begin. Such a view of ticklishness, as a kind of modesty of the skin,
existing merely to be destroyed, need only be regarded as one of its
aspects. Ticklishness certainly arose from a non-sexual starting-point,
and may well have protective uses in the young animal.

The readiness with which tactile sensibility takes on a sexual character
and forms reflex channels of communication with the sexual sphere proper
is illustrated by the existence of certain secondary sexual foci only
inferior in sexual excitability to the genital region. We have seen that
the chief of these normal foci are situated in the orificial regions where
skin and mucous membrane meet, and that the contact of any two orificial
regions between two persons of different sex brought together under
favorable conditions is apt, when prolonged, to produce a very intense
degree of sexual erethism. This is a normal phenomenon in so far as it is
a part of tumescence, and not a method of obtaining detumescence. The kiss
is a typical example of these contacts, while the nipple is of special
interest in this connection, because we are thereby enabled to bring the
psychology of lactation into intimate relationship with the psychology of
sexual love.

The extreme sensitiveness of the skin, the readiness with which its
stimulation reverberates into the sexual sphere, clearly brought out by
the present study, enable us to understand better a very ancient
contest--the moral struggle around the bath. There has always been a
tendency for the extreme cultivation of physical purity to lead on to the
excessive stimulation of the sexual sphere; so that the Christian ascetics
were entirely justified, on their premises, in fighting against the bath
and in directly or indirectly fostering a cult of physical uncleanliness.
While, however, in the past there has clearly been a general tendency for
the cult of physical purity to be associated with moral licentiousness,