Freshwater, Isle of Wight. August 19, 1868.
My dear Wallace,—Thanks for your note. I did sometimes think of going to Norwich, for I should have very much liked it, but it has been quite out of the question. We have been here for five weeks for a change, and it has done me some little good; but I have been forced to live the life of a drone, and for a month before leaving home I was unable to do anything and had to stop all work.
We return to Down to-morrow.
Hooker has been here for two or three days, so that I [pg 220]have had much talk about his Address. I am glad that you will be there.
It is real good news that your book is so advanced that you are negotiating about its publication.
With respect to dimorphic plants: it is a great puzzle, but I fancy I partially see my way—too long for a letter and too speculative for publication. The groundwork of the acquirement of such peculiar fertility (for what you say about any other distinct individual being, as it would appear, sufficient, is very true) rests on the stamens and pistil having varied first in relative length, as actually occurs irrespective of dimorphism, and the peculiar kind of fertility characteristic of dimorphic and the trimorphic plants having been secondarily acquired. Pangenesis makes very few converts: G.H. Lewes is one.
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 further 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 extraordinarily good days.—Believe me, my dear Wallace, ever yours sincerely,
CH. DARWIN.
[pg 221]9 St. Mark's Crescent. August 30, [1868?].
Dear Darwin,—I was very sorry to hear you had been so unwell again, and hope you will not exert yourself to write me such long letters. Darwinianism was in the ascendant at Norwich (I hope you do not dislike the word, for we really must use it), and I think it rather disgusted some of the parsons, joined with the amount of advice they received from Hooker and Huxley. The worst of it is that there are no opponents left who know anything of natural history, so that there are none of the good discussions we used to have. G.H. Lewes seems to me to be making a great mistake in the Fortnightly, advocating many distinct origins for different groups, and even, if I understand him, distinct origins for some allied groups, just as the anthropologists do who make the red man descend from the orang, the black man from the chimpanzee—or rather the Malay and orang one ancestor, the negro and chimpanzee another. Vogt told me that the Germans are all becoming converted by your last book.
I am certainly surprised that you should find so much evidence against protection having checked the acquirement of bright colour in females; but I console myself by presumptuously hoping that I can explain your facts, unless they are derived from the very groups on which I chiefly rest—birds and insects. There is nothing necessarily requiring protection in females; it is a matter of habits. There are groups in which both sexes require protection in an exactly equal degree, and others (I think) in which the male requires most protection, and I feel the greatest confidence that these will ultimately support my view, although I do not yet know the facts they may afford.
Hoping you are in better health, believe me, dear Darwin, yours faithfully,
ALFRED R. WALLACE.
[pg 222]9 St. Mark's Crescent, N.W. September 5, [1868?].
Dear Darwin,—It will give me great pleasure to accept your kind invitation for next Saturday and Sunday, and my wife would very much like to come too, and will if possible. Unfortunately, there is a new servant coming that very day, and there is a baby at the mischievous age of a year and a quarter to be left in somebody's care; but I daresay it will be managed somehow.
I will drop a line on Friday to say if we are coming the time you mention.—Believe me yours very faithfully,
ALFRED R. WALLACE.
Friday.
My dear Darwin,—My wife has arranged to accompany me to-morrow, and we hope to be at Orpington Station at 5.44, as mentioned by you.—Very truly yours,
ALFRED R. WALLACE.
Down, Bromley, Kent, S.E. September 16, 1868.
My dear Wallace,—The beetles have arrived, and cordial thanks: I never saw such wonderful creatures in my life. I was thinking of something quite different. I shall wait till my son Frank returns, before soaking and examining them. I long to steal the box, but return it by this post, like a too honest man.
I am so much pleased about the male musk Callichroma; for by odd chance I told Frank a week ago that next spring he must collect at Cambridge lots of Cerambyx moschatus, for as sure as life he would find the odour sexual!
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 [pg 223]swung back to the old position, out of which I fear I shall never get.
I did most thoroughly enjoy my talk with you three gentlemen, and especially with you, and to my great surprise it has not knocked me up. Pray give my kindest remembrances to Mrs. Wallace, and if my wife were at home she would cordially join in this.—Yours very sincerely,
CH. DARWIN.
I have had this morning a capital letter from Walsh of Illinois; but details too long to give.
Among Wallace's papers was found the following draft of a letter of his to Darwin:
9 St. Mark's Crescent, N.W. September 18, 1868.
Dear Darwin,—The more I think of your views as to the colours of females, the more difficulty I find in accepting them, and as you are now working at the subject I hope it will not interrupt you to hear "counsel on the other side."
I have a "general" and a "special" argument to submit.
1. Female birds and insects are generally exposed to more danger than the male, and in the case of insects their existence is necessary for a longer period.
2. They therefore require in some way or other a special balance of protection.
3. Now, if the male and female were distinct species, with different habits and organisations, you would, I think, at once admit that a difference of colour serving to make that one less conspicuous which evidently required more protection than the other had been acquired by Natural Selection.
4. But you admit that variations appearing in one sex are transmitted (often) to that sex only: there is therefore [pg 224]nothing to prevent Natural Selection acting on the two sexes as if they were two species.
5. Your objection that the same protection would to a certain extent be useful to the male, seems to me utterly unsound, and directly opposed to your own doctrine so convincingly urged in the "Origin," "that Natural Selection never can improve an animal beyond its needs." So that admitting abundant variation of colour in the male, it is impossible that he can be brought by Natural Selection to resemble the female (unless her variations are always transmitted to him), because the difference of their colours is to balance the difference in their organisations and habits, and Natural Selection cannot give to the male more than is needed to effect that balance.
6. The fact that in almost all protected groups the females perfectly resemble the males shows, I think, a tendency to transference of colour from one sex to the other when this tendency is not injurious.
Or perhaps the protection is acquired because this tendency exists. I admit therefore in the case of concealed nests they [habits] may have been acquired for protection.
Now for the special case.
7. In the very weak-flying Leptalis both sexes mimic Heliconidæ.
8. In the much more powerful Papilio, Pieris, and Diadema it is generally the female only that mimics Danaida.
9. In these cases the females often acquire more bright and varied colours than the male. Sometimes, as in Pieris pyrrha, conspicuously so.
10. No single case is known of a male Papilio, Pieris, Diadema (or any other insect?) alone mimicking a Danais, etc. [pg 225] 11. But colour is more frequent in males, and variations always seem ready for purposes of sexual or other selection.
12. The fair inference seems to be that given in proposition 5 of the general argument, viz. that each species and each sex can only be modified by selection just as far as is absolutely necessary, not a step farther. A male, being by structure and habits less exposed to danger and less requiring protection than the female, cannot have more protection given to it by Natural Selection, but a female must have some extra protection to balance the greater danger, and she rapidly acquires it in one way or another.
13. An objection derived from cases like male fish, which seem to require protection, yet having brighter colours, seems to me of no more weight than is that of the existence of many white and unprotected species of Leptalis to Bates's theory of mimicry, that only one or two species of butterflies perfectly resemble leaves, or that the instincts or habits or colours that seem essential to the preservation of one animal are often totally absent in an allied species.
Down, Bromley, Kent. September 23, 1868.
My dear Wallace,—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. We differ, I think, chiefly from fixing our minds perhaps too closely on different points, on which we agree: I lay great stress on what I know takes place under domestication: I think we start with different fundamental notions on inheritance. I find [pg 226]it 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, could come to be transmitted to males alone;73 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 symbol]74 chaffinch, the less red on the head and less clean colours of [female symbol] goldfinch, the much less red on breast of [female symbol] bullfinch, the paler crest of goldencrest wren, etc., have been acquired by them for protection? I cannot think so; any more than I can that the considerable differences between [female symbol] and [male symbol] house-sparrow, or much greater brightness of [male symbol] Parus cæruleus (both of which build under cover) than of [female symbol] Parus are related to protection. I even misdoubt much whether the less blackness of blackbird is for protection.
Again, can you give me reason for believing that the merest differences between female pheasants, the female Gallus bankiva, the female of black grouse, the pea-hen, female partridge, have all special reference to protection [pg 227]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 fishes—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 symbol] finches and Gallinaceæ would suffice.—Believe me, my dear Wallace, yours very sincerely,
CH. DARWIN.
9 St. Mark's Crescent, S.W. September 27, 1868.
Dear Darwin,—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 their 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 protection. [pg 228] 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 who 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.
I think the case of [female symbol] Pieris pyrrha proves that females alone can be greatly modified for protection.
To your second question I can reply more decidedly. I do think the females of the Gallmaceæ 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 symbol] and [female symbol], 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 only by 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 [pg 229]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 be acquired? 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.
We begin printing this week.—Yours very faithfully,
ALFRED R. WALLACE.
P.S.—Pray don't distress yourself on this subject. It will all come right in the end, and after all it is only an episode in your great work.—A.R.W.
9 St. Mark's Crescent, N.W. October 4, 1868.
Dear Darwin,—I should have answered your letter before, but have been very busy reading over my MSS. the last time before going to press, drawing maps, etc. etc.
Your first question cannot be answered, because we have not, in individual cases of slight sexual difference, sufficient evidence to determine how much of that difference is due to sexual selection acting on the male, how much to natural selection (protective) acting on the female, or how much of the difference may be due to inherited differences from ancestors who lived under different conditions. On your second question I can give an opinion. I do think the [pg 230]females of the Gallinaceæ you mention have been either modified; or prevented from acquiring much of the brighter plumage of the males, by the need of protection. I know that Gallus bankiva frequents drier and more open situations than Pavo muticus, which in Java is found among grassy and leafy vegetation corresponding with the colours of the two females. So the Argus pheasants, male and female, are, I feel sure, protected by their tints corresponding to dead leaves of the dry lofty forests in which they dwell; and the female of the gorgeous fire-back pheasant, Lophura viellottii, is of a very similar rich brown colour.
These and many other colours of female birds seem to me exactly analogous to the colours of both sexes in such groups as the snipes, woodcocks, plovers, ptarmigan, desert birds, Arctic animals, greenbirds.
[The second page of this letter has been torn off. This letter and that of September 27 appear both to answer the same letter from Darwin. The last page of this or of another letter was placed with it in the portfolio of letters; it is now given.]
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 [pg 231]doubt be found someone to battle with me over your facts, on this hard problem.
With best wishes and kind regards to Mrs. Darwin and all your family, believe me, dear Darwin, yours very faithfully,
ALFRED R. WALLACE.
Down, Bromley, Kent, S.E. October 6, 1868.
My dear Wallace,—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. Hamburgh) in which both sexes differ much from each other and from both sexes of G. bankiva; and both sexes are kept constant by selection.
The comb of Spanish [male symbol] has been ordered to be upright and that of Spanish [female symbol] to lop over, and this has been effected. There are sub-breeds of game fowl, with [female symbol]s very distinct and [male symbol]s almost identical; but this apparently is the result of spontaneous variation without special selection.
I am very glad to hear of the case of [female symbol] birds of paradise.
I have never in the least doubted the possibility of modifying female birds alone for protection; and I have long believed it for butterflies: I have wanted only evidence for the females alone of birds having had their colours 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, where the male is more beautiful than the female, I believe the variations were sexually limited in their transmission to the males. I am delighted to hear that you have been hard at work on your MS.—Yours most sincerely,
CH. DARWIN.
[pg 232]9 St. Mark's Crescent, N.W. January 20, 1869.
Dear Darwin,—It will give me very great pleasure if you will allow me to dedicate my little book of Malayan Travels to you, although it will be far too small and unpretending a work to be worthy of that honour. Still, I have done what I can to make it a vehicle for communicating a taste for the higher branches of Natural History, and I know that you will judge it only too favourably. We are in the middle of the second volume, and if the printers will get on, shall be out next month.
Have you seen in the last number of the Quarterly Journal of Science the excellent remarks on Fraser's article on Natural Selection failing as to Man? In one page it gets to the heart of the question, and I have written to the editor to ask who the author is.
My friend Spruce's paper on Palms is to be read to-morrow evening at the Linnean. He tells me it contains a discovery which he calls "alteration of function." He found a clump of Geonema all of which were females, and the next year the same clump were all males! He has found other facts analogous to this, and I have no doubt the subject is one that will interest you.
Hoping you are pretty well and are getting on steadily with your next volumes, and with kind regards to Mrs. Darwin and all your circle, believe me, dear Darwin, yours very faithfully,
ALFRED R. WALLACE.
P.S.—Have you seen the admirable article in the Guardian (!) on Lyell's "Principles"? It is most excellent and liberal. It is written by the Rev. Geo. Buckle, of Tiverton Vicarage, Bath, whom I met at Norwich and found a thoroughly scientific and liberal parson. Perhaps you have heard that I have undertaken to write an article for the Quarterly (!) on the same subject, to make [pg 233]up for that on "Modern Geology" last year not mentioning Sir C. Lyell.
Really, what with the Tories passing Radical Reform Bills and the Church periodicals advocating Darwinianism, the millennium must be at hand.—A.R.W.
Down, Bromley, Kent, S.E. January 22, 1869.
My dear Wallace,—Your intended dedication pleases me much and I look at it as a great honour, and this is nothing more than the truth. I am glad to hear, for Lyell's sake and on general grounds, that you are going to write in the Quarterly. Some little time ago I was actually wishing that you wrote in the Quarterly, as I knew that you occasionally contributed to periodicals, and I thought that your articles would thus be more widely read.
Thank you for telling me about the Guardian, which I will borrow from Lyell. I did note the article in the Quarterly Journal of Science and put it aside to read again with the articles in Fraser and the Spectator.
I have been interrupted in my regular work in preparing a new edition75 of the "Origin," which has cost me much labour, and which I hope I have considerably improved in two or three important points. I always thought individual differences more important than single variations, but now I have come to the conclusion that they are of paramount importance, and in this I believe I agree with you. Fleeming Jenkin's arguments have convinced me.76
I heartily congratulate you on your new book being so nearly finished.—Believe me, my dear Wallace, yours very sincerely,
CH. DARWIN.
[pg 234]9 St. Mark's Crescent, N.W. January 30, 1869.
Dear Darwin,—Will you tell me where are Fleeming Jenkin's arguments on the importance of single variation? Because I at present hold most strongly the contrary opinion, that it is the individual differences or general variability of species that enables them to become modified and adapted to new conditions.
Variations or "sports" may be important in modifying an animal in one direction, as in colour for instance, but how it can possibly work in changes requiring co-ordination of many parts, as in Orchids for example, I cannot conceive. And as all the more important structural modifications of animals and plants imply much co-ordination, it appears to me that the chances are millions to one against individual variations ever coinciding so as to render the required modification possible. However, let me read first what has convinced you.
You may tell Mrs. Darwin that I have now a daughter.
Give my kind regards to her and all your family.—Very truly yours,
ALFRED R. WALLACE.
Down, Bromley, Kent, S.E. February 2, 1869.
My dear Wallace,—I must have expressed myself atrociously; I meant to say exactly the reverse of what you have understood. F. Jenkin argued in the North British Review77 against single variations ever being perpetuated, and has convinced me, though not in quite so broad a manner as here put. I always thought individual differences more important, but I was blind and thought that single variations might be preserved much oftener than I now see is possible or probable. I mentioned this in my former note merely because I believed that you had come to similar [pg 235]conclusions, and I like much to be in accord with you. I believe I was mainly deceived by single variations offering such simple illustrations, as when man selects.
We heartily congratulate you on the birth of your little daughter.—Yours very sincerely,
C. DARWIN.
Down, Bromley, Kent, S.E. March 5, 1869.
My dear Wallace,—I was delighted at receiving your book78 this morning. The whole appearance and the illustrations with which it [is] so profusely ornamented are quite beautiful. Blessings on you and your publisher for having the pages cut and gilded.
As for the dedication, putting quite aside how far I deserve what you say, it seems to me decidedly the best expressed dedication which I have ever met.
The reading will probably last me a month, for I dare not have it read aloud, as I know that it will set me thinking.
I see that many points will interest me greatly. When I have finished, if I have anything particular to say, I will write again. Accept my cordial thanks. The dedication is a thing for my children's children to be proud of.—Yours most sincerely,
CH. DARWIN.
9 St. Mark's Crescent, N.W. March 10, 1869.
Dear Darwin,—Thanks for your kind note. I could not persuade Mr. Macmillan to cut more than twenty-five copies for my own friends, and he even seemed to think this a sign of most strange and barbarous taste.
Mr. Weir's paper on the kinds of larvæ, etc., eaten or rejected by insectivorous birds was read at the last meeting of the Entomological Society and was most interesting and satisfactory. His observations and experiments, so far [pg 236]as they have yet gone, confirm in every instance my hypothetical explanation of the colours of caterpillars. He finds that all nocturnal-feeding obscure-coloured caterpillars, all green and brown and mimicking caterpillars, are greedily eaten by almost every insectivorous bird. On the other hand, every gaily coloured, spotted or banded species, which never conceal themselves, and all spiny and hairy kinds, are invariably rejected, either without or after trial. He has also come to the curious and rather unexpected conclusion, that hairy and spiny caterpillars are not protected by their hairs, but by their nauseous taste, the hairs being merely an external mark of their uneatableness, like the gay colours of others. He deduces this from two kinds of facts: (1) that very young caterpillars before the hairs are developed are equally rejected, and (2) that in many cases the smooth pupæ and even the perfect insects of the same species are equally rejected.
His facts, it is true, are at present not very numerous, but they all point one way. They seem to me to lend an immense support to my view of the great importance of protection in determining colour, for it has not only prevented the eatable species from ever acquiring bright colours, spots, or markings injurious to them, but it has also conferred on all the nauseous species distinguishing marks to render their uneatableness more protective to them than it would otherwise be. When you have read my book I shall be glad of any hints for corrections if it comes to another edition. I was horrified myself by coming accidentally on several verbal inelegancies after all my trouble in correcting, and I have no doubt there are many more important errors.—Believe me, dear Darwin, yours very truly,
ALFRED R. WALLACE.
[pg 237]Down, Bromley, Kent, S.E. March 22, 1869.
My dear Wallace,—I have finished your book.79 It seems to me excellent, and at the same time most pleasant to read. That you ever returned alive is wonderful after all your risks from illness and sea voyages, especially that most interesting one to Waigiou and back. Of all the impressions which I have received from your book, the strongest is that your perseverance in the cause of science was heroic. Your descriptions of catching the splendid butterflies have made me quite envious, and at the same time have made me feel almost young again, so vividly have they brought before my mind old days when I collected, though I never made such captures as yours. Certainly collecting is the best sport in the world. I shall be astonished if your book has not a great success; and your splendid generalisations on geographical distribution, with which I am familiar from your papers, will be new to most of your readers. I think I enjoyed most the Timor case, as it is best demonstrated; but perhaps Celebes is really the most valuable. I should prefer looking at the whole Asiatic continent as having formerly been more African in its fauna, than admitting the former existence of a continent across the Indian Ocean. Decaisne's paper on the flora of Timor, in which he points out its close relation to that of the Mascarene Islands, supports your view. On the other hand, I might advance the giraffes, etc., in the Sewalik deposits. How I wish someone would collect the plants of Banca! The puzzle of Java, Sumatra and Borneo is like the three geese and foxes: I have a wish to extend Malacca through Banca to part of Java and thus make three parallel peninsulas, but I cannot get the geese and foxes across the river.
Many parts of your book have interested me much: I [pg 238]always wished to hear an independent judgment about the Rajah Brooke, and now I have been delighted with your splendid eulogium on him.
With respect to the fewness and inconspicuousness of the flowers in the tropics, may it not be accounted for by the hosts of insects, so that there is no need for the flowers to be conspicuous? As, according to Humboldt, fewer plants are social in the tropical than in the temperate regions, the flowers in the former would not make so great a show.
In your note you speak of observing some inelegancies of style. I notice none. All is as clear as daylight. I have detected two or three errata.
In Vol. I. you write londiacus: is this not an error?
Vol. II., p. 236: for western side of Aru read eastern.
Page 315: Do you not mean the horns of the moose? For the elk has not palmated horns.
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 tip 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.
In Vol. II., p. 399, I wish I could see the connection between variations having been first or long ago selected, and their appearance at an earlier age in birds of paradise [pg 239]than the variations which have subsequently arisen and been selected. In fact, I do not understand your explanation of the curious order of development of the ornaments of these birds.
Will you please to tell me whether you are sure that the female Casuarius (Vol. II., p. 150) sits on her eggs as well as the male?—for, if I am not mistaken, Bartlett told me that the male alone, who is less brightly coloured about the neck, sits on the eggs. In Vol. II., p. 255, you speak of male savages ornamenting themselves more than the women, of which I have heard before; now, have you any notion whether they do this to please themselves, or to excite the admiration of their fellow-men, or to please the women, or, as is perhaps probable, from all three motives?
Finally, let me congratulate you heartily on having written so excellent a book, full of thought on all sorts of subjects. Once again, let me thank you for the very great honour which you have done me by your dedication.—Believe me, my dear Wallace, yours very sincerely,
CH. DARWIN.
Vol. II., p. 455: When in New Zealand I thought the inhabitants a mixed race, with the type of Tahiti preponderating over some darker race with more frizzled hair; and now that the stone instruments [have] revealed the existence of ancient inhabitants, is it not probable that these islands were inhabited by true Papuans? Judging from descriptions the pure Tahitans must differ much from your Papuans.
The reference in the following letter is to 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." Wallace points out that here for the first time Sir C. Lyell gave up his opposition to Evolution; and this leads Wallace to give [pg 240]a short account of the views set forth in the "Origin of Species." In this article Wallace makes a definite statement as to his views on the evolution of man, which were opposed to those of 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 p. 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 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 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 in the Anthropological Review, 1864, referred to in his letter to Wallace of May 28, 1864, and again in that of April 14, 1869.
Down, Bromley, Kent, S.E. March 27, 1869.
My dear Wallace,—I must send a line to thank you, but this note will require no answer. This very morning after writing I found that "elk" was used for "moose" in Sweden, but I had been reading lately about elk and moose in North America.
As you put the case in your letter, which I think differs somewhat from your book, I am inclined to agree, and had thought that a feather could hardly be increased in length [pg 241]until it had first grown to full length, and therefore it would be increased late in life and transmitted to a corresponding age. But the Crossoptilon pheasant, and even the common pheasant, show that the tail feathers can be developed very early.
Thanks for other facts, which I will reflect on when I go again over my MS.
I read all that you said about the Dutch Government with much interest, but I do not feel I know enough to form any opinion against yours.
I shall be intensely curious to read the Quarterly: I hope you have not murdered too completely your own and my child.
I have lately, i.e. in the new edition of the "Origin,"80 been moderating my zeal, and attributing much more to mere useless variability. I did think I would send you the sheet, but I daresay you would not care to see it, in which I discuss Nägeli's essay on Natural Selection not affecting characters of no functional importance, and which yet are of high classificatory importance.
Hooker is pretty well satisfied with what I have said on this head. It will be curious if we have hit on similar conclusions. You are about the last man in England who would deviate a hair's breadth from his conviction to please any editor in the world.—Yours very sincerely,
CH. DARWIN.
P.S.—After all, I have thought of one question, but if I receive no answer I shall understand that (as is probable) you have nothing to say. I have seen it remarked that the men and women of certain tribes differ a little in shade or tint; but have you ever seen or heard of any difference in tint between the two sexes which did not appear to follow from a difference in habits of life?
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