impassioned lover eager to give a final proof of his or her
devotion. It must be added that from a scientific point of view
we are not entitled to take either side.

Of the whole of this group of phenomena, the most typical and the most
widespread example is certainly the kiss. We have in the lips a highly
sensitive frontier region between skin and mucous membrane, in many
respects analogous to the vulvo-vaginal orifice, and reinforcible,
moreover, by the active movements of the still more highly sensitive
tongue. Close and prolonged contact of these regions, therefore, under
conditions favorable to tumescence sets up a powerful current of nervous
stimulation. After those contacts in which the sexual regions themselves
take a direct part, there is certainly no such channel for directing
nervous force into the sexual sphere as the kiss. This is nowhere so well
recognized as in France, where a young girl's lips are religiously kept
for her lover, to such an extent, indeed, that young girls sometimes come
to believe that the whole physical side of love is comprehended in a kiss
on the mouth; so highly intelligent a woman as Madam Adam has described
the agony she felt as a girl when kissed on the lips by a man, owing to
the conviction that she had thereby lost her virtue. Although the lips
occupy this highly important position as a secondary sexual focus
in the sphere of touch, the kiss is--unlike _cunnilingus_ and
_fellatio_--confined to man and, indeed, to a large extent, to civilized
man. It is the outcome of a compound evolution which had its beginning
outside the sphere of touch, and it would therefore be out of place to
deal with the interesting question of its development in this place. It
will be discussed elsewhere.[18]

There is yet another orificial frontier region which is a highly important
tactile sexual focus: the nipple. The breasts raise, indeed, several