uence of Lactation on the Sexual
Centres--Suckling and Sexual Emotion--The Significance of the Association
between Suckling and Sexual Emotion--This Association as a Cause of Sexual
Perversity.

We have seen that the skin generally has a high degree of sensibility,
which frequently tends to be in more or less definite association with the
sexual centres. We have seen also that the central and specific sexual
sensation, the sexual embrace itself, is, in large measure, a specialized
kind of skin reflex. Between the generalized skin sensations and the great
primary sexual centre of sensation there are certain secondary sexual
centres which, on account of their importance, may here be briefly
considered.

These secondary centres have in common the fact that they always involve
the entrances and the exits of the body--the regions, that is, where skin
merges into mucous membrane, and where, in the course of evolution,
tactile sensibility has become highly refined. It may, indeed, be said
generally of these frontier regions of the body that their contact with
the same or a similar frontier region in another person of opposite sex,
under conditions otherwise favorable to tumescence, will tend to produce a
minimum and even sometimes a maximum degree of sexual excitation. Contact
of these regions with each other or with the sexual region itself so
closely simulates the central sexual reflex that channels are set up for
the same nervous energy and secondary sexual centres are constituted.

It is important to remember that the phenomena we are here concerned with
are essentially normal. Many of them are commonly spoken of as
perversions. In so far, however, as they are aids to tumescence they must
be regarded as coming within the range of normal variation. They may be
considered unaesthetic, but that is another matter. It has, moreover, to be
remembered that aesthetic values are changed under the influence of sexual
emotion; from the lover's point of view many things are beautiful which
are unbeautiful from the point of view of him who is not a lover, and the
greater the degree to which the lover is swayed by his passion the greater
the extent to which his normal aesthetic standard is liable to be modified.
A broad consideration of the phenomena among civilized and uncivilized
peoples amply suffices to show the fallacy of the tendency, so common
among unscientific writers on these subjects, to introduce normal aesthetic
standar