The sexual life of the child shows from the third year that it has much in common with that of the adult; it is distinguished from the latter, as we already know, by the lack of stable organization under the primacy of the genitals, by the unavoidable traits of perversion, and, naturally, by the far lesser intensity of the whole impulse. Theoretically the most interesting phases of the sexual development or, as we would rather say, the libido-development, so far as theory is concerned, lie back of this period. This development is so rapidly gone through that perhaps it would never have been possible for direct observation to grasp its fleeting pictures. Psychoanalytic investigation of the neuroses has for the first time made it possible to discover more remote phases of the libido-development. These are, to be sure, nothing but constructions, but if you wish to carry on psychoanalysis in a practical way you will find that they are necessary and valuable constructions. You will soon understand why pathology may disclose conditions which we would have overlooked in the normal object. We can now declare what form the sexual life of the child takes before the primacy of the genitals is established. This primacy is prepared in the first infantile epoch prior to the latent period, and is continuously organized from puberty on. There is in this early period a sort of loose organization, which we shall call _pre-genital_. In the foreground of this phase, however, the partial instincts of the genitals are not prominent, rather the _sadistic_ and _anal_. The contrast between _masculine_ and _feminine_ plays no part as yet, its place is taken by the contrast between _active_ and _passive_, which we may designate as the forerunner of sexual polarity, with which it is later fused. That which appears masculine to us in the activity of this phase, observed from the standpoint of the later genital stage, is the expression of an instinct to mastery, which may border on cruelty. Impulses with passive goals attach themselves to the erogenous zone of the rectal opening. Most important at this time, curiosity and the instinct to watch are powerful. The genital really takes part in the sexual life only in its role as excretory organ for the bladder. Objects are not lacking to the partial impulses of this period, but they do not necessarily combine into a single object. The sadistico-anal organization is the step antecedent to the phase of genital primacy. A more penetrating study furnishes proof how much of this is retained for the later and final form, and in what ways its partial instincts are forced into line under the new genital organization. Back of the sadistico-anal phase of libido-development, we get a view of an earlier, even more primitive phase of organization, in which the erogenous mouth-zone plays the chief role. You may surmise that the sexual activity of sucking belongs to it, and may wonder at the intuition of