[In the autobiographical chapter in Volume I., my father gives the circumstances which led to his writing the 'Descent of Man.' He states that his collection of facts, begun in 1837 or 1838, was continued for many years without any definite idea of publishing on the subject. The following letter to Mr. Wallace shows that in the period of ill-health and depression about 1864 he despaired of ever being able to do so:]
CHARLES DARWIN TO A.R. WALLACE.
Down, [May?] 28 [1864].
Dear Wallace, I am so much better that I have just finished a paper for Linnean Society (On the three forms, etc., of Lythrum.); but I am not yet at all strong, Ifelt much disinclination to write, and therefore you must forgive me for not having sooner thanked you for your paper on 'Man' ('Anthropological Review,' March 1864.), received on the 11th. But first let me say that Ihave hardly ever in my life been more struck by any paper than that on 'Variation,' etc. etc., in the "Reader". ('"Reader", April 16, 1864. "On the Phenomena of Variation," etc. Abstract of a paper read before the Linnean Society, March 17, 1864.) 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. Iam 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 dare say Ishall 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. Ican 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 that 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.
Believe me, dear Wallace, yours very sincerely, CH. DARWIN.
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! Ifear my letter will be barely intelligible to you.
[In February 1867, when the manuscript of 'Animals and Plants' had been sent to Messrs. Clowes to be printed, and before the proofs began to come in, he had an interval of spare time, and began a "chapter on Man," but he soon found it growing under his hands, and determined to publish it separately as a "very small volume."The work was interrupted by the necessity of correcting the proofs of 'Animals and Plants,' and by some botanical work, but was resumed in the following year, 1868, the moment he could give himself up to it.