ual ideal we have not yet, however, by any
means stated the complete problem of human sexual selection. The ideal
that is desired and sought is, in a large measure, not the outcome of
experience; it is not even necessarily the expression of the individual's
temperament and idiosyncrasy. It may be largely the result of fortuitous
circumstances, of slight chance attractions in childhood, of accepted
traditions consecrated by romance. In the actual contacts of life the
individual may find that his sexual impulse is stirred by sensory stimuli
which are other than those of the ideal he had cherished and may even be
the reverse of them.

Beyond this, also, we have reason for believing that factors of a still
more fundamentally biological character, to some extent deeper even than
all these psychic elements, enter into the problem of sexual selection.
Certain individuals, apart altogether from the question of whether they
are either ideally or practically the most fit mates, display a greater
energy and achieve a greater success than others in securing partners.
These individuals possess a greater constitutional vigor, physical or
mental, which conduces to their success in practical affairs generally,
and probably also heightens their specifically philogamic activities.

Thus, the problem of human sexual selection is in the highest degree
complicated. When we gather together such scanty data of precise nature as
are at present available, we realize that, while generally according with
the results which the evidence not of a quantitative nature would lead us
to accept, their precise significance is not at present altogether clear.
It would appear on the whole that in choosing a mate we tend to seek
parity of racial and individual characters together with disparity of
secondary sexual characters. But we need a much larger number of groups of
evidence of varying character and obtained under varying conditions. Such
evidence will doubtless accumulate now that its nature is becoming defined
and the need for it recognized. In the meanwhile we are, at all events, in
a position to assert, even with the evidence before us, that now that the
real meaning of sexual selection is becoming clear its efficacy in human
evolution can no longer be questioned.

APPENDICES

APPENDIX A.

THE ORIGINS OF THE KISS.

Manifestations resembling the kiss, whether with the object of expressing
affection or sexual emotion, are found among v