derived from any abstract principle or architectonics or Hogarthian wave-line. A year after my remark, appeared Charles Darwin's Descent of Man, in which the doctrine of sexual selection, which was only indicated in the Origin of Species, was treated in detail and followed out to its consequences. But I have, too, a lively recollection of how Dove, when I was once contending with him against the validity of vitalism, embarrassed me with the objection that profusion prevails in organic nature, as, for example, in the feathers of a peacock, or of a bird-of-paradise, while Maupertuis's law of the least action excludes such waste in inorganic nature. The problem seems to be solved now, under the presumption that a kind of sense of beauty in their species exists among animals. The brightly colored wedding garment of the male bird may have originated in the females giving the preference to the most highly decorated suitor, under which an ever more richly adorned posterity is developed. The male birds-of-paradise may be seen at pairing-time emulously displaying their beauty before the female. The nightingale's gift of song may likewise be accounted for if, instead of pleasure in colored feathers, we ascribe musical perceptions to the females. Darwin carries his idea further, to the extent of assuming that certain sexual marks in the human race, the grave beard of the man and the luxuriant hair of the woman, may have been derived through sexual selection[1]. It is well known that the introduction of handsome Circassian slaves into the harems of prominent Turks has repeatedly changed the original Mongolian type into a figure of nobler pattern. Rising to a higher level, we can now find in the same idea the answer to the question. Where are the roots of the charm which female beauty exercises on man? According to our views, the woman was not made out of a rib of the first man, an assumption which encounters morphological difficulties, but it was the man himself who in the course of numerous generations made his woman by natural selection of such fashion as would please him, and, inversely, the woman her man. "We now call this type beau-
- ↑ The Descent of Man and Selection in Relation to Sex. London, 1871, vol. n, pp. 52, 89, 379, 400, 401. In his book on Darwinism, etc (second London edition, 1889), Mr. Wallace rejected the explanation of the decorative plumage and the song of the male bird through selection by the female, and proposed other interpretations. But a writer recognized by Mr. Wallace himself as equally a student in this line, Mr. C. B. Poulton, in his work, The Colors of Animals, their Meaning and their Use (International Scientific Series), has sturdily taken up the defense of the Darwinian view against this attack, and exposed the untenability of Wallace's later explanation. Mr. Wallace has not failed to reply to this (Nature, No. 1082, vol. xlii, July 24, 1890); while Mr. R. J. Pocock, resting on Mr. G. W. Peckham's investigations, joins Mr. Poulton (ibid. . No. 1086, August 1, 1890, p. 40.'5). This is not the place to enter into the question, especially as my conclusion concerning the doctrine of sexual selection still holds, even if Mr. Wallace should be right on the single points of feather ornament and song.
