oblivion have been discussed in
the first chapter (p. 5).

Yet another reason may be mentioned for regarding a knowledge of the
undifferentiated stage of the sexual impulse as of great importance. In
works on the pathology of the sexual impulse we are frequently assured
that in this or that specific instance the perversion was inborn,
because perverse sensations have existed since the days of childhood.
But the existence of the undifferentiated stage teaches us that we are
not justified in inferring, from the mere fact of the primary occurrence
of a "perverse" mode of sexual sensibility, that this perversion is
congenital; for the primary direction of the contrectation impulse
during the undifferentiated stage often depends to a considerably
greater extent upon chance than upon an inherited predisposition.

The undifferentiated stage begins at very various ages. I have known
instances in which it could be traced back to the fifth, year of life. I
regard it as probable, however, that it may begin even earlier than
this. But more commonly it begins somewhat later; not infrequently at
the age of seven or eight, and very often at the age of nine or ten
years. As previously mentioned, I do not maintain that an
undifferentiated stage is of universal occurrence. When such a stage is
absent, the symptoms of the differentiated sexual impulse often make
their appearance at the age at which in other cases the undifferentiated
stage of the impulse usually begins. In the case of a large number of
men, inquiry will show that at the age of nine or ten they began to
experience an inclination towards persons of the female sex; in a good
many this occurs even at the age of eight, and in a few yet earlier; as
regards women, _mutatis mutandis_, the same conditions obtain. In cases
in which an undifferentiated stage is well marked, its duration is
likewise very variable. In isolated instances it lasts until the age of
twenty, or even a few years longer. Ordinarily, however, the
differentiation of the impulse becomes manifest at an earlier
age--between the ages of fifteen and seventeen years. Beyond question,
in the great majority of cases, the "perverse" sentiments of childhood
subsequently disappear spontaneously. But when I come to discuss sexual
perversions in detail, I shall point out that this disappearance, in
certain circumstances, fails to occur.

I take this opportunity of referring to a beautiful example of the
undifferentiate