116 “The Descent of Man” 
faithful confederate, Huxley, was joined by the botanist Hooker, and, 
after longer resistance, by the famous geologist Lyell, whose 
“conversion” afforded Darwin peculiar satisfaction. All three took 
the field with enthusiasm in defence of the natural descent of man. 
From Wallace, on the other hand, though he shared with him the 
idea of natural selection, Darwin got no support in this matter. 
Wallace expressed himself in a strange manner. He admitted every- 
thing in regard to the morphological descent of man, but maintained, 
in a mystic way, that something else, something of a spiritual nature 
must have been added to what man inherited from his animal 
ancestors. Darwin, whose esteem for Wallace was extraordinarily 
high, could not understand how he could give utterance to such a 
mystical view in regard to man; the idea seemed to him so “incredibly 
strange” that he thought some one else must have added these 
sentences to Wallace’s paper. 
Even now there are thinkers who, like Wallace, shrink from 
applying to man the ultimate consequences of the theory of descent. 
The idea that man is derived from ape-like forms is to them un- 
pleasant and humiliating. 
So far I have been depicting the development of Darwin’s work 
on the descent of man. In what follows I shall endeavour to give a 
condensed survey of the contents of the book. 
It must at once be said that the contents of Darwin’s work fall 
into two parts, dealing with entirely different subjects. The Descent 
of Man includes a very detailed investigation in regard to secondary 
sexual characters in the animal series, and on this investigation 
Darwin founded a new theory, that of sexual selection. With as- 
tonishing patience he gathered together an immense mass of material, 
and showed, in regard to Arthropods and Vertebrates, the wide 
distribution of secondary characters, which develop almost exclusively 
in the male, and which enable him, on the one hand, to get the better 
of his rivals in the struggle for the female by the greater perfection of 
his weapons, and, on the other hand, to offer greater allurements to 
the female through the higher development of decorative characters, 
of song, or of scent-producing glands. The best equipped males will 
thus crowd out the less well-equipped in the matter of reproduction, 
and thus the relevant characters will be increased and perfected 
through sexual selection. It is, of course, a necessary assumption 
that these secondary sexual characters may be transmitted to the 
female, although perhaps in rudimentary form. 
As we have said, this theory of sexual selection takes up a great 
deal of space in Darwin’s book, and it need only be considered here 
in so far as Darwin applied it to the descent of man. To this latter 
problem the whole of Part I is devoted, while Part III contains a 
