Still during infancy the erogenous zone of the genitals begins to make itself noticeable, either by the fact that like any other erogenous zone it furnishes gratification through a suitable sensible stimulus, or because in some incomprehensible way the gratification from other sources causes at the same time the sexual excitement which has a special connection with the genital zone. We found cause to regret that a sufficient explanation of the relations between sexual gratification and sexual excitement, as well as between the activity of the genital zone and the remaining sources of sexuality, was not to be attained. We were unable to state what amount of sexual activity in childhood might be designated as normal to the extent of being incapable of further development. The character of the sexual manifestation showed itself to be preponderantly masturbatic. We, moreover, verified from experience the belief that the external influences of seduction, might produce premature breaches in the latency period leading as far as the suppression of the same, and that the sexual impulse of the child really shows itself to be polymorphous-perverse; furthermore, that every such premature sexual activity impairs the educability of the child. Despite the incompleteness of our examinations of the infantile sexual life we were subsequently forced to attempt to study the serious changes produced by the appearance of puberty. We selected two of the same as criteria, namely, the subordination of all other sources of the sexual feeling to the primacy of the genital zones, and the process of object finding. Both of them are already developed in childhood. The first is accomplished through the mechanism of utilizing the fore-pleasure, whereby all other independent sexual acts which are connected with pleasure and excitement become preparatory acts for the new sexual aim, the voiding of the sexual products, the attainment of which under enormous pleasure puts an end to the sexual feeling. At the same time we had to consider the differentiation of the sexual nature of man and woman, and we found that in order to become a woman a new repression is required which abolishes a piece of infantile masculinity, and prepares the woman for the change of the leading genital zones. Lastly, we found the object selection, tracing it through infancy to its revival in puberty; we also found indications of sexual inclinations on the part of the child for the parents and foster-parents, which, however, were turned away from these persons to others resembling them by the incest barriers which had been erected in the meantime. Let us finally add that during the transition period of puberty the somatic and psychic processes of development proceed side by side, but separately, until with the breaking through of an intense psychic love-stimulus for the innervation of the genitals, the normally demanded unification of the erotic function is established.