not think to
himself, for it was scarcely possible that he could have retained his
mental powers, and he would have suffered dreadfully from their loss. The
last time I saw him he was speaking with the most lively interest about his
last visit to you, and I was grieved to hear from him a very poor account
of your health. I have been working for some time on a special subject,
namely insectivorous plants. I do not know whether the subject will
interest you, but when my book is published I will have the pleasure of
sending you a copy.

I am very much obliged for your photograph, and enclose one of myself.

March 2nd, 1878.

It is the greatest possible satisfaction to a man nearly at the close of
his career to believe that he has aided or stimulated an able and energetic
fellow-worker in the noble cause of science. Therefore your letter has
deeply gratified me. I am writing this away from home, as my health
failed, and I was forced to rest; and this will account for the delay in
answering your letter. No doubt on my return home I shall find the memoir
which you have kindly sent me. I shall read it with much interest, as I
have heard something of your work from Prof. Geikie, and have read his
admirable "Ice Age." (574/5. "The Great Ice Age and its Relation to the
Antiquity of Man": London, 1874. By James Geikie.) I have noticed the
criticisms on your work, but such opposition must be expected by every one
who draws fine grand conclusions, and such assuredly are yours as
abstracted in your letter. (574/6. Mr. S.B.J. Skertchly recorded "the
discovery of palaeolithic flint implements, mammalian bones, and
fresh-water shells in brick-earths below the Boulder-clay of East Anglia,"
in a letter published in the "Geol. Mag." Volume III., page 476, 1876.
(See also "The Fenland, Past and Present." S.H. Miller and S.B.J.
Skertchly, London, 1878.) The conclusions of Mr. Skertchly as to the pre-
Glacial age of the flint implements were not accepted by some authorities.
(See correspondence in "Nature," Volume XV., 1877, pages 141, 142.) We are
indebted to Mr. Marr for calling our attention to Mr. Skertchly's
discovery.) What magnificent progress Geology has made within my lifetime!

I shall have very great pleasure in sending you any of my books with my
autograph, but I really do not know which to send. It will cost you only
the trouble of a postcard to tell me which you would like, and it shall
soon be sent. Forgive this untidy note, as it is rather an effort to

With all good wishes for your continued success in science and for your

CHAPTER 2.X.--BOTANY, 1843-1871.

2.X.I. Miscellaneous.--2.X.II. Melastomaceae.--2.X.III. Correspondence
with John Scott.

2.X.I. MISCELLANEOUS, 1843-1862.

(PLATE: SIR JOSEPH HOOKER, 1897. From a Photograph by W.J. Hawker
Wimborne. Walker & Cockerell, ph. sc.)

Down, March 12th [1843].

...When you next write to your son, will you please remember me kindly to
him and give him my best thanks for his note? I had the pleasure yesterday
of reading a letter from him to Mr. Lyell of Kinnordy, full of the most
interesting details and descriptions, and written (if I may be permitted to
make such a criticism) in a particularly agreeable style. It leads me
anxiously to hope, even more than I did before, that he will publish some
separate natural history journal, and not allow (if it can be avoided) his
materials to be merged in another work. I am very glad to hear you talk of
inducing your son to publish an Antarctic Flora. I have long felt much
curiosity for some discussion on the general character of the flora of
Tierra del Fuego, that part of the globe farthest removed in latitude from
us. How interesting will be a strict comparison between the plants of
these regions and of Scotland and Shetland. I am sure I may speak on the
part of Prof. Henslow that all my collection (which gives a fair
representation of the Alpine flora of Tierra del Fuego and of Southern
Patagonia) will be joyfully laid at his disposal.

Down, Saturday [April 8th, 1843].

I take the liberty, at the suggestion of Dr. Royle, of forwarding to you a
few seeds, which have been found under very singular circumstances. They
have been sent to me by Mr. W. Kemp, of Galashiels, a (partially educated)
man, of whose acuteness and accuracy of observation, from several
communications on geological subjects, I have a VERY HIGH opinion. He
found them in a layer under twenty-five feet thickness of white sand, which
seems to have been deposited on the margins of an anciently existing lake.
These seeds are not known to the provincial botanists of the district. He
states that some of them germinated in eight days after being planted, and
are now alive. Knowing the interest you took in some raspberry seeds,
mentioned, I remember, in one of your works, I hope you will not think me
troublesome in asking you to have these seeds carefully planted, and in
begging you so far to oblige me as to take the trouble to inform me of the
result. Dr. Daubeny has started for Spain, otherwise I would have sent him
some. Mr. Kemp is anxious to publish an account of his discovery himself,
so perhaps you will be so kind as to communicate the result to me, and not
to any periodical. The chance, though appearing so impossible, of
recovering a plant lost to any country if not to the world, appears to me
so very interesting, that I hope you will think it worth while to have
these seeds planted, and not returned to me.

[September, 1843.]

An interesting fact has lately, as it were, passed through my hands. A Mr.
Kemp (almost a working man), who has written on "parallel roads," and has
corresponded with me (577/1. In a letter to Henslow, Darwin wrote: "If he
[Mr. Kemp] had not shown himself a most careful and ingenious observer, I
should have thought nothing of the case."), sent me in the spring some
seeds, with an account of the spot where they were found, namely, in a
layer at the bottom of a deep sand pit, near Melrose, above the level of
the river, and which sand pit he thinks must have been accumulated in a
lake, when the whole features of the valleys were different, ages ago;
since which whole barriers of rock, it appears, must have been worn down.
These seeds germinated freely, and I sent some to the Horticultural
Society, and Lindley writes to me that they turn out to be a common Rumex
and a species of Atriplex, which neither he nor Henslow (as I have since
heard) have ever seen, and certainly not a British plant! Does this not
look like a vivification of a fossil seed? It is not surprising, I think,
that seeds should last ten or twenty thousand [years], as they have lasted
two or three [thousand years] in the Druidical mounds, and have germinated.

When not building, I have been working at my volume on the volcanic islands
which we visited; it is almost ready for press...I hope you will read my
volume, for, if you don't, I cannot think of anyone else who will! We have
at last got our house and place tolerably comfortable, and I am well
satisfied with our anchorage for life. What an autumn we have had:
completely Chilian; here we have had not a drop of rain or a cloudy day for
a month. I am positively tired of the fine weather, and long for the sight
of mud almost as much as I did when in Peru.

(577/2. The vitality of seeds was a subject in which Darwin continued to
take an interest. In July, 1855 ("Life and Letters," II., page 65), he
wrote to Hooker: "A man told me the other day of, as I thought, a splendid
instance--and splendid it was, for according to his evidence the seed came
up alive out of the lower part of the London Clay! I disgusted him by
telling him that palms ought to have come up."

In the "Gardeners' Chronicle," 1855, page 758, appeared a notice (half a
column in length) by Darwin on the "Vitality of Seeds." The facts related
refer to the "Sand-walk" at Down; the wood was planted in 1846 on a piece
of pasture land laid down as grass in 1840. In 1855, on the soil being dug
in several places, Charlock (Brassica sinapistrum) sprang up freely. The
subject continued to interest him, and we find a note dated July 2nd, 1874,
in which Darwin recorded that forty-six plants of Charlock sprang up in
that year over a space (14 x 7 feet) which had been dug to a considerable
depth. In the course of the article in the "Gardeners' Chronicle," Darwin
remarks: "The power in seeds of retaining their vitality when buried in
damp soil may well be an element in preserving the species, and therefore
seeds may be specially endowed with this capacity; whereas the power of
retaining vitality in a dry artificial condition must be an indirect, and
in one sense accidental, quality in seeds of little or no use to the

The point of view expressed in the letter to Lyell above given is of
interest in connection with the research of Horace Brown and F. Escombe
(577/3. "Proc. Roy. Soc." Volume LXII., page 160.) on the remarkable power
possessed by dry seeds of resistance to the temperature of liquid air. The
point of the experiment is that life continues at a temperature "below that
at which ordinary chemical reactions take place." A still more striking
demonstration of the fact has been made by Thiselton-Dyer and Dewar who
employed liquid hydrogen as a refrigerant. (577/4. Read before the
British Association (Dover), 1899, and published in the "Comptes rendus,"
1899, and in the "Proc. R. Soc." LXV., page 361, 1899.) The connection
between these facts and the dormancy of buried seeds is only indirect; but
inasmuch as the experiment proves the possibility of life surviving a
period in which no ordinary chemical change occurs, it is clear that they
help one to believe in greatly prolonged dormancy in conditions which tend
to check metabolism. For a discussion of the bearing of their results on
the life-problem, and for the literature of the subject, reference should
be made to the paper by Brown and Escombe. See also C. de Candolle "On
Latent Life in Seeds," "Brit. Assoc. Report," 1896, page 1023 and F.
Escombe, "Science Progress," Volume I., N.S., page 585, 1897.)

Down, Saturday [November 5th, 1843].

I sent that weariful Atriplex to Babington, as I said I would, and he tells
me that he has reared a facsimile by sowing the seeds of A. angustifolia in
rich soil. He says he knows the A. hastata, and that it is very different.
Until your last note I had not heard that Mr. Kemp's seeds had produced two
Polygonums. He informs me he saw each plant bring up the husk of the
individual seed which he planted. I believe myself in his accuracy, but I
have written to advise him not to publish, for as he collected only two
kinds of seeds--and from them two Polygomuns, two species or varieties of
Atriplex and a Rumex have come up, any one would say (as you suggested)
that more probably all the seeds were in the soil, than that seeds, which
must have been buried for tens of thousands of years, should retain their
vitality. If the Atriplex had turned out new, the evidence would indeed
have been good. I regret this result of poor Mr. Kemp's seeds, especially
as I believed, from his statements and the appearance of the seeds, that
they did germinate, and I further have no doubt that their antiquity must
be immense. I am sorry also for the trouble you have had. I heard the
other day through a circuitous course how you are astonishing all the
clodhoppers in your whole part of the county: and [what is] far more
wonderful, as it was remarked to me, that you had not, in doing this,
aroused the envy of all the good surrounding sleeping parsons. What good
you must do to the present and all succeeding generations. (578/1. For an
account of Professor Henslow's management of his parish of Hitcham see
"Memoir of the Rev. John Stevens Henslow, M.A." by the Rev. Leonard Jenyns:
8vo, London, 1862.)

Down, November 14th [1855].

You well know how credulous I am, and therefore you will not be surprised
at my believing the Raspberry story (579/1. This probably refers to
Lindley's story of the germination of raspberry seeds taken from a barrow
1600 years old.): a very similar case is on record in Germany--viz., seeds
from a barrow; I have hardly zeal to translate it for the "Gardeners'
Chronicle." (579/2. "Vitality of Seeds," "Gardeners' Chronicle," November
17th, 1855, page 758.) I do not go the whole hog--viz., that sixty and two
thousand years are all the same, for I should imagine that some slight
chemical change was always going on in a seed. Is this not so? The
discussions have stirred me up to send my very small case of the charlock;
but as it required some space to give all details, perhaps Lindley will not
insert; and if he does, you, you worse than an unbelieving dog, will not, I
know, believe. The reason I do not care to try Mr. Bentham's plan is that
I think it would be very troublesome, and it would not, if I did not find
seed, convince me myself that none were in the earth, for I have found in
my salting experiments that the earth clings to the seeds, and the seeds
are very difficult to find. Whether washing would do I know not; a gold-
washer would succeed, I daresay.


Testimonial from Charles Darwin, Esq., M.A., F.R.S. and G.S., late
Naturalist to Captain Fitz-Roy's Voyage.

Down House, Farnborough, August 25th, 1845.

I have heard with much interest that your son, Dr. Hooker, is a candidate
for the Botanical Chair at Edinburgh. From my former attendance at that
University, I am aware how important a post it is for the advancement of
science, and I am therefore the more anxious for your son's success, from
my firm belief that no one will fulfil its duties with greater zeal or
ability. Since his return from the famous Antarctic expedition, I have
had, as you are aware, much communication with him, with respect to the
collections brought home by myself, and on other scientific subjects; and I
cannot express too strongly my admiration at the accuracy of his varied
knowledge, and at his powers of generalisation. From Dr. Hooker's
disposition, no one, in my opinion, is more fitted to communicate to
beginners a strong taste for those pursuits to which he is himself so
ardently devoted. For the sake of the advancement of Botany in all its
branches, your son has my warmest wishes for his success.

Down, Thursday [June 11th, 1847].

Many thanks for your kindness about the lodgings--it will be of great use
to me. (581/1. The British Association met at Oxford in 1847.) Please
let me know the address if Mr. Jacobson succeeds, for I think I shall go on
the 22nd and write previously to my lodgings. I have since had a tempting
invitation from Daubeny to meet Henslow, etc., but upon the whole, I
believe, lodgings will answer best, for then I shall have a secure
solitary retreat to rest in.

I am extremely glad I sent the Laburnum (581/2. This refers to the
celebrated form known as Cytisus Adami, of which a full account is given in
"Variation of Animals and Plants, " Volume I., Edition II., page 413. It
has been supposed to be a seminal hybrid or graft-hybrid between C.
laburnum and C. purpureus. It is remarkable for bearing "on the same tree
tufts of dingy red, bright yellow, and purple flowers, borne on branches
having widely different leaves and manner of growth." In a paper by
Camuzet in the "Annales de la Societe d'Horticulture de Paris, XIII., 1833,
page 196, the author tries to show that Cytisus Adami is a seminal hybrid
between C. alpinus and C. laburnum. Fuchs ("Sitz. k. Akad. Wien," Bd. 107)
and Beijerinck ("K. Akad. Amsterdam," 1900) have spoken on Cytisus Adami,
but throw no light on the origin of the hybrid. See letters to Jenner Weir
in the present volume.): the raceme grew in centre of tree, and had a most
minute tuft of leaves, which presented no unusual appearance: there is now
on one raceme a terminal bilateral [i.e., half yellow, half purple] flower,
and on other raceme a single terminal pure yellow and one adjoining
bilateral flower. If you would like them I will send them; otherwise I
would keep them to see whether the bilateral flowers will seed, for Herbert
(581/3. Dean Herbert.) says the yellow ones will. Herbert is wrong in
thinking there are no somewhat analogous facts: I can tell you some, when
we meet. I know not whether botanists consider each petal and stamen an
individual; if so, there seems to me no especial difficulty in the case,
but if a flower-bud is a unit, are not their flowers very strange?

I have seen Dillwyn in the "Gardeners' Chronicle," and was disgusted at it,
for I thought my bilateral flowers would have been a novelty for you.

(581/4. In a letter to Hooker, dated June 2nd, 1847, Darwin makes a bold
suggestion as to floral symmetry:--)

I send you a tuft of the quasi-hybrid Laburnum, with two kinds of flowers
on same stalk, and with what strikes [me] as very curious (though I know it
has been observed before), namely, a flower bilaterally different: one
other, I observe, has half its calyx purple. Is this not very curious, and
opposed to the morphological idea that a flower is a condensed continuous
spire of leaves? Does it not look as if flowers were normally bilateral;
just in the same way as we now know that the radiating star-fish, etc., are
bilateral? The case reminds me of those insects with exactly half having
secondary male characters and the other half female.

(581/5. It is interesting to note his change of view in later years. In
an undated letter written to Mr. Spencer, probably in 1873, he says: "With
respect to asymmetry in the flowers themselves, I remain contented, from
all that I have seen, with adaptation to visits of insects. There is,
however, another factor which it is likely enough may have come into play--
viz., the protection of the anthers and pollen from the injurious effects
of rain. I think so because several flowers inhabiting rainy countries, as
A. Kerner has lately shown, bend their heads down in rainy weather.")

June [1855].

(582/1. This is an early example of Darwin's interest in the movements of
plants. Sleeping plants, as is well-known, may acquire a rhythmic movement
differing from their natural period, but the precise experiment here
described has not, as far as known, been carried out. See Pfeffer,
"Periodische Bewegungen," 1875, page 32.)

I thank you much for Hedysarum: I do hope it is not very precious, for, as
I told you, it is for probably a most foolish purpose. I read somewhere
that no plant closes its leaves so promptly in darkness, and I want to
cover it up daily for half an hour, and see if I can TEACH IT to close by
itself, or more easily than at first in darkness. I am rather puzzled
about its transmission, from not knowing how tender it is...

Down, July 19th, 1856.

I thank you warmly for the very kind manner with which you have taken my
request. It will, in truth, be a most important service to me; for it is
absolutely necessary that I should discuss single and double creations, as
a very crucial point on the general origin of species, and I must confess,
with the aid of all sorts of visionary hypotheses, a very hostile one. I
am delighted that you will take up possibility of crossing, no botanist has
done so, which I have long regretted, and I am glad to see that it was one
of A. De Candolle's desiderata. By the way, he is curiously contradictory
on subject. I am far from expecting that no cases of apparent
impossibility will be found; but certainly I expect that ultimately they
will disappear; for instance, Campanulaceae seems a strong case, but now it
is pretty clear that they must be liable to crossing. Sweet-peas (583/1.
In Lathyrus odoratus the absence of the proper insect has been supposed to
prevent crossing. See "Variation under Domestication," Edition II., Volume
II., page 68; but the explanation there given for Pisum may probably apply
to Lathyrus.), bee-orchis, and perhaps hollyhocks are, at present, my
greatest difficulties; and I find I cannot experimentise by castrating
sweet-peas, without doing fatal injury. Formerly I felt most interest on
this point as one chief means of eliminating varieties; but I feel interest
now in other ways. One general fact [that] makes me believe in my doctrine
(583/2. The doctrine which has been epitomised as "Nature abhors perpetual
self-fertilisation," and is generally known as Knight's Law or the
Knight-Darwin Law, is discussed by Francis Darwin in "Nature," 1898.
References are there given to the chief passages in the "Origin of
Species," etc., bearing on the question. See Letter 19, Volume I.), is
that NO terrestrial animal in which semen is liquid is hermaphrodite except
with mutual copulation; in terrestrial plants in which the semen is dry
there are many hermaphrodites. Indeed, I do wish I lived at Kew, or at
least so that I could see you oftener. To return again to subject of
crossing: I have been inclined to speculate so far, as to think (my!?)
notion (I say MY notion, but I think others have put forward nearly or
quite similar ideas) perhaps explains the frequent separation of the sexes
in trees, which I think I have heard remarked (and in looking over the
mono- and dioecious Linnean classes in Persoon seems true) are very apt to
have sexes separated; for [in] a tree having a vast number of flowers on
the same individual, or at least the same stock, each flower, if only
hermaphrodite on the common plan, would generally get its own pollen or
only pollen from another flower on same stock,--whereas if the sexes were
separate there would be a better chance of occasional pollen from another
distinct stock. I have thought of testing this in your New Zealand Flora,
but I have no standard of comparison, and I found myself bothered by
bushes. I should propound that some unknown causes had favoured
development of trees and bushes in New Zealand, and consequent on this
there had been a development of separation of sexes to prevent too much
intermarriage. I do not, of course, suppose the prevention of too much
intermarriage the only good of separation of sexes. But such wild notions
are not worth troubling you with the reading of.

Moor Park [May 2nd, 1857].

The most striking case, which I have stumbled on, on apparent, but false
relation of structure of plants to climate, seems to be Meyer and Doege's
remark that there is not one single, even moderately-sized, family at the
Cape of Good Hope which has not one or several species with heath-like
foliage; and when we consider this together with the number of true heaths,
any one would have been justified, had it not been for our own British
heaths (584/1. It is well known that plants with xerophytic
characteristics are not confined to dry climates; it is only necessary to
mention halophytes, alpine plants and certain epiphytes. The heaths of
Northern Europe are placed among the xerophytes by Warming ("Lehrbuch der
okologischen Pflanzengeographie," page 234, Berlin, 1896).), in saying that
heath-like foliage must stand in direct relation to a dry and moderately
warm climate. Does this not strike you as a good case of false relation?
I am so pleased with this place and the people here, that I am greatly
tempted to bring Etty here, for she has not, on the whole, derived any
benefit from Hastings. With thanks for your never failing assistance to

I remember that you were surprised at number of seeds germinating in pond
mud. I tried a fourth pond, and took about as much mud (rather more than
in former case) as would fill a very large breakfast cup, and before I had
left home 118 plants had come up; how many more will be up on my return I
know not. This bears on chance of birds by their muddy feet transporting
fresh-water plants.

This would not be a bad dodge for a collector in country when plants were
not in seed, to collect and dry mud from ponds.

Down [1857].

I am very glad to hear that you think of discussing the relative ranges of
the identical and allied U. States and European species, when you have
time. Now this leads me to make a very audacious remark in opposition to
what I imagine Hooker has been writing (585/1. See Letter 338, Volume I.),
and to your own scientific conscience. I presume he has been urging you to
finish your great "Flora" before you do anything else. Now I would say it
is your duty to generalise as far as you safely can from your as yet
completed work. Undoubtedly careful discrimination of species is the
foundation of all good work; but I must look at such papers as yours in
Silliman as the fruit. As careful observation is far harder work than
generalisation, and still harder than speculation, do you not think it very
possible that it may be overvalued? It ought never to be forgotten that
the observer can generalise his own observations incomparably better than
any one else. How many astronomers have laboured their whole lives on
observations, and have not drawn a single conclusion; I think it is
Herschel who has remarked how much better it would be if they had paused in
their devoted work and seen what they could have deduced from their work.
So do pray look at this side of the question, and let us have another paper
or two like the last admirable ones. There, am I not an audacious dog!

You ask about my doctrine which led me to expect that trees would tend to
have separate sexes. I am inclined to believe that no organic being exists
which perpetually self-fertilises itself. This will appear very wild, but
I can venture to say that if you were to read my observations on this
subject you would agree it is not so wild as it will at first appear to
you, from flowers said to be always fertilised in bud, etc. It is a long
subject, which I have attended to for eighteen years. Now, it occurred to
me that in a large tree with hermaphrodite flowers, we will say it would be
ten to one that it would be fertilised by the pollen of its own flower, and
a thousand or ten thousand to one that if crossed it would be crossed only
with pollen from another flower of same tree, which would be opposed to my
doctrine. Therefore, on the great principle of "Nature not lying," I fully
expected that trees would be apt to be dioecious or monoecious (which, as
pollen has to be carried from flower to flower every time, would favour a
cross from another individual of the same species), and so it seems to be
in Britain and New Zealand. Nor can the fact be explained by certain
families having this structure and chancing to be trees, for the rule seems
to hold both in genera and families, as well as in species.

I give you full permission to laugh your fill at this wild speculation; and
I do not pretend but what it may be chance which, in this case, has led me
apparently right. But I repeat that I feel sure that my doctrine has more
probability than at first it appears to have. If you had not asked, I
should not have written at such length, though I cannot give any of my

The Leguminosae are my greatest opposers: yet if I were to trust to
observations on insects made during many years, I should fully expect
crosses to take place in them; but I cannot find that our garden varieties
ever cross each other. I do NOT ask you to take any trouble about it, but
if you should by chance come across any intelligent nurseryman, I wish you
would enquire whether they take any pains in raising the varieties of
papilionaceous plants apart to prevent crossing. (I have seen a statement
of naturally formed crossed Phaseoli near N. York.) The worst is that
nurserymen are apt to attribute all varieties to crossing.

Finally I incline to believe that every living being requires an occasional
cross with a distinct individual; and as trees from the mere multitude of
flowers offer an obstacle to this, I suspect this obstacle is counteracted
by tendency to have sexes separated. But I have forgotten to say that my
maximum difficulty is trees having papilionaceous flowers: some of them, I
know, have their keel-petals expanded when ready for fertilisation; but
Bentham does not believe that this is general: nevertheless, on principle
of nature not lying, I suspect that this will turn out so, or that they are
eminently sought by bees dusted with pollen. Again I do NOT ask you to
take trouble, but if strolling under your Robinias when in full flower,
just look at stamens and pistils whether protruded and whether bees visit
them. I must just mention a fact mentioned to me the other day by Sir W.
Macarthur, a clever Australian gardener: viz., how odd it was that his
Erythrinas in N.S. Wales would not set a seed, without he imitated the
movements of the petals which bees cause. Well, as long as you live, you
will never, after this fearfully long note, ask me why I believe this or

June 18th [1857].

It has been extremely kind of you telling me about the trees: now with
your facts, and those from Britain, N. Zealand, and Tasmania I shall have
fair materials for judging. I am writing this away from home, but I think
your fraction of 95/132 is as large as in other cases, and is at least a
striking coincidence.

I thank you much for your remarks about my crossing notions, to which, I
may add, I was led by exactly the same idea as yours, viz., that crossing
must be one means of eliminating variation, and then I wished to make out
how far in animals and vegetables this was possible. Papilionaceous
flowers are almost dead floorers to me, and I cannot experimentise, as
castration alone often produces sterility. I am surprised at what you say
about Compositae and Gramineae. From what I have seen of latter they
seemed to me (and I have watched wheat, owing to what L. de Longchamps has
said on their fertilisation in bud) favourable for crossing; and from
Cassini's observations and Kolreuter's on the adhesive pollen, and C.C.
Sprengel's, I had concluded that the Compositae were eminently likely (I am
aware of the pistil brushing out pollen) to be crossed. (586/1. This is
an instance of the curious ignorance of the essential principles of floral
mechanism which was to be found even among learned and accomplished
botanists such as Gray, before the publication of the "Fertilisation of
Orchids." Even in 1863 we find Darwin explaining the meaning of dichogamy
in a letter to Gray.) If in some months' time you can find time to tell me
whether you have made any observations on the early fertilisation of plants
in these two orders, I should be very glad to hear, as it would save me
from great blunder. In several published remarks on this subject in
various genera it has seemed to me that the early fertilisation has been
inferred from the early shedding of the pollen, which I think is clearly a
false inference. Another cause, I should think, of the belief of
fertilisation in the bud, is the not-rare, abnormal, early maturity of the
pistil as described by Gartner. I have hitherto failed in meeting with
detailed accounts of regular and normal impregnation in the bud.
Podostemon and Subularia under water (and Leguminosae) seem and are
strongest cases against me, as far as I as yet know. I am so sorry that
you are so overwhelmed with work; it makes your VERY GREAT kindness to me
the more striking.

It is really pretty to see how effectual insects are. A short time ago I
found a female holly sixty measured yards from any other holly, and I cut
off some twigs and took by chance twenty stigmas, cut off their tops, and
put them under the microscope: there was pollen on every one, and in
profusion on most! weather cloudy and stormy and unfavourable, wind in
wrong direction to have brought any.

Down, January 12th [1858].

I want to ask a question which will take you only few words to answer. It
bears on my former belief (and Asa Gray strongly expressed opinion) that
Papilionaceous flowers were fatal to my notion of there being no eternal
hermaphrodites. First let me say how evidence goes. You will remember my
facts going to show that kidney-beans require visits of bees to be
fertilised. This has been positively stated to be the case with Lathyrus
grandiflorus, and has been very partially verified by me. Sir W. Macarthur
tells me that Erythrina will hardly seed in Australia without the petals
are moved as if by bee. I have just met the statement that, with common
bean, when the humble-bees bite holes at the base of the flower, and
therefore cease visiting the mouth of the corolla, "hardly a bean will
set." But now comes a much more curious statement, that [in] 1842-43,
"since bees were established at Wellington (New Zealand), clover seeds all
over the settlement, WHICH IT DID NOT BEFORE." (587/1. See Letter 362,
Volume I.) The writer evidently has no idea what the connection can be.
Now I cannot help at once connecting this statement (and all the foregoing
statements in some degree support each other, as all have been advanced
without any sort of theory) with the remarkable absence of Papilionaceous
plants in N. Zealand. I see in your list Clianthus, Carmichaelia (four
species), a new genus, a shrub, and Edwardsia (is latter Papilionaceous?).
Now what I want to know is whether any of these have flowers as small as
clover; for if they have large flowers they may be visited by humble-bees,
which I think I remember do exist in New Zealand; and which humble-bees
would not visit the smaller clover. Even the very minute little yellow
clover in England has every flower visited and revisited by hive-bees, as I
know by experience. Would it not be a curious case of correlation if it
could be shown to be probable that herbaceous and small Leguminosae do not
exist because when [their] seeds [are] washed ashore (!!!) no small bees
exist there. Though this latter fact must be ascertained. I may not prove
anything, but does it not seem odd that so many quite independent facts, or
rather statements, should point all in one direction, viz., that bees are
necessary to the fertilisation of Papilionaceous flowers?

LETTER 588. TO JOHN LUBBOCK (Lord Avebury).
Sunday [1859].

Do you remember calling my attention to certain flowers in the truss of
Pelargoniums not being true, or not having the dark shade on the two upper
petals? I believe it was Lady Lubbock's observation. I find, as I
expected, it is always the central or sub-central flower; but what is far
more curious, the nectary, which is blended with the peduncle of the
flowers, gradually lessens and quite disappears (588/1. This fact is
mentioned in Maxwell Masters' "Vegetable Teratology" (Ray Society's
Publications), 1869, page 221.), as the dark shade on the two upper petals
disappears. Compare the stalk in the two enclosed parcels, in each of
which there is a perfect flower.

Now, if your gardener will not be outrageous, do look over your geraniums
and send me a few trusses, if you can find any, having the flowers without
the marks, sending me some perfect flowers on same truss. The case seems
to me rather a pretty one of correlation of growth; for the calyx also
becomes slightly modified in the flowers without marks.

Down, April 7th [1860].

I hope that you will excuse the liberty which I take in writing to you and
begging a favour. I have been very much interested by the abstract (too
brief) of your lecture at the Royal Institution. Many of the facts alluded
to are full of interest for me. But on one point I should be infinitely
obliged if you could procure me any information: namely, with respect to
sweet-peas. I am a great believer in the natural crossing of individuals
of the same species. But I have been assured by Mr. Cattell (589/1. The
nurseryman he generally dealt with.), of Westerham, that the several
varieties of sweet-pea can be raised close together for a number of years
without intercrossing. But on the other hand he stated that they go over
the beds, and pull up any false plant, which they very naturally attribute
to wrong seeds getting mixed in the lot. After many failures, I succeeded
in artificially crossing two varieties, and the offspring out of the same
pod, instead of being intermediate, was very nearly like the two pure
parents; yet in one, there was a trace of the cross, and these crossed peas
in the next generation showed still more plainly their mongrel origin.
Now, what I want to know is, whether there is much variation in sweet-peas
which might be owing to natural crosses. What I should expect would be
that they would keep true for many years, but that occasionally, perhaps at
long intervals, there would be a considerable amount of crossing of the
varieties grown close together. Can you give, or obtain from your father,
any information on this head, and allow me to quote your authority? It
would really be a very great favour and kindness.


(590/1. The genera Scaevola and Leschenaultia, to which the following
letter refers, belong to the Goodeniaceae (Goodenovieae, Bentham & Hooker),
an order allied to the Lobeliaceae, although the mechanism of fertilisation
resembles rather more nearly that of Campanula. The characteristic feature
of the flower in this order is the indusium, or, as Delpino (590/2.
Delpino's observations on Dichogamy, summarised by Hildebrand in "Bot.
Zeitung," 1870, page 634.) calls it, the "collecting cup": this cuplike
organ is a development of the style, and serves the same function as the
hairs on the style of Campanula, namely, that of taking the pollen from the
anthers and presenting it to the visiting insect. During this stage the
immature stigma is at the bottom of the cup, and though surrounded by
pollen is incapable of being pollinated. In most genera of the order the
pollen is pushed out of the indusium by the growth of the style or stigma,
very much as occurs in Lobelia or the Compositae. Finally the style
emerges from the indusium (590/3. According to Hamilton ("Proc. Linn. Soc.
N. S. Wales," X., 1895, page 361) the stigma rarely grows beyond the
indusium in Dampiera. In the same journal (1885-6, page 157, and IX.,
1894, page 201) Hamilton has given a number of interesting observations on
Goodenia, Scaevola, Selliera, Brunonia. There seem to be mechanisms for
cross- and also for self-fertilisation.), the stigmas open out and are
pollinated from younger flowers. The mechanism of fertilisation has been
described by F. Muller (590/4. In a letter to Hildebrand published in the
"Bot. Zeitung," 1868, page 113.), and more completely by Delpino (loc.

Mr. Bentham wrote a paper (590/5. "Linn. Soc. Journal," 1869, page 203.)
on the style and stigma in the Goodenovieae, where he speaks of Mr.
Darwin's belief that fertilisation takes place outside the indusium. This
statement, which we imagine Mr. Bentham must have had from an unpublished
source, was incomprehensible to him as long as he confined his work to such
genera as Goodenia, Scaevola, Velleia, Coelogyne, in which the mechanism is
much as above described; but on examining Leschenaultia the meaning became
clear. Bentham writes of this genus:--"The indusium is usually described
as broadly two-lipped, without any distinct stigma. The fact appears to be
that the upper less prominent lip is stigmatic all over, inside and out,
with a transverse band of short glandular hairs at its base outside, while
the lower more prominent lip is smooth and glabrous, or with a tuft of
rigid hairs. Perhaps this lower lip and the upper band of hairs are all
that correspond to the indusium of other genera; and the so-called upper
lip, outside of which impregnation may well take place, as observed by Mr.
Darwin, must be regarded as the true stigma."

Darwin's interest in the Goodeniaceae was due to the mechanism being
apparently fitted for self-fertilisation. In 1871 a writer signing himself
F.W.B. made a communication to the "Gardeners' Chronicle" (590/6. 1871,
page 1103.), in which he expresses himself as "agreeably surprised" to find
Leschenaultia adapted for self-fertilisation, or at least for
self-pollinisation. This led Darwin to publish a short note in the same
journal, in which he describes the penetration of pollen-tubes into the
viscid surface on the outside of the indusium. (590/7. 1871, page 1166.
He had previously written in the "Journal of Horticulture and Cottage
Gardener," May 28th, 1861, page 151:--"Leschenaultia formosa has apparently
the most effective contrivance to prevent the stigma of one flower ever
receiving a grain of pollen from another flower; for the pollen is shed in
the early bud, and is there shut up round the stigma within a cup or
indusium. But some observations led me to suspect that nevertheless insect
agency here comes into play; for I found by holding a camel-hair pencil
parallel to the pistil, and moving it as if it were a bee going to suck the
nectar, the straggling hairs of the brush opened the lip of the indusium,
entered it, stirred up the pollen, and brought out some grains. I did this
to five flowers, and marked them. These five flowers all set pods; whereas
only two other pods set on the whole plant, though covered with innumerable
flowers...I wrote to Mr. James Drummond, at Swan River in Australia,...and
he soon wrote to me that he had seen a bee cleverly opening the indusium
and extracting pollen.") He also describes how a brush, pushed into the
flower in imitation of an insect, presses "against the slightly projecting
lower lip of the indusium, opens it, and some of the hairs enter and become
smeared with pollen." The yield of pollen is therefore differently
arranged in Leschenaultia; for in the more typical genera it depends on the
growth of the style inside the indusium. Delpino, however (see
Hildebrand's version, loc. cit.), describes a similar opening of the cup
produced by pressure on the hairs in some genera of the order.)

Down, June 7th [1860].

Best and most beloved of men, I supplicate and entreat you to observe one
point for me. Remember that the Goodeniaceae have weighed like an incubus
for years on my soul. It relates to Scaevola microcarpa. I find that in
bud the indusium collects all the pollen splendidly, but, differently from
Leschenaultia, cannot be afterwards easily opened. Further, I find that at
an early stage, when the flower first opens, a boat-shaped stigma lies at
the bottom of the indusium, and further that this stigma, after the flower
has some time expanded, grows very rapidly, when the plant is kept hot, and
pushes out of the indusium a mass of pollen; and at same time two horns
project at the corners of the indusium. Now the appearance of these horns
makes me suppose that these are the stigmatic surfaces. Will you look to
this? for if they be by the relative position of the parts (with indusium
and stigma bent at right angles to style) [I am led to think] that an
insect entering a flower could not fail to have [its] whole back (at the
period when, as I have seen, a whole mass of pollen is pushed out) covered
with pollen, which would almost certainly get rubbed on the two horns.
Indeed, I doubt whether, without this aid, pollen would get on to the
horns. What interests me in the case is the analogy in result with the
Lobelia, but by very different means. In Lobelia the stigma, before it is
mature, pushes by its circular brush of hairs the pollen out of the
conjoined anthers; here the indusium collects pollen, and then the growth
of the stigma pushes it out. In the course of about 1 1/2 hour, I found an
indusium with hairs on the outer edge perfectly clogged with pollen, and
horns protruded, which before the 1 1/2 hour had not one grain of pollen
outside the indusium, and no trace of protruding horns. So you will see
how I wish to know whether the horns are the true stigmatic surfaces. I
would try the case experimentally by putting pollen on the horns, but my
greenhouse is so cold, and my plant so small, and in such a little pot,
that I suppose it would not seed...

The little length of stigmatic horns at the moment when pollen is forced
out of the indusium, compared to what they ultimately attain, makes me
fancy that they are not then mature or ready, and if so, as in Lobelia,
each flower must be fertilised by pollen from another and earlier flower.

How curious that the indusium should first so cleverly collect pollen and
then afterwards push it out! Yet how closely analogous to Campanula
brushing pollen out of the anther and retaining it on hairs till the stigma
is ready. I am going to try whether Campanula sets seed without insect


(591/1. The following letters are given here rather than in chronological
order, as bearing on the Leschenaultia problem. The latter part of Letter
591 refers to the cleistogamic flowers of Viola.)

Down, May 1st [1862].

If you can screw out time, do look at the stigma of the blue Leschenaultia
biloba. I have just examined a large bud with the indusium not yet closed,
and it seems to me certain that there is no stigma within. The case would
be very important for me, and I do not like to trust solely to myself. I
have been impregnating flowers, but it is rather difficult...

I have just looked again at Viola canina. The case is odder: only 2
stamens which embrace the stigma have pollen; the 3 other stamens have no
anther-cells and no pollen. These 2 fertile anthers are of different shape
from the 3 sterile others, and the scale representing the lower lip is
larger and differently shaped from the 4 other scales representing 4 other

In V. odorata (single flower) all five stamens produce pollen. But I
daresay all this is known.

November 3rd [1862].

Do you remember the scarlet Leschenaultia formosa with the sticky margin
outside the indusium? Well, this is the stigma--at least, I find the
pollen-tubes here penetrate and nowhere else. What a joke it would be if
the stigma is always exterior, and this by far the greatest difficulty in
my crossing notions should turn out a case eminently requiring insect aid,
and consequently almost inevitably ensuring crossing. By the way, have you
any other Goodeniaceae which you could lend me, besides Leschenaultia and
Scaevola, of which I have seen enough?

I had a long letter the other day from Crocker of Chichester; he has the
real spirit of an experimentalist, but has not done much this summer.

Down, April 9th and 15th [1866].

I am very much obliged by your letter of February 13th, abounding with so
many highly interesting facts. Your account of the Rubiaceous plant is one
of the most extraordinary that I have ever read, and I am glad you are
going to publish it. I have long wished some one to observe the
fertilisation of Scaevola, and you must permit me to tell you what I have
observed. First, for the allied genus of Leschenaultia: utterly
disbelieving that it fertilises itself, I introduced a camel-hair brush
into the flower in the same way as a bee would enter, and I found that the
flowers were thus fertilised, which never otherwise happens; I then
searched for the stigma, and found it outside the indusium with the pollen-
tubes penetrating it; and I convinced Dr. Hooker that botanists were quite
wrong in supposing that the stigma lay inside the indusium. In Scaevola
microcarpa the structure is very different, for the immature stigma lies at
the base within the indusium, and as the stigma grows it pushes the pollen
out of the indusium, and it then clings to the hairs which fringe the tips
of the indusium; and when an insect enters the flower, the pollen (as I
have seen) is swept from these long hairs on to the insect's back. The
stigma continues to grow, but is not apparently ready for impregnation
until it is developed into two long protruding horns, at which period all
the pollen has been pushed out of the indusium. But my observations are
here at fault, for I did not observe the penetration of the pollen-tubes.
The case is almost parallel with that of Lobelia. Now, I hope you will get
two plants of Scaevola, and protect one from insects, leaving the other
uncovered, and observe the results, both in the number of capsules
produced, and in the average number of seeds in each. It would be well to
fertilise half a dozen flowers under the net, to prove that the cover is
not injurious to fertility.

With respect to your case of Aristolochia, I think further observation
would convince you that it is not fertilised only by larvae, for in a
nearly parallel case of an Arum and a Aristolochia, I found that insects
flew from flower to flower. I would suggest to you to observe any cases of
flowers which catch insects by their probosces, as occurs with some of the
Apocyneae (593/1. Probably Asclepiadeae. See H. Muller, "Fertilisation of
Flowers," page 396.); I have never been able to conceive for what purpose
(if any) this is effected; at the same time, if I tempt you to neglect your
zoological work for these miscellaneous observations I shall be guilty of a
great crime.

To return for a moment to the indusium: how curious it is that the pollen
should be thus collected in a special receptacle, afterwards to be swept
out by insects' agency!

I am surprised at what you tell me about the fewness of the flowers of your
native orchids which produce seed-capsules. What a contrast with our
temperate European species, with the exception of some species of Ophrys!--
I now know of three or four cases of self-fertilising orchids, but all
these are provided with means for an occasional cross.

I am sorry to say Dr. Cruger is dead from a fever.

I received yesterday your paper in the "Botanische Zeitung" on the wood of
climbing plants. (593/2. Fritz Muller, "Ueber das Holz einiger um
Desterro wachsenden Kletterpflanzen." "Botanische Zeitung," 1866, pages
57, 65.) I have read as yet only your very interesting and curious remarks
on the subject as bearing on the change of species; you have pleased me by
the very high compliments which you pay to my paper. I have been at work
since March 1st on a new English edition (593/3. The 4th Edition.) of my
"Origin," of which when published I will send you a copy. I have much
regretted the time it has cost me, as it has stopped my other work. On the
other hand, it will be useful for a new third German edition, which is now
wanted. I have corrected it largely, and added some discussions, but not
nearly so much as I wished to do, for, being able to work only two hours
daily, I feared I should never get it finished. I have taken some facts
and views from your work "Fur Darwin"; but not one quarter of what I should
like to have quoted.

Down, June 24th, 1860.

I hope that you will forgive the liberty which I take in writing to you and
requesting a favour. Mr. H.C. Watson has given me your address, and has
told me that he thought that you would be willing to oblige me. Will you
please to read the enclosed, and then you will understand what I wish
observed with respect to the bee-orchis. (594/1. Ophrys apifera.) What I
especially wish, from information which I have received since publishing
the enclosed, is that the state of the pollen-masses should be noted in
flowers just beginning to wither, in a district where the bee-orchis is
extremely common. I have been assured that in parts of Isle of Wight,
viz., Freshwater Gate, numbers occur almost crowded together: whether
anything of this kind occurs in your vicinity I know not; but, if in your
power, I should be infinitely obliged for any information. As I am
writing, I will venture to mention another wish which I have: namely, to
examine fresh flowers and buds of the Aceras, Spiranthes, marsh Epipactis,
and any other rare orchis. The point which I wish to examine is really
very curious, but it would take too long space to explain. Could you
oblige me by taking the great trouble to send me in an old tin canister any
of these orchids, permitting me, of course, to repay postage? It would be
a great kindness, but perhaps I am unreasonable to make such a request. If
you will inform me whether you have leisure so far to oblige me, I would
tell you my movements, for on account of my own health and that of my
daughter, I shall be on the move for the next two or three weeks.

I am sure I have much cause to apologise for the liberty which I have

Down, August 3rd, 1860.

I thank you most sincerely for sending me the Epipactis [palustris]. You
can hardly imagine what an interesting morning's work you have given me, as
the rostellum exhibited a quite new modification of structure. It has been
extremely kind of you to take so very much trouble for me. Have you looked
at the pollen-masses of the bee-Ophrys? I do not know whether the
Epipactis grows near to your house: if it does, and any object takes you
to the place (pray do not for a moment think me so very unreasonable as to
ask you to go on purpose), would you be so kind [as] to watch the flowers
for a quarter of an hour, and mark whether any insects (and what?) visit
these flowers.

I should suppose they would crawl in by depressing the terminal portion of
the labellum; and that when within the flower this terminal portion would
resume its former position; and lastly, that the insect in crawling out
would not depress the labellum, but would crawl out at back of flower.
(595/1. The observations of Mr. William Darwin on Epipactis palustris
given in the "Fertilisation of Orchids," Edition II., 1877, page 99, bear
on this point. The chief fertilisers are hive-bees, which are too big to
crawl into the flower. They cling to the labellum, and by depressing it
open up the entrance to the flower. Owing to the elasticity of the
labellum and its consequent tendency to spring up when released, the bees,
"as they left the flower, seemed to fly rather upwards." This agrees with
Darwin's conception of the mechanism of the flower as given in the first
edition of the Orchid book, 1862, page 100, although at that time he
imagined that the fertilising insect crawled into the flower. The extreme
flexibility and elasticity of the labellum was first observed by Mr. More
(see first edition, page 99). The description of the flower given in the
above letter to Mr. More is not quite clear; the reader is referred to the
"Fertilisation of Orchids," loc. cit.) An insect crawling out of a
recently opened flower would, I believe, have parts of the pollen-masses
adhering to the back or shoulder. I have seen this in Listera. How I
should like to watch the Epipactis.

If you can it any time send me Spiranthes or Aceras or O. ustulata, you
would complete your work of kindness.

P.S.--If you should visit the Epipactis again, would you gather a few of
the lower flowers which have been opened for some time and have begun to
wither a little, and observe whether pollen is well cleared out of anther-
case. I have been struck with surprise that in nearly all the lower
flowers sent by you, though much of the pollen has been removed, yet a good
deal of pollen is left wasted within the anthers. I observed something of
this kind in Cephalanthera grandiflora. But I fear that you will think me
an intolerable bore.

Down, August 5th, 1860.

I am infinitely obliged for your most clearly stated observations on the
bee-orchis. It is now perfectly clear that something removes the pollen-
masses far more with you than in this neighbourhood. But I am utterly
puzzled about the foot-stalk being so often cut through. I should suspect
snails. I yesterday found thirty-nine flowers, and of them only one
pollen-mass in three flowers had been removed, and as these were extremely
much-withered flowers I am not quite sure of the truth of this. The wind
again is a new element of doubt. Your observations will aid me extremely
in coming to some conclusion. (596/1. Mr. More's observations on the
percentage of flowers in which the pollinia were absent are quoted in
"Fertilisation of Orchids," Edition I., page 68.) I hope in a day or two
to receive some day-moths, on the probosces of which I am assured the
pollen-masses of the bee-orchis still adhere (596/2. He was doomed to
disappointment. On July 17th, 1861, he wrote to Mr. More:--"I found the
other day a lot of bee-Ophrys with the glands of the pollinia all in their
pouches. All facts point clearly to eternal self-fertilisation in this
species; yet I cannot swallow the bitter pill. Have you looked at any this

I wrote yesterday to thank you for the Epipactis. For the chance of your
liking to look at what I have found: take a recently opened flower, drag
gently up the stigmatic surface almost any object (the side of a hooked
needle), and you will find the cap of the hemispherical rostellum comes off
with a touch, and being viscid on under-surface, clings to needle, and as
pollen-masses are already attached to the back of rostellum, the needle
drags out much pollen. But to do this, the curiously projecting and fleshy
summits of anther-cases must at some time be pushed back slightly. Now
when an insect's head gets into the flower, when the flap of the labellum
has closed by its elasticity, the insect would naturally creep out by the
back-side of the flower. And mark when the insect flies to another flower
with the pollen-masses adhering to it, if the flap of labellum did not
easily open and allow free ingress to the insect, it would surely rub off
the pollen on the upper petals, and so not leave it on stigma. It is to
know whether I have rightly interpreted the structure of this whole flower
that I am so curious to see how insects act. Small insects, I daresay,
would crawl in and out and do nothing. I hope that I shall not have
wearied you with these details.

If you would like to see a pretty and curious little sight, look to Orchis
pyramidalis, and you will see that the sticky glands are congenitally
united into a saddle-shaped organ. Remove this under microscope by pincers
applied to foot-stalk of pollen-mass, and look quickly at the spontaneous
movement of the saddle-shaped organs and see how beautifully adapted to
seize proboscis of moth.

December 4th [1860].

Many thanks about Apocynum and Meyen.

The latter I want about some strange movements in cells of Drosera, which
Meyen alone seems to have observed. (597/1. No observations of Meyen are
mentioned in "Insectivorous Plants.) It is very curious, but Trecul
disbelieves that Drosera really clasps flies! I should very much wish to
talk over Drosera with you. I did chloroform it, and the leaves which were
already expanded did not recover thirty seconds of exposure for three days.
I used the expression weight for the bit of hair which caused movement and
weighed 1/78000 of a grain; but I do not believe it is weight, and what it
is, I cannot after many experiments conjecture. (597/2. The doubt here
expressed as to whether the result is due to actual weight is interesting
in connection with Pfeffer's remarkable discovery that a smooth object in
contact with the gland produces no effect if the plant is protected from
all vibration; on an ordinary table the slight shaking which reaches the
plant is sufficient to make the body resting on the gland tremble, and thus
produce a series of varying pressures--under these circumstances the gland
is irritated, and the tentacle moves. See Pfeffer, "Untersuchungen aus d.
bot. Institut zu Tubingen," Volume I., 1885, page 483; also "Insectivorous
Plants," Edition II., page 22.) The movement in this case does not depend
on the chemical nature of substance. Latterly I have tried experiments on
single glands, and a microscopical atom of raw meat causes such rapid
movement that I could see it move like hand of clock. In this case it is
the nature of the object. It is wonderful the rapidity of the absorption:
in ten seconds weak solution of carbonate of ammonia changes not the
colour, but the state of contents within the glands. In two minutes thirty
seconds juice of meat has been absorbed by gland and passed from cell to
cell all down the pedicel (or hair) of the gland, and caused the sap to
pass from the cells on the upper side of the pedicel to the lower side, and
this causes the curvature of the pedicel. I shall work away next summer
when Drosera opens again, for I am much interested in subject. After the
glandular hairs have curved, the oddest changes take place--viz., a
segregation of the homogeneous pink fluid and necessary slow movements in
the thicker matter. By Jove, I sometimes think Drosera is a disguised
animal! You know that I always so like telling you what I do, that you
must forgive me scribbling on my beloved Drosera. Farewell. I am so very
glad that you are going to reform your ways; I am sure that you would have
injured your health seriously. There is poor Dana has done actually
nothing--cannot even write a letter--for a year, and it is hoped that in
another YEAR he may quite recover.

After this homily, good night, my dear friend. Good heavens, I ought not
to scold you, but thank you, for writing so long and interesting a letter.

Down, December 12th [1860?].

After writing out the greater part of my paper on Drosera, I thought of so
many points to try, and I wished to re-test the basis of one large set of
experiments, namely, to feel still more sure than I am, that a drop of
plain water never produces any effect, that I have resolved to publish
nothing this year. For I found in the record of my daily experiments one
suspicious case. I must wait till next summer. It will be difficult to
try any solid substances containing nitrogen, such as ivory; for two quite
distinct causes excite the movement, namely, mechanical irritation and
presence of nitrogen. When a solid substance is placed on leaf it becomes
clasped, but is released sooner than when a nitrogenous solid is clasped;
yet it is difficult (except with raw meat and flies) to be sure of the
result, owing to differences in vigour of different plants. The last
experiments which I tried before my plants became too languid are very
curious, and were tried by putting microscopical atoms on the gland itself
of single hairs; and it is perfectly evident that an atom of human hair,
1/76000 of a grain (as ascertained by weighing a length of hair) in weight,
causes conspicuous movement. I do not believe (for atoms of cotton thread
acted) it is the chemical nature; and some reasons make me doubt whether it
is actual weight; it is not the shadow; and I am at present, after many
experiments, confounded to know what the cause is. That these atoms did
really act and alter the state of the contents of all the cells in the
glandular hair, which moved, was perfectly clear. But I hope next summer
to make out a good deal more...

Down, May 14th [1861].

I have been putting off writing from day to day, as I did not wish to
trouble you, till my wish for a little news will not let me rest...

I have no news to tell you, for I have had no interesting letters for some
time, and have not seen a soul. I have been going through the "Cottage
Gardener" of last year, on account chiefly of Beaton's articles (599/1.
Beaton was a regular contributor to the "Cottage Gardener," and wrote
various articles on cross breeding, etc., in 1861. One of these was in
reply to a letter published in the "Cottage Gardener," May 14th, 1861, page
112, in which Darwin asked for information as to the Compositae and the
hollyhock being crossed by insect visitors. In the number for June 8th,
1861, page 211, Darwin wrote on the variability of the central flower of
the carrot and the peloria of the central flower in Pelargonium. An
extract from a letter by Darwin on Leschenaultia, "Cottage Gardener," May
28th, 1861, page 151, is given in Letter 590, note.); he strikes me as a
clever but d--d cock-sure man (as Lord Melbourne said), and I have some
doubts whether to be much trusted. I suspect he has never recorded his
experiment at the time with care. He has made me indignant by the way he
speaks of Gartner, evidently knowing nothing of his work. I mean to try
and pump him in the "Cottage Gardener," and shall perhaps defend Gartner.
He alludes to me occasionally, and I cannot tell with what spirit. He
speaks of "this Mr. Darwin" in one place as if I were a very noxious

Let me have a line about poor Henslow pretty soon.

(599/2. In a letter of May 18th, 1861, Darwin wrote again:--)

By the way, thanks about Beaton. I have now read more of his writings, and
one answer to me in "Cottage Gardener." I can plainly see that he is not
to be trusted. He does not well know his own subject of crossing.


(600/1. Part of this letter has been published in "Life and Letters,"
III., page 265.)

2, Hesketh Crescent, Torquay [1861].

...The beauty of the adaptation of parts seems to me unparalleled. I
should think or guess [that] waxy pollen was most differentiated. In
Cypripedium, which seems least modified, and a much exterminated group, the
grains are single. In all others, as far as I have seen, they are in
packets of four; and these packets cohere into many wedge-formed masses in
Orchis, into eight, four, and finally two. It seems curious that a flower
should exist which could, at most, fertilise only two other flowers, seeing
how abundant pollen generally is; this fact I look at as explaining the
perfection of the contrivance by which the pollen, so important from its
fewness, is carried from flower to flower. By the way, Cephalanthera has
single pollen-grains, but this seems to be a case of degradation, for the
rostellum is utterly aborted. Oddly, the columns of pollen are here kept
in place by very early penetration of pollen-tubes into the edge of the
stigma; nevertheless, it receives more pollen by insect agency. Epithecia
[Dichaea] has done me one good little turn. I often speculated how the
caudicle of Orchis had been formed. (600/2. The gradation here suggested
is thoroughly worked out in the "Fertilisation of Orchids," Edition I.,
page 323, Edition II., page 257.) I had noticed slight clouds in the
substance half way down; I have now dissected them out, and I find they are
pollen-grains fairly embedded and useless. If you suppose the pollen-
grains to abort in the lower half of the pollinia of Epipactis, but the
parallel elastic threads to remain and cohere, you have the caudicle of
Orchis, and can understand the few embedded and functionless pollen-grains.
I must not look at any more exotic orchids: hearty thanks for your offer.
But if you would make one single observation for me on Cypripedium, I
should be glad. Asa Gray writes to me that the outside of the pollen-
masses is sticky in this genus; I find that the whole mass consists of
pollen-grains immersed in a sticky brownish thick fluid. You could tell by
a mere lens and penknife. If it is, as I find it, pollen could not get on
the stigma without insect aid. Cypripedium confounds me much. I
conjecture that drops of nectar are secreted by the surface of the labellum
beneath the anthers and in front of the stigma, and that the shield over
the anthers and the form of labellum is to compel insects to insert their
proboscis all round both organs. (600/3. This view was afterwards given
up.) It would be troublesome for you to look at this, as it is always
bothersome to catch the nectar secreting, and the cup of the labellum gets
filled with water by gardener's watering.

I have examined Listera ovata, cordata, and Neottia nidus avis: the pollen
is uniform; I suspect you must have seen some observation founded on a
mistake from the penetration and hardening of sticky fluid from the
rostellum, which does penetrate the pollen a little.

It is mere virtue which makes me not wish to examine more orchids; for I
like it far better than writing about varieties of cocks and hens and
ducks. Nevertheless, I have just been looking at Lindley's list in the
"Vegetable Kingdom," and I cannot resist one or two of his great division
of Arethuseae, which includes Vanilla. And as I know so well the Ophreae,
I should like (God forgive me) any one of the Satyriadae, Disidae and

I fear my long lucubrations will have wearied you, but it has amused me to
write, so forgive me.


(601/1. Part of the following letter is published in the "Life and
Letters," the remainder, with the omission of part bearing on the Glen Roy
problem, is now given as an example of the varied botanical assistance
Darwin received from Sir Joseph Hooker. For the part relating to Verbascum
see the "Variation of Animals and Plants," Edition II., 1875, Volume II.,
page 83. The point is that the white and yellow flowered plants which
occur in two species of Verbascum are undoubted varieties, yet "the
sterility which results from the crossing of the differently coloured
varieties of the same species is fully as great as that which occurs in
many cases when distinct species are crossed."

The sterility of the long-styled form (B) of Linum grandiflorum, with its
own pollen is described in "Forms of Flowers," Edition II., page 87: his
conclusions on the short-styled form (A) differ from those in the present

September 28th [1861].

I am going to beg for help, and I will explain why I want it.

You offer Cypripedium; I should be very glad of a specimen, and of any
good-sized Vandeae, or indeed any orchids, for this reason: I never
thought of publishing separately, and therefore did not keep specimens in
spirits, and now I should be very glad of a few woodcuts to illustrate my
few remarks on exotic orchids. If you can send me any, send them by post
in a tin canister on middle of day of Saturday, October 5th, for Sowerby
will be here.

Secondly: Have you any white and yellow varieties of Verbascum which you
could give me, or propagate for me, or LEND me for a year? I have resolved
to try Gartner's wonderful and repeated statement, that pollen of white and
yellow varieties, whether used on the varieties or on DISTINCT species, has
different potency. I do not think any experiment can be more important on
the origin of species; for if he is correct we certainly have what Huxley
calls new physiological species arising. I should require several species
of Verbascum besides the white and yellow varieties of the same species.
It will be tiresome work, but if I can anyhow get the plants, it shall be

Thirdly: Can you give me seeds of any Rubiaceae of the sub-order
Cinchoneae, as Spermacoce, Diodia, Mitchella, Oldenlandia? Asa Gray says
they present two forms like Primula. I am sure that this subject is well
worth working out. I have just almost proved a very curious case in Linum
grandiflorum which presents two forms, A and B. Pollen of A is perfectly
fertile on stigma of A. But pollen of B is absolutely barren on its own
stigma; you might as well put so much flour on it. It astounded me to see
the stigmas of B purple with its own pollen; and then put a few grains of
similar-looking pollen of A on them, and the germen immediately and always
swelled; those not thus treated never swelling.

Fourthly: Can you give me any very hairy Saxifraga (for their functions)
[i.e. the functions of the hairs]?

I send you a resume of my requests, to save you trouble. Nor would I ask
for so much aid if I did not think all these points well worth trying to

My dear old friend, a letter from you always does me a world of good. And,
the Lord have mercy on me, what a return I make.

Down, October 4th [1861].

Will you have the kindness to read the enclosed, and look at the diagram.
Six words will answer my question. It is not an important point, but there
is to me an irresistible charm in trying to make out homologies. (602/1.
In 1880 he wrote to Mr. Bentham: "It was very kind of you to write to me
about the Orchideae, for it has pleased me to an extreme degree that I
could have been of the least use to you about the nature of the parts."--
"Life and Letters," III., page 264.) You know the membranous cup or
clinandrum, in many orchids, behind the stigma and rostellum: it is formed
of a membrane which unites the filament of the normal dorsal anther with
the edges of the pistil. The clinandrum is largely developed in Malaxis,
and is of considerable importance in retaining the pollinia, which as soon
as the flower opens are quite loose.

The appearance and similarity of the tissues, etc., at once gives suspicion
that the lateral membranes of the clinandrum are the two other and
rudimentary anthers, which in Orchis and Cephalanthera, etc., exist as mere
papillae, here developed and utilised.

Now for my question. Exactly in the middle of the filament of the normal
anther, and exactly in the middle of the lateral membrane of the
clinandrum, and running up to the same height, are quite similar bundles of
spiral vessels; ending upwards almost suddenly. Now is not this structure
a good argument that I interpret the homologies of the sides of clinandrum
rightly? (602/2. Though Robert Brown made use of the spiral vessels of
orchids, yet according to Eichler, "Bluthendiagramme," 1875, Volume I.,
page 184, Darwin was the first to make substantial additions to the
conclusions deducible from the course of the vessels in relation to the
problem of the morphology of these plants. Eichler gives Darwin's diagram
side by side with that of Van Tieghem without attempting to decide between
the differences in detail by which they are characterised.)

I find that the great Bauer does not draw very correctly! (602/3. F.
Bauer, whom Pritzel calls "der grosste Pflanzenmaler." The reference is to
his "Illustrations of Orchidaceous Plants, with Notes and Prefatory Remarks
by John Lindley," London, 1830-38, Folio. See "Fertilisation of Orchids,"
Edition II., page 82.) And, good Heavens, what a jumble he makes on

Down, October 22nd. [1861].

Acropera is a beast,--stigma does not open, everything seems contrived that
it shall NOT be anyhow fertilised. There is something very odd about it,
which could only be made out by incessant watching on several individual

I never saw the very curious flower of Canna; I should say the pollen was
deposited where it is to prevent inevitable self-fertilisation. You have
no time to try the smallest experiment, else it would be worth while to put
pollen on some stigmas (supposing that it does not seed freely with you).
Anyhow, insects would probably carry pollen from flower to flower, for Kurr
states the tube formed by pistil, stamen and "nectarblatt" secretes (I
presume internally) much nectar. Thanks for sending me the curious flower.

Now I want much some wisdom; though I must write at considerable length,
your answer may be very brief.

The "missing bundle" could not be found in some species.)

In R. Brown's admirable paper in the "Linnean Transacts." (603/4. Volume
XVI., page 685.) he suggests (and Lindley cautiously agrees) that the
flower of orchids consists of five whorls, the inner whorl of the two
whorls of anthers being all rudimentary, and when the labellum presents
ridges, two or three of the anthers of both whorls [are] combined with it.
In the ovarium there are six bundles of vessels: R. Brown judged by
transverse sections. It occurred to me, after what you said, to trace the
vessels longitudinally, and I have succeeded well. Look at my diagram
[Figure 8] (which please return, for I am transported with admiration at
it), which shows the vessels which I have traced, one bundle to each of
fifteen theoretical organs, and no more. You will see the result is
nothing new, but it seems to confirm strongly R. Brown, for I have
succeeded (perhaps he did, but he does not say so) in tracing the vessels
belonging to each organ in front of each other to the same bundle in the
ovarium: thus the vessels going to the lower sepal, to the side of the
labellum, and to one stigma (when there are two) all distinctly branch from
one ovarian bundle. So in other cases, but I have not completely traced
(only seen) that going to the rostellum. But here comes my only point of
novelty: in all orchids as yet looked at (even one with so simple a
labellum as Gymnadenia and Malaxis) the vessels on the two sides of the
labellum are derived from the bundle which goes to the lower sepal, as in
the diagram. This leads me to conclude that the labellum is always a
compound organ. Now I want to know whether it is conceivable that the
vessels coming from one main bundle should penetrate an organ (the
labellum) which receives its vessels from another main bundle? Does it not
imply that all that part of the labellum which is supplied by vessels
coming from a lateral bundle must be part of a primordially distinct organ,
however closely the two may have become united? It is curious in
Gymnadenia to trace the middle anterior bundle in the ovarium: when it
comes to the orifice of the nectary it turns and runs right down it, then
comes up the opposite side and runs to the apex of the labellum, whence
each side of the nectary is supplied by vessels from the bundles, coming
from the lower sepals. Hence even the thin nectary is essentially, I
infer, tripartite; hence its tendency to bifurcation at its top. This view
of the labellum always consisting of three organs (I believe four when
thick, as in Mormodes, at base) seems to me to explain its great size and
tripartite form, compared with the other petals. Certainly, if I may trust
the vessels, the simple labellum of Gymnadenia consists of three organs
soldered together. Forgive me for writing at such length; a very brief
answer will suffice. I am desperately interested in the subject: the
destiny of the whole human race is as nothing to the course of vessels of

What plant has the most complex single stigma and pistil? The most complex
I, in my ignorance, can think of is in Iris. I want to know whether
anything beats in modification the rostellum of Catasetum. To-morrow I
mean to be at Catasetum. Hurrah! What species is it? It is wonderfully
different from that which Veitch sent me, which was C. saccatum.

According to the vessels, an orchid flower consists of three sepals and two
petals free; and of a compound organ (its labellum), consisting of one
petal and of two (or three) modified anthers; and of a second compound body
consisting of three pistils, one normal anther, and two modified anthers
often forming the sides of the clinandrum.


(604/1. It was in the autumn of 1861 that Darwin made up his mind to
publish his Orchid work as a book, rather than as a paper in the Linnean
Society's "Journal." (604/2. See "Life and Letters," III., page 266.)
The following letter shows that the new arrangement served as an incitement
to fresh work.)

Down, October 25th [1861?]

Mr. James Veitch has been most generous. I did not know that you had
spoken to him. If you see him pray say I am truly grateful; I dare not
write to a live Bishop or a Lady, but if I knew the address of "Rucker"?
and might use your name as introduction, I might write. I am half mad on
the subject. Hooker has sent me many exotics, but I stopped him, for I
thought I should make a fool of myself; but since I have determined to
publish I much regret it.

(FIGURE 9.--HABENARIA CHLORANTHA (Longitudinal course of bundles).)

(605/1. The three upper curved outlines, two of which passing through the
words "upper sepal," "upper petal," "lower sepal," were in red in the
original; for explanation see text.)


(605/2. The following letter is of interest because it relates to one of
the two chief difficulties Darwin met with in working out the morphology of
the orchid flower. In the orchid book (605/3. Edition I., page 303.) he
wrote, "This anomaly [in Habenaria] is so far of importance, as it throws
some doubt on the view which I have taken of the labellum being always an
organ compounded of one petal and two petaloid stamens." That is to say,
it leaves it open for a critic to assert that the vessels which enter the
sides of the labellum are lateral vessels of the petal and do not
necessarily represent petaloid stamens. In the sequel he gives a
satisfactory answer to the supposed objector.)

Down, November 10th, [1861].

For the love of God help me. I believe all my work (about a fortnight) is
useless. Look at this accursed diagram (Figure 9) of the butterfly-orchis
[Habenaria], which I examined after writing to you yesterday, when I
thought all my work done. Some of the ducts of the upper sepal (605/4.
These would be described by modern morphologists as lower, not upper,
sepals, etc. Darwin was aware that he used these terms incorrectly.) and
upper petal run to the wrong bundles on the column. I have seen no such

This case apparently shows that not the least reliance can be placed on the
course of ducts. I am sure of my facts.

There is great adhesion and extreme displacement of parts where the organs
spring from the top of the ovarium. Asa Gray says ducts are very early
developed, and it seems to me wonderful that they should pursue this
course. It may be said that the lateral ducts in the labellum running into
the antero-lateral ovarian bundle is no argument that the labellum consists
of three organs blended together.

In desperation (and from the curious way the base of upper petals are
soldered at basal edges) I fancied the real form of upper sepal, upper
petal and lower sepal might be as represented by red lines, and that there
had been an incredible amount of splitting of sepals and petals and
subsequent fusion.

This seems a monstrous notion, but I have just looked at Bauer's drawing of
allied Bonatea, and there is a degree of lobing of petals and sepals which
would account for anything.

Now could you spare me a dry flower out of your Herbarium of Bonatea
speciosa (605/5. See "Fertilisation of Orchids," Edition I., page 304
(note), where the resemblances between the anomalous vessels of Bonatea and
Habenaria are described. On November 14th, 1861, he wrote to Sir Joseph:
"You are a true friend in need. I can hardly bear to let the Bonatea soak
long enough."), that I might soak and look for ducts. If I cannot explain
the case of Habenaria all my work is smashed. I was a fool ever to touch

Down, November 17th [1861].

What two very interesting and useful letters you have sent me. You rather
astound me with respect to value of grounds of generalisation in the
morphology of plants. It reminds me that years ago I sent you a grass to
name, and your answer was, "It is certainly Festuca (so-and-so), but it
agrees as badly with the description as most plants do." I have often
laughed over this answer of a great botanist...Lindley, from whom I asked
for an orchid with a simple labellum, has most kindly sent me a lot of what
he marks "rare" and "rarissima" of peloric orchids, etc., but as they are
dried I know not whether they will be of use. He has been most kind, and
has suggested my writing to Lady D. Nevill, who has responded in a
wonderfully kind manner, and has sent a lot of treasures. But I must stop;
otherwise, by Jove, I shall be transformed into a botanist. I wish I had
been one; this morphology is surprisingly interesting. Looking to your
note, I may add that certainly the fifteen alternating bundles of spiral
vessels (mingled with odd beadlike vessels in some cases) are present in
many orchids. The inner whorl of anther ducts are oftenest aborted. I
must keep clear of Apostasia, though I have cast many a longing look at it
in Bauer. (606/1. Apostasia has two fertile anthers like Cypripedium. It
is placed by Engler and Prantl in the Apostasieae or Apostasiinae, among
the Orchideae, by others in a distinct but closely allied group.)

I hope I may be well enough to read my own paper on Thursday, but I have
been very seedy lately. (606/2. "On the two Forms, or Dimorphic
Condition, in the Species of the Genus Primula," "Linn. Soc. Journ." 1862.
He did read the paper, but it cost him the next day in bed. "Life and
Letters," III., page 299.) I see there is a paper at the Royal on the same
night, which will more concern you, on fossil plants of Bovey (606/3.
Oswald Heer, "The Fossil Flora of Bovey Tracey," "Phil. Trans. R. Soc."
1862, page 1039.), so that I suppose I shall not have you; but you must
read my paper when published, as I shall very much like to hear what you
think. It seems to me a large field for experiment. I shall make use of
my Orchid little volume in illustrating modification of species doctrine,
but I keep very, very doubtful whether I am not doing a foolish action in
publishing. How I wish you would keep to your old intention and write a
book on plants. (606/4. Possibly a book similar to that described in
Letter 696.)

Down, November 26th [1861].

Our notes have crossed on the road. I know it is an honour to have a paper
in the "Transactions," and I am much obliged to you for proposing it, but I
should greatly prefer to publish in the "Journal." Nor does this apply
exclusively to myself, for in old days at the Geological Society I always
protested against an abstract appearing when the paper itself might appear.
I abominate also the waste of time (and it would take me a day) in making
an abstract. If the referee on my paper should recommend it to appear in
the "Transactions," will you be so kind as to lay my earnest request before
the Council that it may be permitted to appear in the "Journal?"

You must be very busy with your change of residence; but when you are
settled and have some leisure, perhaps you will be so kind as to give me
some cases of dimorphism, like that of Primula. Should you object to my
adding them to those given me by A. Gray? By the way, I heard from A. Gray
this morning, and he gives me two very curious cases in Boragineae.


(608/1. In the following fragment occurs the earliest mention of Darwin's
work on the three sexual forms of Catasetum tridentatum. Sir R. Schomburgk
(608/2. "Trans. Linn. Soc." XVII., page 522.) described Catasetum
tridentatum, Monacanthus viridis and Myanthus barbatus occurring on a
single plant, but it remained for Darwin to make out that they are the
male, female and hermaphrodite forms of a single species. (608/3.
"Fertilisation of Orchids," Edition I., page 236; Edition II., page 196.)

With regard to the species of Acropera (Gongora) (608/4. Acropera
Loddigesii = Gongora galeata: A. luteola = G. fusca ("Index Kewensis").)
he was wrong in his surmise. The apparent sterility seems to be explicable
by Hildebrand's discovery (608/5. "Bot. Zeitung," 1863 and 1865.) that in
some orchids the ovules are not developed until pollinisation has occurred.
(608/6. "Fertilisation of Orchids," Edition II., page 172. See Letter

Down, December 15th [1861].

I am so nearly ready for press that I will not ask for anything more;
unless, indeed, you stumbled on Mormodes in flower. As I am writing I will
just mention that I am convinced from the rudimentary state of the ovules,
and from the state of the stigma, that the whole plant of Acropera luteola
(and I believe A. Loddigesii) is male. Have you ever seen any form from
the same countries which could be the females? Of course no answer is
expected unless you have ever observed anything to bear on this. I may add
[judging from the] state of the ovules and of the pollen [that]:--

Catasetum tridentatum is male (and never seeds, according to Schomburgk,
whom you have accidentally misquoted in the "Vegetable Kingdom").
Monacanthus viridis is female. Myanthus barbatus is the hermaphrodite form
of same species.

Down, December 18th [1861].

Thanks for your note. I have not written for a long time, for I always
fancy, busy as you are, that my letters must be a bore; though I like
writing, and always enjoy your notes. I can sympathise with you about fear
of scarlet fever: to the day of my death I shall never forget all the
sickening fear about the other children, after our poor little baby died of
it. The "Genera Plantarum" must be a tremendous work, and no doubt very
valuable (such a book, odd as it may appear, would be very useful even to
me), but I cannot help being rather sorry at the length of time it must
take, because I cannot enter on and understand your work. Will you not be
puzzled when you come to the orchids? It seems to me orchids alone would
be work for a man's lifetime; I cannot somehow feel satisfied with
Lindley's classification; the Malaxeae and Epidendreae seem to me very
artificially separated. (609/1. Pfitzer (in the "Pflanzenfamilien")
places Epidendrum in the Laeliinae-Cattleyeae, Malaxis in the Liparidinae.
He states that Bentham united the Malaxideae and Epidendreae.) Not that I
have seen enough to form an opinion worth anything.

Your African plant seems to be a vegetable Ornithorhynchus, and indeed much
more than that. (609/2. See Sir J.D. Hooker, "On Welwitschia, a new genus
of Gnetaceae." "Linn. Soc. Trans." XXIV., 1862-3.) The more I read about
plants the more I get to feel that all phanerogams seem comparable with one
class, as lepidoptera, rather than with one kingdom, as the whole insecta.
(609/3. He wrote to Hooker (December 28th, 1861): "I wrote carelessly
about the value of phanerogams; what I was thinking of was that the sub-
groups seemed to blend so much more one into another than with most classes
of animals. I suspect crustacea would show more difference in the extreme
forms than phanerogams, but, as you say, it is wild speculation. Yet it is
very strange what difficulty botanists seem to find in grouping the
families together into masses.")

Thanks for your comforting sentence about the accursed ducts (accursed
though they be, I should like nothing better than to work at them in the
allied orders, if I had time). I shall be ready for press in three or four
weeks, and have got all my woodcuts drawn. I fear much that publishing
separately will prove a foolish job, but I do not care much, and the work
has greatly amused me. The Catasetum has not flowered yet!

In writing to Lindley about an orchid which he sent me, I told him a little
about Acropera, and in answer he suggests that Gongora may be its female.
He seems dreadfully busy, and I feel that I have more right to kill you
than to kill him; so can you send me one or at most two dried flowers of
Gongora? if you know the habitat of Acropera luteola, a Gongora from the
same country would be the best, but any true Gongora would do; if its
pollen should prove as rudimentary as that of Monacanthus relatively to
Catasetum, I think I could easily perceive it even in dried specimens when
well soaked.

I have picked a little out of Lecoq, but it is awful tedious hunting.

Bates is getting on with his natural history travels in one volume.
(609/4. H.W. Bates, the "Naturalist on the Amazons," 1863. See Volume I.,
Letters 123, 148, also "Life and Letters," Volume II., page 381.) I have
read the first chapter in MS., and I think it will be an excellent book and
very well written; he argues, in a good and new way to me, that tropical
climate has very little direct relation to the gorgeous colouring of
insects (though of course he admits the tropics have a far greater number
of beautiful insects) by taking all the few genera common to Britain and
Amazonia, and he finds that the species proper to the latter are not at all
more beautiful. I wonder how this is in species of the same restricted
genera of plants.

If you can remember it, thank Bentham for getting my Primula paper printed
so quickly. I do enjoy getting a subject off one's hands completely.

I have now got dimorphism in structure in eight natural orders just like
Primula. Asa Gray sent me dried flowers of a capital case in Amsinkia
spectabilis, one of the Boragineae. I suppose you do not chance to have
the plant alive at Kew.

Down, June 7th, 1862.

If you are well and have leisure, will you kindly give me one bit of
information: Does Ophrys arachnites occur in the Isle of Wight? or do the
intermediate forms, which are said to connect abroad this species and the
bee-orchis, ever there occur?

Some facts have led me to suspect that it might just be possible, though
improbable in the highest degree, that the bee [orchis] might be the
self-fertilising form of O. arachnites, which requires insects' aid,
something [in the same way] as we have self-fertilising flowers of the
violet and others requiring insects. I know the case is widely different,
as the bee is borne on a separate plant and is incomparably commoner. This
would remove the great anomaly of the bee being a perpetual self-
fertiliser. Certain Malpighiaceae for years produce only one of the two
forms. What has set my head going on this is receiving to-day a bee having
one alone of the best marked characters of O. arachnites. (610/1. Ophrys
arachnites is probably more nearly allied to O. aranifera than to O.
apifera. For a case somewhat analogous to that suggested see the
description of O. scolopax in "Fertilisation of Orchids," Edition II., page
52.) Pray forgive me troubling you.

Down, June 22nd [1862?].

Here is a piece of presumption! I must think that you are mistaken in
ranking Hab[enaria] chlorantha (611/1. In Hooker's "Students' Flora,"
1884, page 395, H. chlorantha is given as a subspecies of H. bifolia. Sir
J.D. Hooker adds that they are "according to Darwin, distinct, and require
different species of moths to fertilise them. They vary in the position
and distances of their anther-cells, but intermediates occur." See
"Fertilisation of Orchids," Edition II., page 73.) as a variety of H.
bifolia; the pollen-masses and stigma differ more than in most of the best
species of Orchis. When I first examined them I remember telling Hooker
that moths would, I felt sure, fertilise them in a different manner; and I
have just had proof of this in a moth sent me with the pollinia (which can
be easily recognised) of H. chlorantha attached to its proboscis, instead
of to the sides of its face, as an H. bifolia.

Forgive me scribbling this way; but when a man gets on his hobby-horse he
always is run away with. Anyhow, nothing here requires any answer.

Down, [September] 14th [1862].

Your letter is a mine of wealth, but first I must scold you: I cannot
abide to hear you abuse yourself, even in joke, and call yourself a stupid
dog. You, in fact, thus abuse me, because for long years I have looked up
to you as the man whose opinion I have valued more on any scientific
subject than any one else in the world. I continually marvel at what you
know, and at what you do. I have been looking at the "Genera" (612/1.
"Genera Plantarum," by Bentham and Hooker, Volume I., Part I., 1862.), and
of course cannot judge at all of its real value, but I can judge of the
amount of condensed facts under each family and genus.

I am glad you know my feeling of not being able to judge about one's own
work; but I suspect that you have been overworking. I should think you
could not give too much time to Wellwitchia (I spell it different every
time I write it) (612/2. "On Welwitschia," "Linn. Soc. Trans." [1862],
XXIV., 1863.); at least I am sure in the animal kingdom monographs cannot
be too long on the osculant groups.

Hereafter I shall be excessively glad to read a paper about Aldrovanda
(612/3. See "Insectivorous Plants," page 321.), and am very much obliged
for reference. It is pretty to see how the caught flies support Drosera;
nothing else can live.

Thanks about plants with two kinds of anthers. I presume (if an included
flower was a Cassia) (612/4. Todd has described a species of Cassia with
an arrangement of stamens like the Melastomads. See Chapter 2.X.II.) that
Cassia is like lupines, but with some stamens still more rudimentary. If I
hear I will return the three Melastomads; I do not want them, and, indeed,
have cuttings. I am very low about them, and have wasted enormous labour
over them, and cannot yet get a glimpse of the meaning of the parts. I
wish I knew any botanical collector to whom I could apply for seeds in
their native land of any Heterocentron or Monochoetum; I have raised plenty
of seedlings from your plants, but I find in other cases that from a
homomorphic union one generally gets solely the parent form. Do you chance
to know of any botanical collector in Mexico or Peru? I must not now
indulge myself with looking after vessels and homologies. Some future time
I will indulge myself. By the way, some time I want to talk over the
alternation of organs in flowers with you, for I think I must have quite
misunderstood you that it was not explicable.

I found out the Verbascum case by pure accident, having transplanted one
for experiment, and finding it to my astonishment utterly sterile. I
formerly thought with you about rarity of natural hybrids, but I am
beginning to change: viz., oxlips (not quite proven), Verbascum, Cistus
(not quite proven), Aegilops triticoides (beautifully shown by Godron),
Weddell's and your orchids (612/5. For Verbascum see "Animals and Plants,"
Edition II., Volume I., page 356; for Cistus, Ibid., Edition II., Volume
I., page 356, Volume II., page 122; for Aegilops, Ibid., Edition II.,
Volume I., page 330, note.), and I daresay many others recorded. Your
letters are one of my greatest pleasures in life, but I earnestly beg you
never to write unless you feel somewhat inclined, for I know how hard you
work, as I work only in the morning it is different with me, and is only a
pleasant relaxation. You will never know how much I owe to you for your
constant kindness and encouragement.

LETTER 613. TO JOHN LUBBOCK (Lord Avebury).
Cliff Cottage, Bournemouth, Hants, September 2nd [1862].

Hearty thanks for your note. I am so glad that your tour answered so
splendidly. My poor patients (613/1. Mrs. Darwin and one of her sons,
both recovering from scarlet fever.) got here yesterday, and are doing
well, and we have a second house for the well ones. I write now in great
haste to beg you to look (though I know how busy you are, but I cannot
think of any other naturalist who would be careful) at any field of common
red clover (if such a field is near you) and watch the hive-bees: probably
(if not too late) you will see some sucking at the mouth of the little
flowers and some few sucking at the base of the flowers, at holes bitten
through the corollas. All that you will see is that the bees put their
heads deep into the [flower] head and rout about. Now, if you see this, do
for Heaven's sake catch me some of each and put in spirits and keep them
separate. I am almost certain that they belong to two castes, with long
and short proboscids. This is so curious a point that it seems worth
making out. I cannot hear of a clover field near here.

LETTER 614. TO JOHN LUBBOCK (Lord Avebury).
Cliff Cottage, Bournemouth, Wednesday, September 3rd [1862].

I beg a million pardons. Abuse me to any degree, but forgive me: it is
all an illusion (but almost excusable) about the bees. (614/1. H. Muller,
"Fertilisation of Flowers," page 186, describes hive-bees visiting
Trifolium pratense for the sake of the pollen. Darwin may perhaps have
supposed that these were the variety of bees whose proboscis was long
enough to reach the nectar. In "Cross and Self Fertilisation," page 361,
Darwin describes hive-bees apparently searching for a secretion on the
calyx. In the same passage in "Cross and Self Fertilisation" he quotes
Muller as stating that hive-bees obtain nectar from red clover by breaking
apart the petals. This seems to us a misinterpretation of the "Befruchtung
der Blumen," page 224.) I do so hope that you have not wasted any time
from my stupid blunder. I hate myself, I hate clover, and I hate bees.



Laid flat open, showing by dotted lines the course of spiral vessels in all
the organs; sepals and petals shown on one side alone, with the stamens on
one side above with course of vessels indicated, but not prolonged. Near
side of pistil with one spiral vessel cut away.)

Cliff Cottage, Bournemouth, September 11th, 1862.

You once told me that Cruciferous flowers were anomalous in alternation of
parts, and had given rise to some theory of dedoublement.

Having nothing on earth to do here, I have dissected all the spiral vessels
in a flower, and instead of burning my diagrams [Figures 10 and 11], I send
them to you, you miserable man. But mind, I do not want you to send me a
discussion, but just some time to say whether my notions are rubbish, and
then burn the diagrams. It seems to me that all parts alternate
beautifully by fours, on the hypothesis that two short stamens of outer
whorl are aborted (615/1. The view given by Darwin is (according to
Eichler) that previously held by Knuth, Wydler, Chatin, and others.
Eichler himself believes that the flower is dimerous, the four longer
stamens being produced by the doubling or splitting of the upper (i.e.
antero-posterior) pair of stamens. If this view is correct, and there are
good reasons for it, it throws much suspicion on the evidence afforded by
the course of vessels, for there is no trace of the common origin of the
longer stamens in the diagram (Figure 11). Again, if Eichler is right, the
four vessels shown in the section of the ovary are misleading. Darwin
afterwards gave a doubtful explanation of this, and concluded that the
ovary is dimerous. See Letter 616.); and this view is perhaps supported by
their being so few, only two sub-bundles in the two lateral main bundles,
where I imagine two short stamens have aborted, but I suppose there is some
valid objection against this notion. The course of the side vessels in the
sepals is curious, just like my difficulty in Habenaria. (615/2. See
Letter 605.) I am surprised at the four vessels in the ovarium. Can this
indicate four confluent pistils? anyhow, they are in the right alternating
position. The nectary within the base of the shorter stamens seems to
cause the end sepals apparently, but not really, to arise beneath the
lateral sepals.

I think you will understand my diagrams in five minutes, so forgive me for
bothering you. My writing this to you reminds me of a letter which I
received yesterday from Claparede, who helped the French translatress of
the "Origin" (615/3. The late Mlle. Royer.), and he tells me he had
difficulty in preventing her (who never looked at a bee's cell) from
altering my whole description, because she affirmed that an hexagonal prism
must have an hexagonal base! Almost everywhere in the "Origin," when I
express great doubt, she appends a note explaining the difficulty, or
saying that there is none whatever!! (615/4. See "Life and Letters," II.,
page 387.) It is really curious to know what conceited people there are in
the world (people, for instance, after looking at one Cruciferous flower,
explain their homologies).

This is a nice, but most barren country, and I can find nothing to look at.
Even the brooks and ponds produce nothing. The country is like Patagonia.
my wife is almost well, thank God, and Leonard is wonderfully improved
...Good God, what an illness scarlet fever is! The doctor feared rheumatic
fever for my wife, but she does not know her risk. It is now all over.

(FIGURE 12.)

Cliff Cottage, Bournemouth, Thursday Evening [September 18th, 1862].

Thanks for your pleasant note, which told me much news, and upon the whole
good, of yourselves. You will be awfully busy for a time, but I write now
to say that if you think it really worth while to send me a few Dielytra,
or other Fumariaceous plant (which I have already tried in vain to find
here) in a little tin box, I will try and trace the vessels; but please
observe, I do not know that I shall have time, for I have just become
wonderfully interested in experimenting on Drosera with poisons, etc. If
you send any Fumariaceous plant, send if you can, also two or three single
balsams. After writing to you, I looked at vessels of ovary of a
sweet-pea, and from this and other cases I believe that in the ovary the
midrib vessel alone gives homologies, and that the vessels on the edge of
the carpel leaf often run into the wrong bundle, just like those on the
sides of the sepals. Hence I [suppose] in Crucifers that the ovarium
consists of two pistils; AA [Figure 12] being the midrib vessels, and BB
being those formed of the vessels on edges of the two carpels, run
together, and going to wrong bundles. I came to this conclusion before
receiving your letter.

I wonder why Asa Gray will not believe in the quaternary arrangement; I had
fancied that you saw some great difficulty in the case, and that made me
think that my notion must be wrong.

Down, September 27th [1862].

Masdevallia turns out nothing wonderful (617/1. This may refer to the
homologies of the parts. He was unable to understand the mechanism of the
flower.--"Fertilisation of Orchids," Edition II., page 136.); I was merely
stupid about it; I am not the less obliged for its loan, for if I had lived
till 100 years old I should have been uneasy about it. It shall be
returned the first day I send to Bromley. I have steamed the other plants,
and made the sensitive plant very sensitive, and shall soon try some
experiments on it. But after all it will only be amusement. Nevertheless,
if not causing too much trouble, I should be very glad of a few young
plants of this and Hedysarum in summer (617/2. Hedysarum or Desmodium
gyrans, the telegraph-plant.), for this kind of work takes no time and
amuses me much. Have you seeds of Oxalis sensitiva, which I see mentioned
in books? By the way, what a fault it is in Henslow's "Botany" that he
gives hardly any references; he alludes to great series of experiments on
absorption of poison by roots, but where to find them I cannot guess.
Possibly the all-knowing Oliver may know. I can plainly see that the
glands of Drosera, from rapid power (almost instantaneous) of absorption
and power of movement, give enormous advantage for such experiments. And
some day I will enjoy myself with a good set to work; but it will be a
great advantage if I can get some preliminary notion on other sensitive
plants and on roots.

Oliver said he would speak about some seeds of Lythrum hyssopifolium being
preserved for me. By the way, I am rather disgusted to find I cannot
publish this year on Lythrum salicaria; I must make 126 additional crosses.
All that I expected is true, but I have plain indication of much higher
complexity. There are three pistils of different structure and functional
power, and I strongly suspect altogether five kinds of pollen all
different in this one species! (617/3. See "Forms of Flowers," Edition
II., page 138.)

By any chance have you at Kew any odd varieties of the common potato? I
want to grow a few plants of every variety, to compare flowers, leaves,
fruit, etc., as I have done with peas, etc. (617/4. "Animals and Plants,"
Edition II., Volume I., page 346. Compare also the similar facts with
regard to cabbages, loc. cit., page 342. Some of the original specimens
are in the Botanical Museum at Cambridge.)


(618/1. The following is part of Letter 144, Volume I. It refers to
reviews of "Fertilisation of Orchids" in the "Gardeners' Chronicle," 1862,
pages 789, 863, 910, and in the "Natural History Review," October, 1862,
page 371.)

November 7th, 1862.

Dear old Darwin,

I assure you it was not my fault! I worried Lindley over and over again to
notice your orchid book in the "Chronicle" by the very broadest hints man
could give. (618/2. See "Life and Letters," III., page 273.) At last he
said, "really I cannot, you must do it for me," and so I did--volontiers.
Lindley felt that he ought to have done it himself, and my main effort was
to write it "a la Lindley," and in this alone I have succeeded--that people
all think it is exactly Lindley's style!!! which diverts me vastly. The
fact is, between ourselves, I fear that poor L. is breaking up--he said
that he could not fix his mind on your book. He works himself beyond his
mental or physical powers.

And now, my dear Darwin, I may as well make a clean breast of it, and tell
you that I wrote the "Nat. Hist. Review" notice too--to me a very difficult
task, and one I fancied I failed in, comparatively. Of this you are no
judge, and can be none; you told me to tell Oliver it pleased you, and so I
am content and happy.

Down, 4th [about 1862-3?]

I have been looking at the fertilisation of wheat, and I think possibly you
might find something curious. I observed in almost every one of the
pollen-grains, which had become empty and adhered to (I suppose the viscid)
branching hairs of the stigma, that the pollen-tube was always (?) emitted
on opposite side of grain to that in contact with the branch of the stigma.
This seems very odd. The branches of the stigma are very thin, formed
apparently of three rows of cells of hardly greater diameter than pollen-
tube. I am astonished that the tubes should be able to penetrate the
walls. The specimens examined (not carefully by me) had pollen only during
few hours on stigma; and the mere SUSPICION has crossed me that the pollen-
tubes crawl down these branches to the base and then penetrate the
stigmatic tissue. (619/1. See Strasburger's "Neue Untersuchungen uber den
Befruchtungsvorgang bei den Phanerogamen," 1884. In Alopecurus pratensis
he describes the pollen as adhering to the end of a projection from the
stigma where it germinates; the tube crawls along or spirally round this
projection until it reaches the angle where the stigmatic branch is given
off; here it makes an entrance and travels in the middle lamella between
two cells.) The paleae open for a short period for stigma to be dusted,
and then close again, and such travelling down would take place under
protection. High powers and good adjustment are necessary. Ears expel
anthers when kept in water in room; but the paleae apparently do not open
and expose stigma; but the stigma could easily be artificially impregnated.

If I were you I would keep memoranda of points worth attending to.

2.X.II. MELASTOMACEAE, 1862-1881.

(620/1. The following series of letters (620-630) refers to the
Melastomaceae and certain other flowers of analogous form. In 1862 Darwin
attempted to explain the existence of two very different sets of stamens in
these plants as a case of dimorphism, somewhat analogous to the state of
things in Primula. In this view he was probably wrong, but this does not
diminish the interest of the crossing experiments described in the letters.
The persistence of his interest in this part of the subject is shown in the
following passage from his Preface to the English translation of H.
Muller's "Befruchtung der Blumen"; the passage is dated February, 1882, but
was not published until the following year.

"There exist also some few plants the flowers of which include two sets of
stamens, differing in the shape of the anthers and in the colour of the
pollen; and at present no one knows whether this difference has any
functional significance, and this is a point which ought to be determined."

It is not obvious why he spoke of the problem as if no light had been
thrown on it, since in 1881 Fritz Muller had privately (see Letter 629)
offered an explanation which Darwin was strongly inclined to accept.
(620/2. H. Muller published ("Nature," August 4th, 1881) a letter from his
brother Fritz giving the theory in question for Heeria. Todd ("American
Naturalist," April 1882), described a similar state of things in Solanum
rostratum and in Cassia: and H.O. Forbes ("Nature," August 1882, page 386)
has done the same for Melastoma. In Rhexia virginica Mr. W.H. Leggett
("Bulletin Torrey Bot. Club, New York," VIII., 1881, page 102) describes
the curious structure of the anther, which consists of two inflated
portions and a tubular part connecting the two. By pressing with a blunt
instrument on one of the ends, the pollen is forced out in a jet through a
fine pore in the other inflated end. Mr. Leggett has seen bees treading on
the anthers, but could not get near enough to see the pollen expelled. In
the same journal, Volume IX., page 11, Mr. Bailey describes how in
Heterocentron roseum, "upon pressing the bellows-like anther with a blunt
pencil, the pollen was ejected to a full inch in distance." On
Lagerstroemia as comparable with the Melastomads see Letter 689.) Fritz
Muller's theory with regard to the Melastomads and a number of analogous
cases in other genera are discussed in H. Muller's article in "Kosmos"
(620/3. "Kosmos," XIII., 1883, page 241.), where the literature is given.
F. Muller's theory is that in Heeria the yellow anthers serve merely as a
means of attracting pollen-collecting bees, while the longer stamens with
purple or crimson anthers supply pollen for fertilising purposes. If
Muller is right the pollen from the yellow anthers would not normally reach
the stigma. The increased vigour observed in the seedlings from the yellow
anthers would seem to resemble the good effect of a cross between different
individuals of the same species as worked out in "Cross and Self
Fertilisation," for it is difficult to believe that the pollen of the
purple anthers has become, by adaptation, less effective than that of the
yellow anthers. In the letters here given there is some contradiction
between the statements as to the position of the two sets of stamens in
relation to the sepals. According to Eichler ("Bluthendiagramme, II., page
482) the longer stamens may be either epipetalous or episepalous in this

The work on the Melastomads is of such intrinsic importance that we have
thought it right to give the correspondence in considerable detail; we have
done so in spite of the fact that Darwin arrived at no definite conclusion,
and in spite of an element of confusion and unsatisfactoriness in the
series of letters. This applies also to Letter 629, written after Darwin
had learned Fritz Muller's theory, which is obscured by some errors or
slips of the pen.)

Down, February 3rd [1862?]

As you so kindly helped me before on dimorphism, will you forgive me
begging for a little further information, if in your power to give it? The
case is that of the Melastomads with eight stamens, on which I have been
experimenting. I am perplexed by opposed statements: Lindley says the
stamens which face the petals are sterile; Wallich says in Oxyspora
paniculata that the stamens which face the sepals are destitute of pollen;
I find plenty of apparently good pollen in both sets of stamens in
Heterocentron [Heeria], Monochoetum, and Centradenia. Can you throw any
light on this? But there is another point on which I am more anxious for
information. Please look at the enclosed miserable diagram. I find that
the pollen of the yellow petal-facing stamens produce more than twice as
much seed as the pollen of the purple sepal-facing stamens. This is
exactly opposed to Lindley's statement--viz., that the petal-facing stamens
are sterile. But I cannot at present believe that the case has any
relation to abortion; it is hardly possible to believe that the longer and
very curious stamens, which face the sepals in this Heterocentron, are
tending to be rudimentary, though their pollen applied to their own flowers
produces so much less seed. It is conformable with what we see in Primula
that the [purple] sepal-facing anthers, which in the plant seen by me stood
quite close on each side of the stigma, should have been rendered less
fitted to fertilise the stigma than the stamens on the opposite side of the
flower. Hence the suspicion has crossed me that if many plants of the
Heterocentron roseum were examined, half would be found with the pistil
nearly upright, instead of being rectangularly bent down, as shown in the
diagram (620/4. According to Willis, "Flowering Plants and Ferns," 1897,
Volume II., page 252, the style in Monochoetum, "at first bent downwards,
moves slowly up till horizontal."); or, if the position of pistil is fixed,
that in half the plants the petal-facing stamens would bend down, and in
the other half of the plants the sepal-facing stamens would bend down as in
the diagram. I suspect the former case, as in Centradenia I find the
pistil nearly straight. Can you tell me? (620/5. No reply by Mr. Bentham
to this or the following queries has been found.) Can the name
Heterocentron have any reference to such diversity? Would it be asking too
great a favour to ask you to look at dried specimens of Heterocentron
roseum (which would be best), or of Monochoetum, or any eight-stamened
Melastomad, of which you have specimens from several localities (as this
would ensure specimens having been taken from distinct plants), and observe
whether the pistil bends differently or stamens differently in different
plants? You will at once see that, if such were the fact, it would be a
new form of dimorphism, and would open up a large field of inquiry with
respect to the potency of the pollen in all plants which have two sets of
stamens--viz., longer and shorter. Can you forgive me for troubling you at
such unreasonable length? But it is such waste of time to experiment
without some guiding light. I do not know whether you have attended
particularly to Melastoma; if you have not, perhaps Hooker or Oliver may
have done so. I should be very grateful for any information, as it will
guide future experiments.

P.S.--Do you happen to know, when there are only four stamens, whether it
is the petal or sepal-facers which are preserved? and whether in the four-
stamened forms the pistil is rectangularly bent or is straight?

Down, February 16th [1862?].

I have been trying a few experiments on Melastomads; and they seem to
indicate that the pollen of the two curious sets of anthers (i.e. the
petal-facers and the sepal-facers) have very different powers; and it does
not seem that the difference is connected with any tendency to abortion in
the one set. Now I think I can understand the structure of the flower and
means of fertilisation, if there be two forms,--one with the pistil bent
rectangularly out of the flower, and the other with it nearly straight.

Our hot-house and green-house plants have probably all descended by
cuttings from a single plant of each species; so I can make out nothing
from them. I applied in vain to Bentham and Hooker; but Oliver picked out
some sentences from Naudin, which seem to indicate differences in the
position of the pistil.

I see that Rhexia grows in Massachusetts; and I suppose has two different
sets of stamens. Now, if in your power, would you observe the position of
the pistil in different plants, in lately opened flowers of the same age?
(I specify this because in Monochaetum I find great changes of position in
the pistils and stamens, as flower gets old). Supposing that my prophecy
should turn out right, please observe whether in both forms the passage
into the flower is not [on] the upper side of the pistil, owing to the
basal part of the pistil lying close to the ring of filaments on the under
side of the flower. Also I should like to know the colour of the two sets
of anthers. This would take you only a few minutes, and is the only way I
see that I can find out whether these plants are dimorphic in this peculiar
way--i.e., only in the position of the pistil (621/1. In Exacum and in
Saintpaulia the flowers are dimorphic in this sense: the style projects to
either the right or the left side of the corolla, from which it follows
that a right-handed flower would fertilise a left-handed one, and vice
versa. See Willis, "Flowering Plants and Ferns," 1897, Volume I., page
73.) and in its relation to the two kinds of pollen. I am anxious about
this, because if it should prove so, it will show that all plants with
longer and shorter or otherwise different anthers will have to be examined
for dimorphism.

March 15th [1862].

...I wrote some little time ago about Rhexia; since then I have been
carefully watching and experimenting on another genus, Monochaetum; and I
find that the pistil is first bent rectangularly (as in the sketch sent),
and then in a few days becomes straight: the stamens also move. If there
be not two forms of Rhexia, will you compare the position of the part in
young and old flowers? I have a suspicion (perhaps it will be proved wrong
when the seed-capsules are ripe) that one set of anthers are adapted to the
pistil in early state, and the other set for it in its later state. If
bees visit the Rhexia, for Heaven's sake watch exactly how the anther and
stigma strike them, both in old and young flowers, and give me a sketch.

Again I say, do not hate me.

Leith Hill Place, Dorking, Thursday, 15th [May 1862].

You stated at the Linnean Society that different sets of seedling Cinchona
(623/1. Cinchona is apparently heterostyled: see "Forms of Flowers,"
Edition II., page 134.) grew at very different rate, and from my Primula
case you attributed it probably to two sorts of pollen. I confess I
thought you rash, but I now believe you were quite right. I find the
yellow and crimson anthers of the same flower in the Melastomatous
Heterocentron roseum have different powers; the yellow producing on the
same plant thrice as many seeds as the crimson anthers. I got my
neighbour's most skilful gardener to sow both kinds of seeds, and yesterday
he came to me and said it is a most extraordinary thing that though both
lots have been treated exactly alike, one lot all remain dwarfs and the
other lot are all rising high up. The dwarfs were produced by the pollen
of the crimson anthers. In Monochaetum ensiferum the facts are more
complex and still more strange; as the age and position of the pistils
comes into play, in relation to the two kinds of pollen. These facts seem
to me so curious that I do not scruple to ask you to see whether you can
lend me any Melastomad just before flowering, with a not very small flower,
and which will endure for a short time a greenhouse or sitting-room; when
fertilised and watered I could send it to Mr. Turnbull's to a cool stove to
mature seed. I fully believe the case is worth investigation.

P.S.--You will not have time at present to read my orchid book; I never
before felt half so doubtful about anything which I published. When you
read it, do not fear "punishing" me if I deserve it.

Adios. I am come here to rest, which I much want.

Whenever you have occasion to write, pray tell me whether you have
Rhododendron Boothii from Bhootan, with a smallish yellow flower, and
pistil bent the wrong way; if so, I would ask Oliver to look for nectary,
for it is an abominable error of Nature that must be corrected. I could
hardly believe my eyes when I saw the pistil.

January 19th [1863].

I have been at those confounded Melastomads again; throwing good money
(i.e. time) after bad. Do you remember telling me you could see no nectar
in your Rhexia? well, I can find none in Monochaetum, and Bates tells me
that the flowers are in the most marked manner neglected by bees and
lepidoptera in Amazonia. Now the curious projections or horns to the
stamens of Monochaetum are full of fluid, and the suspicion occurs to me
that diptera or small hymenoptera may puncture these horns like they
puncture (proved since my orchid book was published) the dry nectaries of
true Orchis. I forget whether Rhexia is common; but I very much wish you
would next summer watch on a warm day a group of flowers, and see whether
they are visited by small insects, and what they do.

Down, January 20th [1863].

...You must kindly permit me to mention any point on which I want
information. If you are so inclined, I am curious to know from systematic
experiments whether Mr. D. Beaton's statement that the pollen of two
shortest anthers of scarlet Pelargonium produce dwarf plants (625/1. See
"Animals and Plants," Edition II., Volume II., page 150, for a brief
account of Darwin's experiments on this genus. Also loc. cit., page 338
(note), for a suggested experiment.), in comparison with plants produced
from the same mother-plant by the pollen of longer stamens from the same
flower. It would aid me much in some laborious experiments on Melastomads.
I confess I feel a little doubtful; at least, I feel pretty nearly sure
that I know the meaning of short stamens in most plants. This summer (for
another object) I crossed Queen of Scarlet Pelargonium with pollen of long
and short stamens of multiflora alba, and it so turns out that plants from
short stamens are the tallest; but I believe this to have been mere chance.
My few crosses in Pelargonium were made to get seed from the central
peloric or regular flower (I have got one from peloric flower by pollen of
peloric), and this leads me to suggest that it would be very interesting to
test fertility of peloric flowers in three ways,--own peloric pollen on
peloric stigma, common pollen on peloric stigma, peloric pollen on common
stigma of same species. My object is to discover whether with change of
structure of flower there is any change in fertility of pollen or of female
organs. This might also be tested by trying peloric and common pollen on
stigma of a distinct species, and conversely. I believe there is a peloric
and common variety of Tropaeolum, and a peloric or upright and common
variation of some species of Gloxinia, and the medial peloric flowers of
Pelargonium, and probably others unknown to me.

Hartfield, May 2nd [1863].

In scarlet dwarf Pelargonium, you will find occasionally an additional and
abnormal stamen on opposite and lower side of flower. Now the pollen of
this one occasional short stamen, I think, very likely would produce dwarf
plants. If you experiment on Pelargonium I would suggest your looking out
for this single stamen.

I observed fluctuations in length of pistil in Phloxes, but thought it was
mere variability.

If you could raise a bed of seedling Phloxes of any species except P.
Drummondii, it would be highly desirable to see if two forms are presented,
and I should be very grateful for information and flowers for inspection.
I cannot remember, but I know that I had some reason to look after Phloxes.
(626/1. See "Forms of Flowers," Edition II., page 119, where the
conjecture is hazarded that Phlox subulata shows traces of a former
heterostyled condition.)

I do not know whether you have used microscopes much yet. It adds
immensely to interest of all such work as ours, and is indeed indispensable
for much work. Experience, however, has fully convinced me that the use of
the compound without the simple microscope is absolutely injurious to
progress of N[atural] History (excepting, of course, with Infusoria). I
have, as yet, found no exception to the rule, that when a man has told me
he works with the compound alone his work is valueless.

March 20th [1863].

I wrote to him [Dr. H. Cruger, of Trinidad] to ask him to observe what the
insects did in the flowers of Melastomaceae: he says not proper season
yet, but that on one species a small bee seemed busy about the horn-like
appendages to the anthers. It will be too good luck if my study of the
flowers in the greenhouse has led me to right interpretation of these

Down, November 28th [1871].

If you had come here on Sunday I should have asked you whether you could
give me seed or seedlings of any Melastomad which would flower soon to
experiment on! I wrote also to J. Scott to ask if he could give me seed.

Several years ago I raised a lot of seedlings of a Melastomad greenhouse
bush (Monochaetus or some such name) (628/1. Monochaetum.) from stigmas
fertilised separately by the two kinds of pollen, and the seedlings
differed remarkably in size, and whilst young, in appearance; and I never
knew what to think of the case (so you must not use it), and have always
wished to try again, but they are troublesome beasts to fertilise.

On the other hand I could detect no difference in the product from the two
coloured anthers of Clarkia. (628/2. Clarkia has eight stamens divided
into two groups which differ in the colour of the anthers.) If you want to
know further particulars of my experiments on Monochaetum (?) and Clarkia,
I will hunt for my notes. You ask about difference in pollen in the same
species. All dimorphic and trimorphic plants present such difference in
function and in size. Lythrum and the trimorphic Oxalis are the most
wonderful cases. The pollen of the closed imperfect cleistogamic flowers
differ in the transparency of the integument, and I think in size. The
latter point I could ascertain from my notes. The pollen or female organs
must differ in almost every individual in some manner; otherwise the pollen
of varieties and even distinct individuals of same varieties would not be
so prepotent over the individual plant's own pollen. Here follows a case
of individual differences in function of pollen or ovules or both. Some
few individuals of Reseda odorata and R. lutea cannot be fertilised, or
only very rarely, by pollen of the same plant, but can by pollen of any
other individual. I chanced to have two plants of R. odorata in this
state; so I crossed them and raised five seedlings, all of which were self
sterile and all perfectly fertile with pollen of any other individual
mignonette. So I made a self sterile race! I do not know whether these
are the kinds of facts which you require.

Think whether you can help me to seed or better seedlings (not cuttings) of
any Melastomad.

Down, March 20th, 1881.

I have received the seeds and your most interesting letter of February 7th.
The seeds shall be sown, and I shall like to see the plants sleeping; but I
doubt whether I shall make any more detailed observations on this subject,
as, now that I feel very old, I require the stimulus of some novelty to
make me work. This stimulus you have amply given me in your remarkable
view of the meaning of the two-coloured stamens in many flowers. I was so
much struck with this fact with Lythrum, that I began experimenting on some
Melastomaceae, which have two sets of extremely differently coloured
anthers. After reading your letter I turned to my notes (made 20 years
ago!) to see whether they would support or contradict your suggestion. I
cannot tell yet, but I have come across one very remarkable result, that
seedlings from the crimson anthers were not 11/20ths of the size of
seedlings from the yellow anthers of the same flowers. Fewer good seeds
were produced by the crimson pollen. I concluded that the shorter stamens
were aborting, and that the pollen was not good. (629/1. "Shorter stamens"
seems to be a slip of the pen for "longer,"--unless the observations were
made on some genus in which the structure is unusual.) The mature pollen
is incoherent, and must be [word illegible] against the visiting insect's
body. I remembered this, and I find it said in my EARLY notes that bees
would never visit the flowers for pollen. This made me afterwards write to
the late Dr. Cruger in the West Indies, and he observed for me the flowers,
and saw bees pressing the anthers with their mandibles from the base
upwards, and this forced a worm-like thread of pollen from the terminal
pore, and this pollen the bees collected with their hind legs. So that the
Melastomads are not opposed to your views.

I am now working on the habits of worms, and it tires me much to change my
subject; so I will lay on one side your letter and my notes, until I have a
week's leisure, and will then see whether my facts bear on your views. I
will then send a letter to "Nature" or to the Linn. Soc., with the extract
of your letter (and this ought to appear in any case), with my own
observations, if they appear worth publishing. The subject had gone out of
my mind, but I now remember thinking that the imperfect action of the
crimson stamens might throw light on hybridism. If this pollen is
developed, according to your view, for the sake of attracting insects, it
might act imperfectly, as well as if the stamens were becoming rudimentary.
(629/2. As far as it is possible to understand the earlier letters it
seems that the pollen of the shorter stamens, which are adapted for
attracting insects, is the most effective.) I do not know whether I have
made myself intelligible.

Down, March 21st [1881].

I have had a letter from Fritz Muller suggesting a novel and very curious
explanation of certain plants producing two sets of anthers of different
colour. This has set me on fire to renew the laborious experiments which I
made on this subject, now 20 years ago. Now, will you be so kind as to
turn in your much worked and much holding head, whether you can think of
any plants, especially annuals, producing 2 such sets of anthers. I
believe that this is the case with Clarkia elegans, and I have just written
to Thompson for seeds. The Lythraceae must be excluded, as these are

I have got seeds from Dr. King of some Melastomaceae, and will write to
Veitch to see if I can get the Melastomaceous genera Monochaetum and
Heterocentron or some such name, on which I before experimented. Now, if
you can aid me, I know that you will; but if you cannot, do not write and
trouble yourself.


"If he had leisure he would make a wonderful observer, to my judgment; I
have come across no one like him."--Letter to J.D. Hooker, May 29th [1863].

(631/1. The following group of letters to John Scott, of whom some account
is given elsewhere (Volume I., Letters 150 and 151, and Index.) deal
chiefly with experimental work in the fertilisation of flowers. In
addition to their scientific importance, several of the letters are of
special interest as illustrating the encouragement and friendly assistance
which Darwin gave to his correspondent.)

Edinburgh Botanic Gardens, November 11th, 1862.

I take the liberty of addressing you for the purpose of directing your
attention to an error in one of your ingenious explanations of the
structural adaptations of the Orchidaceae in your late work. This occurs
in the genus Acropera, two species of which you assume to be unisexual, and
so far as known represented by male individuals only. Theoretically you
have no doubt assigned good grounds for this view; nevertheless,
experimental observations that I am now making have already convinced me of
its fallacy. And I thus hurriedly, and as you may think prematurely, direct
your attention to it, before I have seen the final result of my own
experiment, that you might have the longer time for reconsidering the
structure of this genus for another edition of your interesting book, if
indeed it be not already called for. I am furthermore induced to
communicate the results of my yet imperfect experiments in the belief that
the actuating principle of your late work is the elicitation of truth, and
that you will gladly avail yourself of this even at the sacrifice of much
ingenious theoretical argumentation.

Since I have had an opportunity of perusing your work on orchid
fertilisation, my attention has been particularly directed to the curiously
constructed floral organs of Acropera. I unfortunately have as yet had
only a few flowers for experimental enquiry, otherwise my remarks might
have been clearer and more satisfactory. Such as they are, however, I
respectfully lay [them] before you, with a full assurance of their
veracity, and I sincerely trust that as such you will receive them.

Your observations seem to have been chiefly directed to the A. luteola,
mine to the A. Loddigesii, which, however, as you remark, is in a very
similar constructural condition with the former; having the same narrow
stigmatic chamber, abnormally developed placenta, etc. In regard to the
former point--contraction of stigmatic chamber--I may remark that it does
not appear to be absolutely necessary that the pollen-masses penetrate this
chamber for effecting fecundation. Thus a raceme was produced upon a plant
of A. Loddigesii in the Botanic Gardens here lately; upon this I left only
six flowers. These I attempted to fertilise, but with two only of the six
have I been successful: I succeeded in forcing a single pollen-mass into
the stigmatic chamber of one of the latter, but I failed to do this on the
other; however, by inserting a portion of a pedicel with a pollinium
attached, I caused the latter to adhere, with a gentle press, to the mouth
of the stigmatic chamber. Both of these, as I have already remarked, are
nevertheless fertilised; one of them I have cut off for examination, and
its condition I will presently describe; the other is still upon the plant,
and promises fair to attain maturity. In regard to the other four flowers,
I may remark that though similarly fertilised--part having pollinia
inserted, others merely attached--they all withered and dropped off without
the least swelling of the ovary. Can it be, then, that this is really an
[andro-monoecious] species?--part of the flowers male, others truly

In making longitudinal sections of the fertilised ovary before mentioned, I
found the basal portion entirely destitute of ovules, their place being
substituted by transparent cellular ramification of the placentae. As I
traced the placentae upwards, the ovules appeared, becoming gradually more
abundant towards its apex. A transverse section near the apex of the
ovary, however, still exhibited a more than ordinary placental
development--i.e. [congenitally?] considered--each end giving off two
branches, which meet each other in the centre of the ovary, the ovules
being irregularly and sparingly disposed upon their surfaces.

In regard to the mere question of fertilisation, then, I am perfectly
satisfied, but there are other points which require further elucidation.
Among these I may particularly refer to the contracted stigmatic chamber,
and the slight viscidity of its disk. The latter, however, may be a
consequence of uncongenial conditions--as you do not mention particularly
its examination by any author in its natural habitat. If such be the case,
the contracted stigmatic chamber will offer no real difficulty, should the
viscous exudations be only sufficient to render the mouth adhesive. For,
as I have already shown, the pollen-tubes may be emitted in this condition,
and effect fecundation without being in actual contact with the stigmatic
surface, as occurs pretty regularly in the fertilisation of the Stapelias,
for example. But, indeed, your own discovery of the independent
germinative capabilities of the pollen-grains of certain Orchidaceae is
sufficiently illustrative of this.

I may also refer to the peculiar abnormal condition that many at least of
the ovaries present in a comparative examination of the placentae, and of
which I beg to suggest the following explanation, though it is as yet
founded on limited observations. In examining certain young ovaries of A.
Loddigesii, I found some of them filled with the transparent membranous
fringes of more or less distinctly cellular matter, which, from your
description of the ovaries of luteola, appears to differ simply in the
greater development in the former species. Again, in others I found small
mammillary bodies, which appeared to be true ovules, though I could not
perfectly satisfy myself as to the existence of the micropyle or nucleus.
I unfortunately neglected to apply any chemical test. The fact, however,
that in certain of the examined ovaries few or none of the latter bodies
occurred--the placenta alone being developed in an irregular membranous
form, taken in conjunction with the results of my experiments--before
alluded to--on their fertilisation, leads me to infer that two sexual
conditions are presented by the flowers of this plant. In short, that many
of the ovaries are now normally abortive, though Nature occasionally makes
futile efforts for their perfect development, in the production of ovuloid
bodies; these then I regard as the male flowers. The others that are still
capable of fertilisation, and likewise possessing male organs, are
hermaphrodite, and must, I think, from the results of your comparative
examinations, present a somewhat different condition; as it can scarcely be
supposed that ovules in the condition you describe could ever be

This is at least the most plausible explanation I can offer for the
different results in my experiments on the fertilisation of apparently
similar morphologically constructed flowers; others may, however, occur to
you. Here there is not, as in the Catasetum, any external change visible
in the respective unisexual and bisexual flowers. And yet it would appear
from your researches that the ovules of Acropera are in a more highly
atrophied condition than occurs in Catasetum, though, as you likewise
remark, M. Neumann has never succeeded in fertilising C. tridentatum. If
there be not, then, an arrangement of the reproductive structures, such as
I have indicated, how can the different results in M. Neumann's experiments
and mine be accounted for? However, as you have examined many flowers of
both A. luteola and Loddigesii, such a difference in the ovulary or
placental structures could scarcely have escaped your observation. But, be
this as it may, the--to me at least--demonstrated fact still remains, that
certain flowers of A. Loddigesii are capable of fertilisation, and that,
though there are good grounds for supposing that important physiological
changes are going on in the sexual phenomena of this species, there is no
evidence whatever for supposing that external morphological changes have so
masked certain individuals as to prevent their recognition.

I would now, sir, in conclusion beg you to excuse me for this infringement
upon your valuable time, as I have been induced to write you in the belief
that you have had negative results from other experimenters, before you
ventured to propose your theoretical explanation, and consequently that you
have been unknowingly led into error. I will continue, as opportunities
present themselves, to examine the many peculiarities you have pointed out
in this as well as others of the Orchid family; and at present I am looking
forward with anxiety for the maturation of the ovary of A. Loddigesii,
which will bear testimony to the veracity of the remarks I have ventured to
lay before you.

Down, 18th [November 1862].

Strange to say, I have only one little bother for you to-day, and that is
to let me know about what month flowers appear in Acropera Loddigesii and
luteola; for I want extremely to beg a few more flowers, and if I knew the
time I would keep a memorandum to remind you. Why I want these flowers is
(and I am much alarmed) that Mr. J. Scott, of Bot. Garden of Edinburgh (do
you know anything of him?) has written me a very long and clever letter, in
which he confirms most of my observations; but tells me that with much
difficulty he managed to get pollen into orifice, or as far as mouth of
orifice, of six flowers of A. Loddigesii (the ovarium of which I did not
examine), and two pods set; one he gathered, and saw a very few ovules, as
he thinks, on the large and mostly rudimentary placenta. I shall be most
curious to hear whether the other pod produces a good lot of seed. He says
he regrets that he did not test the ovules with chemical agents: does he
mean tincture of iodine? He suggests that in a state of nature the viscid
matter may come to the very surface of stigmatic chamber, and so pollen-
masses need not be inserted. This is possible, but I should think
improbable. Altogether the case is very odd, and I am very uneasy, for I
cannot hope that A. Loddigesii is hermaphrodite and A. luteola the male of
the same species. Whenever I can get Acropera would be a very good time
for me to look at Vanda in spirits, which you so kindly preserved for me.


(633/1. The following is Darwin's reply to the above letter from Scott.
In the first edition of "Fertilisation of Orchids" (page 209) he assumed
that the sexes in Acropera, as in Catasetum, were separate. In the second
edition (page 172) he writes: "I was, however, soon convinced of my error
by Mr. Scott, who succeeded in artificially fertilising the flowers with
their own pollen. A remarkable discovery by Hildebrand (633/2. "Bot.
Zeitung," 1863 and 1865.), namely, that in many orchids the ovules are not
developed unless the stigma is penetrated by the pollen-tubes...explains
the state of the ovarium in Acropera, as observed by me." In regard to
this subject see Letter 608.)

Down, November 12th, 1862.

I thank you most sincerely for your kindness in writing to me, and for
[your] very interesting letter. Your fact has surprised me greatly, and
has alarmed me not a little, for if I am in error about Acropera I may be
in error about Catasetum. Yet when I call to mind the state of the
placentae in A. luteola, I am astonished that they should produce ovules.
You will see in my book that I state that I did not look at the ovarium of
A. Loddigesii. Would you have the kindness to send me word which end of
the ovarium is meant by apex (that nearest the flower?), for I must try and
get this species from Kew and look at its ovarium. I shall be extremely
curious to hear whether the fruit, which is now maturing, produces a large
number of good and plump seed; perhaps you may have seen the ripe capsules
of other Vandeae, and may be able to form some conjecture what it ought to
produce. In the young, unfertilised ovaria of many Vandeae there seemed an
infinitude of ovules. In desperation it occurs to me as just possible, as
almost everything in nature goes by gradation, that a properly male flower
might occasionally produce a few seeds, in the same manner as female plants
sometimes produce a little pollen. All your remarks seem to me excellent
and very interesting, and I again thank you for your kindness in writing to
me. I am pleased to observe that my description of the structure of
Acropera seems to agree pretty well with what you have observed. Does it
not strike you as very difficult to understand how insects remove the
pollinia and carry them to the stigmas? Your suggestion that the mouth of
the stigmatic cavity may become charged with viscid matter and thus secure
the pollinia, and that the pollen-tubes may then protrude, seems very
ingenious and new to me; but it would be very anomalous in orchids, i.e. as
far as I have seen. No doubt, however, though I tried my best, I shall be
proved wrong in many points. Botany is a new subject to me. With respect
to the protrusion of pollen-tubes, you might like to hear (if you do not
already know the fact) that, as I saw this summer, in the little imperfect
flowers of Viola and Oxalis, which never open, the pollen-tubes always come
out of the pollen-grain, whilst still in the anthers, and direct themselves
in a beautiful manner to the stigma seated at some little distance. I hope
that you will continue your very interesting observations.

Down, November 19th [1862].

I am much obliged for your letter, which is full of interesting matter. I
shall be very glad to look at the capsule of the Acropera when ripe, and
pray present my thanks to Mr. MacNab. (634/1. See Letter 608 (Lindley,
December 15th, 1861). Also "Fertilisation of Orchids," Edition II., page
172, for an account of the observations on Acropera which were corrected by
Scott.) I should like to keep it till I could get a capsule of some other
member of the Vandeae for comparison, but ultimately all the seeds shall be
returned, in case you would like to write any notice on the subject. It
was, as I said (634/2. Letter 633.), only "in desperation" that I
suggested that the flower might be a male and occasionally capable of
producing a few seeds. I had forgotten Gartner's remark; in fact, I know
only odds and ends of Botany, and you know far more. One point makes the
above view more probable in Acropera than in other cases, viz. the presence
of rudimentary placentae or testae, for I cannot hear that these have been
observed in the male plants. They do not occur in male Lychnis dioica, but
next spring I will look to male holly flowers. I fully admit the
difficulty of similarity of stigmatic chamber in the two Acroperas. As far
as I remember, the blunt end of pollen-mass would not easily even stick in
the orifice of the chamber. Your view may be correct about abundance of
viscid matter, but seems rather improbable. Your facts about female
flowers occurring where males alone ought to occur is new to me; if I do
not hear that you object, I will quote the Zea case on your authority in
what I am now writing on the varieties of the maize. (634/3. See "Animals
and Plants," Edition II., Volume I., page 339: "Mr. Scott has lately
observed the rarer case of female flowers on a true male panicle, and
likewise hermaphrodite flowers." Scott's paper on the subject is in
"Trans. Bot. Soc. Edinburgh," Volume VIII. See Letter 151, Volume I.) I
am glad to hear that you are now working on the most curious subject of
parthenogenesis. I formerly fancied that I observed female Lychnis dioica
seeded without pollen. I send by this post a paper on Primula, which may
interest you. (634/4. "Linn. Soc. Journal," 1862.) I am working on the
subject, and if you should ever observe any analogous case I should be glad
to hear. I have added another very clever pamphlet by Prof. Asa Gray.
Have you a copy of my Orchis book? If you have not, and would like one, I
should be pleased to send one. I plainly see that you have the true spirit
of an experimentalist and good observer. Therefore, I ask whether you have
ever made any trials on relative fertility of varieties of plants (like
those I quote from Gartner on the varieties of Verbascum). I much want
information on this head, and on those marvellous cases (as some Lobelias
and Crinum passiflora) in which a plant can be more easily fertilised by
the pollen of another species than by its own good pollen. I am compelled
to write in haste. With many thanks for your kindness.

Down, 20th [1862?].

What a magnificent capsule, and good Heavens, what a number of seeds! I
never before opened pods of larger orchids. It did not signify a few seed
being lost, as it would be hopeless to estimate number in comparison with
other species. If you sow any, had you not better sow a good many? so I
enclose small packet. I have looked at the seeds; I never saw in the
British orchids nearly so many empty testae; but this goes for nothing, as
unnatural conditions would account for it. I suspect, however, from the
variable size and transparency, that a good many of the seeds when dry (and
I have put the capsule on my chimney-piece) will shrivel up. So I will
wait a month or two till I get the capsule of some large Vandeae for
comparison. It is more likely that I have made some dreadful blunder about
Acropera than that it should be male yet not a perfect male. May there be
some sexual relation between A. Loddigesii and luteola; they seem very
close? I should very much like to examine the capsule of the unimpregnated
flower of A. Loddigesii. I have got both species from Kew, but whether we
shall have skill to flower them I know not. One conjectures that it is
imperfect male; I still should incline to think it would produce by seed
both sexes. But you are right about Primula (and a very acute thought it
was): the long-styled P. sinensis, homomorphically fertilised with
own-form pollen, has produced during two successive homomorphic generations
only long-styled plants. (635/1. In "Forms of Flowers," Edition II., page
216, a summary of the transmission of forms in the "homomorphic" unions of
P. sinensis is given. Darwin afterwards used "illegitimate" for
homomorphic, and "legitimate" for "heteromorphic" ("Forms of Flowers,"
Edition i., page 24).) The short-styled the same, i.e. produced
short-styled for two generations with the exception of a single plant. I
cannot say about cowslips yet. I should like to hear your case of the
Primula: is it certainly propagated by seed?

Down, December 3rd, [1862?].

What a capital observer you are! and how well you have worked the primulas.
All your facts are new to me. It is likely that I overrate the interest of
the subject; but it seems to me that you ought to publish a paper on the
subject. It would, however, greatly add to the value if you were to cover
up any of the forms having pistil and anther of the same height, and prove
that they were fully self-fertile. The occurrence of dimorphic and non-
dimorphic species in the same genus is quite the same as I find in Linum.
(636/1. Darwin finished his paper on Linum in December 1862, and it was
published in the "Linn. Soc. Journal" in 1863.) Have any of the forms of
Primula, which are non-dimorphic, been propagated for some little time by
seed in garden? I suppose not. I ask because I find in P. sinensis a
third rather fluctuating form, apparently due to culture, with stigma and
anthers of same height. I have been working successive generations
homomorphically of this Primula, and think I am getting curious results; I
shall probably publish next autumn; and if you do not (but I hope you will)
publish yourself previously, I should be glad to quote in abstract some of
your facts. But I repeat that I hope you will yourself publish. Hottonia
is dimorphic, with pollen of very different sizes in the two forms. I
think you are mistaken about Siphocampylus, but I feel rather doubtful in
saying this to so good an observer. In Lobelia the closed pistil grows
rapidly, and pushes out the pollen and then the stigma expands, and the
flower in function is monoecious; from appearance I believe this is the
case with your plant. I hope it is so, for this plant can hardly require a
cross, being in function monoecious; so that dimorphism in such a case
would be a heavy blow to understanding its nature or good in all other
cases. I see few periodicals: when have you published on Clivia? I
suppose that you did not actually count the seeds in the hybrids in
comparison with those of the parent-forms; but this is almost necessary
after Gartner's observations. I very much hope you will make a good series
of comparative trials on the same plant of Tacsonia. (636/2. See Scott in
"Linn. Soc. Journal," VIII.) I have raised 700-800 seedlings from
cowslips, artificially fertilised with care; and they presented not a
hair's-breadth approach to oxlips. I have now seed in pots of cowslip
fertilised by pollen of primrose, and I hope they will grow; I have also
got fine seedlings from seed of wild oxlips; so I hope to make out the
case. You speak of difficulties on Natural Selection: there are indeed
plenty; if ever you have spare time (which is not likely, as I am sure you
must be a hard worker) I should be very glad to hear difficulties from one
who has observed so much as you have. The majority of criticisms on the
"Origin" are, in my opinion, not worth the paper they are printed on. Sir
C. Lyell is coming out with what, I expect, will prove really good remarks.
(636/3. Lyell's "Antiquity of Man" was published in the spring of 1863.
In the "Life and Letters," Volume III., pages 8, 11, Darwin's
correspondence shows his deep disappointment at what he thought Lyell's
half-heartedness in regard to evolution. See Letter 164, Volume I.) Pray
do not think me intrusive; but if you would like to have any book I have
published, such as my "Journal of Researches" or the "Origin," I should
esteem it a compliment to be allowed to send it. Will you permit me to
suggest one experiment, which I should much like to see tried, and which I
now wish the more from an extraordinary observation by Asa Gray on
Gymnadenia tridentata (in number just out of Silliman's N. American
Journal) (636/4. In Gymnadenia tridentata, according to Asa Gray, the
anther opens in the bud, and the pollen being somewhat coherent falls on
the stigma and on the rostellum which latter is penetrated by the pollen-
tubes. "Fertilisation of Orchids," Edition II., page 68. Asa Gray's
papers are in "American Journal of Science," Volume XXXIV., 1862, and
XXXVI., 1863.); namely, to split the labellum of a Cattleya, or of some
allied orchis, remove caudicle from pollen-mass (so that no loose grains
are about) and put it carefully into the large tongue-like rostellum, and
see if pollen-tubes will penetrate, or better, see if capsule will swell.
Similar pollen-masses ought to be put on true stigmas of two or three other
flowers of same plants for comparison. It is to discover whether rostellum
yet retains some of its primordial function of being penetrated by pollen-
tubes. You will be sorry that you ever entered into correspondence with
me. But do not answer till at leisure, and as briefly as you like. My
handwriting, I know, is dreadfully bad. Excuse this scribbling paper, as I
can write faster on it, and I have a rather large correspondence to keep

Down, January 21st, 1863.

I thank you for your very interesting letter; I must answer as briefly as I
can, for I have a heap of other letters to answer. I strongly advise you
to follow up and publish your observations on the pollen-tubes of orchids;
they promise to be very interesting. If you could prove what I only
conjectured (from state of utriculi in rostellum and in stigma of Catasetum
and Acropera) that the utriculi somehow induce, or are correlated with,
penetration of pollen-tubes you will make an important physiological
discovery. I will mention, as worth your attention (and what I have
anxiously wished to observe, if time had permitted, and still hope to do)--
viz., the state of tissues or cells of stigma in an utterly sterile hybrid,
in comparison with the same in fertile parent species; to test these cells,
immerse stigmas for 48 hours in spirits of wine. I should expect in
hybrids that the cells would not show coagulated contents. It would be an
interesting discovery to show difference in female organs of hybrids and
pure species. Anyhow, it is worth trial, and I recommend you to make it,
and publish if you do. The pollen-tubes directing themselves to stigma is
also very curious, though not quite so new, but well worth investigation
when you get Cattleya, etc., in flower. I say not so new, for remember
small flowers of Viola and Oxalis; or better, see Bibliography in "Natural
History Review," No. VIII., page 419 (October, 1862) for quotation from M.
Baillon on pollen-tubes finding way from anthers to stigma in Helianthemum.
I should doubt gum getting solid from [i.e. because of] continued
secretion. Why not sprinkle fresh plaster of Paris and make impenetrable
crust? (637/1. The suggestion that the stigma should be covered with a
crust of plaster of Paris, pierced by a hole to allow the pollen-tubes to
enter, bears a resemblance to Miyoshi's experiments with germinating pollen
and fungal spores. See "Pringsheim's Jahrbucher," 1895; "Flora," 1894.)
You might modify experiment by making little hole in one lower corner, and
see if tubes find it out. See in my future paper on Linum pollen and
stigma recognising each other. If you will tell me that pollen smells the
stigma I will try and believe you; but I will not believe the Frenchman (I
forget who) who says that stigma of Vanilla actually attracts mechanically,
by some unknown force, the solid pollen-masses to it! Read Asa Gray in 2nd
Review of my Orchis book on pollen of Gymnadenia penetrating rostellum. I
can, if you like, lend you these Reviews; but they must be returned. R.
Brown, I remember, says pollen-tubes separate from grains before the lower
ends of tubes reach ovules. I saw, and was interested by, abstract of your
Drosera paper (637/2. A short note on the irritability of Drosera in the
"Trans. Bot. Soc. Edin." Volume VII.); we have been at very much the same

Down, February 16th [1863].

Absence from home has prevented me from answering you sooner. I should
think that the capsule of Acropera had better be left till it shows some
signs of opening, as our object is to judge whether the seeds are good; but
I should prefer trusting to your better judgment. I am interested about
the Gongora, which I hope hereafter to try myself, as I have just built a
small hot-house.

Asa Gray's observations on the rostellum of Gymnadenia are very imperfect,
yet worth looking at. Your case of Imatophyllum is most interesting
(638/1. A sucker of Imatophyllum minatum threw up a shoot in which the
leaves were "two-ranked instead of four-ranked," and showed other
differences from the normal.--"Animals and Plants," Edition II., Volume I.,
page 411.); even if the sport does not flower it will be worth my giving.
I did not understand, or I had forgotten, that a single frond on a fern
will vary; I now see that the case does come under bud-variation, and must
be given by me. I had thought of it only as proof [of] inheritance in
cryptogams; I am much obliged for your correction, and will consult again
your paper and Mr. Bridgeman's. (638/2. The facts are given in "Animals
and Plants," Edition II., Volume I., page 408.) I enclose varieties of
maize from Asa Gray. Pray do not thank me for trusting you; the thanks
ought to go the other way. I felt a conviction after your first letter
that you were a real lover of Natural History.

If you can advance good evidence showing that bisexual plants are more
variable than unisexual, it will be interesting. I shall be very glad to
read the discussion which you are preparing. I admit as fully as any one
can do that cross-impregnation is the great check to endless variability;
but I am not sure that I understand your view. I do not believe that the
structure of Primula has any necessary relation to a tendency to a
dioecious structure, but seeing the difference in the fertility of the two
forms, I felt bound unwillingly to admit that they might be a step towards
dioeciousness; I allude to this subject in my Linum paper. (638/3. "Linn.
Soc. Journal," 1863.) Thanks for your answers to my other queries. I
forgot to say that I was at Kew the other day, and I find that they can
give me capsules of several Vandeae.

Down, March 24th [1863].

Your letter, as every one you have written, has greatly interested me. If
you can show that certain individual Passifloras, under certain known or
unknown conditions of life, have stigmas capable of fertilisation by pollen
from another species, or from another individual of its own species, yet
not by its own individual pollen (its own individual pollen being proved to
be good by its action on some other species), you will add a case of great
interest to me; and which in my opinion would be quite worth your
publication. (639/1. Cases nearly similar to those observed by Scott were
recorded by Gartner and Kolreuter, but in these instances only certain
individuals were self-impotent. In "Animals and Plants," Edition II.,
Volume II., page 114, where the phenomenon is fully discussed, Scott's
observations ("Trans. Bot. Soc. Edin." 1863) are given as the earliest,
except for one case recorded by Lecoq ("Fecondation," 1862). Interesting
work was afterwards done by Hildebrand and Fritz Muller, as illustrated in
many of the letters addressed to the latter.) I always imagined that such
recorded cases must be due to unnatural conditions of life; and think I
said so in the "Origin." (639/2. See "Origin of Species," Edition I.,
page 251, for Herbert's observations on self-impotence in Hippeastrum. In
spite of the uniformness of the results obtained in many successive years,
Darwin inferred that the plants must have been in an "unnatural state.") I
am not sure that I understand your result, [nor] whether it means what I
have above obscurely expressed. If you can prove the above, do publish;
but if you will not publish I earnestly beg you to let me have the facts in
detail; but you ought to publish, for I may not use the facts for years. I
have been much interested by what you say on the rostellum exciting pollen
to protrude tubes; but are you sure that the rostellum does excite them?
Would not tubes protrude if placed on parts of column or base of petals,
etc., near to the stigma? Please look at the "Cottage Gardener" (or
"Journal of Horticulture") (639/3. "Journal of Horticulture" and "Cottage
Gardener," March 31st, 1863. A short note describing Cruger's discovery of
self-fertilisation in Cattleya, Epidendrum, etc., and referring to the work
of "an excellent observer, Mr. J. Scott." Darwin adds that he is convinced
that he has underrated the power of tropical orchids occasionally to
produce seeds without the aid of insects.) to be published to-morrow week
for letter of mine, in which I venture to quote you, and in which you will
see a curious fact about unopened orchid flowers setting seed in West
Indies. Dr. Cruger attributes protrusion of tubes to ants carrying
stigmatic secretion to pollen (639/4. In Cruger's paper ("Linn. Soc.
Journ." VIII., 1865; read March 3rd 1864) he speaks of the pollen-masses in
situ being acted on by the stigmatic secretion, but no mention is made of
the agency of ants. He describes the pollen-tubes descending "from the
[pollen] masses still in situ down into the ovarian canal."); but this is
mere hypothesis. Remember, pollen-tubes protrude within anther in Neottia
nidus-avis. I did think it possible or probable that perfect fertilisation
might have been effected through rostellum. What a curious case your
Gongora must be: could you spare me one of the largest capsules? I want
to estimate the number of seed, and try my hand if I can make them grow.
This, however, is a foolish attempt, for Dr. Hooker, who was here a day or
two ago, says they cannot at Calcutta, and yet imported species have seeded
and have naturally spread on to the adjoining trees! Dr. Cruger thinks I
am wrong about Catasetum: but I cannot understand his letter. He admits
there are three forms in two species; and he speaks as if the sexes were
separate in some and that others were hermaphrodites (639/5. Cruger
("Linn. Soc. Journal," VIII., page 127) says that the apparently
hermaphrodite form is always sterile in Trinidad. Darwin modified his
account in the second edition of the orchid book.); but I cannot understand
what he means. He has seen lots of great humble-bees buzzing about the
flowers with the pollinia sticking to their backs! Happy man!! I have the
promise, but not yet surety, of some curious results with my homomorphic
seedling cowslips: these have not followed the rule of Chinese Primula;
homomorphic seedlings from short-styled parent have presented both forms,
which disgusts me.

You will see that I am better; but still I greatly fear that I must have a
compulsory holiday. With sincere thanks and hearty admiration at your
powers of observation...

My poor P. scotica looks very sick which you so kindly sent me. (639/6.
Sent by Scott, January 6th, 1863.)

April 12th [1863].

I really hardly know how to thank you enough for your very interesting
letter. I shall certainly use all the facts which you have given me (in a
condensed form) on the sterility of orchids in the work which I am now
slowly preparing for publication. But why do you not publish these facts
in a separate little paper? (640/1. See Letter 642, note, for reference
to Scott's paper.) They seem to me well worth it, and you really ought to
get your name known. I could equally well use them in my book. I
earnestly hope that you will experiment on Passiflora, and let me give your
results. Dr. A. Gray's observations were made loosely; he said in a letter
he would attend this summer further to the case, which clearly surprised
him much. I will say nothing about the rostellum, stigmatic utriculi,
fertility of Acropera and Catasetum, for I am completely bewildered: it
will rest with you to settle these points by your excellent observations
and experiments. I must own I never could help doubting Dr. Hooker's case
of the poppy. You may like to hear what I have seen this morning: I found
(640/2. See Letter 658.) a primrose plant with flowers having three
pistils, which when pulled asunder, without any tearing, allowed pollen to
be placed on ovules. This I did with three flowers--pollen-tubes did not
protrude after several days. But this day, the sixteenth (N.B.--primulas
seem naturally slowly fertilised), I found many tubes protruded, and, what
is very odd, they certainly seemed to have penetrated the coats of the
ovules, but in no one instance the foramen of the ovule!! I mention this
because it directly bears on your explanation of Dr. Cruger's case.
(640/3. Cruger's case here referred to is doubtless the cleistogamic
fertilisation of Epidendrum, etc. Scott discusses the question of
self-fertilisation at great length in a letter to Darwin dated April, and
obviously written in 1863. In Epidendrum he observed a viscid matter
extending from the stigmatic chamber to the anther: pollen-tubes had
protruded from the anther not only where it was in contact with the viscid
matter, but also from the central part, and these spread "over the anterior
surface of the rostellum downward into the stigma." Cruger believed the
viscid matter reaching the anther was a necessary condition for the
germination of the pollen-grains. Scott points out that the viscid matter
is produced in large quantity only after the pollen-grains have penetrated
the stigma, and that it is, in fact, a consequence, not a preliminary to
fertilisation. He finally explains Cruger's case thus: "The greater
humidity and equability of temperature consequent on such conditions [i.e.
on the flowers being closed] is, I believe, the probable cause of these
abnormally conditioned flowers so frequently fertilising themselves."
Scott also calls attention to the danger of being deceived by fungal hyphae
in observations on germination of pollen.) I believe that your explanation
is right; I should never have thought of it; yet this was stupid of me, for
I remember thinking that the almost closed imperfect flowers of Viola and
Oxalis were related to the protrusion of the pollen-tubes. My case of the
Aceras with the aborted labellum squeezed against stigma supports your
view. (640/4. See "Fertilisation of Orchids," Edition II., page 258: the
pollen germinated within the anther of a monstrous flower.) Dr. Cruger's
notion about the ants was a simple conjecture. About cryptogamic
filaments, remember Dr. C. says that the unopened flowers habitually set
fruit. I think that you will change your views on the imperfect flowers of
Viola and Oxalis...

LETTER 641. (?)

May 2nd [1863].

I have left home for a fortnight to see if I can, with little hope, improve
my health. The parcel of orchid pods, which you have so kindly sent me,
has followed me. I am sure you will forgive the liberty which I take in
returning you the postage stamps. I never heard of such a scheme as that
you were compelled to practise to fertilise the Gongora! (642/1. See
"Fertilisation of Orchids," Edition, II., page 169. "Mr. Scott tried
repeatedly, but in vain, to force the pollen-masses into the stigma of
Gongora atro-purpurea and truncata; but he readily fertilised them by
cutting off the clinandrum and placing pollen-masses on the now exposed
stigma.") It is a most curious problem what plan Nature follows in this
genus and Acropera. (642/2. In the "Fertilisation of Orchids," Edition
II., page 169, Darwin speculates as to the possible fertilisation of
Acropera by an insect with pollen-masses adhering to the extremity of its
abdomen. It would appear that this guess (which does not occur in the
first edition) was made before he heard of Cruger's observation on the
allied genus Gongora, which is visited by a bee with a long tongue, which
projects, when not in use, beyond and above the tip of the abdomen. Cruger
believes that this tongue is the pollinating agent. Cruger's account is in
the "Journal of the Linn. Soc." VIII., 1865, page 130.) Some day I will
try and estimate how many seeds there are in Gongora. I suppose and hope
you have kept notes on all your observations on orchids, for, with my
broken health and many other subjects, I do not know whether I shall ever
have time to publish again; though I have a large collection of notes and
facts ready. I think you show your wisdom in not wishing to publish too
soon; a young author who publishes every trifle gets, sometimes unjustly,
to be disregarded. I do not pretend to be much of a judge; but I can
conscientiously say that I have never written one word to you on the merit
of your letters that I do not fully believe in. Please remember that I
should very much wish for a copy of your paper on sterility of individual
orchids (642/3. "On the Individual Sterility and Cross-Impregnation of
Certain Species of Oncidium." [Read June 2nd, 1864.] "Linn. Soc. Journal,"
VIII., 1865. This paper gives a full account of the self-sterility of
Oncidium in cases where the pollen was efficient in fertilising other
individuals of the same species and of distinct species. Some of the facts
were given in Scott's paper, "Experiments on the Fertilisation of Orchids
in the Royal Botanic Garden of Edinburgh," published in the "Proc. Bot.
Soc. Edinb." 1863. It is probably to the latter paper that Darwin refers.)
and on Drosera. (642/4. "Trans. Bot. Soc. Edinburgh," Volume VII.)
Thanks for [note] about Campanula perfoliata. I have asked Asa Gray for
seeds, to whom I have mentioned your observations on rostellum, and asked
him to look closer to the case of Gymnadenia. (642/5. See "Fertilisation
of Orchids," Edition II., page 68.) Let me hear about the sporting
Imatophyllum if it flowers. Perhaps I have blundered about Primula; but
certainly not about mere protrusion of pollen-tubes. I have been idly
watching bees of several genera and diptera fertilising O. morio at this
place, and it is a very pretty sight. I have confirmed in several ways the
entire truth of my statement that there is no vestige of nectar in the
spur; but the insects perforate the inner coat. This seems to me a curious
little fact, which none of my reviewers have noticed.

Down, May 23rd [1863].

You can confer a real service on a good man, John Scott, the writer of the
enclosed letter, by reading it and giving me your opinion. I assure [you]
John Scott is a truly remarkable man. The part struck out is merely that
he is not comfortable under Mr. McNab, and this part must be considered as
private. Now the question is, what think you of the offer? Is expense of
living high at Darjeeling? May I say it is healthy? Will he find the
opportunity for experimental observations, which are a passion with him?
It seems to me rather low pay. Will you advise me for him? I shall say
that as far as experiments in hand at the Botanical Garden in Edinburgh are
concerned, it would be a pity to hesitate to accept the offer.

J. Scott is head of the propagating department. I know you will not grudge
aiding by your advice a good man. I shall tell him that I have not the
slightest power to aid him in any way for the appointment. I should think
voyage out and home ought to be paid for?

Down, May 25th, 1863.

Now for a few words on science. I do not think I could be mistaken about
the stigma of Bolbophyllum (644/1. Bolbophyllum is remarkable for the
closure of the stigmatic cavity which comes on after the flower has been
open a little while, instead of after fertilisation, as in other genera.
Darwin connects the fact with the "exposed condition of the whole flower."
--"Fertilisation of Orchids," Edition II., page 137.); I had the plant
alive from Kew, and watched many flowers. That is a most remarkable
observation on foreign pollen emitting tubes, but not causing orifice to
close (644/2. See Scott, "Bot. Soc. Edin." 1863, page 546, note. He
applied pollinia from Cypripedium and Asclepias to flowers of Tricopilia
tortilis; and though the pollen germinated, the stigmatic chamber remained
open, yet it invariably closes eighteen hours after the application of its
own pollen.); it would have been interesting to have observed how close an
alliance of form would have acted on the orifice of the stigma. It will
probably be so many years, if ever, [before] I work up my observations on
Drosera, that I will not trouble you to send your paper, for I could not
now find time to read it. If you have spare copy of your Orchid paper,
please send it, but do not get a copy of the journal, for I can get one,
and you must often want to buy books. Let me know when it is published. I
have been glad to hear about Mercurialis, but I will not accept your offer
of seed on account of time, time, time, and weak health. For the same
reason I must give up Primula mollis. What a wonderful, indefatigable
worker you are! You seem to have made a famous lot of interesting
experiments. D. Beaton once wrote that no man could cross any species of
Primula. You have apparently proved the contrary with a vengeance. Your
numerous experiments seem very well selected, and you will exhaust the
subject. Now when you have completed your work you should draw up a paper,
well worth publishing, and give a list of all the dimorphic and non-
dimorphic forms. I can give you, on the authority of Prof. Treviranus in
"Bot. Zeitung," case of P. longiflora non-dimorphic. I am surprised at
your cowslips in this state. Is it a common yellow cowslip? I have seen
oxlips (which from some experiments I now look at as certainly natural
hybrids) in same state. If you think the Botanical Society of Edinburgh
would not do justice and publish your paper, send it to me to be
communicated to the Linnean Society. I will delay my paper on successive
dimorphic generations in Primula (644/3. Published in the "Journ. Linn.
Soc." X., 1869 [1868].) till yours appears, so as in no way to interfere
with your paper. Possibly my results may be hardly worth publishing, but I
think they will; the seedlings from two successive homomorphic generations
seem excessively sterile. I will keep this letter till I hear from Dr.
Hooker. I shall be very glad if you try Passiflora. Your experiments on
Primula seem so well chosen that whatever the result is they will be of
value. But always remember that not one naturalist out of a dozen cares
for really philosophical experiments.

Down, May 31st [1863].

I am unwell, and must write briefly. I am very much obliged for the
"Courant." (645/1. The Edinburgh "Evening Courant" used to publish
notices of the papers read at the Botanical Society of Edinburgh. The
paper referred to here was Scott's on Oncidium.) The facts will be of
highest use to me. I feel convinced that your paper will have permanent
value. Your case seems excellently and carefully worked out. I agree that
the alteration of title was unfortunate, but, after all, title does not
signify very much. So few have attended to such points that I do not
expect any criticism; but if so, I should think you had much better reply,
but I could if you wished it much. I quite understand about the cases
being individual sterility; so Gartner states it was with him. Would it be
worth while to send a corrected copy of the "Courant" to the "Gardeners'
Chronicle?" (645/2. An account of Scott's work appeared in the
"Gardeners' Chronicle," June 13th, 1863, which is, at least partly, a
reprint of the "Courant," since it contains the awkward sentence criticised
by Darwin and referred to below. The title is "On the Fertilisation of
Orchids," which was no doubt considered unfortunate as not suggesting the
subject of the paper, and as being the same as that of Darwin's book.) I
did not know that you had tried Lobelia fulgens: can you give me any
particulars on the number of plants and kinds used, etc., that I may quote,
as in a few days I shall be writing on this whole subject? No one will
ever convince me that it is not a very important subject to philosophical
naturalists. The Hibiscus seems a very curious case, and I agree with your
remarks. You say that you are glad of criticisms (by the way avoid "former
and latter," the reader is always forced to go back to look). I think you
would have made the case more striking if you had first showed that the
pollen of Oncidium sphacelatum was good; secondly, that the ovule was
capable of fertilisation; and lastly, shown that the plant was impotent
with its own pollen. "Impotence of organs capable of elimination"--capable
here strictly refers to organs; you mean to impotence. To eliminate
impotence is a curious expression; it is removing a non-existent quality.
But style is a trifle compared with facts, and you are capable of writing
well. I find it a good rule to imagine that I want to explain the case in
as few and simple words as possible to one who knows nothing of the
subject. (645/3. See Letter 151, Volume I.) I am tired. In my opinion
you are an excellent observer.

Down, June 6th, 1863.

I fear that you think that I have done more than I have with respect to Dr.
Hooker. I did not feel that I had any right to ask him to remember you for
a colonial appointment: all that I have done is to speak most highly of
your scientific merits. Of course this may hereafter fructify. I really
think you cannot go on better, for educational purposes, than you are now
doing,--observing, thinking, and some reading beat, in my opinion, all
systematic education. Do not despair about your style; your letters are
excellently written, your scientific style is a little too ambitious. I
never study style; all that I do is to try to get the subject as clear as I
can in my own head, and express it in the commonest language which occurs
to me. But I generally have to think a good deal before the simplest
arrangement and words occur to me. Even with most of our best English
writers, writing is slow work; it is a great evil, but there is no help for
it. I am sure you have no cause to despair. I hope and suppose your
sending a paper to the Linnean Society will not offend your Edinburgh
friends; you might truly say that you sent the paper to me, and that (if it
turns out so) I thought it worth communicating to the Linnean Society. I
shall feel great interest in studying all your facts on Primula, when they
are worked out and the seed counted. Size of capsules is often very
deceptive. I am astonished how you can find time to make so many
experiments. If you like to send me your paper tolerably well written, I
would look it over and suggest any criticisms; but then this would cause
you extra copying. Remember, however, that Lord Brougham habitually wrote
everything important three times over. The cases of the Primulae which
lose by variation their dimorphic characters seem to me very interesting.
I find that the mid-styled (by variation) P. sinensis is more fertile with
own pollen, even, than a heteromorphic union! If you have time it will be
very good to experiment on Linum Lewisii. I wrote formerly to Asa Gray
begging for seed. If you have time, I think experiments on any peloric
flowers would be useful. I shall be sorry (and I am certain it is a
mistake on the part of the Society) if your orchid paper is not printed in
extenso. I am now at work compiling all such cases, and shall give a very
full abstract of all your observations. I hope to add in autumn some from
you on Passiflora. I would suggest to you the advantage, at present, of
being very sparing in introducing theory in your papers (I formerly erred
much in Geology in that way): LET THEORY GUIDE YOUR OBSERVATIONS, but till
your reputation is well established be sparing in publishing theory. It
makes persons doubt your observations. How rarely R. Brown ever indulged
in theory: too seldom perhaps! Do not work too hard, and do not be
discouraged because your work is not appreciated by the majority.

July 2nd [1863?]

Many thanks for capsules. I would give table of the Auricula (647/1. In
Scott's paper ("Linn. Soc. Journ." VIII.) many experiments on the Auricula
are recorded.), especially owing to enclosed extract, which you can quote.
Your facts about varying fertility of the primulas will be appreciated by
but very few botanists; but I feel sure that the day will come when they
will be valued. By no means modify even in the slightest degree any
result. Accuracy is the soul of Natural History. It is hard to become
accurate; he who modifies a hair's breadth will never be accurate. It is a
golden rule, which I try to follow, to put every fact which is opposed to
one's preconceived opinion in the strongest light. Absolute accuracy is
the hardest merit to attain, and the highest merit. Any deviation is ruin.
Sincere thanks for all your laborious trials on Passiflora. I am very
busy, and have got two of my sons ill--I very much fear with scarlet fever;
if so, no more work for me for some days or weeks. I feel greatly
interested about your Primula cases. I think it much better to count seed
than to weigh. I wish I had never weighed; counting is more accurate,
though so troublesome.

Down, 25th [1863?]

From what you say I looked again at "Bot. Zeitung." (648/1. "Ueber
Dichogamie," "Bot. Zeit." January 1863.) Treviranus speaks of P.
longiflora as short-styled, but this is evidently a slip of the pen, for
further on, I see, he says the stigma always projects beyond anthers. Your
experiments on coloured primroses will be most valuable if proved true.
(648/2. The reference seems to be to Scott's observation that the variety
rubra of the primrose was sterile when crossed with pollen from the common
primrose. Darwin's caution to Scott was in some measure justified, for in
his experiments on seedlings raised by self-fertilisation of the Edinburgh
plants, he failed to confirm Scott's result. See "Forms of Flowers,"
Edition II., page 225. Scott's facts are in the "Journal Linn. Soc."
VIII., page 97 (read February 4th, 1864).) I will advise to best of my
power when I see MS. If evidence is not good I would recommend you, for
your reputation's sake, to try them again. It is not likely that you will
be anticipated, and it is a great thing to fully establish what in future
time will be considered an important discovery (or rediscovery, for no one
has noticed Gartner's facts). I will procure coloured primroses for next
spring, but you may rely I will not publish before you. Do not work too
hard to injure your health. I made some crosses between primrose and
cowslip, and I send the results, which you may use if you like. But
remember that I am not quite certain that I well castrated the short-styled
primrose; I believe any castration would be superfluous, as I find all
[these] plants sterile when insects are excluded. Be sure and save seed of
the crossed differently coloured primroses or cowslips which produced least
seed, to test the fertility of the quasi-hybrid seedlings. Gartner found
the common primrose and cowslip very difficult to cross, but he knew
nothing on dimorphism. I am sorry about delay [of] your orchid paper; I
should be glad of abstract of your new observations of self-sterility in
orchids, as I should probably use the new facts. There will be an
important paper in September in "Annals and Magazine of Natural History,"
on ovules of orchids being formed after application of pollen, by Dr. F.
Hildebrand of Bonn. (648/3. "Ann. Mag. Nat. Hist." XII., 1863, page 169.
The paper was afterwards published in the "Bot. Zeitung," 1863.)

Down, November 7th [1863].

Every day that I could do anything, I have read a few pages of your paper,
and have now finished it, and return it registered. (649/1. This refers
to the MS. of Scott's paper on the Primulaceae, "Linn. Soc. Journ." VIII.
[February 4th, 1864] 1865.) It has interested me deeply, and is, I am
sure, an excellent memoir. It is well arranged, and in most parts well
written. In the proof sheets you can correct a little with advantage. I
have suggested a few alterations in pencil for your consideration, and have
put in here and there a slip of paper. There will be no occasion to
rewrite the paper--only, if you agree with me, to alter a few pages. When
finished, return it to me, and I will with the highest satisfaction
communicate it to the Linnean Society. I should be proud to be the author
of the paper. I shall not have caused much delay, as the first meeting of
the Society was on November 5th. When your Primula paper is finished, if
you are so inclined, I should like to hear briefly about your Verbascum and
Passiflora experiments. I tried Verbascum, and have got the pods, but do
not know when I shall be able to see to the results. This subject might
make another paper for you. I may add that Acropera luteola was fertilised
by me, and had produced two fine pods. I congratulate you on your
excellent paper.

P.S.--In the summary to Primula paper can you conjecture what is the
typical or parental form, i.e. equal, long or short styled?

Down, [January 24th, 1864].

(650/1. Darwin's interest in Scott's Primula work is shown by the
following extracts from a letter to Hooker of January 24th, 1864, written,
therefore, before the paper was read, and also by the subsequent
correspondence with Hooker and Asa Gray. The first part of this letter
illustrates Darwin's condition during a period of especially bad health.)

As I do nothing all day I often get fidgety, and I now fancy that Charlie
or some of your family [are] ill. When you have time let me have a short
note to say how you all are. I have had some fearful sickness; but what a
strange mechanism one's body is; yesterday, suddenly, I had a slight attack
of rheumatism in my back, and I instantly became almost well, and so
wonderfully strong that I walked to the hot-houses, which must be more than
a hundred yards. I have sent Scott's paper to the Linnean Society; I feel
sure it is really valuable, but I fear few will care about it. Remember my
URGENT wish to be able to send the poor fellow a word of praise from any
one. I have had work to get him to allow me to send the paper to the
Linnean Society, even after it was written out.

Down, February 9th, 1864.

(651/1. Scott's paper on Primulaceae was read at the Linnean Society on
February 4th, 1864.)

The President, Mr. Bentham, I presume, was so much struck by your paper
that he sent me a message to know whether you would like to be elected an
associate. As only one is elected annually, this is a decided honour. The
enclosed list shows what respectable men are associates. I enclose the
rules of admission. I feel sure that the rule that if no communication is
received within three years the associate is considered to have voluntarily
withdrawn, is by no means rigorously adhered to. Therefore, I advise you
to accept; but of course the choice is quite free. You will see there is
no payment. You had better write to me on this subject, as Dr. Hooker or I
will propose you.

September 13th, 1864.

I have been greatly interested by Scott's paper. I probably overrate it
from caring for the subject, but it certainly seems to me one of the very
most remarkable memoirs on such subjects which I have ever read. From the
subject being complex, and the style in parts obscure, I suppose very few
will read it. I think it ought to be noticed in the "Natural History
Review," otherwise the more remarkable facts will never be known. Try and
persuade Oliver to do it; with the summary it would not be troublesome. I
would offer, but I have sworn to myself I will do nothing till my volume on
"Variation under Domestication" is complete. I know you will not have time
to read Scott, and therefore I will just point out the new and, as they
seem to me, important points.

Firstly, the red cowslip, losing its dimorphic structure and changing so
extraordinarily in its great production of seed with its own pollen,
especially being nearly sterile when fertilised by, or fertilising, the
common cowslip. The analogous facts with red and white primrose.
Secondly, the utter dissimilarity of action of the pollen of long- and
short-styled form of one species in crossing with a distinct species. And
many other points. Will you suggest to Oliver to review this paper? if he
does so, and if it would be of any service to him, I would (as I have
attended so much to these subjects) just indicate, with pages, leading and
new points. I could send him, if he wishes, a separate and spare copy
marked with pencil.

September 13th [1864].

(653/1. In September, 1864, Darwin wrote to Asa Gray describing Scott's
work on the Primulaceae as:--)

A paper which has interested me greatly by a gardener, John Scott; it seems
to me a most remarkable production, though written rather obscurely in
parts, but worth the labour of studying. I have just bethought me that for
the chance of your noticing it in the "Journal," I will point out the new
and very remarkable facts. I have paid the poor fellow's passage out to
India, where I hope he will succeed, as he is a most laborious and able
man, with the manners almost of a gentleman.

(653/2. The following is an abstract of the paper which was enclosed in
the letter to Asa Gray.)

Pages 106-8. Red cowslip by variation has become non-dimorphic, and with
this change of structure has become much more productive of seed than even
the heteromorphic union of the common cowslip. Pages 91-2, similar case
with Auricula; on the other hand a non-dimorphic variety of P. farinosa
(page 115) is less fertile. These changes, or variations, in the
generative system seem to me very remarkable. But far more remarkable is
the fact that the red cowslip (pages 106-8) is very sterile when
fertilising, or fertilised by the common cowslip. Here we have a new
"physiological species." Analogous facts given (page 98) on the crossing
of red and white primroses with common primroses. It is very curious that
the two forms of the same species (pages 93, 94, 95, and 117) hybridise
with extremely different degrees of facility with distinct species.

He shows (page 94) that sometimes a cross with a quite distinct species
yields more seed than a homomorphic union with own pollen. He shows (page
111) that of the two homomorphic unions possible with each dimorphic
species the short-styled (as I stated) is the most sterile, and that my
explanation is probably true. There is a good summary to the paper.


(654/1. The following letters to Hooker, April 1st, April 5th and May
22nd, refer to Darwin's scheme of employing Scott as an assistant at Down,
and to Scott's appointment to the Botanic Garden at Calcutta.)

Down, April 1st, 1864.

I shall not at present allude to your very interesting letter (which as yet
has been read to me only twice!), for I am full of a project which I much
want you to consider.

You will have seen Scott's note. He tells me he has no plans for the
future. Thinking over all his letters, I believe he is a truly remarkable
man. He is willing to follow suggestions, but has much originality in
varying his experiments. I believe years may pass before another man
appears fitted to investigate certain difficult and tedious points--viz.
relative fertility of varieties of plants, including peloric and other
monsters (already Scott has done excellent work on this head); and,
secondly, whether a plant's own pollen is less effective than that of
another individual. Now, if Scott is moderate in his wishes, I would pay
him for a year or two to work and publish on these or other such subjects
which might arise. But I dare not have him here, for it would quite
overwork me. There would not be plants sufficient for his work, and it
would probably be an injury to himself, as it would put him out of the way
of getting a good situation. Now, I believe you have gardeners at Kew who
work and learn there without pay. What do you think of having Scott there
for a year or two to work and experiment? I can see enormous difficulties.
In the first place you will not perhaps think the points indicated so
highly important as I do. Secondly, he would require ground in some
out-of-the-way place where the plants could be covered by a net, which
would be unsightly. On the other hand, I presume you would like a series
of memoirs published on work done at Kew, which I am fully convinced would
have permanent value. It would, of course I conceive, be absolutely
necessary that Scott should be under the regular orders of the
superintendent. The only way I can fancy that it could be done would be to
explain to the superintendent that I temporarily supported Scott solely for
the sake of science, and appeal to his kindness to assist him. If you
approved of having him (which I can see is improbable), and you simply
ordered the superintendent to assist him, I believe everything would go to
loggerheads. As for Scott himself, it would be of course an advantage to
him to study the cultivation at Kew. You would get to know him, and if he
really is a good man you could perhaps be able to recommend him to some
situation at home or abroad. Pray turn this [over] in your mind. I have
no idea whether Scott would like the place, but I can see that he has a
burning zeal for science. He told me that his parents were in better
circumstances, and that he chose a gardener's life solely as the best way
of following science. I may just add that in his last letter he gives me
the results of many experiments on different individuals of the same
species of orchid, showing the most remarkable diversity in their sexual
condition. It seems to me a grievous loss that such a man should have all
his work cut short. Please remember that I know nothing of him excepting
from his letters: these show remarkable talent, astonishing perseverance,
much modesty, and what I admire, determined difference from me on many

What will Sir William say?

Down, April 5th [1864].

I see my scheme for Scott has invincible difficulties, and I am very much
obliged to you for explaining them at such length. If ever I get decently
well, and Scott is free and willing, I will have him here for a couple of
years to work out several problems, which otherwise would never be done. I
cannot see what will become of the poor fellow. I enclose a little
pamphlet from him, which I suppose is not of much scientific value, but is
surprising as the work of a gardener. If you have time do just glance over
it. I never heard anything so extraordinary as what you say about
poisoning plants, etc.

...The post has just come in. Your interest about Scott is extraordinarily
kind, and I thank you cordially. It seems absurd to say so, but I suspect
that X is prejudiced against Scott because he partially supports my views.
(655/1. In a letter to Scott (dated June 11th) Darwin warns him to keep
his views "pretty quiet," and quotes Hooker's opinion that "if it is known
that you agree at all with my views on species it is enough to make you
unpopular in Edinburgh.")

You must not trust my former letter about Clematis. I worked on too old a
plant, and blundered. I have now gone over the work again. It is really
curious that the stiff peduncles are acted upon by a bit of thread weighing
.062 of a grain.

Clematis glandulosa was a valuable present to me. My gardener showed it to
me and said, "This is what they call a Clematis," evidently disbelieving
it. So I put a little twig to the peduncle, and the next day my gardener
said, "You see it is a Clematis, for it feels." That's the way we make out
plants at Down.

My dear old friend, God bless you!

[May 22nd, 1864].

What a good kind heart you have got. You cannot tell how your letter has
pleased me. I will write to Scott and ask him if he chooses to go out and
risk engagement. If he will not he must want all energy. He says himself
he wants stoicism, and is too sensitive. I hope he may not want courage.
I feel sure he is a remarkable man, with much good in him, but no doubt
many errors and blemishes. I can vouch for his high intellect (in my
judgment he is the best observer I ever came across); for his modesty, at
least in correspondence; and there is something high-minded in his
determination not to receive money from me. I shall ask him whether he can
get a good character for probity and sobriety, and whether he can get aid
from his relations for his voyage out. I will help, and, if necessary, pay
the whole voyage, and give him enough to support him for some weeks at
Calcutta. I will write when I hear from him. God bless you; you, who are
so overworked, are most generous to take so much trouble about a man you
have had nothing to do with.

(656/1. Scott had left the Botanic Gardens at Edinburgh in March 1864,
chagrined at what, justly or unjustly, he considered discouragement and
slight. The Indian offer was most gladly and gratefully accepted.)

Down, November 1st, 1871.

Dr. Hooker has forwarded to me your letter as the best and simplest plan of
explaining affairs. I am sincerely grieved to hear of the pecuniary
problem which you have undergone, but now fortunately passed. I assure you
that I have never entertained any feelings in regard to you which you
suppose. Please to remember that I distinctly stated that I did not
consider the sum which I advanced as a loan, but as a gift; and surely
there is nothing discreditable to you, under the circumstances, in
receiving a gift from a rich man, as I am. Therefore I earnestly beg you
to banish the whole subject from your mind, and begin laying up something
for yourself in the future. I really cannot break my word and accept
payment. Pray do not rob me of my small share in the credit of aiding to
put the right man in the right place. You have done good work, and I am
sure will do more; so let us never mention the subject again.

I am, after many interruptions, at work again on my essay on Expression,
which was written out once many months ago. I have found your remarks the
best of all which have been sent me, and so I state.

CHAPTER 2.XI.--BOTANY, 1863-1881.

2.XI.I. Miscellaneous, 1863-1866.--2.XI.II. Correspondence with Fritz
Muller, 1865-1881.--2.XI.III. Miscellaneous, 1868-1881.

2.XI.I. MISCELLANEOUS, 1863-1866.

Down [April, 1863].

(658/1. The following letter illustrates the truth of Sir W. Thiselton-
Dyer's remark that Darwin was never "afraid of his facts." (658/2.
"Charles Darwin" (Nature Series), 1882, page 43.) The entrance of pollen-
tubes into the nucellus by the chalaza, instead of through the micropyle,
was first fully demonstrated by Treub in his paper "Sur les Casuarinees et
leur place dans le Systeme naturel," published in the "Ann. Jard. Bot.
Buitenzorg," X., 1891. Two years later Miss Benson gave an account of a
similar phenomenon in certain Amentiferae ("Trans. Linn. Soc." 1888-94,
page 409). This chalazogamic method of fertilisation has since been
recognised in other flowering plants, but not, so far as we are aware, in
the genus Primula.)

It is a shame to trouble [you], but will you tell me whether the ovule of
Primula is "anatropal," nearly as figured by Gray, page 123, "Lessons in
Botany," or rather more tending to "amphitropal"? I never looked at such a
point before. Why I am curious to know is because I put pollen into the
ovarium of monstrous primroses, and now, after sixteen days, and not before
(the length of time agrees with slowness of natural impregnation), I find
abundance of pollen-tubes emitted, which cling firmly to the ovules, and, I
think I may confidently state, penetrate the ovule. But here is an odd
thing: they never once enter at (what I suppose to be) the "orifice," but
generally at the chalaza...Do you know how pollen-tubes go naturally in
Primula? Do they run down walls of ovarium, and then turn up the placenta,
and so debouch near the "orifices" of the ovules?

If you thought it worth while to examine ovules, I would see if there are
more monstrous flowers, and put pollen into the ovarium, and send you the
flowers in fourteen or fifteen days afterwards. But it is rather
troublesome. I would not do it unless you cared to examine the ovules.
Like a foolish and idle man, I have wasted a whole morning over them...

In two ovules there was an odd appearance, as if the outer coat of ovule at
the chalaza end (if I understand the ovule) had naturally opened or
withered where most of the pollen-tubes seemed to penetrate, which made me
at first think this was a widely open foramen. I wonder whether the ovules
could be thus fertilised?

Down [April, 1863].

Many thanks about the Primula. I see that I was pretty right about the
ovules. I have been thinking that the apparent opening at the chalaza end
must have been withering or perhaps gnawing by some very minute insects, as
the ovarium is open at the upper end. If I have time I will have another
look at pollen-tubes, as, from what you say, they ought to find their way
to the micropyle. But ovules to me are far more troublesome to dissect
than animal tissue; they are so soft, and muddy the water.

Down, April 6th [1863].

I have been very glad to read your paper on Peloria. (660/1. "On the
Existence of Two Forms of Peloria." "Natural History Review," April, 1863,
page 258.) For the mere chance of the following case being new I send it.
A plant which I purchased as Corydalis tuberosa has, as you know, one
nectary--short, white, and without nectar; the pistil is bowed towards the
true nectary; and the hood formed by the inner petals slips off towards the
opposite side (all adaptations to insect agency, like many other pretty
ones in this family). Now on my plants there are several flowers (the
fertility of which I will observe) with both nectaries equal and purple and
secreting nectar; the pistil is straight, and the hood slips off either
way. In short, these flowers have the exact structure of Dielytra and
Adlumia. Seeing this, I must look at the case as one of reversion; though
it is one of the spreading of irregularity to two sides.

As columbine [Aquilegia] has all petals, etc., irregular, and as monkshood
[Aconitum] has two petals irregular, may not the case given by Seringe, and
referred to [by] you (660/2. "Seringe describes and figures a flower [of
Aconitum] wherein all the sepals were helmet-shaped," and the petals
similarly affected. Maxwell Masters, op. cit., page 260.), by you be
looked at as reversion to the columbine state? Would it be too bold to
suppose that some ancient Linaria, or allied form, and some ancient Viola,
had all petals spur-shaped, and that all cases of "irregular peloria" in
these genera are reversions to such imaginary ancient form? (660/3.
"'Regular or Congenital Peloria' would include those flowers which,
contrary to their usual habit, retain throughout the whole of their growth
their primordial regularity of form and equality of proportion. 'Irregular
or Acquired Peloria,' on the other hand, would include those flowers in
which the irregularity of growth that ordinarily characterises some
portions of the corolla is manifested in all of them." Maxwell Masters,
loc. cit.)

It seems to me, in my ignorance, that it would be advantageous to consider
probably due to the same general law--viz., one as reversion to very early
state, and the other as reversion to a later state when all the petals were
irregularly formed. This seems at least to me a priori a more probable
view than to look at one form of Peloria as due to reversion and the other
as something distinct. (660/4. See Maxwell Masters, "Vegetable
Teratology," 1869, page 235; "Variation of Animals and Plants," Edition
II., Volume II., page 33.)

What do you think of this notion?


(661/1. The following was written in reply to Mr. Gosse's letter of May
30th asking for a solution of his difficulties in fertilising Stanhopea.
It is reprinted by the kind permission of Mr. Edmund Gosse from his
delightful book, the "Life of Philip Henry Gosse," London, 1890, page 299.)

Down, June 2nd, 1863.

It would give me real pleasure to resolve your doubts, but I cannot. I can
give only suspicions and my grounds for them. I should think the non-
viscidity of the stigmatic hollow was due to the plant not living under its
natural conditions. Please see what I have said on Acropera. An excellent
observer, Mr. J. Scott, of the Botanical Gardens, Edinburgh, finds all that
I say accurate, but, nothing daunted, he with the knife enlarged the
orifice and forced in pollen-masses; or he simply stuck them into the
contracted orifice without coming into contact with the stigmatic surface,
which is hardly at all viscid, when, lo and behold, pollen-tubes were
emitted and fine seed capsules obtained. This was effected with Acropera
Loddigesii; but I have no doubt that I have blundered badly about A.
luteola. I mention all this because, as Mr. Scott remarks, as the plant is
in our hot-houses, it is quite incredible it ever could be fertilised in
its native land. The whole case is an utter enigma to me. Probably you
are aware that there are cases (and it is one of the oddest facts in
Physiology) of plants which, under culture, have their sexual functions in
so strange a condition, that though their pollen and ovules are in a sound
state and can fertilise and be fertilised by distinct but allied species,
they cannot fertilise themselves. Now, Mr. Scott has found this the case
with certain orchids, which again shows sexual disturbance. He had read a
paper at the Botanical Society of Edinburgh, and I daresay an abstract
which I have seen will appear in the "Gardeners' Chronicle"; but blunders
have crept in in copying, and parts are barely intelligible. How insects
act with your Stanhopea I will not pretend to conjecture. In many cases I
believe the acutest man could not conjecture without seeing the insect at
work. I could name common English plants in this predicament. But the
musk-orchis [Herminium monorchis] is a case in point. Since publishing, my
son and myself have watched the plant and seen the pollinia removed, and
where do you think they invariably adhere in dozens of specimens?--always
to the joint of the femur with the trochanter of the first pair of legs,
and nowhere else. When one sees such adaptation as this, it would be
hopeless to conjecture on the Stanhopea till we know what insect visits it.
I have fully proved that my strong suspicion was correct that with many of
our English orchids no nectar is excreted, but that insects penetrate the
tissues for it. So I expect it must be with many foreign species. I
forgot to say that if you find that you cannot fertilise any of your
exotics, take pollen from some allied form, and it is quite probable that
will succeed. Will you have the kindness to look occasionally at your bee-
Ophrys near Torquay, and see whether pollinia are ever removed? It is my
greatest puzzle. Please read what I have said on it, and on O. arachnites.
I have since proved that the account of the latter is correct. I wish I
could have given you better information.

P.S.--If the Flowers of the Stanhopea are not too old, remove pollen-masses
from their pedicels, and stick them with a little liquid pure gum to the
stigmatic cavity. After the case of the Acropera, no one can dare
positively say that they would not act.

Down, Saturday, 5th [December 1863].

I am very glad that this will reach you at Kew. You will then get rest,
and I do hope some lull in anxiety and fear. Nothing is so dreadful in
this life as fear; it still sickens me when I cannot help remembering some
of the many illnesses our children have endured. My father, who was a
sceptical man, was convinced that he had distinctly traced several cases of
scarlet fever to handling letters from convalescents.

The vases (662/1. Probably Wedgwood ware.) did come from my sister Susan.
She is recovering, and was much pleased to hear that you liked them; I have
now sent one of your notes to her, in which you speak of them as
"enchanting," etc. I have had a bad spell--vomiting, every day for eleven
days, and some days many times after every meal. It is astonishing the
degree to which I keep up some strength. Dr. Brinton was here two days
ago, and says he sees no reason [why] I may not recover my former degree of
health. I should like to live to do a little more work, and often I feel
sure I shall, and then again I feel that my tether is run out.

Your Hastings note, my dear old fellow, was a Copley Medal to me and more
than a Copley Medal: not but what I know well that you overrate what I
have been able to do. (662/2. The proposal to give the medal to Darwin
failed in 1863, but his friends were successful in 1864: see "Life and
Letters," III., page 28.) Now that I am disabled, I feel more than ever
what a pleasure observing and making out little difficulties is. By the
way, here is a very little fact which may interest you. A partridge foot
is described in "Proc. Zoolog. Soc." with a huge ball of earth attached to
it as hard as rock. (662/3. "Proc. Zool. Soc." 1863, page 127, by Prof.
Newton, who sent the foot to Darwin: see "Origin," Edition VI., page 328.)
Bird killed in 1860. Leg has been sent me, and I find it diseased, and no
doubt the exudation caused earth to accumulate; now already thirty-two
plants have come up from this ball of earth.

By Jove! I must write no more. Good-bye, my best of friends.

There is an Italian edition of the "Origin" preparing. This makes the
fifth foreign edition--i.e. in five foreign countries. Owen will not be
right in telling Longmans that the book would be utterly forgotten in ten
years. Hurrah!

Down, February 17th [1864].

Many thanks for the Epacrids, which I have kept, as they will interest me
when able to look through the microscope.

Dr. Cruger has sent me the enclosed paper, with power to do what I think
fit with it. He would evidently prefer it to appear in the "Nat. Hist.
Review." Please read it, and let me have your decision pretty soon. Some
germanisms must be corrected; whether woodcuts are necessary I have not
been able to pay attention enough to decide. If you refuse, please send it
to the Linnean Society as communicated by me. (663/1. H. Cruger's "A Few
Notes on the Fecundation of Orchids, etc." [Read March, 1864.] "Linn. Soc.
Journ." VIII., 1864-5, page 127.) The paper has interested me extremely,
and I shall have no peace till I have a good boast. The sexes are separate
in Catasetum, which is a wonderful relief to me, as I have had two or three
letters saying that the male C. tridentatum seeds. (663/2. See footnote
Letter 608 on the sexual relation between the three forms known as
Catasetum tridentatum, Monacanthus viridis, and Myanthus barbatus. For
further details see Darwin, "Linn. Soc. Journ." VI., 1862, page 151, and
"Fertilisation of Orchids," Edition II., page 196.) It is pretty clear to
me that two or three forms are confounded under this name. Observe how
curiously nearly perfect the pollen of the female is, according to Cruger,
--certainly more perfect than the pollen from the Guyana species described
by me. I was right in the manner in which the pollen adheres to the hairy
back of the humble-bee, and hence the force of the ejection of the pollina.
(663/3. This view was given in "Fertilisation of Orchids," Edition I.,
1862, page 230.) I am still more pleased that I was right about insects
gnawing the fleshy labellum. This is important, as it explains all the
astounding projections on the labellum of Oncidium, Phalaenopsis, etc.

Excuse all my boasting. It is the best medicine for my stomach. Tell me
whether you mean to take up orchids, as Hooker said you were thinking of
doing. Do you know Coryanthes, with its wonderful basket of water? See
what Cruger says about it. It beats everything in orchids. (663/4. For
Coryanthes see "Fertilisation of Orchids," Edition II., page 173.)

Down [September 13th, 1864].

Thanks for your note of the 5th. You think much and greatly too much of me
and my doings; but this is pleasant, for you have represented for many
years the whole great public to me.

I have read with interest Bentham's address on hybridism. I am glad that
he is cautious about Naudin's view, for I cannot think that it will hold.
(664/1. C. Naudin's "Nouvelles Recherches sur l'Hydridite dans les
Vegetaux." The complete paper, with coloured plates, was presented to the
Academy in 1861, and published in full in the "Nouvelles Archives de Museum
d'Hist. Nat." Volume I., 1865, page 25. The second part only appeared in
the "Ann. Sci. Nat." XIX., 1863. Mr. Bentham's address dealing with
hybridism is in "Proc. Linn. Soc." VIII., 1864, page ix. A review of
Naudin is given in the "Natural History Review," 1864, page 50. Naudin's
paper is of much interest, as containing a mechanical theory of
reproduction of the same general character as that of pangenesis. In the
"Variation of Animals and Plants," Edition II., Volume II., page 395,
Darwin states that in his treatment of hybridism in terms of gemmules he is
practically following Naudin's treatment of the same theme in terms of
"essences." Naudin, however, does not clearly distinguish between hybrid
and pure gemmules, and makes the assumption that the hybrid or mixed
essences tend constantly to dissociate into pure parental essences, and
thus lead to reversion. It is to this view that Darwin refers when he says
that Naudin's view throws no light on the reversion to long-lost
characters. His own attempt at explaining this fact occurs in "Variation
under Domestication," II., Edition II., page 395. Mr. Bateson ("Mendel's
Principle of Heredity," Cambridge, 1902, page 38) says: "Naudin clearly
enuntiated what we shall henceforth know as the Mendelian conception of the
dissociation of characters of cross-breds in the formation of the germ-
cells, though apparently he never developed this conception." It is
remarkable that, as far as we know, Darwin never in any way came across
Mendel's work. One of Darwin's correspondents, however, the late Mr. T.
Laxton, of Stamford, was close on the trail of Mendelian principle. Mr.
Bateson writes (op. cit., page 181): "Had he [Laxton] with his other gifts
combined this penetration which detects a great principle hidden in the
thin mist of 'exceptions,' we should have been able to claim for him that
honour which must ever be Mendel's in the history of discovery.") The
tendency of hybrids to revert to either parent is part of a wider law
(which I am fully convinced that I can show experimentally), namely, that
crossing races as well as species tends to bring back characters which
existed in progenitors hundreds and thousands of generations ago. Why this
should be so, God knows. But Naudin's view throws no light, that I can
see, on this reversion of long-lost characters. I wish the Ray Society
would translate Gartner's "Bastarderzeugung"; it contains more valuable
matter than all other writers put together, and would do great service if
better known. (664/2. "Versuche uber die Bastarderzeugung im
Pflanzenreich": Stuttgart, 1849.)


(665/1. Mr. Huxley had doubted the accuracy of observations on Catasetum
published in the "Fertilisation of Orchids." In what formed the postscript
to the following letter, Darwin wrote: "I have had more Catasetums,--all
right, you audacious 'caviller.'")

Down, October 31st [1862].

In a little book, just published, called the "Three Barriers" (a
theological hash of old abuse of me), Owen gives to the author a new resume
of his brain doctrine; and I thought you would like to hear of this. He
ends with a delightful sentence. "No science affords more scope or easier
ground for the caviller and controversialist; and these do good by
preventing scholars from giving more force to generalisations than the
master propounding them does, or meant his readers or hearers to give."

You will blush with pleasure to hear that you are of some use to the

[February, 1864?]

I shall write again. I write now merely to ask, if you have Naravelia
(666/1. Ranunculaceae.) (the Clematis-like plant told me by Oliver), to
try and propagate me a plant at once. Have you Clematis cirrhosa? It will
amuse me to tell you why Clematis interests me, and why I should so very
much like to have Naravelia. The leaves of Clematis have no spontaneous
movement, nor have the internodes; but when by growth the peduncles of
leaves are brought into contact with any object, they bend and catch hold.
The slightest stimulus suffices, even a bit of cotton thread a few inches
long; but the stimulus must be applied during six or twelve hours, and when
the peduncles once bend, though the touching object be removed, they never
get straight again. Now mark the difference in another leaf-climber--viz.,
Tropaeolum: here the young internodes revolve day and night, and the
peduncles of the leaves are thus brought into contact with an object, and
the slightest momentary touch causes them to bend in any direction and
catch the object, but as the axis revolves they must be often dragged away
without catching, and then the peduncles straighten themselves again, and
are again ready to catch. So that the nervous system of Clematis feels
only a prolonged touch--that of Tropaeolum a momentary touch: the
peduncles of the latter recover their original position, but Clematis, as
it comes into contact by growth with fixed objects, has no occasion to
recover its position, and cannot do so. You did send me Flagellaria, but
most unfortunately young plants do not have tendrils, and I fear my plant
will not get them for another year, and this I much regret, as these leaf-
tendrils seem very curious, and in Gloriosa I could not make out the
action, but I have now a young plant of Gloriosa growing up (as yet with
simple leaves) which I hope to make out. Thank Oliver for decisive answer
about tendrils of vines. It is very strange that tendrils formed of
modified leaves and branches should agree in all their four highly
remarkable properties. I can show a beautiful gradation by which LEAVES
produce tendrils, but how the axis passes into a tendril utterly puzzles
me. I would give a guinea if vine-tednrils could be found to be leaves.

(666/2. It is an interesting fact that Darwin's work on climbing plants
was well advanced before he discovered the existence of the works of Palm,
Mohl, and Dutrochet on this subject. On March 22nd, 1864, he wrote to
Hooker:--"You quite overrate my tendril work, and there is no occasion to
plague myself about priority." In June he speaks of having read "two
German books, and all, I believe, that has been written on climbers, and it
has stirred me up to find that I have a good deal of new matter.")

Down, June 2nd [1864].

You once offered me a Combretum. (667/1. The two forms of shoot in C.
argenteum are described in "Climbing Plants," page 41.) I having C.
purpureum, out of modesty like an ass refused. Can you now send me a
plant? I have a sudden access of furor about climbers. Do you grow
Adlumia cirrhosa? Your seed did not germinate with me. Could you have a
seedling dug up and potted? I want it fearfully, for it is a leaf-climber,
and therefore sacred.

I have some hopes of getting Adlumia, for I used to grow the plant, and
seedlings have often come up, and we are now potting all minute reddish-
coloured weeds. (667/2. We believe that the Adlumia which came up year by
year in flower boxes in the Down verandah grew from seed supplied by Asa
Gray.) I have just got a plant with sensitive axis, quite a new case; and
tell Oliver I now do not care at all how many tendrils he makes axial,
which at one time was a cruel torture to me.

Down, November 3rd [1864].

Many thanks for your splendid long letter. But first for business. Please
look carefully at the enclosed specimen of Dicentra thalictriformis, and
throw away. (668/1. Dicentra thalictrifolia, a Himalayan species of
Fumariaceae, with leaf-tendrils.) When the plant was young I concluded
certainly that the tendrils were axial, or modified branches, which Mohl
says is the case with some Fumariaceae. (668/2. "Ueber den Bau und das
Winden der Ranken und Schlingpflanzen. Eine gekronte Preisschrift," 4to,
Tubingen, 1827. At page 43 Mohl describes the tips of the branches of
Fumaria [Corydalis] clavicualta as being developed into tendrils, as well
as the leaves. For this reason Darwin placed the plant among the tendril-
bearers rather than among the true leaf-climbers: see "Climbing Plants,"
Edition II., 1875, page 121.) You looked at them here and agreed. But now
the plant is old, what I thought was a branch with two leaves and ending in
a tendril looks like a gigantic leaf with two compound leaflets, and the
terminal part converted into a tendril. For I see buds in the fork between
supposed branch and main stem. Pray look carefully--you know I am
profoundly ignorant--and save me from a horrid mistake.


(669/1. The following is interesting, as containing a foreshadowing of the
chemotaxis of antherozoids which was shown to exist by Pfeffer in 1881:
see "Untersuchungen aus dem botanischen Institut zu Tubingen," Volume I.,
page 363. There are several papers by H.J. Carter on the reproduction of
the lower organisms in the "Annals and Magazine of Natural History" between
1855 and 1865.)

Down, Sunday, 22nd, and Saturday, 28th [October, 1865].

I have been wading through the "Annals and Mag. of N. History." for last
ten years, and have been interested by several papers, chiefly, however,
translations; but none have interested me more than Carter's on lower
vegetables, infusoria, and protozoa. Is he as good a workman as he
appears? for if so he would deserve a Royal medal. I know it is not new;
but how wonderful his account of the spermatozoa of some dioecious alga or
conferva, swimming and finding the minute micropyle in a distinct plant,
and forcing its way in! Why, these zoospores must possess some sort of
organ of sense to guide their locomotive powers to the small micropyle; and
does not this necessarily imply something like a nervous system, in the
same way as complemental male cirripedes have organs of sense and
locomotion, and nothing else but a sack of spermatozoa?

May 16th, 1866.

Since writing to you before, I have read your admirable memoir on Salvia
(670/1. "Pringsheim's Jahrbucher," Volume IV., 1866.), and it has
interested me almost as much as when I first investigated the structure of
orchids. Your paper illustrates several points in my "Origin of Species,"
especially the transition of organs. Knowing only two or three species in
the genus, I had often marvelled how one cell of the anther could have been
transformed into the moveable plate or spoon; and how well you show the
gradations. But I am surprised that you did not more strongly insist on
this point.

I shall be still more surprised if you do not ultimately come to the same
belief with me, as shown by so many beautiful contrivances,--that all
plants require, from some unknown cause, to be occasionally fertilised by
pollen from a distinct individual.



(671/1. The letters from Darwin to Muller are given as a separate group,
instead of in chronological sequence with the other botanical letters, as
better illustrating the uninterrupted friendship and scientific comradeship
of the two naturalists.)

Down, October 17th [1865].

I received about a fortnight ago your second letter on climbing plants,
dated August 31st. It has greatly interested me, and it corrects and fills
up a great hiatus in my paper. As I thought you could not object, I am
having your letter copied, and will send the paper to the Linnean Society.
(671/2. "Notes on some of the Climbing Plants near Desterro" [1865],
"Linn. Soc. Journ." IX., 1867.) I have slightly modified the arrangement
of some parts and altered only a few words, as you write as good English as
an Englishman. I do not quite understand your account of the arrangement
of the leaves of Strychnos, and I think you use the word "bracteae"
differently to what English authors do; therefore I will get Dr. Hooker to
look over your paper.

I cannot, of course, say whether the Linnean Society will publish your
paper; but I am sure it ought to do so. As the Society is rather poor, I
fear that it will give only a few woodcuts from your truly admirable


(672/1. In Darwin's book on Climbing Plants, 1875 (672/2. First given as
a paper before the Linnean Society, and published in the "Linn. Soc.
Journ." Volume IX.,), he wrote (page 205): "The conclusion is forced on
our minds that the capacity of revolving, on which most climbing plants
depend, is inherent, though undeveloped, in almost every plant in the
vegetable Kingdom"--a conclusion which was verified in the "Power of
Movement in Plants." The present letter is interesting in referring to
Fritz Muller's observations on the "revolving nutation," or circumnutation
of Alisma macrophylla and Linum usitatissimum, the latter fact having been
discovered by F. Muller's daughter Rosa. This was probably the earliest
observation on the circumnutation of a non-climbing plant, and Muller, in a
paper dated 1868, and published in Volume V. of the "Jenaische
Zeitschrift," page 133, calls attention to its importance in relation to
the evolution of the habit of climbing. The present letter was probably
written in 1865, since it refers to Muller's paper read before the Linnean
Soc. on December 7th, 1865. If so, the facts on circumnutation must have
been communicated to Darwin some years before their publication in the
"Jenaische Zeitschrift.")

Down, December 9th [1865].

I have received your interesting letter of October 10th, with its new facts
on branch-tendrils. If the Linnean Society publishes your paper (672/3.
Ibid., 1867, page 344.), as I am sure it ought to do, I will append a note
with some of these new facts.

I forwarded immediately your MS. to Professor Max Schultze, but I did not
read it, for German handwriting utterly puzzles me, and I am so weak, I am
capable of no exertion. I took the liberty, however, of asking him to send
me a copy, if separate ones are printed, and I reminded him about the
Sponge paper.

You will have received before this my book on orchids, and I wish I had
known that you would have preferred the English edition. Should the German
edition fail to reach you, I will send an English one. That is a curious
observation of your daughter about the movement of the apex of the stem of
Linum, and would, I think, be worth following out. (672/4. F. Muller,
"Jenaische Zeitschrift," Bd. V., page 137. Here, also, are described the
movements of Alisma.) I suspect many plants move a little, following the
sun; but all do not, for I have watched some pretty carefully.

I can give you no zoological news, for I live the life of the most secluded

I occasionally hear from Ernest Hackel, who seems as determined as you are
to work out the subject of the change of species. You will have seen his
curious paper on certain medusae reproducing themselves by seminal
generation at two periods of growth.

(672/5. On April 3rd, 1868, Darwin wrote to F. Muller: "Your diagram of
the movements of the flower-peduncle of the Alisma is extremely curious. I
suppose the movement is of no service to the plant, but shows how easily
the species might be converted into a climber. Does it bend through
irritability when rubbed?"

Down, September 25th [1866].

I have just received your letter of August 2nd, and am, as usual,
astonished at the number of interesting points which you observe. It is
quite curious how, by coincidence, you have been observing the same
subjects that have lately interested me.

Your case of the Notylia is quite new to me (673/1. See F. Muller, "Bot.
Zeitung," 1868, page 630; "Fertilisation of Orchids," Edition II., page
171.); but it seems analogous with that of Acropera, about the sexes of
which I blundered greatly in my book. I have got an Acropera now in
flower, and have no doubt that some insect, with a tuft of hairs on its
tail, removes by the tuft, the pollinia, and inserts the little viscid cap
and the long pedicel into the narrow stigmatic cavity, and leaves it there
with the pollen-masses in close contact with, but not inserted into, the
stigmatic cavity. I find I can thus fertilise the flowers, and so I can
with Stanhopea, and I suspect that this is the case with your Notylia. But
I have lately had an orchis in flower--viz. Acineta, which I could not
anyhow fertilise. Dr. Hildebrand lately wrote a paper (673/2. "Bot.
Zeitung," 1863, 1865.) showing that with some orchids the ovules are not
mature and are not fertilised until months after the pollen-tubes have
penetrated the column, and you have independently observed the same fact,
which I never suspected in the case of Acropera. The column of such
orchids must act almost like the spermatheca of insects. Your orchis with
two leaf-like stigmas is new to me; but I feel guilty at your wasting your
valuable time in making such beautiful drawings for my amusement.

Your observations on those plants being sterile which grow separately, or
flower earlier than others, are very interesting to me: they would be
worth experimenting on with other individuals. I shall give in my next
book several cases of individual plants being sterile with their own
pollen. I have actually got on my list Eschscholtzia (673/3. See "Animals
and Plants," II., Edition II., page 118.) for fertilising with its own
pollen, though I did not suspect it would prove sterile, and I will try
next summer. My object is to compare the rate of growth of plants raised
from seed fertilised by pollen from the same flower and by pollen from a
distinct plant, and I think from what I have seen I shall arrive at
interesting results. Dr. Hildebrand has lately described a curious case of
Corydalis cava which is quite sterile with its own pollen, but fertile with
pollen of any other individual plant of the species. (673/4.
"International Horticultural Congress," London, 1866, quoted in "Variation
of Animals and Plants," Edition II., Volume II., page 113.) What I meant
in my paper on Linum about plants being dimorphic in function alone, was
that they should be divided into two equal bodies functionally but not
structurally different. I have been much interested by what you say on
seeds which adhere to the valves being rendered conspicuous. You will see
in the new edition of the "Origin" (673/5. "Origin of Species," Edition
IV., 1866, page 238. A discussion on the origin of beauty, including the
bright colours of flowers and fruits.) why I have alluded to the beauty and
bright colours of fruit; after writing this it troubled me that I
remembered to have seen brilliantly coloured seed, and your view occurred
to me. There is a species of peony in which the inside of the pod is
crimson and the seeds dark purple. I had asked a friend to send me some of
these seeds, to see if they were covered with anything which could prove
attractive to birds. I received some seeds the day after receiving your
letter, and I must own that the fleshy covering is so thin that I can
hardly believe it would lead birds to devour them; and so it was in an
analogous case with Passiflora gracilis. How is this in the cases
mentioned by you? The whole case seems to me rather a striking one.

I wish I had heard of Mikania being a leaf-climber before your paper was
printed (673/6. See "Climbing Plants (3rd thousand, 1882), page 116.
Mikania and Mutisia both belong to the Compositae. Mikania scandens is a
twining plant: it is another species which, by its leaf-climbing habit,
supplies a transition to the tendril-climber Mutisia. F. Muller's paper is
in "Linn. Soc. Journ." IX., page 344.), for we thus get a good gradation
from M. scandens to Mutisia, with its little modified, leaf-like tendrils.

I am glad to hear that you can confirm (but render still more wonderful)
Hackel's most interesting case of Linope. Huxley told me that he thought
the case would somehow be explained away.

Down [Received January 24th, 1867].

I have so much to thank you for that I hardly know how to begin. I have
received the bulbils of Oxalis, and your most interesting letter of October
1st. I planted half the bulbs, and will plant the other half in the
spring. The case seems to me very curious, and until trying some
experiments in crossing I can form no conjecture what the abortion of the
stamens in so irregular a manner can signify. But I fear from what you say
the plant will prove sterile, like so many others which increase largely by
buds of various kinds. Since I asked you about Oxalis, Dr. Hildebrand has
published a paper showing that a great number of species are trimorphic,
like Lythrum, but he has tried hardly any experiments. (674/1.
Hildebrand's work, published in the "Monatsb. d. Akad. d. Wiss. Berlin,"
1866, was chiefly on herbarium specimens. His experimental work was
published in the "Bot. Zeitung," 1871.)

I am particularly obliged for the information and specimens of Cordia
(674/2. Cordiaceae: probably dimorphic.), and shall be most grateful for
seed. I have not heard of any dimorphic species in this family. Hardly
anything in your letter interested me so much as your account and drawing
of the valves of the pod of one of the Mimoseae with the really beautiful
seeds. I will send some of these seeds to Kew to be planted. But these
seeds seem to me to offer a very great difficulty. They do not seem hard
enough to resist the triturating power of the gizzard of a gallinaceous
bird, though they must resist that of some other birds; for the skin is as
hard as ivory. I presume that these seeds cannot be covered with any
attractive pulp? I soaked one of the seeds for ten hours in warm water,
which became only very slightly mucilaginous. I think I will try whether
they will pass through a fowl uninjured. (674/3. The seeds proved to be
those of Adenanthera pavonina. The solution of the difficulty is given in
the following extract from a letter to Muller, March 2nd, 1867: "I wrote
to India on the subject, and I hear from Mr. J. Scott that parrots are
eager for the seeds, and, wonderful as the fact is, can split them open
with their beaks; they first collect a large number in their beaks, and
then settle themselves to split them, and in doing so drop many; thus I
have no doubt they are disseminated, on the same principle that the acorns
of our oaks are most widely disseminated." Possibly a similar explanation
may hold good for the brightly coloured seeds of Abrus precatorius.) I
hope you will observe whether any bird devours them; and could you get any
young man to shoot some and observe whether the seeds are found low down in
the intestines? It would be well worth while to plant such seeds with
undigested seeds for comparison. An opponent of ours might make a capital
case against us by saying that here beautiful pods and seeds have been
formed not for the good of the plant, but for the good of birds alone.
These seeds would make a beautiful bracelet for one of my daughters, if I
had enough. I may just mention that Euonymus europoeus is a case in point:
the seeds are coated by a thin orange layer, which I find is sufficient to
cause them to be devoured by birds.

I have received your paper on Martha [Posoqueria (674/4. "Bot. Zeitung,"
1866.)]; it is as wonderful as the most wonderful orchis; Ernst Hackel
brought me the paper and stayed a day with me. I have seldom seen a more
pleasant, cordial, and frank man. He is now in Madeira, where he is going
to work chiefly on the Medusae. His great work is now published, and I
have a copy; but the german is so difficult I can make out but little of
it, and I fear it is too large a work to be translated. Your fact about
the number of seeds in the capsule of the Maxillaria (674/5. See "Animals
and Plants," Edition II., Volume II., page 115.) came just at the right
time, as I wished to give one or two such facts. Does this orchid produce
many capsules? I cannot answer your question about the aerial roots of
Catasetum. I hope you have received the new edition of the "Origin." Your
paper on climbing plants (674/6. "Linn. Soc. Journal," IX., 1867, page
344.) is printed, and I expect in a day or two to receive the spare copies,
and I will send off three copies as before stated, and will retain some in
case you should wish me to send them to any one in Europe, and will
transmit the remainder to yourself.

Down [received February 24th, 1867].

Your letter of November 2nd contained an extraordinary amount of
interesting matter. What a number of dimorphic plants South Brazil
produces: you observed in one day as many or more dimorphic genera than
all the botanists in Europe have ever observed. When my present book is
finished I shall write a final paper upon these plants, so that I am
extremely glad to hear of your observations and to see the dried flowers;
nevertheless, I should regret MUCH if I prevented you from publishing on
the subject. Plumbago (675/1. Plumbago has not been shown to be
dimorphic.) is quite new to me, though I had suspected it. It is curious
how dimorphism prevails by groups throughout the world, showing, as I
suppose, that it is an ancient character; thus Hedyotis is dimorphic in
India (675/2. Hedyotis was sent to Darwin by F. Muller; it seems possible,
therefore, that Hedyotis was written by mistake for some other Rubiaceous
plant, perhaps Oldenlandia, which John Scott sent him from India.); the two
other genera in the same sub-family with Villarsia are dimorphic in Europe
and Ceylon; a sub-genus of Erythroxylon (675/3. No doubt Sethia.) is
dimorphic in Ceylon, and Oxalis with you and at the Cape of Good Hope. If
you can find a dimorphic Oxalis it will be a new point, for all known
species are trimorphic or monomorphic. The case of Convolvulus will be
new, if proved. I am doubtful about Gesneria (675/4. Neither Convolvulus
nor Gesneria have been shown to be dimorphic.), and have been often myself
deceived by varying length of pistil. A difference in the size of the
pollen-grains would be conclusive evidence; but in some cases experiments
by fertilisation can alone decide the point. As yet I know of no case of
dimorphism in flowers which are very irregular; such flowers being
apparently always sufficiently visited and crossed by insects.

Down, April 22nd [1867].

I am very sorry your papers on climbing plants never reached you. They
must be lost, but I put the stamps on myself and I am sure they were right.
I despatched on the 20th all the remaining copies, except one for myself.
Your letter of March 4th contained much interesting matter, but I have to
say this of all your letters. I am particularly glad to hear that Oncidium
flexuosum (676/1. See "Animals and Plants," Edition II., Volume II., page
114. Observations on Oncidium were made by John Scott, and in Brazil by F.
Muller, who "fertilised above one hundred flowers of the above-mentioned
Oncidium flexuosum, which is there endemic, with its own pollen, and with
that taken from distinct plants: all the former were sterile, whilst those
fertilised by pollen from any OTHER PLANT of the same species were
fertile.') is endemic, for I always thought that the cases of self-
sterility with orchids in hot-houses might have been caused by their
unnatural conditions. I am glad, also, to hear of the other analogous
cases, all of which I will give briefly in my book that is now printing.
The lessened number of good seeds in the self-fertilising Epidendrums is to
a certain extent a new case. You suggest the comparison of the growth of
plants produced from self-fertilised and crossed seeds. I began this work
last autumn, and the result, in some cases, has been very striking; but
only, as far as I can yet judge, with exotic plants which do not get freely
crossed by insects in this country. In some of these cases it is really a
wonderful physiological fact to see the difference of growth in the plants
produced from self-fertilised and crossed seeds, both produced by the same
parent-plant; the pollen which has been used for the cross having been
taken from a distinct plant that grew in the same flower-pot. Many thanks
for the dimorphic Rubiaceous plant. Three of your Plumbagos have
germinated, but not as yet any of the Lobelias. Have you ever thought of
publishing a work which might contain miscellaneous observations on all
branches of Natural History, with a short description of the country and of
any excursions which you might take? I feel certain that you might make a
very valuable and interesting book, for every one of your letters is so
full of good observations. Such books, for instance Bates' "Travels on the
Amazons," are very popular in England. I will give your obliging offer
about Brazilian plants to Dr. Hooker, who was to have come here to-day, but
has failed. He is an excellent good fellow, as well as naturalist. He has
lately published a pamphlet, which I think you would like to read; and I
will try and get a copy and send you. (676/2. Sir J.D. Hooker's lecture
on Insular Floras, given before the British Association in August, 1866, is
doubtless referred to. It appeared in the "Gardeners' Chronicle," and was
published as a pamphlet in January, 1867. This fact helps to fix the date
of the present letter.)


(677/1. The following refers to the curious case of Eschscholtzia
described in "Cross and Self-Fertilisation," pages 343-4. The offspring of
English plants after growing for two generations in Brazil became
self-sterile, while the offspring of Brazilian plants became partly
self-fertile in England.)

January 30th [1868].

...The flowers of Eschscholtzia when crossed with pollen from a distinct
plant produced 91 per cent. of capsules; when self-fertilised the flowers
produced only 66 per cent. of capsules. An equal number of crossed and
self-fertilised capsules contained seed by weight in the proportion of 100
to 71. Nevertheless, the self-fertilised flowers produced an abundance of
seed. I enclose a few crossed seeds in hopes that you will raise a plant,
cover it with a net, and observe whether it is self-fertile; at the same
time allowing several uncovered plants to produce capsules, for the
sterility formerly observed by you seems to me very curious.

Down, November 28th [1868].

You end your letter of September 9th by saying that it is a very dull one;
indeed, you make a very great mistake, for it abounds with interesting
facts and thoughts. Your account of the tameness of the birds which
apparently have wandered from the interior, is very curious. But I must
begin on another subject: there has been a great and very vexatious, but
unavoidable delay in the publication of your book. (678/1. "Facts and
Arguments for Darwin," 1869, a translation by the late Mr. Dallas of F.
Muller's "Fur Darwin," 1864: see Volume I., Letter 227.) Prof. Huxley
agrees with me that Mr. Dallas is by far the best translator, but he is
much overworked and had not quite finished the translation about a
fortnight ago. He has charge of the Museum at York, and is now trying to
get the situation of Assistant Secretary at the Geological Society; and all
the canvassing, etc., and his removal, if he gets the place, will, I fear,
cause more than a month's delay in the completion of the translation; and
this I very much regret.

I am particularly glad to hear that you intend to repeat my experiments on
illegitimate offspring, for no one's observations can be trusted until
repeated. You will find the work very troublesome, owing to the death of
plants and accidents of all kinds. Some dimorphic plant will probably
prove too sterile for you to raise offspring; and others too fertile for
much sterility to be expected in their offspring. Primula is bad on
account of the difficulty of deciding which seeds may be considered as
good. I have earnestly wished that some one would repeat these
experiments, but I feared that years would elapse before any one would take
the trouble. I received your paper on Bignonia in "Bot. Zeit." and it
interested me much. (678/2. See "Variation of Animals and Plants,"
Edition II., Volume II., page 117. Fritz Muller's paper,
"Befruchtungsversuche an Cipo alho (Bignonia)," "Botanische Zeitung,"
September 25th, 1868, page 625, contains an interesting foreshadowing of
the generalisation arrived at in "Cross and Self-Fertilisation." Muller
wrote: "Are the three which grow near each other seedlings from the same
mother-plant or perhaps from seeds of the same capsule? Or have they, from
growing in the same place and under the same conditions, become so like
each other that the pollen of one has hardly any more effect on the others
than their own pollen? Or, on the contrary, were the plants originally
one--i.e., are they suckers from a single stock, which have gained a slight
degree of mutual fertility in the course of an independent life? Or,
lastly, is the result 'ein neckische Zufall,'" (The above is a free
translation of Muller's words.)) I am convinced that if you can prove that
a plant growing in a distant place under different conditions is more
effective in fertilisation than one growing close by, you will make a great
step in the essence of sexual reproduction.

Prof. Asa Gray and Dr. Hooker have been staying here, and, oddly enough,
they knew nothing of your paper on Martha (678/3. F. Muller has described
("Bot. Zeitung," 1866, page 129) the explosive mechanism by which the
pollen is distributed in Martha (Posoqueria) fragrans. He also gives an
account of the remarkable arrangement for ensuring cross-fertilisation.
See "Forms of Flowers," Edition II., page 131.), though the former was
aware of the curious movements of the stamens, but so little understood the
structure of the plant that he thought it was probably a dimorphic species.
Accordingly, I showed them your drawings and gave them a little lecture,
and they were perfectly charmed with your account. Hildebrand (678/4. See
Letter 206, Volume I.) has repeated his experiments on potatoes, and so
have I, but this summer with no result.

Down, March 14th [1869].

I received some time ago a very interesting letter from you with many facts
about Oxalis, and about the non-seeding and spreading of one species. I
may mention that our common O. acetosella varies much in length of pistils
and stamens, so that I at first thought it was certainly dimorphic, but
proved it by experiment not to be so. Boiseria (679/1. This perhaps
refers to Boissiera (Ladizabala).) has after all seeded well with me when
crossed by opposite form, but very sparingly when self-fertilised. Your
case of Faramea astonishes me. (679/2. See "Forms of Flowers," Edition
II., page 129. Faramea is placed among the dimorphic species.) Are you
sure there is no mistake? The difference in size of flower and wonderful
difference in size and structure of pollen-grains naturally make me rather
sceptical. I never fail to admire and to be surprised at the number of
points to which you attend. I go on slowly at my next book, and though I
never am idle, I make but slow progress; for I am often interrupted by
being unwell, and my subject of sexual selection has grown into a very
large one. I have also had to correct a new edition of my "Origin,"
(679/3. The 5th edition.), and this has taken me six weeks, for science
progresses at railroad speed. I cannot tell you how rejoiced I am that
your book is at last out; for whether it sells largely or not, I am certain
it will produce a great effect on all capable judges, though these are few
in number.

P.S.--I have just received your letter of January 12th. I am greatly
interested by what you say on Eschscholtzia; I wish your plants had
succeeded better. It seems pretty clear that the species is much more
self-sterile under the climate of Brazil than here, and this seems to me an
important result. (679/4. See Letter 677.) I have no spare seeds at
present, but will send for some from the nurseryman, which, though not so
good for our purpose, will be worth trying. I can send some of my own in
the autumn. You could simply cover up separately two or three single
plants, and see if they will seed without aid,--mine did abundantly. Very
many thanks for seeds of Oxalis: how I wish I had more strength and time
to carry on these experiments, but when I write in the morning, I have
hardly heart to do anything in the afternoon. Your grass is most
wonderful. You ought to send account to the "Bot. Zeitung." Could you not
ascertain whether the barbs are sensitive, and how soon they become spiral
in the bud? Your bird is, I have no doubt, the Molothrus mentioned in my
"Journal of Travels," page 52, as representing a North American species,
both with cuckoo-like habits. I know that seeds from same spike
transmitted to a certain extent their proper qualities; but as far as I
know, no one has hitherto shown how far this holds good, and the fact is
very interesting. The experiment would be well worth trying with flowers
bearing different numbers of petals. Your explanation agrees beautifully
with the hypothesis of pangenesis, and delights me. If you try other
cases, do draw up a paper on the subject of inheritance of separate flowers
for the "Bot. Zeitung" or some journal. Most men, as far as my experience
goes, are too ready to publish, but you seem to enjoy making most
interesting observations and discoveries, and are sadly too slow in

Barmouth, July 18th, 1869.

I received your last letter shortly before leaving home for this place.
Owing to this cause and to having been more unwell than usual I have been
very dilatory in writing to you. When I last heard, about six or eight
weeks ago, from Mr. Murray, one hundred copies of your book had been sold,
and I daresay five hundred may now be sold. (680/1. "Facts and Arguments
for Darwin," 1869: see Volume I., Letter 227.) This will quite repay me,
if not all the money; for I am sure that your book will have got into the
hands of a good many men capable of understanding it: indeed, I know that
it has. But it is too deep for the general public. I sent you two or
three reviews--one of which, in the "Athenaeum," was unfavourable; but this
journal has abused me, and all who think with me, for many years. (680/2.
"Athenaeum," 1869, page 431.) I enclose two more notices, not that they
are worth sending: some other brief notices have appeared. The case of
the Abitulon sterile with some individuals is remarkable (680/3.
"Bestaubungsversuche an Abutilon-Arten." "Jenaische Zeitschr." VII., 1873,
page 22.): I believe that I had one plant of Reseda odorata which was
fertile with own pollen, but all that I have tried since were sterile
except with pollen from some other individual. I planted the seeds of the
Abitulon, but I fear that they were crushed in the letter. Your
Eschscholtzia plants were growing well when I left home, to which place we
shall return by the end of this month, and I will observe whether they are
self-sterile. I sent your curious account of the monstrous Begonia to the
Linnean Society, and I suppose it will be published in the "Journal."
(680/4. "On the Modification of the Stamens in a Species of Begonia."
"Journ. Linn. Soc." XI., 1871, page 472.) I sent the extract about grafted
orange trees to the "Gardeners' Chronicle," where it appeared. I have
lately drawn up some notes for a French translation of my Orchis book: I
took out your letters to make an abstract of your numerous discussions, but
I found I had not strength or time to do so, and this caused me great
regret. I have [in the French edition] alluded to your work, which will
also be published in English, as you will see in my paper, and which I will
send you. (680/5. "Notes on the Fertilisation of Orchids." "Ann. Mag.
Nat. Hist." 1869, Volume IV., page 141. The paper gives an English version
of the notes prepared for the French edition of the Orchid book.)

P.S.--By an odd chance, since I wrote the beginning of this letter, I have
received one from Dr. Hooker, who has been reading "Fur Darwin": he finds
that he has not knowledge enough for the first part; but says that Chapters
X. and XI. "strike me as remarkably good." He is also particularly struck
with one of your highly suggestive remarks in the note to page 119.
Assuredly all who read your book will greatly profit by it, and I rejoice
that it has appeared in English.

Down, December 1st [1869].

I am much obliged for your letter of October 18th, with the curious account
of Abutilon, and for the seeds. A friend of mine, Mr. Farrer, has lately
been studying the fertilisation of Passiflora (681/1. See Letters 701 and
704.), and concluded from the curiously crooked passage into the nectary
that it could not be fertilised by humming-birds; but that Tacsonia was
thus fertilised. Therefore I sent him the passage from your letter, and I
enclose a copy of his answer. If you are inclined to gratify him by making
a few observations on this subject I shall be much obliged, and will send
them on to him. I enclose a copy of my rough notes on your Eschscholtzia,
as you might like to see them. Somebody has sent me from Germany two
papers by you, one with a most curious account of Alisma (681/2. See
Letter 672.), and the other on crustaceans. Your observations on the
branchiae and heart have interested me extremely.

Alex. Agassiz has just paid me a visit with his wife. He has been in
England two or three months, and is now going to tour over the Continent to
see all the zoologists. We liked him very much. He is a great admirer of
yours, and he tells me that your correspondence and book first made him
believe in evolution. This must have been a great blow to his father, who,
as he tells me, is very well, and so vigorous that he can work twice as
long as he (the son) can.

Dr. Meyer has sent me his translation of Wallace's "Malay Archipelago,"
which is a valuable work; and as I have no use for the translation, I will
this day forward it to you by post, but, to save postage, via England.

Down, May 12th [1870].

I thank you for your two letters of December 15th and March 29th, both
abounding with curious facts. I have been particularly glad to hear in
your last about the Eschscholtzia (682/1. See Letter 677.); for I am now
rearing crossed and self-fertilised plants, in antagonism to each other,
from your semi-sterile plants so that I may compare this comparative growth
with that of the offspring of English fertile plants. I have forwarded
your postscript about Passiflora, with the seeds, to Mr. Farrer, who I am
sure will be greatly obliged to you; the turning up of the pendant flower
plainly indicates some adaptation. When I next go to London I will take up
the specimens of butterflies, and show them to Mr. Butler, of the British
Museum, who is a learned lepidopterist and interested on the subject. This
reminds me to ask you whether you received my letter [asking] about the
ticking butterfly, described at page 33 of my "Journal of Researches";
viz., whether the sound is in anyway sexual? Perhaps the species does not
inhabit your island. (682/2. Papilio feronia, a Brazilian species capable
of making "a clicking noise, similar to that produced by a toothed wheel
passing under a spring catch."--"Journal," 1879, page 34.)

The case described in your last letter of the trimorphic monocotyledon
Pontederia is grand. (682/3. This case interested Darwin as the only
instance of heterostylism in Monocotyledons. See "Forms of Flowers,"
Edition II., page 183. F. Muller's paper is in the "Jenaische
Zeitschrift," 1871.) I wonder whether I shall ever have time to recur to
this subject; I hope I may, for I have a good deal of unpublished material.

Thank you for telling me about the first-formed flower having additional
petals, stamens, carpels, etc., for it is a possible means of transition of
form; it seems also connected with the fact on which I have insisted of
peloric flowers being so often terminal. As pelorism is strongly inherited
(and [I] have just got a curious case of this in a leguminous plant from
India), would it not be worth while to fertilise some of your early flowers
having additional organs with pollen from a similar flower, and see whether
you could not make a race thus characterised? (682/4. See Letters 588,
589. Also "Variation under Domestication," Edition II., Volume I., pages
388-9.) Some of your Abutilons have germinated, but I have been very
unfortunate with most of your seed.

You will remember having given me in a former letter an account of a very
curious popular belief in regard to the subsequent progeny of asses, which
have borne mules; and now I have another case almost exactly like that of
Lord Morton's mare, in which it is said the shape of the hoofs in the
subsequent progeny are affected. (Pangenesis will turn out true some day!)
(682/5. See "Animals and Plants," Edition II., Volume I., page 435. For
recent work on telegony see Ewart's "Experimental Investigations on
Telegony," "Phil. Trans. R. Soc." 1899. A good account of the subject is
given in the "Quarterly Review," 1899, page 404. See also Letter 275,
Volume I.)

A few months ago I received an interesting letter and paper from your
brother, who has taken up a new and good line of investigation, viz., the
adaptation in insects for the fertilisation of flowers.

The only scientific man I have seen for several months is Kolliker, who
came here with Gunther, and whom I liked extremely.

I am working away very hard at my book on man and on sexual selection, but
I do not suppose I shall go to press till late in the autumn.

Down, January 1st, 1874.

No doubt I owe to your kindness two pamphlets received a few days ago,
which have interested me in an extraordinary degree. (683/1. This refers
to F. Muller's "Bestaubungsversuche an Abutilon-Arten" in the "Jenaische
Zeitschr." Volume VII., which are thus referred to by Darwin ("Cross and
Self Fert." pages 305-6): "Fritz Muller has shown by his valuable
experiments on hybrid Abutilons, that the union of brothers and sisters,
parents and children, and of other near relations is highly injurious to
the fertility of the offspring." The Termite paper is in the same volume
(viz., VII.) of the "Jenaische Zeitschr.") It is quite new to me what you
show about the effects of relationship in hybrids--that is to say, as far
as direct proof is concerned. I felt hardly any doubt on the subject, from
the fact of hybrids becoming more fertile when grown in number in nursery
gardens, exactly the reverse of what occurred with Gartner. (683/2. When
many hybrids are grown together the pollination by near relatives is
minimised.) The paper on Termites is even still more interesting, and the
analogy with cleistogene flowers is wonderful. (683/3. On the back of his
copy of Muller's paper Darwin wrote: "There exist imperfectly developed
male and female Termites, with wings much shorter than those of queen and
king, which serve to continue the species if a fully developed king and
queen do not after swarming (which no doubt is for an occasional cross)
enter [the] nest. Curiously like cleistogamic flowers.") The manner in
which you refer to to my chapter on crossing is one of the most elegant
compliments which I have ever received.

I have directed to be sent to you Belt's "Nicaragua," which seems to me the
best Natural History book of travels ever published. Pray look to what he
says about the leaf-carrying ant storing the leaves up in a minced state to
generate mycelium, on which he supposes that the larvae feed. Now, could
you open the stomachs of these ants and examine the contents, so as to
prove or disprove this remarkable hypothesis? (683/4. The hypothesis has
been completely confirmed by the researches of Moller, a nephew of F.
Muller's: see his "Brasilische Pilzblumen" ("Botan. Mittheilgn. aus den
Tropen," hrsg. von A.F.W. Schimper, Heft 7).)

Down, May 9th, 1877.

I have been particularly glad to receive your letter of March 25th on
Pontederia, for I am now printing a small book on heterostyled plants, and
on some allied subjects. I feel sure you will not object to my giving a
short account of the flowers of the new species which you have sent me. I
am the more anxious to do so as a writer in the United States has described
a species, and seems to doubt whether it is heterostyled, for he thinks the
difference in the length of the pistil depends merely on its growth! In my
new book I shall use all the information and specimens which you have sent
me with respect to the heterostyled plants, and your published notices.

One chapter will be devoted to cleistogamic species, and I will just notice
your new grass case. My son Francis desires me to thank you much for your
kindness with respect to the plants which bury their seeds.

I never fail to feel astonished, when I receive one of your letters, at the
number of new facts you are continually observing. With respect to the
great supposed subterranean animal, may not the belief have arisen from the
natives having seen large skeletons embedded in cliffs? I remember finding
on the banks of the Parana a skeleton of a Mastodon, and the Gauchos
concluded that it was a borrowing animal like the Bizcacha. (684/1. On
the supposed existence in Patagonia of a gigantic land-sloth, see "Natural
Science," XIII., 1898, page 288, where Ameghino's discovery of the skin of
Neomylodon listai was practically first made known, since his privately
published pamphlet was not generally seen. The animal was afterwards
identified with a Glossotherium, closely allied to Owen's G. Darwini, which
has been named Glossotherium listai or Grypotherium domesticum. For a good
account of the discoveries see Smith Woodward in "Natural Science," XV.,
1899, page 351, where the literature is given.)

Down, May 14th [1877].

I wrote to you a few days ago to thank you about Pontederia, and now I am
going to ask you to add one more to the many kindnesses which you have done
for me. I have made many observations on the waxy secretion on leaves
which throw off water (e.g., cabbage, Tropoeolum), and I am now going to
continue my observations. Does any sensitive species of Mimosa grow in
your neighbourhood? If so, will you observe whether the leaflets keep shut
during long-continued warm rain. I find that the leaflets open if they are
continuously syringed with water at a temperature of about 19 deg C., but
if the water is at a temperature of 33-35 deg C., they keep shut for more
than two hours, and probably longer. If the plant is continuously shaken
so as to imitate wind the leaflets soon open. How is this with the native
plants during a windy day? I find that some other plants--for instance,
Desmodium and Cassia--when syringed with water, place their leaves so that
the drops fall quickly off; the position assumed differing somewhat from
that in the so-called sleep. Would you be so kind as to observe whether
any [other] plants place their leaves during rain so as to shoot off the
water; and if there are any such I should be very glad of a leaf or two to
ascertain whether they are coated with a waxy secretion. (685/1. See
Letters 737-41.)

There is another and very different subject, about which I intend to write,
and should be very glad of a little information. Are earthworms
(Lumbricus) common in S. Brazil (685/2. F. Muller's reply is given in
"Vegetable Mould," page 122.), and do they throw up on the surface of the
ground numerous castings or vermicular masses such as we so commonly see in
Europe? Are such castings found in the forests beneath the dead withered
leaves? I am sure I can trust to your kindness to forgive me for asking
you so many questions.

Down, July 24th, 1878.

Many thanks for the five kinds of seeds; all have germinated, and the
Cassia seedlings have interested me much, and I daresay that I shall find
something curious in the other plants. Nor have I alone profited, for Sir
J. Hooker, who was here on Sunday, was very glad of some of the seeds for
Kew. I am particularly obliged for the information about the earthworms.
I suppose the soil in your forests is very loose, for in ground which has
lately been dug in England the worms do not come to the surface, but
deposit their castings in the midst of the loose soil.

I have some grand plants (and I formerly sent seeds to Kew) of the
cleistogamic grass, but they show no signs of producing flowers of any kind
as yet. Your case of the panicle with open flowers being sterile is
parallel to that of Leersia oryzoides. I have always fancied that
cross-fertilisation would perhaps make such panicles fertile. (686/1. The
meaning of this sentence is somewhat obscure. Darwin apparently implies
that the perfect flowers, borne on the panicles which occasionally emerge
from the sheath, might be fertile if pollinated from another individual.
See "Forms of Flowers," page 334.)

I am working away as hard as I can at all the multifarious kinds of
movements of plants, and am trying to reduce them to some simple rules, but
whether I shall succeed I do not know.

I have sent the curious lepidopteron case to Mr. Meldola.


(687/1. In November, 1880, on receipt of an account of a flood in Brazil
from which Fritz Muller had barely escaped with his life ("Life and
Letters," III., 242); Darwin immediately wrote to Hermann Muller begging to
be allowed to help in making good any loss in books or scientific
instruments that his brother had sustained. It is this offer of help that
is referred to in the first paragraph of the following letter: Darwin
repeats the offer in Letter 690.)

Blumenau, Sa Catharina, Brazil, January 9th, 1881.

I do not know how to express [to] you my deep heartfelt gratitude for the
generous offer which you made to my brother on hearing of the late dreadful
flood of the Itajahy. From you, dear sir, I should have accepted
assistance without hesitation if I had been in need of it; but fortunately,
though we had to leave our house for more than a week, and on returning
found it badly damaged, my losses have not been very great.

I must thank you also for your wonderful book on the movements of plants,
which arrived here on New Year's Day. I think nobody else will have been
delighted more than I was with the results which you have arrived at by so
many admirably conducted experiments and observations; since I observed the
spontaneous revolving movement of Alisma I had seen similar movements in so
many and so different plants that I felt much inclined to consider
spontaneous revolving movement or circumnutation as common to all plants
and the movements of climbing plants as a special modification of that
general phenomenon. And this you have now convincingly, nay,
superabundantly, proved to be the case.

I was much struck with the fact that with you Maranta did not sleep for two
nights after having its leaves violently shaken by wind, for here we have
very cold nights only after storms from the west or south-west, and it
would be very strange if the leaves of our numerous species of Marantaceae
should be prevented by these storms to assume their usual nocturnal
position, just when nocturnal radiation was most to be feared. It is
rather strange, also, that Phaseolus vulgaris should not sleep during the
early part of the summer, when the leaves are most likely to be injured
during cold nights. On the contrary, it would not do any harm to many sub-
tropical plants, that their leaves must be well illuminated during the day
in order that they may assume at night a vertical position; for, in our
climate at least, cold nights are always preceded by sunny days.

Of nearly allied plants sleeping very differently I can give you some more
instances. In the genus Olyra (at least, in the one species observed by
me) the leaves bend down vertically at night; now, in Endlicher's "Genera
plantarum" this genus immediately precedes Strephium, the leaves of which
you saw rising vertically.

In one of two species of Phyllanthus, growing as weeds near my house, the
leaves of the erect branches bend upwards at night, while in the second
species, with horizontal branches, they sleep like those of Phyllanthus
Niruri or of Cassia. In this second species the tips of the branches also
are curled downwards at night, by which movement the youngest leaves are
yet better protected. From their vertical nyctitropic position the leaves
of this Phyllanthus might return to horizontality, traversing 90 deg, in
two ways, either to their own or to the opposite side of the branch; on the
latter way no rotation would be required, while on the former each leaf
must rotate on its own axis in order that its upper surface may be turned
upwards. Thus the way to the wrong side appears to be even less
troublesome. And indeed, in some rare cases I have seen three, four or
even almost all the leaves of one side of a branch horizontally expanded on
the opposite side, with their upper surfaces closely appressed to the lower
surfaces of the leaves of that side.

This Phyllanthus agrees with Cassia not only in its manner of sleeping, but
also by its leaves being paraheliotropic. (687/2. Paraheliotropism is the
movement by which some leaves temporarily direct their edges to the source
of light. See "Movements of Plants," page 445.) Like those of some
Cassiae its leaves take an almost perfectly vertical position, when at
noon, on a summer day, the sun is nearly in the zenith; but I doubt whether
this paraheliotropism will be observable in England. To-day, though
continuing to be fully exposed to the sun, at 3 p.m. the leaves had already
returned to a nearly horizontal position. As soon as there are ripe seeds
I will send you some; of our other species of Phyllanthus I enclose a few
seeds in this letter.

In several species of Hedychium the lateral halves of the leaves when
exposed to bright sunshine, bend downwards so that the lateral margins
meet. It is curious that a hybrid Hedychium in my garden shows scarcely
any trace of this paraheliotropism, while both the parent species are very

Might not the inequality of the cotyledons of Citrus and of Pachira be
attributed to the pressure, which the several embryos enclosed in the same
seed exert upon each other? I do not know Pachira aquatica, but [in] a
species, of which I have a tree in my garden, all the seeds are
polyembryonic, and so were almost all the seeds of Citrus which I examined.
With Coffea arabica also seeds including two embryos are not very rare; but
I have not yet observed whether in this case the cotyledons be inequal.

I repeated to-day Duval-Jouve's measurements on Bryophyllum calycinum
(687/3. "Power of Movement in Plants," page 237. F. Muller's measurements
show, however, that there is a tendency in the leaves to be more highly
inclined at night than in the middle of the day, and so far they agree with
Duval-Jouve's results.); but mine did not agree with his; they are as

Distances in mm. between the tips of the upper pair of leaves.

January 9th, 1881 3 A.M. 1 P.M. 6 P.M.
1st plant 54 43 36
2nd plant 28 25 23
3rd plant 28 27 27
4th plant 51 46 39
5th plant 61 52 45

222 193 170

Down, February 23rd, 1881.

Your letter has interested me greatly, as have so many during many past
years. I thought that you would not object to my publishing in "Nature"
(688/1. "Nature," March 3rd, 1881, page 409.) some of the more striking
facts about the movements of plants, with a few remarks added to show the
bearing of the facts. The case of the Phyllanthus (688/2. See Letter
687.), which turns up its leaves on the wrong side, is most extraordinary
and ought to be further investigated. Do the leaflets sleep on the
following night in the usual manner? Do the same leaflets on successive
nights move in the same strange manner? I was particularly glad to hear of
the strongly marked cases of paraheliotropism. I shall look out with much
interest for the publication about the figs. (688/3. F. Muller published
on Caprification in "Kosmos," 1882.) The creatures which you sketch are
marvellous, and I should not have guessed that they were hymenoptera.
Thirty or forty years ago I read all that I could find about caprification,
and was utterly puzzled. I suggested to Dr. Cruger in Trinidad to
investigate the wild figs, in relation to their cross-fertilisation, and
just before he died he wrote that he had arrived at some very curious
results, but he never published, as I believe, on the subject.

I am extremely glad that the inundation did not so greatly injure your
scientific property, though it would have been a real pleasure to me to
have been allowed to have replaced your scientific apparatus. (688/4. See
Letter 687.) I do not believe that there is any one in the world who
admires your zeal in science and wonderful powers of observation more than
I do. I venture to say this, as I feel myself a very old man, who probably
will not last much longer.

P.S.--With respect to Phyllanthus, I think that it would be a good
experiment to cut off most of the leaflets on one side of the petiole, as
soon as they are asleep and vertically dependent; when the pressure is thus
removed, the opposite leaflets will perhaps bend beyond their vertically
dependent position; if not, the main petiole might be a little twisted so
that the upper surfaces of the dependent and now unprotected leaflets
should face obliquely the sky when the morning comes. In this case
diaheliotropism would perhaps conquer the ordinary movements of the leaves
when they awake, and [assume] their diurnal horizontal position. As the
leaflets are alternate, and as the upper surface will be somewhat exposed
to the dawning light, it is perhaps diaheliotropism which explains your
extraordinary case.

Down, April 12th, 1881.

I have delayed answering your last letter of February 25th, as I was just
sending to the printers the MS. of a very little book on the habits of
earthworms, of which I will of course send you a copy when published. I
have been very much interested by your new facts on paraheliotropism, as I
think that they justify my giving a name to this kind of movement, about
which I long doubted. I have this morning drawn up an account of your
observations, which I will send in a few days to "Nature." (689/1.
"Nature," 1881, page 603. Curious facts are given on the movements of
Cassia, Phyllanthus, sp., Desmodium sp. Cassia takes up a sunlight
position unlike its own characteristic night-position, but resembling
rather that of Haematoxylon (see "Power of Movement," figure 153, page
369). One species of Phyllanthus takes up in sunshine the nyctitropic
attitude of another species. And the same sort of relation occurs in the
genus Bauhinia.) I have thought that you would not object to my giving
precedence to paraheliotropism, which has been so little noticed. I will
send you a copy of "Nature" when published. I am glad that I was not in
too great a hurry in publishing about Lagerstroemia. (689/2.
Lagerstraemia was doubtfully placed among the heterostyled plants ("Forms
of Flowers," page 167). F. Muller's observations showed that a totally
different interpretation of the two sizes of stamen is possible. Namely,
that one set serves merely to attract pollen-collecting bees, who in the
act of visiting the flowers transfer the pollen of the longer stamens to
other flowers. A case of this sort in Heeria, a Melastomad, was described
by Muller ("Nature," August 4th, 1881, page 308), and the view was applied
to the cases of Lagerstroemia and Heteranthera at a later date ("Nature,"
1883, page 364). See Letters 620-30.) I have procured some plants of
Melastomaceae, but I fear that they will not flower for two years, and I
may be in my grave before I can repeat my trials. As far as I can
imperfectly judge from my observations, the difference in colour of the
anthers in this family depends on one set of anthers being partially
aborted. I wrote to Kew to get plants with differently coloured anthers,
but I learnt very little, as describers of dried plants do not attend to
such points. I have, however, sowed seeds of two kinds, suggested to me as
probable. I have, therefore, been extremely glad to receive the seeds of
Heteranthera reniformis. As far as I can make out it is an aquatic plant;
and whether I shall succeed in getting it to flower is doubtful. Will you
be so kind as to send me a postcard telling me in what kind of station it
grows. In the course of next autumn or winter, I think that I shall put
together my notes (if they seem worth publishing) on the use or meaning of
"bloom" (689/3. See Letters 736-40.), or the waxy secretion which makes
some leaves glaucous. I think that I told you that my experiments had led
me to suspect that the movement of the leaves of Mimosa, Desmodium and
Cassia, when shaken and syringed, was to shoot off the drops of water. If
you are caught in heavy rain, I should be very much obliged if you would
keep this notion in your mind, and look to the position of such leaves.
You have such wonderful powers of observation that your opinion would be
more valued by me than that of any other man. I have among my notes one
letter from you on the subject, but I forget its purport. I hope, also,
that you may be led to follow up your very ingenious and novel view on the
two-coloured anthers or pollen, and observe which kind is most gathered by

[Patterdale], June 21st, 1881.

I should be much obliged if you could without much trouble send me seeds of
any heterostyled herbaceous plants (i.e. a species which would flower
soon), as it would be easy work for me to raise some illegitimate seedlings
to test their degree of infertility. The plant ought not to have very
small flowers. I hope that you received the copies of "Nature," with
extracts from your interesting letters (690/1. "Nature," March 3rd, 1881,
Volume XXIII., page 409, contains a letter from C. Darwin on "Movements of
Plants," with extracts from Fritz Muller's letter. Another letter, "On the
Movements of Leaves," was published in "Nature," April 28th, 1881, page
603, with notes on leaf-movements sent to Darwin by Muller.), and I was
glad to see a notice in "Kosmos" on Phyllanthus. (690/2. "Verirrte
Blatter," by Fritz Muller ("Kosmos," Volume V., page 141, 1881). In this
article an account is given of a species of Phyllanthus, a weed in Muller's
garden. See Letter 687.) I am writing this note away from my home, but
before I left I had the satisfaction of seeing Phyllanthus sleeping. Some
of the seeds which you so kindly sent me would not germinate, or had not
then germinated. I received a letter yesterday from Dr. Breitenbach, and
he tells me that you lost many of your books in the desolating flood from
which you suffered. Forgive me, but why should you not order, through your
brother Hermann, books, etc., to the amount of 100 pounds, and I would send
a cheque to him as soon as I heard the exact amount? This would be no
inconvenience to me; on the contrary, it would be an honour and lasting
pleasure to me to have aided you in your invaluable scientific work to this
small and trifling extent. (690/3. See Letter 687, also "Life and
Letters," III., page 242.)


(691/1. The following extract from a letter to F. Muller shows what was
the nature of Darwin's interest in the effect of carbonate of ammonia on
roots, etc. He was, we think, wrong in adhering to the belief that the
movements of aggregated masses are of an amoeboid nature. The masses
change shape, just as clouds do under the moulding action of the wind. In
the plant cell the moulding agent is the flowing protoplasm, but the masses
themselves are passive.)

September 10th, 1881.

Perhaps you may remember that I described in "Insectivorous Plants" a
really curious phenomenon, which I called the aggregation of the protoplasm
in the cells of the tentacles. None of the great German botanists will
admit that the moving masses are composed of protoplasm, though it is
astonishing to me that any one could watch the movement and doubt its
nature. But these doubts have led me to observe analogous facts, and I
hope to succeed in proving my case.

Down, November 13th, 1881.

I received a few days ago a small box (registered) containing dried
flower-heads with brown seeds somewhat sculptured on the sides. There was
no name, and I should be much obliged if some time you would tell me what
these seeds are. I have planted them.

I sent you some time ago my little book on earthworms, which, though of no
importance, has been largely read in England. I have little or nothing to
tell you about myself. I have for a couple of months been observing the
effects of carbonate of ammonia on chlorophyll and on the roots of certain
plants (692/1. Published under the title "The Action of Carbonate of
Ammonia on the Roots of Certain Plants and on Chlorophyll Bodies," "Linn.
Soc. Journ." XIX., 1882, pages 239-61, 262-84.), but the subject is too
difficult for me, and I cannot understand the meaning of some strange facts
which I have observed. The mere recording new facts is but dull work.

Professor Wiesner has published a book (692/2. See Letter 763.), giving a
different explanation to almost every fact which I have given in my "Power
of Movement in Plants." I am glad to say that he admits that almost all my
statements are true. I am convinced that many of his interpretations of
the facts are wrong, and I am glad to hear that Professor Pfeffer is of the
same opinion; but I believe that he is right and I wrong on some points. I
have not the courage to retry all my experiments, but I hope to get my son
Francis to try some fresh ones to test Wiesner's explanations. But I do
not know why I have troubled you with all this.

[4, Bryanston Street], December 19th, 1881.

I hope that you may find time to go on with your experiments on such plants
as Lagerstroemia, mentioned in your letter of October 29th, for I believe
you will arrive at new and curious results, more especially if you can
raise two sets of seedlings from the two kinds of pollen.

Many thanks for the facts about the effect of rain and mud in relation to
the waxy secretion. I have observed many instances of the lower side being
protected better than the upper side, in the case, as I believe, of bushes
and trees, so that the advantage in low-growing plants is probably only an
incidental one. (693/1. The meaning is here obscure: it appears to us
that the significance of bloom on the lower surface of the leaves of both
trees and herbs depends on the frequency with which all or a majority of
the stomata are on the lower surface--where they are better protected from
wet (even without the help of bloom) than on the exposed upper surface. On
the correlation between bloom and stomata, see Francis Darwin "Linn. Soc.
Journ." XXII., page 99.) As I am writing away from my home, I have been
unwilling to try more than one leaf of the Passiflora, and this came out of
the water quite dry on the lower surface and quite wet on the upper. I
have not yet begun to put my notes together on this subject, and do not at
all know whether I shall be able to make much of it. The oddest little
fact which I have observed is that with Trifolium resupinatum, one half of
the leaf (I think the right-hand side, when the leaf is viewed from the
apex) is protected by waxy secretion, and not the other half (693/2. In
the above passage "leaf" should be "leaflet": for a figure of Trifolium
resupinatum see Letter 740.); so that when the leaf is dipped into water,
exactly half the leaf comes out dry and half wet. What the meaning of this
can be I cannot even conjecture. I read last night your very interesting
article in "Kosmos" on Crotalaria, and so was very glad to see the dried
leaves sent by you: it seems to me a very curious case. I rather doubt
whether it will apply to Lupinus, for, unless my memory deceives me, all
the leaves of the same plant sometimes behaved in the same manner; but I
will try and get some of the same seeds of the Lupinus, and sow them in the
spring. Old age, however, is telling on me, and it troubles me to have
more than one subject at a time on hand.

(693/3. In a letter to F. Muller (September 10, 1881) occurs a sentence
which may appropriately close this series: "I often feel rather ashamed of
myself for asking for so many things from you, and for taking up so much of
your valuable time, but I can assure you that I feel grateful.")


Down, April 22nd, 1868.

I have been extremely much pleased by your letter, and I take it as a very
great compliment that you should have written to me at such length...I am
not at all surprised that you cannot digest pangenesis: it is enough to
give any one an indigestion; but to my mind the idea has been an immense
relief, as I could not endure to keep so many large classes of facts all
floating loose in my mind without some thread of connection to tie them
together in a tangible method.

With respect to the men who have recently written on the crossing of
plants, I can at present remember only Hildebrand, Fritz Muller, Delpino,
and G. Henslow; but I think there are others. I feel sure that Hildebrand
is a very good observer, for I have read all his papers, and during the
last twenty years I have made unpublished observations on many of the
plants which he describes. [Most of the criticisms which I sometimes meet
with in French works against the frequency of crossing I am certain are the
result of mere ignorance. I have never hitherto found the rule to fail
that when an author describes the structure of a flower as specially
adapted for self-fertilisation, it is really adapted for crossing. The
Fumariaceae offer a good instance of this, and Treviranus threw this order
in my teeth; but in Corydalis Hildebrand shows how utterly false the idea
of self-fertilisation is. This author's paper on Salvia (694/1.
Hildebrand, "Pringsheim's Jahrbucher," IV.) is really worth reading, and I
have observed some species, and know that he is accurate]. (694/2. The
passage within [] was published in the "Life and Letters," III., page 279.)
Judging from a long review in the "Bot. Zeitung", and from what I know of
some the plants, I believe Delpino's article especially on the Apocynaea,
is excellent; but I cannot read Italian. (694/3. Hildebrand's paper in
the "Bot. Zeitung," 1867, refers to Delpino's work on the Asclepiads,
Apocyneae and other Orders.) Perhaps you would like just to glance at such
pamphlets as I can lay my hands on, and therefore I will send them, as if
you do not care to see them you can return them at once; and this will
cause you less trouble than writing to say you do not care to see them.
With respect to Primula, and one point about which I feel positive is that
the Bardfield and common oxlips are fundamentally distinct plants, and that
the common oxlip is a sterile hybrid. (694/4. For a general account of
the Bardfield oxlip (Primula elatior) see Miller Christy, "Linn. Soc.
Journ." Volume XXXIII., page 172, 1897.) I have never heard of the common
oxlip being found in great abundance anywhere, and some amount of
difference in number might depend on so small a circumstance as the
presence of some moth which habitually sucked the primrose and cowslip. To
return to the subject of crossing: I am experimenting on a very large
scale on the difference in power and growth between plants raised from
self-fertilised and crossed seeds, and it is no exaggeration to say that
the difference in growth and vigour is sometimes truly wonderful. Lyell,
Huxley, and Hooker have seen some of my plants, and been astonished; and I
should much like to show them to you. I always supposed until lately that
no evil effects would be visible until after several generations of
self-fertilisation, but now I see that one generation sometimes suffices,
and the existence of dimorphic plants and all the wonderful contrivances of
orchids are quite intelligible to me.

LETTER 695. TO T.H. FARRER (Lord Farrer).
Down, June 5th, 1868.

I must write a line to cry peccavi. I have seen the action in Ophrys
exactly as you describe, and am thoroughly ashamed of my inaccuracy.
(695/1. See "Fertilisation of Orchids," Edition II., page 46, where Lord
Farrer's observations on the movement of the pollinia in Ophrys muscifera
are given.) I find that the pollinia do not move if kept in a very damp
atmosphere under a glass; so that it is just possible, though very
improbable, that I may have observed them during a very damp day.

I am not much surprised that I overlooked the movement in Habenaria, as it
takes so long. (695/2. This refers to Peristylus viridis, sometimes known
as Habenaria viridis. Lord Farrer's observations are given in
"Fertilisation of Orchids," Edition II., page 63.)

I am glad you have seen Listera; it requires to be seen to believe in the
co-ordination in the position of the parts, the irritability, and the
chemical nature of the viscid fluid. This reminds me that I carefully
described to Huxley the shooting out of the pollinia in Catasetum, and
received for an answer, "Do you really think that I can believe all that!"
(695/3. See Letter 665.)

Down, December 2nd, 1868.

It is a splendid scheme, and if you make only a beginning on a "Flora,"
which shall serve as an index to all papers on curious points in the
life-history of plants, you will do an inestimable good service. Quite
recently I was asked by a man how he could find out what was known on
various biological points in our plants, and I answered that I knew of no
such book, and that he might ask half a dozen botanists before one would
chance to remember what had been published on this or that point. Not long
ago another man, who had been experimenting on the quasi-bulbs on the
leaves of Cardamine, wrote to me to complain that he could not find out
what was known on the subject. It is almost certain that some early or
even advanced students, if they found in their "Flora" a line or two on
various curious points, with references for further investigation, would be
led to make further observations. For instance, a reference to the viscid
threads emitted by the seeds of Compositae, to the apparatus (if it has
been described) by which Oxalis spurts out its seeds, to the sensitiveness
of the young leaves of Oxalis acetosella with reference to O. sensitiva.
Under Lathyrus nissolia it would [be] better to refer to my hypothetical
explanation of the grass-like leaves than to nothing. (696/1. No doubt the
view given in "Climbing Plants," page 201, that L. nissolia has been
evolved from a form like L. aphaca.) Under a twining plant you might say
that the upper part of the shoot steadily revolves with or against the sun,
and so, when it strikes against any object it turns to the right or left,
as the case may be. If, again, references were given to the parasitism of
Euphrasia, etc., how likely it would be that some young man would go on
with the investigation; and so with endless other facts. I am quite
enthusiastic about your idea; it is a grand idea to make a "Flora" a guide
for knowledge already acquired and to be acquired. I have amused myself by
speculating what an enormous number of subjects ought to be introduced into
a Eutopian (696/2. A mis-spelling of Utopian.) Flora, on the quickness of
the germination of the seeds, on their means of dispersal; on the
fertilisation of the flower, and on a score of other points, about almost
all of which we are profoundly ignorant. I am glad to read what you say
about Bentham, for my inner consciousness tells me that he has run too many
forms together. Should you care to see an elaborate German pamphlet by
Hermann Muller on the gradation and distinction of the forms of Epipactis
and of Platanthera? (696/3. "Verhand. d. Nat. Ver. f. Pr. Rh. u. Wesfal."
Jahrg. XXV.: see "Fertilisation of Orchids," Edition II., pages 74, 102.)
It may be absurd in me to suggest, but I think you would find curious
facts and references in Lecoq's enormous book (696/4. "Geographie
Botanique," 9 volumes, 1854-58.), in Vaucher's four volumes (696/5.
"Plantes d'Europe," 4 volumes, 1841.), in Hildebrand's "Geschlechter
Vertheilung" (696/6 "Geschlechter Vertheilung bei den Pflanzen," 1 volume,
Leipzig, 1867.), and perhaps in Fournier's "De la Fecondation." (696/7.
"De la Fecondation dans les Phanerogames," par Eugene Fournier: thesis
published in Paris in 1863. The facts noted in Darwin's copy are the
explosive stamens of Parietaria, the submerged flowers of Alisma containing
air, the manner of fertilisation of Lopezia, etc.) I wish you all success
in your gigantic undertaking; but what a pity you did not think of it ten
years ago, so as to have accumulated references on all sorts of subjects.
Depend upon it, you will have started a new era in the floras of various
countries. I can well believe that Mrs. Hooker will be of the greatest
possible use to you in lightening your labours and arranging your

Down, December 5th, 1868.

...Now I want to beg for assistance for the new edition of "Origin."
Nageli himself urges that plants offer many morphological differences,
which from being of no service cannot have been selected, and which he
accounts for by an innate principle of progressive development. (697/1.
Nageli's "Enstehung und Begriff der Naturhistorischen Art." An address
delivered at the public session of the Royal Academy of Sciences of Munich,
March 28th, 1865; published by the Academy. Darwin's copy is the 2nd
edition; it bears signs, in the pencilled notes on the margins, of having
been read with interest. Much of it was translated for him by a German
lady, whose version lies with the original among his pamphlets. At page 27
Nageli writes: "It is remarkable that the useful adaptations which Darwin
brings forward in the case of animals, and which may be discovered in
numbers among plants, are exclusively of a physiological kind, that they
always show the formation or transformation of an organ to a special
function. I do not know among plants a morphological modification which
can be explained on utilitarian principles." Opposite this passage Darwin
has written "a very good objection": but Nageli's sentence seems to us to
be of the nature of a truism, for it is clear that any structure whose
evolution can be believed to have come about by Natural Selection must have
a function, and the case falls into the physiological category. The
various meanings given to the term morphological makes another difficulty.
Nageli cannot use it in the sense of "structural"--in which sense it is
often applied, since that would mean that no plant structures have a
utilitarian origin. The essence of morphology (in the better and more
precise sense) is descent; thus we say that a pollen-grain is
morphologically a microspore. And this very example serves to show the
falseness of Nageli's view, since a pollen-grain is an adaptation to aerial
as opposed to aquatic fertilisation. In the 5th edition of the "Origin,"
1869, page 151, Darwin discusses Nageli's essay, confining himself to the
simpler statement that there are many structural characters in plants to
which we cannot assign uses. See Volume I., Letter 207.) I find old notes
about this difficulty; but I have hitherto slurred it over. Nageli gives
as instances the alternate and spiral arrangement of leaves, and the
arrangement of the cells in the tissues. Would you not consider as a
morphological difference the trimerous, tetramerous, etc., divisions of
flowers, the ovules being erect or suspended, their attachment being
parietal or placental, and even the shape of the seed when of no service to
the plant.

Now, I have thought, and want to show, that such differences follow in some
unexplained manner from the growth or development of plants which have
passed through a long series of adaptive changes. Anyhow, I want to show
that these differences do not support the idea of progressive development.
Cassini states that the ovaria on the circumference and centre of Compos.
flowers differ in essential characters, and so do the seeds in sculpture.
The seeds of Umbelliferae in the same relative positions are coelospermous
and orthospermous. There is a case given by Augt. St. Hilaire of an erect
and suspended ovule in the same ovarium, but perhaps this hardly bears on
the point. The summit flower, in Adoxa and rue differ from the lower
flowers. What is the difference in flowers of the rue? how is the ovarium,
especially in the rue? As Augt. St. Hilaire insists on the locularity of
the ovarium varying on the same plant in some of the Rutaceae, such
differences do not speak, as it seems to me, in favour of progressive
development. Will you turn the subject in your mind, and tell me any more
facts. Difference in structure in flowers in different parts of the same
plant seems best to show that they are the result of growth or position or
amount of nutriment.

I have got your photograph (697/2. A photograph by Mrs. Cameron.) over my
chimneypiece, and like it much; but you look down so sharp on me that I
shall never be bold enough to wriggle myself out of any contradiction.

Owen pitches into me and Lyell in grand style in the last chapter of volume
3 of "Anat. of Vertebrates." He is a cool hand. He puts words from me in
inverted commas and alters them. (697/3. The passage referred to seems to
be in Owen's "Anatomy of Vertebrata," III., pages 798, 799, note. "I
deeply regretted, therefore, to see in a 'Historical Sketch' of the
Progress of Enquiry into the origin of species, prefixed to the fourth
edition of that work (1866), that Mr. Darwin, after affirming inaccurately
and without evidence, that I admitted Natural Selection to have done
something toward that end, to wit, the 'origin of species,' proceeds to
remark: 'It is surprising that this admission should not have been made
earlier, as Prof. Owen now believes that he promulgated the theory of
Natural Selection in a passage read before the Zoological Society in
February, 1850, ("Trans." Volume IV., page 15).'" The first of the two
passages quoted by Owen from the fourth edition of the "Origin" runs: "Yet
he [Prof. Owen] at the same time admits that Natural Selection MAY [our
italics] have done something towards this end." In the sixth edition of
the "Origin," page xviii., Darwin, after referring to a correspondence in
the "London Review" between the Editor of that Journal and Owen, goes on:
"It appeared manifest to the editor, as well as to myself, that Prof. Owen
claimed to have promulgated the theory of Natural Selection before I had
done so;...but as far as it is possible to understand certain recently
published passages (Ibid. ["Anat. of Vert."], Volume III., page 798), I
have either partly or wholly again fallen into error. It is consolatory to
me that others find Prof. Owen's controversial writings as difficult to
understand and to reconcile with each other, as I do. As far as the mere
enunciation of the principle of Natural Selection is concerned, it is quite
immaterial whether or no Prof. Owen preceded me, for both of us, as shown
in this historical sketch, were long ago preceded by Dr. Wells and Mr.

Down, December 29th, 1868.

Your letter is quite invaluable, for Nageli's essay (698/1. See preceding
Letter.) is so clever that it will, and indeed I know it has produced a
great effect; so that I shall devote three or four pages to an answer. I
have been particularly struck by your statements about erect and suspended
ovules. You have given me heart, and I will fight my battle better than I
should otherwise have done. I think I cannot resist throwing the
contrivances in orchids into his teeth. You say nothing about the flowers
of the rue. (698/2. For Ruta see "Origin," Edition V., page 154.) Ask
your colleagues whether they know anything about the structure of the
flower and ovarium in the uppermost flower. But don't answer on purpose.

I have gone through my long Index of "Gardeners' Chronicle," which was made
solely for my own use, and am greatly disappointed to find, as I fear,
hardly anything which will be of use to you. (698/3. For Hooker's
projected biological book, see Letter 696.) I send such as I have for the
chance of their being of use.

Down, January 16th [1869].

Your two notes and remarks are of the utmost value, and I am greatly
obliged to you for your criticism on the term. "Morphological" seems quite
just, but I do not see how I can avoid using it. I found, after writing to
you, in Vaucher about the Rue (699/1. "Plantes d'Europe," Volume I., page
559, 1841.), but from what you say I will speak more cautiously. It is the
Spanish Chesnut that varies in divergence. Seeds named Viola nana were
sent me from Calcutta by Scott. I must refer to the plants as an "Indian
species," for though they have produced hundreds of closed flowers, they
have not borne one perfect flower. (699/2. The cleistogamic flowers of
Viola are used in the discussion on Nageli's views. See "Origin," Edition
V., page 153.) You ask whether I want illustrations "of ovules differing
in position in different flowers on the same plant." If you know of such
cases, I should certainly much like to hear them. Again you speak of the
angle of leaf-divergence varying and the variations being transmitted. Was
the latter point put in in a hurry to round the sentence, or do you really
know of cases?

Whilst looking for notes on the variability of the divisions of the
ovarium, position of the ovules, aestivation, etc., I found remarks written
fifteen or twenty years ago, showing that I then supposed that characters
which were nearly uniform throughout whole groups must be of high vital
importance to the plants themselves; consequently I was greatly puzzled
how, with organisms having very different habits of life, this uniformity
could have been acquired through Natural Selection. Now, I am much
inclined to believe, in accordance with the view given towards the close of
my MS., that the near approach to uniformity in such structures depends on
their not being of vital importance, and therefore not being acted on by
Natural Selection. (699/3. This view is given in the "Origin," Edition
VI., page 372.) If you have reflected on this point, what do you think of
it? I hope that you approved of the argument deduced from the
modifications in the small closed flowers.

It is only about two years since last edition of "Origin," and I am fairly
disgusted to find how much I have to modify, and how much I ought to add;
but I have determined not to add much. Fleeming Jenkin has given me much
trouble, but has been of more real use to me than any other essay or
review. (699/4. On Fleeming Jenkin's review, "N. British Review," June,
1867, see "Life and Letters," III., page 107.)

Down [January 22nd, 1869].

Your letter is quite splenditious. I am greatly tempted, but shall, I
hope, refrain from using some of your remarks in my chapter on
Classification. It is very true what you say about unimportant characters
being so important systematically; yet it is hardly paradoxical bearing in
mind that the natural system is genetic, and that we have to discover the
genealogies anyhow. Hence such parts as organs of generation are so useful
for classification though not concerned with the manner of life. Hence use
for same purpose of rudimentary organs, etc. You cannot think what a
relief it is that you do not object to this view, for it removes PARTLY a
heavy burden from my shoulders. If I lived twenty more years and was able
to work, how I should have to modify the "Origin," and how much the views
on all points will have to be modified! Well, it is a beginning, and that
is something...

LETTER 701. TO T.H. FARRER (Lord Farrer).
Down, August 10th, 1869.

Your view seems most ingenious and probable; but ascertain in a good many
cases that the nectar is actually within the staminal tube. (701/1. It
seems that Darwin did not know that the staminal tube in the diadelphous
Leguminosae serves as a nectar-holder, and this is surprising, as Sprengel
was aware of the fact.) One can see that if there is to be a split in the
tube, the law of symmetry would lead it to be double, and so free one
stamen. Your view, if confirmed, would be extremely well worth publication
before the Linnean Society. It is to me delightful to see what appears a
mere morphological character found to be of use. It pleases me the more as
Carl Nageli has lately been pitching into me on this head. Hooker, with
whom I discussed the subject, maintained that uses would be found for lots
more structures, and cheered me by throwing my own orchids into my teeth.
(701/2. See Letters 697-700.)

All that you say about changed position of the peduncle in bud, in flower,
and in seed, is quite new to me, and reminds me of analogous cases with
tendrils. (701/3. See Vochting, "Bewegung der Bluthen und Fruchte," 1882;
also Kerner, "Pflanzenleben," Volume I., page 494, Volume II., page 121.)
This is well worth working out, and I dare say the brush of the stigma.

With respect to the hairs or filaments (about which I once spoke) within
different parts of flowers, I have a splendid Tacsonia with perfectly
pendent flowers, and there is only a microscopical vestige of the corona of
coloured filaments; whilst in most common passion-flowers the flowers stand
upright, and there is the splendid corona which apparently would catch
pollen. (701/4. Sprengel ("Entdeckte Geheimniss," page 164) imagined that
the crown of the Passion-flower served as a nectar-guide and as a platform
for insects, while other rings of filaments served to keep rain from the
nectar. F. Muller, quoted in H. Muller ("Fertilisation," page 268), looks
at the crowns of hairs, ridges in some species, etc., as gratings serving
to imprison flies which attract the fertilising humming-birds. There is,
we believe, no evidence that the corona catches pollen. See Letter 704,

On the lower side of corolla of foxglove there are some fine hairs, but
these seem of not the least use (701/5. It has been suggested that the
hairs serve as a ladder for humble bees; also that they serve to keep out
"unbidden guests.")--a mere purposeless exaggeration of down on outside--as
I conclude after watching the bees at work, and afterwards covering up some
plants; for the protected flowers rarely set any seed, so that the hairy
lower part of corolla does not come into contact with stigma, as some
Frenchman says occurs with some other plants, as Viola odorata and I think

I heartily wish I could accept your kind invitation, for I am not by nature
a savage, but it is impossible. Forgive my dreadful handwriting, none of
my womenkind are about to act as amanuensis.


(702/1. Mr. Tait, to whom the following letter is addressed, was resident
in Portugal. His kindness in sending plants of Drosophyllum lusitanicum is
acknowledged in "Insectivorous Plants.")

Down, March 12th, 1869.

I have received your two letters of March 2nd and 5th, and I really do not
know how to thank you enough for your extraordinary kindness and energy. I
am glad to hear that the inhabitants notice the power of the Drosophyllum
to catch flies, for this is the subject of my studies. (702/2. The
natives are said to hang up plants of Drosophyllum in their cottages to act
as fly-papers ("Insectivorous Plants," page 332).) I have observed during
several years the manner in which this is effected, and the results
produced in several species of Drosera, and in the wonderful American
Dionoea, the leaves of which catch insects just like a steel rat-trap.
Hence I was most anxious to learn how the Drosophyllum would act, so that
the Director of the Royal Gardens at Kew wrote some years ago to Portugal
to obtain specimens for me, but quite failed. So you see what a favour you
have conferred on me. With Drosera it is nothing less than marvellous how
minute a fraction of a grain of any nitrogenised matter the plant can
detect; and how differently it behaves when matter, not containing
nitrogen, of the same consistence, whether fluid or solid, is applied to
the glands. It is also exquisitely sensitive to a weight of even the
1/70000 of a grain. From what I can see of the glands on Drosophyllum I
suspect that I shall find only the commencement, or nascent state of the
wonderful capacities of the Drosera, and this will be eminently interesting
to me. My MS. on this subject has been nearly ready for publication during
some years, but when I shall have strength and time to publish I know not.

And now to turn to other points in your letter. I am quite ignorant of
ferns, and cannot name your specimen. The variability of ferns passes all
bounds. With respect to your Laugher Pigeons, if the same with the two
sub-breeds which I kept, I feel sure from the structure of the skeleton,
etc., that it is a descendant of C. livia. In regard to beauty, I do not
feel the difficulty which you and some others experience. In the last
edition of my "Origin" I have discussed the question, but necessarily very
briefly. (702/3. Fourth Edition, page 238.) A new and I hope amended
edition of the "Origin" is now passing through the press, and will be
published in a month or two, and it will give me great pleasure to send you
a copy. Is there any place in London where parcels are received for you,
or shall I send it by post? With reference to dogs' tails, no doubt you
are aware that a rudimentary stump is regularly inherited by certain breeds
of sheep-dogs, and by Manx cats. You speak of a change in the position of
the axis of the earth: this is a subject quite beyond me, but I believe
the astronomers reject the idea. Nevertheless, I have long suspected that
some periodical astronomical or cosmical cause must be the agent of the
incessant oscillations of level in the earth's crust. About a month ago I
suggested this to a man well capable of judging, but he could not conceive
any such agency; he promised, however, to keep it in mind. I wish I had
time and strength to write to you more fully. I had intended to send this
letter off at once, but on reflection will keep it till I receive the

Down, March 14th, 1870.

I think you have set yourself a new, very interesting, and difficult line
of research. As far as I know, no one has carefully observed the structure
of insects in relation to flowers, although so many have now attended to
the converse relation. (703/1. See Letter 462, also H. Muller,
"Fertilisation of Flowers," English Translation, page 30, on "The insects
which visit flowers." In Muller's book references are given to several of
his papers on this subject.) As I imagine few or no insects are adapted to
suck the nectar or gather the pollen of any single family of plants, such
striking adaptations can hardly, I presume, be expected in insects as in

LETTER 704. TO T.H. FARRER (Lord Farrer).

Down, May 28th, 1870.

I suppose I must have known that the stamens recovered their former
position in Berberis (704/1. See Farrer, "Nature," II., 1870, page 164.
Lord Farrer was before H. Muller in making out the mechanism of the
barberry.), for I formerly tried experiments with anaesthetics, but I had
forgotten the facts, and I quite agree with you that it is a sound argument
that the movement is not for self-fertilisation. The N. American
barberries (Mahonia) offer a good proof to what an extent natural crossing
goes on in this genus; for it is now almost impossible in this country to
procure a true specimen of the two or three forms originally introduced.

I hope the seeds of Passiflora will germinate, for the turning up of the
pendent flower must be full of meaning. (704/2. Darwin had (May 12th,
1870) sent to Farrer an extract from a letter from F. Muller, containing a
description of a Passiflora visited by humming-birds, in which the long
flower-stalk curls up so that "the flower itself is upright." Another
species visited by bees is described as having "dependent flowers." In a
letter, June 29th, 1870, Mr. Farrer had suggested that P. princeps, which
he described as having sub-erect flowers, is fitted for humming-birds'
visits. In another letter, October 13th, 1869, he says that Tacsonia,
which has pendent flowers and no corona, is not fertilised by insects in
English glass-houses, and may be adapted for humming-birds. See "Life and
Letters," III., page 279, for Farrer's remarks on Tacsonia and Passiflora;
also H. Muller's "Fertilisation of Flowers," page 268, for what little is
known on the subject; also Letter 701 in the present volume.) I am so glad
that you are able to occupy yourself a little with flowers: I am sure it
is most wise in you, for your own sake and children's sakes.

Some little time ago Delpino wrote to me praising the Swedish book on the
fertilisation of plants; as my son George can read a little Swedish, I
should like to have it back for a time, just to hear a little what it is
about, if you would be so kind as to return it by book-post. (704/3.
Severin Axell, "Om anordningarna for de Fanerogama Vaxternas Befruktning,"
Stockholm, 1869.)

I am going steadily on with my experiments on the comparative growth of
crossed and self-fertilised plants, and am now coming to some very curious
anomalies and some interesting results. I forget whether I showed you any
of them when you were here for a few hours. You ought to see them, as they
explain at a glance why Nature has taken such extraordinary pains to ensure
frequent crosses between distinct individuals.

If in the course of the summer you should feel any inclination to come here
for a day or two, I hope that you will propose to do so, for we should be
delighted to see you...

Down, December 7th, 1870.

I have been very glad to receive your letter this morning. I have for some
time been wishing to write to you, but have been half worked to death in
correcting my uncouth English for my new book. (705/1. "Descent of Man.")
I have been glad to hear of your cases appearing like incipient dimorphism.
I believe that they are due to mere variability, and have no significance.
I found a good instance in Nolana prostrata, and experimented on it, but
the forms did not differ in fertility. So it was with Amsinckia, of which
you told me. I have long thought that such variations afforded the basis
for the development of dimorphism. I was not aware of such cases in Phlox,
but have often admired the arrangement of the anthers, causing them to be
all raked by an inserted proboscis. I am glad also to hear of your curious
case of variability in ovules, etc.

I said that I had been wishing to write to you, and this was about your
Drosera, which after many fluctuations between life and death, at last made
a shoot which I could observe. The case is rather interesting; but I must
first remind you that the filament of Dionoea is not sensitive to very
light prolonged pressure, or to nitrogenous matter, but is exquisitely
sensitive to the slightest touch. (705/2. In another connection the
following reference to Dionoea is of some interest: "I am sure I never
heard of Curtis's observations on Dionoea, nor have I met with anything
more than general statements about this plant or about Nepenthes catching
insects." (From a letter to Sir J.D. Hooker, July 12th, 1860.)) In our
Drosera the filaments are not sensitive to a slight touch, but are
sensitive to prolonged pressure from the smallest object of any nature;
they are also sensitive to solid or fluid nitrogenous matter. Now in your
Drosera the filaments are not sensitive to a rough touch or to any pressure
from non-nitrogenous matter, but are sensitive to solid or fluid
nitrogenous matter. (705/3. Drosera filiformis: see "Insectivorous
Plants," page 281. The above account does not entirely agree with Darwin's
published statement. The filaments moved when bits of cork or cinder were
placed on them; they did not, however, respond to repeated touches with a
needle, thus behaving differently from D. rotundifolia. It should be
remembered that the last-named species is somewhat variable in reacting to
repeated touches.) Is it not curious that there should be such diversified
sensitiveness in allied plants?

I received a very obliging letter from Mr. Morgan, but did not see him, as
I think he said he was going to start at once for the Continent. I am
sorry to hear rather a poor account of Mrs. Gray, to whom my wife and I
both beg to be very kindly remembered.


(706/1. In Riley's opinion his most important work was the series entitled
"Annual Report on the Noxious, Beneficial, and other Insects of the State
of Missouri" (Jefferson City), beginning in 1869. These reports were
greatly admired by Mr. Darwin, and his copies of them, especially of Nos. 3
and 4, show signs of careful reading.)

Down, June 1st [1871].

I received some little time ago your report on noxious insects, and have
now read the whole with the greatest interest. (706/2. "Third Annual
Report on the Noxious, Beneficial, and other Insects of the State of
Missouri" (Jefferson City, Mo.). The mimetic case occurs at page 67; the
1875 pupae of Pterophorus periscelidactylus, the "Grapevine Plume," have
pupae either green or reddish brown, the former variety being found on the
leaves, the latter on the brown stems of the vine.) There are a vast
number of facts and generalisations of value to me, and I am struck with
admiration at your powers of observation.

The discussion on mimetic insects seems to me particularly good and
original. Pray accept my cordial thanks for the instruction and interest
which I have received.

What a loss to Natural Science our poor mutual friend Walsh has been; it is
a loss ever to be deplored...

Your country is far ahead of ours in some respects; our Parliament would
think any man mad who should propose to appoint a State Entomologist.


(706A/1. We have found it convenient to place the two letters to Riley
together, rather than separate them chronologically.)

Down, September 28th, 1881.

I must write half a dozen lines to say how much interested I have been by
your "Further Notes" on Pronuba which you were so kind as to send me.
(706A/2. "Proc. Amer. Assoc. Adv. Sci." 1880.) I had read the various
criticisms, and though I did not know what answer could be made, yet I felt
full confidence in your result, and now I see that I was right...If you
make any further observation on Pronuba it would, I think, be well worth
while for you to observe whether the moth can or does occasionally bring
pollen from one plant to the stigma of a distinct one (706A/3. Riley
discovered the remarkable fact that the Yucca moth (Pronuba yuccasella)
lays its eggs in the ovary of Yucca flowers, which it has previously
pollinated, thus making sure of a supply of ovules for the larvae.), for I
have shown that the cross-fertilisation of the flowers on the same plant
does very little good; and, if I am not mistaken, you believe that Pronuba
gathers pollen from the same flower which she fertilises.

What interesting and beautiful observations you have made on the
metamorphoses of the grasshopper-destroying insects.

Down, February 9th [1872].

Owing to other occupations I was able to read only yesterday your paper on
the dispersal of the seeds of Compositae. (707/1. "Ueber die
Verbreitungsmittel der Compositenfruchte." "Bot. Zeitung," 1872, page 1.)
Some of the facts which you mention are extremely interesting.

I write now to suggest as worthy of your examination the curious adhesive
filaments of mucus emitted by the achenia of many Compositae, of which no
doubt you are aware. My attention was first called to the subject by the
achenia of an Australian Pumilio (P. argyrolepis), which I briefly
described in the "Gardeners' Chronicle," 1861, page 5. As the threads of
mucus dry and contract they draw the seeds up into a vertical position on
the ground. It subsequently occurred to me that if these seeds were to
fall on the wet hairs of any quadruped they would adhere firmly, and might
be carried to any distance. I was informed that Decaisne has written a
paper on these adhesive threads. What is the meaning of the mucus so
copiously emitted from the moistened seeds of Iberis, and of at least some
species of Linum? Does the mucus serve as a protection against their being
devoured, or as a means of attachment. (707/2. Various theories have been
suggested, e.g., that the slime by anchoring the seed to the soil
facilitates the entrance of the radicle into the soil: the slime has also
been supposed to act as a temporary water-store. See Klebs in Pfeffer's
"Untersuchungen aus dem Bot. Inst. zu Tubingen," I., page 581.) I have
been prevented reading your paper sooner by attempting to read Dr.
Askenasy's pamphlet, but the German is too difficult for me to make it all
out. (707/3. E. Askenasy, "Beitrage zur Kritik der Darwin'schen Lehre."
Leipzig, 1872.) He seems to follow Nageli completely. I cannot but think
that both much underrate the utility of various parts of plants; and that
they greatly underrate the unknown laws of correlated growth, which leads
to all sorts of modifications, when some one structure or the whole plant
is modified for some particular object.

LETTER 708. TO T.H. FARRER. (Lord Farrer).

(708/1. The following letter refers to a series of excellent observations
on the fertilisation of Leguminosae, made by Lord Farrer in the autumn of
1869, in ignorance of Delpino's work on the subject. The result was
published in "Nature," October 10th and 17th, 1872, and is full of
interesting suggestions. The discovery of the mechanism in Coronilla
mentioned in a note was one of the cases in which Lord Farrer was

Down [1872].

I declare I am almost as sorry as if I had been myself forestalled--indeed,
more so, for I am used to it. It is, however, a paramount, though
bothersome duty in every naturalist to try and make out all that has been
done by others on the subject. By all means publish next summer your
confirmation and a summary of Delpino's observations, with any new ones of
your own. Especially attend about the nectary exterior to the staminal
tube. (708/2. This refers to a species of Coronilla in which Lord Farrer
made the remarkable discovery that the nectar is secreted on the outside of
the calyx. See "Nature," July 2nd, 1874, page 169; also Letter 715.) This
will in every way be far better than writing to Delpino. It would not be
at all presumptuous in you to criticise Delpino. I am glad you think him
so clever; for so it struck me.

Look at hind legs yourself of some humble and hive-bees; in former take a
very big individual (if any can be found) for these are the females, the
males being smaller, and they have no pollen-collecting apparatus. I do
not remember where it is figured--probably in Kirby & Spence--but actual
inspection better...

Please do not return any of my books until all are finished, and do not

I feel certain you will make fine discoveries.

LETTER 709. TO T.H. FARRER. (Lord Farrer).
Sevenoaks, October 13th, 1872.

I must send you a line to say how extremely good your article appears to me
to be. It is even better than I thought, and I remember thinking it very
good. I am particularly glad of the excellent summary of evidence about
the common pea, as it will do for me hereafter to quote; nocturnal insects
will not do. I suspect that the aboriginal parent had bluish flowers. I
have seen several times bees visiting common and sweet peas, and yet
varieties, purposely grown close together, hardly ever intercross. This is
a point which for years has half driven me mad, and I have discussed it in
my "Var. of Animals and Plants under Dom." (709/1. In the second edition
(1875) of the "Variation of Animals and Plants," Volume I., page 348,
Darwin added, with respect to the rarity of spontaneous crosses in Pisum:
"I have reason to believe that this is due to their stignas being
prematurely fertilised in this country by pollen from the same flower."
This explanation is, we think, almost certainly applicable to Lathyrus
odoratus, though in Darwin's latest publication on the subject he gives
reasons to the contrary. See "Cross and Self-Fertilisation," page 156,
where the problem is left unsolved. Compare Letter 714 to Delpino. In
"Life and Letters," III., page 261, the absence of cross-fertilisation is
explained as due to want of perfect adaptation between the pea and our
native insects. This is Hermann Muller's view: see his "Fertilisation of
Flowers," page 214. See Letter 583, note.) I now suspect (and I wish I
had strength to experimentise next spring) that from changed climate both
species are prematurely fertilised, and therefore hardly ever cross. When
artificially crossed by removal of own pollen in bud, the offspring are
very vigorous.

Farewell.--I wish I could compel you to go on working at fertilisation
instead of so insignificant a subject as the commerce of the country!

You pay me a very pretty compliment at the beginning of your paper.


(710/1. The following letters to Sir J.D. Hooker and the late Mr.
Moggridge refer to Moggridge's observation that seeds stored in the nest
of the ant Atta at Mentone do not germinate, though they are certainly
not dead. Moggridge's observations are given in his book, "Harvesting
Ants and Trap-Door Spiders," 1873, which is full of interesting details.
The book is moreover remarkable in having resuscitated our knowledge of
the existence of the seed-storing habit. Mr. Moggridge points out that
the ancients were familiar with the facts, and quotes the well-known
fable of the ant and the grasshopper, which La Fontaine borrowed from
Aesop. Mr. Moggridge (page 5) goes on: "So long as Europe was taught
Natural History by southern writers the belief prevailed; but no sooner
did the tide begin to turn, and the current of information to flood from
north to south, than the story became discredited."

In Moggridge's "supplement" on the same subject, published in 1874, the
author gives an account of his experiments made at Darwin's suggestion,
and concludes (page 174) that "the vapour of formic acid is incapable of
rendering the seeds dormant after the manner of the ants," and that
indeed "its influence is always injurious to the seeds, even when
present only in excessively minute quantities." Though unable to
explain the method employed, he was convinced "that the non-germination
of the seeds is due to some direct influence voluntarily exercised by
the ants, and not merely to the conditions found in the nest" (page
172). See Volume I., Letter 251.)

Down, February 21st [1873].

You have given me exactly the information which I wanted.

Geniuses jump. I have just procured formic acid to try whether its
vapour or minute drops will delay germination of fresh seeds; trying
others at same time for comparison. But I shall not be able to try them
till middle of April, as my despotic wife insists on taking a house in
London for a month from the middle of March.

I am glad to hear of the Primer (710/2. "Botany" (Macmillan's Science
Primers).); it is not at all, I think, a folly. Do you know Asa Gray's
child book on the functions of plants, or some such title? It is very
good in giving an interest to the subject.

By the way, can you lend me the January number of the "London Journal of
Botany" for an article on insect-agency in fertilisation?

Down, August 27th, 1873.

I thank you for your very interesting letter, and I honour you for your
laborious and careful experiments. No one knows till he tries how many
unexpected obstacles arise in subjecting plants to experiments.

I can think of no suggestions to make; but I may just mention that I had
intended to try the effects of touching the dampened seeds with the
minutest drop of formic acid at the end of a sharp glass rod, so as to
imitate the possible action of the sting of the ant. I heartily hope
that you may be rewarded by coming to some definite result; but I fail
five times out of six in my own experiments. I have lately been trying
some with poor success, and suppose that I have done too much, for I
have been completely knocked up for some days.

Down, March 10th, 1874.

I am very sorry to hear that the vapour experiments have failed; but
nothing could be better, as it seems to me, than your plan of enclosing
a number of the ants with the seeds. The incidental results on the
power of different vapours in killing seeds and stopping germination
appear very curious, and as far as I know are quite new.

P.S.--I never before heard of seeds not germinating except during a
certain season; it will be a very strange fact if you can prove this.
(712/1. Certain seeds pass through a resting period before germination.
See Pfeffer's "Pflanzenphysiologie," Edition I., Volume II., page III.)

Down, May 30th, 1873.

I am much obliged for your letter received this morning. I write now
chiefly to give myself the pleasure of telling you how cordially I
admire the last part of your book, which I have finished. (713/1. "Die
Befruchtung der Blumen durch Insekten": Leipzig, 1873. An English
translation was published in 1883 by Prof. D'Arcy Thompson. The
"Prefatory Notice" to this work (February 6th, 1882) is almost the last
of Mr. Darwin's writings. See "Life and Letters," page 281.) The whole
discussion seems to me quite excellent, and it has pleased me not a
little to find that in the rough MS. of my last chapter I have arrived
on many points at nearly the same conclusions that you have done, though
we have reached them by different routes. (713/2. "The Effects of
Cross and Self-Fertilisation in the Vegetable Kingdom": London, 1876.)

Down, June 25th [1873].

I thank you sincerely for your letter. I am very glad to hear about
Lathyrus odoratus, for here in England the vars. never cross, and yet
are sometimes visited by bees. (714/1. In "Cross and
Self-Fertilisation," page 156, Darwin quotes the information received
from Delpino and referred to in the present letter--namely, that it is
the fixed opinion of the Italian gardeners that the varieties do
intercross. See Letter 709.) Pisum sativum I have also many times seen
visited by Bombus. I believe the cause of the many vars. not crossing
is that under our climate the flowers are self-fertilised at an early
period, before the corolla is fully expanded. I shall examine this
point with L. odoratus. I have read H. Muller's book, and it seems to
me very good. Your criticism had not occurred to me, but is, I think
just--viz. that it is much more important to know what insects
habitually visit any flower than the various kinds which occasionally
visit it. Have you seen A. Kerner's book "Schutzmittel des Pollens,"
1873, Innsbruck. (714/2. Afterwards translated by Dr. Ogle as "Flowers
and their Unbidden Guests," with a prefatory letter by Charles Darwin,
1878.) It is very interesting, but he does not seem to know anything
about the work of other authors.

I have Bentham's paper in my house, but have not yet had time to read a
word of it. He is a man with very sound judgment, and fully admits the
principle of evolution.

I have lately had occasion to look over again your discussion on
anemophilous plants, and I have again felt much admiration at your work.
(714/3. "Atti della Soc. Italiana di Scienze Nat." Volume XIII.)

(714/4. In the beginning of August, 1873, Darwin paid the first of
several visits to Lord Farrer's house at Abinger. When sending copies
of Darwin's letters for the "Life and Letters," Lord Farrer was good
enough to add explanatory notes and recollections, from which we quote
the following sketch.)

"Above my house are some low hills, standing up in the valley, below the
chalk range on the one hand and the more distant range of Leith Hill on
the other, with pretty views of the valley towards Dorking in one
direction and Guildford in the other. They are composed of the less
fertile Greensand strata, and are covered with fern, broom, gorse, and
heath. Here it was a particular pleasure of his to wander, and his tall
figure, with his broad-brimmed Panama hat and long stick like an
alpenstock, sauntering solitary and slow over our favourite walks, is
one of the pleasantest of the many pleasant associations I have with the

LETTER 715. TO T.H. FARRER (Lord Farrer).

(715/1. The following note by Lord Farrer explains the main point of
the letter, which, however, refers to the "bloom" problem as well as to

"I thought I had found out what puzzled us in Coronilla varia: in most
of the Papilionaceae, when the tenth stamen is free, there is nectar in
the staminal tube, and the opening caused by the free stamen enables the
bee to reach the nectar, and in so doing the bee fertilises the plant.
In Coronilla varia, and in several other species of Coronilla, there is
no nectar in the staminal tube or in the tube of the corolla. But there
are peculiar glands with nectar on the outside of the calyx, and
peculiar openings in the tube of the corolla through which the proboscis
of the bee, whilst entering the flower in the usual way and dusting
itself with pollen, can reach these glands, thus fertilising the plant
in getting the nectar. On writing this to Mr. Darwin, I received the
following characteristic note.

The first postscript relates to the rough ground behind my house, over
which he was fond of strolling. It had been ploughed up and then
allowed to go back, and the interest was to watch how the numerous
species of weeds of cultivation which followed the plough gradually gave
way in the struggle for existence to the well-known and much less varied
flora of an English common.")

Bassett, Southampton, August 14th, 1873.

You are the man to conquer a Coronilla. (715/2. In a former letter to
Lord Farrer, Darwin wrote: "Here is a maxim for you, 'It is disgraceful
to be beaten by a Coronilla.'") I have been looking at the half-dried
flowers, and am prepared to swear that you have solved the mystery. The
difference in the size of the cells on the calyx under the vexillum
right down to the common peduncle is conspicuous. The flour still
adhered to this side; I see little bracteae or stipules apparently with
glandular ends at the base of the calyces. Do these secrete? It seems
to me a beautiful case. When I saw the odd shape of the base of the
vexillum, I concluded that it must have some meaning, but little dreamt
what that was. Now there remains only the one serious point--viz.the
separation of the one stamen. I daresay that you are right in that
nectar was originally secreted within the staminal tube; but why has not
the one stamen long since cohered? The great difference in structure
for fertilisation within the same genus makes one believe that all such
points are vary variable. (715/3. Coronilla emerus is of the ordinary
papilionaceous type.) With respect to the non-coherence of the one
stamen, do examine some flower-buds at a very early age; for parts which
are largely developed are often developed to an unusual degree at a very
early age, and it seems to me quite possible that the base of the
vexillum (to which the single stamen adhered) might thus be developed,
and thus keep it separate for a time from the other stamens. The
cohering stamens to the right and left of the single one seem to me to
be pushed out a little laterally. When you have finished your
observations, you really ought to send an account with a diagram to
"Nature," recalling your generalisation about the diadelphous structure,
and now explaining the exception of Coronilla. (715/4. The
observations were published in "Nature," Volume X., 1874, page 169.)

Do add a remark how almost every detail of structure has a meaning where
a flower is well examined.

Your observations pleased me so much that I could not sit still for half
an hour.

Please to thank Mr. Payne (715/5. Lord Farrer's gardener.) for his
remarks, which are of value to me, with reference to Mimosa. I am very
much in doubt whether opening the sashes can act by favouring the
evaporation of the drops; may not the movement of the leaves shake off
the drops, or change their places? If Mr. Payne remembers any plant
which is easily injured by drops, I wish he would put a drop or two on a
leaf on a bright day, and cover the plant with a clean bell-glass, and
do the same for another plant, but without a bell-glass over it, and
observe the effects.

Thank you much for wishing to see us again at Abinger, and it is very
doubtful whether it will be Coronilla, Mr. Payne, the new garden, the
children, E. [Lady Farrer], or yourself which will give me the most
pleasure to see again.

P.S. 1.--It will be curious to note in how many years the rough ground
becomes quite uniform in its flora.

P.S. 2.--One may feel sure that periodically nectar was secreted within
the flower and then secreted by the calyx, as in some species of Iris
and orchids. This latter being taken advantage of in Coronilla would
allow of the secretion within the flower ceasing, and as this change was
going on in the two secretions, all the parts of the flower would become
modified and correlated.

Down, Tuesday, September 9th [1873].

(716/1. Sir J. Burdon Sanderson showed that in Dionoea movement is
accompanied by electric disturbances closely analogous to those
occurring in muscle (see "Nature," 1874, pages 105, 127; "Proc. R. Soc."
XXI., and "Phil. Trans." Volume CLXXIII., 1883, where the results are
finally discussed).)

I will send up early to-morrow two plants [of Dionoea] with five goodish
leaves, which you will know by their being tied to sticks. Please
remember that the slightest touch, even by a hair, of the three
filaments on each lobe makes the leaf close, and it will not open for
twenty-four hours. You had better put 1/4 in. of water into the saucers
of the pots. The plants have been kept too cool in order to retard
them. You had better keep them rather warm (i.e. temperature of warm
greenhouse) for a day, and in a good light.

I am extremely glad you have undertaken this subject. If you get a
positive result, I should think you ought to publish it separately, and
I could quote it; or I should be most glad to introduce any note by you
into my account.

I have no idea whether it is troublesome to try with the thermo-electric
pile any change of temperature when the leaf closes. I could detect
none with a common thermometer. But if there is any change of
temperature I should expect it would occur some eight to twelve or
twenty-four hours after the leaf has been given a big smashed fly, and
when it is copiously secreting its acid digestive fluid.

I forgot to say that, as far as I can make out, the inferior surface of
the leaf is always in a state of tension, and that the contraction is
confined to the upper surface; so that when this contraction ceases or
suddenly fails (as by immersion in boiling water) the leaf opens again,
or more widely than is natural to it.

Whenever you have quite finished, I will send for the plants in their
basket. My son Frank is staying at 6, Queen Anne Street, and comes home
on Saturday afternoon, but you will not have finished by that time.

P.S. I have repeated my experiment on digestion in Drosera with
complete success. By giving leaves a very little weak hydrochloric
acid, I can make them digest albumen--i.e. white of egg--quicker than
they can do naturally. I most heartily thank you for all your kindness.
I have been pretty bad lately, and must work very little.

September 13th [1873].

How very kind it was of you to telegraph to me. I am quite delighted
that you have got a decided result. Is it not a very remarkable fact?
It seems so to me, in my ignorance. I wish I could remember more
distinctly what I formerly read of Du Bois Raymond's results. My poor
memory never serves me for more than a vague guide. I really think you
ought to try Drosera. In a weak solution of phosphate of ammonia (viz.
1 gr. to 20 oz. of water) it will contract in about five minutes, and
even more quickly in pure warm water; but then water, I suppose, would
prevent your trial. I forget, but I think it contracts pretty quickly
(i.e. in an hour or two) with a large drop of a rather stronger solution
of the phosphate, or with an atom of raw meat on the disc of the leaf.

October 31st, 1873.

Now I want to tell you, for my own pleasure, about the movements of

1. When the plant goes to sleep, the terminal leaflets hang vertically
down, but the petioles move up towards the axis, so that the dependent
leaves are all crowded round it. The little leaflets never go to sleep,
and this seems to me very odd; they are at their games of play as late
as 11 o'clock at night and probably later. (718/1. Stahl ("Botanische
Zeitung," 1897, page 97) has suggested that the movements of the dwarf
leaflets in Desmodium serve to shake the large terminal leaflets, and
thus increase transpiration. According to Stahl's view their movement
would be more useful at night than by day, because stagnation of the
transpiration-current is more likely to occur at night.)

2. If the plant is shaken or syringed with tepid water, the terminal
leaflets move down through about an angle of 45 deg, and the petioles
likewise move about 11 deg downwards; so that they move in an opposite
direction to what they do when they go to sleep. Cold water or air
produces the same effect as does shaking. The little leaflets are not
in the least affected by the plant being shaken or syringed. I have no
doubt, from various facts, that the downward movement of the terminal
leaflets and petioles from shaking and syringing is to save them from
injury from warm rain.

3. The axis, the main petiole, and the terminal leaflets are all, when
the temperature is high, in constant movement, just like that of
climbing plants. This movement seems to be of no service, any more than
the incessant movement of amoeboid bodies. The movement of the terminal
leaflets, though insensible to the eye, is exactly the same as that of
the little lateral leaflets--viz. from side to side, up and down, and
half round their own axes. The only difference is that the little
leaflets move to a much greater extent, and perhaps more rapidly; and
they are excited into movement by warm water, which is not the case with
the terminal leaflet. Why the little leaflets, which are rudimentary in
size and have lost their sleep-movements and their movements from being
shaken, should not only have retained, but have their spontaneous
movements exaggerated, I cannot conceive. It is hardly credible that it
is a case of compensation. All this makes me very anxious to examine
some plant (if possible one of the Leguminosae) with either the terminal
or lateral leaflets greatly reduced in size, in comparison with the
other leaflets on the same leaf. Can you or any of your colleagues
think of any such plant? It is indirectly on this account that I so
much want the seeds of Lathyrus nissolia.

I hear from Frank that you think that the absence of both lateral
leaflets, or of one alone, is due to their having dropped off; I thought
so at first, and examined extremely young leaves from the tips of the
shoots, and some of them presented the same characters. Some
appearances make me think that they abort by becoming confluent with the
main petiole.

I hear also that you doubt about the little leaflets ever standing not
opposite to each other: pray look at the enclosed old leaf which has
been for a time in spirits, and can you call the little leaflets
opposite? I have seen many such cases on both my plants, though few so
well marked.

Down, October 23rd [1873].

How good you have been about the plants; but indeed I did not intend you
to write about Drosophyllum, though I shall be very glad to have a
specimen. Experiments on other plants lead to fresh experiments.
Neptunia is evidently a hopeless case. I shall be very glad of the
other plants whenever they are ready. I constantly fear that I shall
become to you a giant of bores.

I am delighted to hear that you are at work on Nepenthes, and I hope
that you will have good luck. It is good news that the fluid is acid;
you ought to collect a good lot and have the acid analysed. I hope that
the work will give you as much pleasure as analogous work has me.
(719/1. Hooker's work on Nepenthes is referred to in "Insectivorous
Plants," page 97: see also his address at the Belfast meeting of the
British Association, 1874.) I do not think any discovery gave me more
pleasure than proving a true act of digestion in Drosera.

Down, November 24th, 1873.

I have been greatly interested by Mimosa albida, on which I have been
working hard. Whilst your memory is pretty fresh, I want to ask a
question. When this plant was most sensitive, and you irritated it, did
the opposite leaflets shut up quite close, as occurs during sleep, when
even a lancet could not be inserted between the leaflets? I can never
cause the leaflets to come into contact, and some reasons make me doubt
whether they ever do so except during sleep; and this makes me wish much
to hear from you. I grieve to say that the plant looks more unhealthy,
even, than it was at Kew. I have nursed it like the tenderest infant;
but I was forced to cut off one leaf to try the bloom, and one was
broken by the manner of packing. I have never syringed (with tepid
water) more than one leaf per day; but if it dies, I shall feel like a
murderer. I am pretty well convinced that I shall make out my case of
movements as a protection against rain lodging on the leaves. As far as
I have as yet made out, M. albida is a splendid case.

I have had no time to examine more than one species of Eucalyptus. The
seedlings of Lathyrus nissolia are very interesting to me; and there is
something wonderful about them, unless seeds of two distinct leguminous
species have got somehow mingled together.

Down, December 4th, 1873.

As Hooker is so busy, I should be very much obliged if you could give me
the name of the enclosed poor specimen of Cassia. I want much to know
its name, as its power of movement, when it goes to sleep, is very
remarkable. Linnaeus, I find, was aware of this. It twists each
separate leaflet almost completely round (721/1. See "Power of Movement
in Plants," Figure 154, page 370.), so that the lower surface faces the
sky, at the same time depressing them all. The terminal leaflets are
pointed towards the base of the leaf. The whole leaf is also raised up
about 12 deg. When I saw that it possessed such complex powers of
movement, I thought it would utilise its power to protect the leaflets
from rain. Accordingly I syringed the plant for two minutes, and it was
really beautiful to see how each leaflet on the younger leaves twisted
its short sub-petiole, so that the blade was immediately directed at an
angle between 45 and 90 deg to the horizon. I could not resist the
pleasure of just telling you why I want to know the name of the Cassia.
I should add that it is a greenhouse plant. I suppose that there will
not be any better flowers till next summer or autumn.


(722/1. Belt's account, discussed in this letter, is probably that
published in his "Naturalist in Nicaragua" (1874), where he describes
"the relation between the presence of honey-secreting glands on plants,
and the protection to the latter secured by the attendance of ants
attracted by the honey." (Op. cit., pages 222 et seq.))

Thursday [1874?].

Your account of the ants and their relations seems to me to possess
extraordinary interest. I do not doubt that the excretion of sweet
fluid by the glands is in your cases of great advantage to the plants by
means of the ants, but I cannot avoid believing that primordially it is
a simple excretion, as occasionally occurs from the surface of the
leaves of lime trees. It is quite possible that the primordial
excretion may have been beneficially increased to serve the plant. In
the common laurel [Prunus laurocerasus] of our gardens the hive-bees
visit incessantly the glands of the young leaves, on their under sides;
and I should altogether doubt whether their visits or the occasional
visits of ants was of any service to the laurel. The stipules of the
common vetch secrete largely during sunshine, and hive-bees collect the
sweet fluid. So I think it is with the common bean.

I am writing this away from home, and I have come away to get some rest,
having been a good deal overworked. I shall read your book with great
interest when published, but will not trouble you to send the MS., as I
really have no spare strength or time. I believe that your book,
judging by the chapter sent, will be extremely valuable.


(723/1. The following letter refers to Darwin's prediction as to the
manner in which Hedychium (Zinziberaceae) is fertilised. Sir J.D.
Hooker seems to have made inquiries in India in consequence of which
Darwin received specimens of the moth which there visits the flower,
unfortunately so much broken as to be useless (see "Life and Letters,"
III., page 284).)

Down, March 25th [1874].

I am glad to hear about the Hedychium, and how soon you have got an
answer! I hope that the wings of the Sphinx will hereafter prove to be
bedaubed with pollen, for the case will then prove a fine bit of
prophecy from the structure of a flower to special and new means of

By the way, I suppose you have noticed what a grand appearance the plant
makes when the green capsules open, and display the orange and crimson
seeds and interior, so as to attract birds, like the pale buff flowers
to attract dusk-flying lepidoptera. I presume you do not want seeds of
this plant, as I have plenty from artificial fertilisation.

(723/2. In "Nature," June 22nd, 1876, page 173, Hermann Muller
communicated F. Muller's observation on the fertilisation of a
bright-red-flowered species of Hedychium, which is visited by
Callidryas, chiefly the males of C. Philea. The pollen is carried by
the tips of the butterfly's wing, to which it is temporarily fixed by
the slimy layer produced by the degeneration of the anther-wall.

Down, June 4th [1874].

I am greatly obliged to you about the Opuntia, and shall be glad if you
can remember Catalpa. I wish some facts on the action of water, because
I have been so surprised at a stream not acting on Dionoea and Drosera.
(724/1. See Pfeffer, "Untersuchungen Bot. Inst. zu Tubingen," Bd. I.,
1885, page 518. Pfeffer shows that in some cases--Drosera, for
instance--water produces movement only when it contains fine particles
in suspension. According to Pfeffer the stamens of Berberis, and the
stigma of Mimulus, are both stimulated by gelatine, the action of which
is, generally speaking, equivalent to that of water.) Water does not
act on the stamens of Berberis, but it does on the stigma of Mimulus.
It causes the flowers of the bedding-out Mesembryanthemum and Drosera to
close, but it has not this effect on Gazania and the daisy, so I can
make out no rule.

I hope you are going on with Nepenthes; and if so, you will perhaps like
to hear that I have just found out that Pinguicula can digest albumen,
gelatine, etc. If a bit of glass or wood is placed on a leaf, the
secretion is not increased; but if an insect or animal-matter is thus
placed, the secretion is greatly increased and becomes feebly acid,
which was not the case before. I have been astonished and much
disturbed by finding that cabbage seeds excite a copious secretion, and
am now endeavouring to discover what this means. (724/2. Clearly it
had not occurred to Darwin that seeds may supply nitrogenous food as
well as insects: see "Insectivorous Plants," page 390.) Probably in a
few days' time I shall have to beg a little information from you, so I
will write no more now.

P.S. I heard from Asa Gray a week ago, and he tells me a beautiful
fact: not only does the lid of Sarracenia secrete a sweet fluid, but
there is a line or trail of sweet exudation down to the ground so as to
tempt insects up. (724/3. A dried specimen of Sarracenia, stuffed with
cotton wool, was sometimes brought from his study by Mr. Darwin, and
made the subject of a little lecture to visitors of natural history

Down, June 23rd, 1874.

I wrote to you about a week ago, thanking you for information on cabbage
seeds, asking you the name of Luzula or Carex, and on some other points;
and I hope before very long to receive an answer. You must now, if you
can, forgive me for being very troublesome, for I am in that state in
which I would sacrifice friend or foe. I have ascertained that bits of
certain leaves, for instance spinach, excite much secretion in
Pinguicula, and that the glands absorb matter from the leaves. Now this
morning I have received a lot of leaves from my future daughter-in-law
in North Wales, having a surprising number of captured insects on them,
a good many leaves, and two seed-capsules. She informs me that the
little leaves had excited secretion; and my son and I have ascertained
this morning that the protoplasm in the glands beneath the little leaves
has undoubtedly undergone aggregation. Therefore, absurd as it may
sound, I am prepared to affirm that Pinguicula is not only
insectivorous, but graminivorous, and granivorous! Now I want to beg
you to look under the simple microscope at the enclosed leaves and
seeds, and, if you possibly can, tell me their genera. The little
narrow leaves are remarkable (725/1. Those of Erica tetralix.); they
are fleshy, with the edges much curled from the axis of the plant, and
bear a few long glandular hairs; these grow in little tufts. These are
the commonest in Pinguicula, and seem to afford most nutritious matter.
A second leaf is like a miniature sycamore. With respect to the seeds,
I suppose that one is a Carex; the other looks like that of Rumex, but
is enclosed in a globular capsule. The Pinguicula grew on marshy, low,
mountainous land.

I hope you will think this subject sufficiently interesting to make you
willing to aid me as far as you can. Anyhow, forgive me for being so
very troublesome.

Down, August 30th [1874].

I am particularly obliged for your address. (726/1. Presidential
address (Biological Section) at the Belfast meeting of the British
Association, 1874.) It strikes me as quite excellent, and has
interested me in the highest degree. Nor is this due to my having
worked at the subject, for I feel sure that I should have been just as
much struck, perhaps more so, if I had known nothing about it. You
could not, in my opinion, have put the case better. There are several
lights (besides the facts) in your essay new to me, and you have greatly
honoured me. I heartily congratulate you on so splendid a piece of
work. There is a misprint at page 7, Mitschke for Nitschke. There is a
partial error at page 8, where you say that Drosera is nearly
indifferent to organic substances. This is much too strong, though they
do act less efficiently than organic with soluble nitrogenous matter;
but the chief difference is in the widely different period of subsequent
re-expansion. Thirdly, I did not suggest to Sanderson his electrical
experiments, though, no doubt, my remarks led to his thinking of them.

Now for your letter: you are very generous about Dionoea, but some of
my experiments will require cutting off leaves, and therefore injuring
plants. I could not write to Lady Dorothy [Nevill]. Rollisson says
that they expect soon a lot from America. If Dionoea is not despatched,
have marked on address, "to be forwarded by foot-messenger."

Mrs. Barber's paper is very curious, and ought to be published (726/2.
Mrs. Barber's paper on the pupa of Papilio Nireus assuming different
tints corresponding to the objects to which it was attached, was
communicated by Mr. Darwin to the "Trans. Entomolog. Soc." 1874.); but
when you come here (and REMEMBER YOU OFFERED TO COME) we will consult
where to send it. Let me hear when you recommence on Cephalotus or
Sarracenia, as I think I am now on right track about Utricularia, after
wasting several weeks in fruitless trials and observations. The
negative work takes five times more time than the positive.

Down, September 18th [1874].

I have had a splendid day's work, and must tell you about it.

Lady Dorothy sent me a young plant of U[tricularia] montana (727/1. See
"Life and Letters," III., page 327, and "Insectivorous Plants," page
431.), which I fancy is the species you told me of. The roots or
rhizomes (for I know not which they are; I can see no scales or
internodes or absorbent hairs) bear scores of bladders from 1/20 to
1/100 of an inch in diameter; and I traced these roots to the depth of 1
1/2 in. in the peat and sand. The bladders are like glass, and have the
same essential structure as those of our species, with the exception
that many exterior parts are aborted. Internally the structure is
perfect, as is the minute valvular opening into the bladder, which is
filled with water. I then felt sure that they captured subterranean
insects, and after a time I found two with decayed remnants, with clear
proof that something had been absorbed, which had generated protoplasm.
When you are here I shall be very curious to know whether they are roots
or rhizomes.

Besides the bladders there are great tuber-like swellings on the
rhizomes; one was an inch in length and half in breadth. I suppose
these must have been described. I strongly suspect that they serve as
reservoirs for water. (727/2. The existence of water-stores is quite in
accordance with the epiphytic habit of the plant.) But I shall
experimentise on this head. A thin slice is a beautiful object, and
looks like coarsely reticulated glass.

If you have an old plant which could be turned out of its pot (and can
spare the time), it would be a great gain to me if you would tear off a
bit of the roots near the bottom, and shake them well in water, and see
whether they bear these minute glass-like bladders. I should also much
like to know whether old plants bear the solid bladder-like bodies near
the upper surface of the pot. These bodies are evidently enlargements
of the roots or rhizomes. You must forgive this long letter, and make
allowance for my delight at finding this new sub-group of
insect-catchers. Sir E. Tennent speaks of an aquatic species of
Utricularia in Ceylon, which has bladders on its roots, and rises
annually to the surface, as he says, by this means. (727/3.
Utricularia stellaris. Emerson Tennent's "Ceylon," Volume I., page 124,

We shall be delighted to see you here on the 26th; if you will let us
know your train we will send to meet you. You will have to work like a
slave while you are here.


(728/1. In 1870 Mr. Jenner Weir wrote to Darwin: "My brother has but
two kinds of laburnum, viz., Cytisus purpureus, very erect, and Cytisus
alpinus, very pendulous. He has several stocks of the latter grafted
with the purple one; and this year, the grafts being two years old, I
saw in one, fairly above the stock, about four inches, a raceme of
purely yellow flowers with the usual dark markings, and above them a
bunch of purely purple flowers; the branches of the graft in no way
showed an intermediate character, but had the usual rigid growth of

Early in July 1875, when Darwin was correcting a new edition of
"Variation under Domestication," he again corresponded with Mr. Weir on
the subject.)

Down, July 8th [1875].

I thank you cordially. The case interests me in a higher degree than
anything which I have heard for a very long time. Is it your brother
Harrison W., whom I know? I should like to hear where the garden is.
There is one other very important point which I am most anxious to
hear--viz., the nature of the leaves at the base of the yellow racemes,
for leaves are always there produced with the yellow laburnums, and I
suppose so in the case of C. purpureus. As the tree has produced yellow
racemes several times, do you think you could ask your brother to cut
off and send me by post in a box a small branch of the purple stock with
the pods or leaves of the yellow sport? (728/2. "The purple stock"
here means the supposed C. purpureus, on which a yellow-flowered branch
was borne.) This would be an immense favour, for then I would cut the
point of junction longitudinally and examine slice under the microscope,
to be able to state no trace of bud of yellow kind having been inserted.
I do not suspect anything of the kind, but it is sure to be said that
your brother's gardener, either by accident or fraud, inserted a bud.
Under this point of view it would be very good to gather from your
brother how many times the yellow sport has appeared. The case appears
to me so very important as to be worth any trouble. Very many thanks
for all assistance so kindly given.

I will of course send a copy of new edition of "Variation under
Domestication" when published in the autumn.


(729/1. On July 9th Mr. Weir wrote to say that a branch of the Cytisus
had been despatched to Down. The present letter was doubtless written
after Darwin had examined the specimen. In "Variation under
Domestication," Edition II., Volume I., page 417, note, he gives for a
case recorded in the "Gardeners' Chronicle" in 1857 the explanation here
offered (viz. that the graft was not C. purpureus but C. Adami), and
adds, "I have ascertained that this occurred in another instance." This
second instance is doubtless Mr. Weir's.)

Down, July 10th, 1875.

I do not know how to thank you enough; pray give also my thanks and kind
remembrances to your brother. I am sure you will forgive my expressing
my doubts freely, as I well know that you desire the truth more than
anything else. I cannot avoid the belief that some nurseryman has sold
C[ytisus] Adami to your brother in place of the true C. purpureus. The
latter is a little bush only 3 feet high (Loudon), and when I read your
account, it seemed to me a physical impossibility that a sporting branch
of C. alpinus could grow to any size and be supported on the extremely
delicate branches of C. purpureus. If I understand rightly your letter,
you consider the tuft of small shoots on one side of the sporting C.
alpinus from Weirleigh as C. purpureus; but these shoots are certainly
those of C. Adami. I earnestly beg you to look at the specimens
enclosed. The branch of the true C. purpureus is the largest which I
could find. If C. Adami was sold to your brother as C. purpureus,
everything is explained; for then the gardener has grafted C. Adami on
C. alpinus, and the former has sported in the usual manner; but has not
sported into C. purpureus, only into C. alpinus. C. Adami does not
sport less frequently into C. purpureus than into C. alpinus. Are the
purple flowers borne on moderately long racemes? If so, the plant is
certainly C. Adami, for the true C. purpureus bears flowers close to the
branches. I am very sorry to be so troublesome, but I am very anxious
to hear again from you.

C. purpureus bears "flowers axillary, solitary, stalked."

P.S.--I think you said that the purple [tree] at Weirleigh does not
seed, whereas the C. purpureus seeds freely, as you may see in enclosed.
C. Adami never produces seeds or pods.


(730/1. The following extract refers to Darwin's book on "Cross and

November 13th, 1875.

I am now busy in drawing up an account of ten years' experiments in the
growth and fertility of plants raised from crossed and self-fertilised
flowers. It is really wonderful what an effect pollen from a distinct
seedling plant, which has been exposed to different conditions of life,
has on the offspring in comparison with pollen from the same flower or
from a distinct individual, but which has been long subjected to the
same conditions. The subject bears on the very principle of life, which
seems almost to require changes in the conditions.


(731/1. The following extract from a letter to Romanes refers to
Francis Darwin's paper, "Experiments on the Nutrition of Drosera
rotundifolia." "Linn. Soc. Journ." [1878], published 1880, page 17.)

August 9th [1876].

The second point which delights me, seeing that half a score of
botanists throughout Europe have published that the digestion of meat by
plants is of no use to them (a mere pathological phenomenon, as one man
says!), is that Frank has been feeding under exactly similar conditions
a large number of plants of Drosera, and the effect is wonderful. On
the fed side the leaves are much larger, differently coloured, and more
numerous; flower-stalks taller and more numerous, and I believe far more
seed capsules,--but these not yet counted. It is particularly
interesting that the leaves fed on meat contain very many more starch
granules (no doubt owing to more protoplasm being first formed); so that
sections stained with iodine, of fed and unfed leaves, are to the naked
eye of very different colours.

There, I have boasted to my heart's content, and do you do the same, and
tell me what you have been doing.

Down, October 25th [1876].

If you can put the following request into any one's hands pray do so;
but if not, ignore my request, as I know how busy you are.

I want any and all plants of Hoya examined to see if any imperfect
flowers like the one enclosed can be found, and if so to send them to
me, per post, damp. But I especially want them as young as possible.

They are very curious. I have examined some sent me from Abinger
(732/1. Lord Farrer's house.), but they were a month or two too old,
and every trace of pollen and anthers had disappeared or had never been
developed. Yet a very fine pod with apparently good seed had been
formed by one such flower. (732/2. The seeds did not germinate; see
the account of Hoya carnosa in "Forms of Flowers," page 331.)


(733/1. Published in the "Life of Romanes," page 62.)

Down, August 10th [1877].

When I went yesterday I had not received to-day's "Nature," and I
thought that your lecture was finished. (733/2. Abstract of a lecture
on "Evolution of Nerves and Nervo-Systems," delivered at the Royal
Institution, May 25th, 1877. "Nature," July 19th, August 2nd, August
9th, 1877.) This final part is one of the grandest essays which I ever

It was very foolish of me to demur to your lines of conveyance like the
threads in muslin (733/3. "Nature," August 2nd, page 271.), knowing how
you have considered the subject: but still I must confess I cannot feel
quite easy. Everyone, I suppose, thinks on what he has himself seen,
and with Drosera, a bit of meat put on any one gland on its disc causes
all the surrounding tentacles to bend to this point, and here there can
hardly be differentiated lines of conveyance. It seems to me that the
tentacles probably bend to that point wherever a molecular wave strikes
them, which passes through the cellular tissue with equal ease in all
directions in this particular case. (733/4. Speaking generally, the
transmission takes place more readily in the longitudinal direction than
across the leaf: see "Insectivorous Plants," page 239.) But what a
fine case that of the Aurelia is! (733/5. Aurelia aurita, one of the
medusae. "Nature," pages 269-71.)

6, Queen Anne Street [December 1876].

Tell Hooker I feel greatly aggrieved by him: I went to the Royal
Society to see him for once in the chair of the Royal, to admire his
dignity and enjoy it, and lo and behold, he was not there. My outing
gave me much satisfaction, and I was particularly glad to see Mr.
Bentham, and to see him looking so wonderfully well and young. I saw
lots of people, and it has not done me a penny's worth of harm, though I
could not get to sleep till nearly four o'clock.

Down, October, 13th [1876?].

You must be a clair-voyant or something of that kind to have sent me
such useful plants. Twenty-five years ago I described in my father's
garden two forms of Linum flavum (thinking it a case of mere variation);
from that day to this I have several times looked, but never saw the
second form till it arrived from Kew. Virtue is never its own reward:
I took paper this summer to write to you to ask you to send me flowers,
[so] that I might beg plants of this Linum, if you had the other form,
and refrained, from not wishing to trouble you. But I am now sorry I
did, for I have hardly any doubt that L. flavum never seeds in any
garden that I have seen, because one form alone is cultivated by slips.
(735/1. Id est, because, the plant being grown from slips, one form
alone usually occurs in any one garden. It is also arguable that it is
grown by slips because only one form is common, and therefore seedlings
cannot be raised.)

(736/1. The following five letters refer to Darwin's work on "bloom"--a
subject on which he did not live to complete his researches:--

One of his earliest letters on this subject was addressed in August,
1873, to Sir Joseph Hooker (736/2. Published in "Life and Letters,"
III., page 339.):

"I want a little information from you, and if you do not yourself know,
please to enquire of some of the wise men of Kew.

"Why are the leaves and fruit of so many plants protected by a thin
layer of waxy matter (like the common cabbage), or with fine hair, so
that when such leaves or fruit are immersed in water they appear as if
encased in thin glass? It is really a pretty sight to put a pod of the
common pea, or a raspberry, into water. I find several leaves are thus
protected on the under surface and not on the upper.

"How can water injure the leaves, if indeed this is at all the case?"

On this latter point Darwin wrote to the late Lord Farrer:

"I am now become mad about drops of water injuring leaves. Please ask
Mr. Payne (736/3. Lord Farrer's gardener.) whether he believes, FROM
HIS OWN EXPERIENCE, that drops of water injure leaves or fruit in his
conservatories. It is said that the drops act as burning-glasses; if
this is true, they would not be at all injurious on cloudy days. As he
is so acute a man, I should very much like to hear his opinion. I
remember when I grew hothouse orchids I was cautioned not to wet their
leaves; but I never then thought on the subject."

The next letter, though of later date than some which follow it, is
printed here because it briefly sums his results and serves as guide to
the letters dealing with the subject.)


(736/4. Published in "Life and Letters," III., page 341.)

Down, September 5th [1877].

One word to thank you. I declare, had it not been for your kindness, we
should have broken down. As it is we have made out clearly that with
some plants (chiefly succulent) the bloom checks evaporation--with some
certainly prevents attacks of insects; with SOME sea-shore plants
prevents injury from salt water, and, I believe, with a few prevents
injury from pure water resting on the leaves. This latter is as yet the
most doubtful and the most interesting point in relation to the
movements of plants.

(736/5. Modern research, especially that of Stahl on transpiration
("Bot. Zeitung," 1897, page 71) has shown that the question is more
complex than it appeared in 1877. Stahl's point of view is that
moisture remaining on a leaf checks the transpiration-current; and by
thus diminishing the flow of mineral nutriment interferes with the
process of assimilation. Stahl's idea is doubtless applicable to the
whole problem of bloom on leaves. For other references to bloom see
letters 685, 689 and 693.)

Down, August 19th, 1873.

The next time you walk round the garden ask Mr. Smith (737/1. Probably
John Smith (1798-1888), for some years Curator, Royal Gardens, Kew.), or
any of your best men, what they think about injury from watering during
sunshine. One of your men--viz., Mr. Payne, at Abinger, who seems very
acute--declares that you may water safely any plant out of doors in
sunshine, and that you may do the same for plants under glass if the
sashes are opened. This seems to me very odd, but he seems positive on
the point, and acts on it in raising splendid grapes. Another good
gardener maintains that it is only COLD water dripping often on the same
point of a leaf that ever injures it. I am utterly perplexed, but
interested on the point. Give me what you learn when you come to Down.

I should like to hear what plants are believed to be most injured by
being watered in sunshine, so that I might get such.

I expect that I shall be utterly beaten, as on so many other points; but
I intend to make a few experiments and observations. I have already
convinced myself that drops of water do NOT act as burning lenses.

December 20th [1873].

I find that it is no use going on with my experiments on the evil
effects of water on bloom-divested leaves. Either I erred in the early
autumn or summer in some incomprehensible manner, or, as I suspect to be
the case, water is only injurious to leaves when there is a good supply
of actinic rays. I cannot believe that I am all in the wrong about the
movements of the leaves to shoot off water.

The upshot of all this is that I want to keep all the plants from Kew
until the spring or early summer, as it is mere waste of time going on
at present.

Down, July 22nd [1877].

Many thanks for seeds of the Malva and information about Averrhoa, which
I perceived was sensitive, as A. carambola is said to be; and about
Mimosa sensitiva. The log-wood [Haematoxylon] has interested me much.
The wax is very easily removed, especially from the older leaves, and I
found after squirting on the leaves with water at 95 deg, all the older
leaves became coated, after forty-eight hours, in an astonishing manner
with a black Uredo, so that they looked as if sprinkled with soot and
water. But not one of the younger leaves was affected. This has set me
to work to see whether the "bloom" is not a protection against
parasites. As soon as I have ascertained a little more about the case
(and generally I am quite wrong at first) I will ask whether I could
have a very small plant, which should never be syringed with water above
60 deg, and then I suspect the leaves would not be spotted, as were the
older ones on the plant, when it arrived from Kew, but nothing like what
they were after my squirting.

In an old note of yours (which I have just found) you say that you have
a sensitive Schrankia: could this be lent me?

I have had lent me a young Coral-tree (Erythrina), which is very sickly,
yet shows odd sleep movements. I suppose I could buy one, but Hooker
told me first to ask you for anything.

Lastly, have you any seaside plants with bloom? I find that drops of
sea-water corrode sea-kale if bloom is removed; also the var. littorum
of Triticum repens. (By the way, my plants of the latter, grown in pots
here, are now throwing up long flexible green blades, and it is very odd
to see, ON THE SAME CULM, the rigid grey bloom-covered blades and the
green flexible ones.) Cabbages, ill-luck to them, do not seem to be
hurt by salt water. Hooker formerly told me that Salsola kali, a var.
of Salicornia, one species of Suaeda, Euphorbia peplis, Lathyrus
maritimus, Eryngium maritimum, were all glaucous and seaside plants. It
is very improbable that you have any of these or of foreigners with the
same attributes.

God forgive me: I hope that I have not bored you greatly.

By all the rules of right the leaves of the logwood ought to move (as if
partially going to sleep) when syringed with tepid water. The leaves of
my little plant do not move at all, and it occurs to me as possible,
though very improbable, that it would be different with a larger plant
with perhaps larger leaves. Would you some day get a gardener to
syringe violently, with water kept in a hothouse, a branch on one of
your largest logwood plants and observe [whether?] leaves move together
towards the apex of leaf?

By the way, what astonishing nonsense Mr. Andrew Murray has been writing
about leaves and carbonic acid! I like to see a man behaving

What a lot I have scribbled to you!

(FIGURE 13. Leaf of Trifolium resupinatum (from a drawing by Miss

[August, 1877.]

There is no end to my requests. Can you spare me a good plant (or even
two) of Oxalis sensitiva? The one which I have (formerly from Kew) has
been so maltreated that I dare not trust my results any longer.

Please give the enclosed to Mr. Lynch. (740/1. Mr. Lynch, now Curator
of the Cambridge Botanic Garden, was at this time in the R. Bot. Garden,
Kew. Mr. Lynch described the movements of Averrhoa bilimbi in the
"Linn. Soc. Journ," Volume XVI., page 231. See also "The Power of
Movement in Plants," page 330.) The spontaneous movements of the
Averrhoa are very curious.

You sent me seeds of Trifolium resupinatum, and I have raised plants,
and some former observations which I did not dare to trust have proved
accurate. It is a very little fact, but curious. The half of the
lateral leaflets (marked by a cross) on the lower side have no bloom and
are wetted, whereas the other half has bloom and is not wetted, so that
the two sides look different to the naked eye. The cells of the
eipdermis appear of a different shape and size on the two sides of the
leaf [Figure 13].

When we have drawings and measurements of cells made, and are sure of
our facts, I shall ask you whether you know of any case of the same leaf
differing histologically on the two sides, for Hooker always says you
are a wonderful man for knowing what has been made out.

(740/2. The biological meaning of the curious structure of the leaves
of Trifolium resupinatum remains a riddle. The stomata and (speaking
from memory) the trichomes differ on the two halves of the lateral


(741/1. Professor L. Errera, of Brussels wrote, as a student, to
Darwin, asking permission to send the MS. of an essay by his friend S.
Gevaert and himself on cross and self-fertilisation, and which was
afterwards published in the "Bull. Soc. Bot. Belg." XVII., 1878. The
terms xenogamy, geitonogamy, and autogamy were first suggested by Kerner
in 1876; their definition will be found at page 9 of Ogle's translation
of Kerner's "Flowers and their Unbidden Guests," 1878. In xenogamy the
pollen comes from another PLANT; in geitonogamy from another FLOWER on
the same PLANT; in autogamy from the androecium of the fertilised
FLOWER. Allogamy embraces xenogamy and geitonogamy.)

Down, October 4th, 1877.

I have now read your MS. The whole has interested me greatly, and is
very clearly written. I wish that I had used some such terms as
autogamy, xenogamy, etc...I entirely agree with you on the a priori
probability of geitonogamy being more advantageous than autogamy; and I
cannot remember having ever expressed a belief that autogamy, as a
general rule, was better than geitonogamy; but the cases recorded by me
seem too strong not to make me suspect that there was some unknown
advantage in autogamy. In one place I insert the caution "if this be
really the case," which you quote. (741/2. See "Cross and
Self-Fertilisation," pages 352, 386. The phrase referred to occurs in
both passages; that on page 386 is as follows: "We have also seen
reason to suspect that self-fertilisation is in some peculiar manner
beneficial to certain plants; but if this be really the case, the
benefit thus derived is far more than counterbalanced by a cross with a
fresh stock or with a slightly different variety." Errera and Gevaert
conclude (pages 79-80) that the balance of the available evidence is in
favour of the belief that geitonogamy is intermediate, in effectiveness,
between autogamy and xenogamy.) I shall be very glad to be proved to be
altogether in error on this point.

Accept my thanks for pointing out the bad erratum at page 301. I hope
that you will experimentise on inconspicuous flowers (741/3. See Miss
Bateson, "Annals of Botany," 1888, page 255, "On the Cross-Fertilisation
of Inconspicuous Flowers:" Miss Bateson showed that Senecio vulgaris
clearly profits by cross-fertilisation; Stellaria media and Capsella
bursa-pastoris less certainly.); if I were not too old and too much
occupied I would do so myself.

Finally let me thank you for the kind manner in which you refer to my
work, and with cordial good wishes for your success...

Down, October 9th, 1877.

One line to thank you much about Mertensia. The former plant has begun
to make new leaves, to my great surprise, so that I shall be now well
supplied. We have worked so well with the Averrhoa that unless the
second species arrives in a very good state it would be superfluous to
send it. I am heartily glad that you and Mrs. Dyer are going to have a
holiday. I will look at you as a dead man for the next month, and
nothing shall tempt me to trouble you. But before you enter your grave
aid me if you can. I want