per.

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 unpleasant 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
astonishing 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 story 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 discussion
of sexual selection in relation to man, and a general summary. Part
II treats of sexual selection in general, and may be disregarded in
our present study. Moreover, many interesting details must necessarily
be passed over in what follows, for want of space.

The first part of the _Descent of Man_ begins with an enumeration of
the proofs of the animal descent of man taken from the structure of
the human body. Darwin chiefly emphasises the fact that the human body
consists of the same organs and of the same tissues as those of the
other mammals; he shows also that man is subject