een overlooked simply for the
reason that recent investigations dealing with the sexual impulse have
in most cases dealt exclusively with morbid manifestations; whilst the
psychologists by profession, whose province it was to study the normal
sexual life, have with few exceptions (Max Dessoir, Binet, Jodl, and
Ribot) completely ignored this field of inquiry. For this reason many
phenomena, _e.g._, early activity of the sexual impulse, and
hyperaesthesia of that impulse, have been assumed to be characteristic of
the perverse modes of sexual sensibility, whereas the like phenomena may
readily be observed in association with a qualitatively normal mode of
sexual sensibility.

The theory of the congenital nature of homosexuality was based for the
most part on the common assumption that the condition is primary and
premature in its occurrence, and that it is exclusive of the opposite
mode of sexual sensibility. But for several reasons the inference is not
justified. For, first of all, for many cases it is incorrect to assume
that the homosexual inclinations are thus exclusive in their character;
as I have previously explained, the adult homosexual's belief that from
early childhood he has never experienced any other than homosexual
inclinations, depends in many instances on an illusion of memory. Owing
to the fact that in consequence of the fuller development of
homosexuality he is no longer interested in the heterosexual, he is apt
to forget any early heterosexual inclinations. Secondly, the primary
appearance of homosexual inclinations does not prove that these
inclinations are congenital; for in homosexuals, as in heterosexuals,
the specialised mode of sexual sensibility is preceded by a period in
which the sexual impulse is undifferentiated; and, in homosexuals and
heterosexuals alike, chance plays a great part in determining which mode
of sexual sensibility first manifests itself. The congenital nature of
heterosexuality is not disproved by the fact that one who in adult life
possesses a normal mode of sexual sensibility, may as a schoolboy have
first experienced sexual desire towards a school-fellow; just as little,
then, does a similar early history in one who in adult life is
homosexual in his inclinations, prove that his homosexuality is
congenital. In the animal world also, before the occurrence of sexual
maturity, the love-games occasionally display a similar confusion of
roles, so that the sexually immature femal