such as breast, nipple or genitals, it naturally has the preference.  A quite analogous tendency to displacement is again found in the symptomatology of hysteria.  In this neurosis the repression mostly concerns the genital zones proper; these in turn transmit their excitation to the other erogenous zones, usually dormant in mature life, which then behave exactly like genitals.  But besides this, just as in thumbsucking, any other region of the body may become endowed with the excitation of the genitals and raised to an erogenous zone.  Erogenous and hysterogenous zones show the same characters.[12]

The Infantile Sexual Aim.—­The sexual aim of the infantile impulse consists in the production of gratification through the proper excitation of this or that selected erogenous zone.  In order to leave a desire for its repetition this gratification must have been previously experienced, and we may be sure that nature has devised definite means so as not to leave this occurrence to mere chance.  The arrangement which has fulfilled this purpose for the lip-zone we have already discussed; it is the simultaneous connection of this part of the body with the taking of nourishment.  We shall also meet other similar mechanisms as sources of sexuality.  The state of desire for repetition of gratification can be recognized through a peculiar feeling of tension which in itself is rather of a painful character, and through a centrally-determined feeling of itching or sensitiveness which is projected into the peripheral erogenous zone.  The sexual aim may therefore be formulated as follows:  the chief object is to substitute for the projected feeling of sensitiveness in the erogenous zone that outer stimulus which removes the feeling of sensitiveness by evoking the feeling of gratification.  This external stimulus consists usually in a manipulation which is analogous to sucking.

It is in full accord with our physiological knowledge if the desire happens to be awakened also peripherally through an actual change in the erogenous zone.  The action is puzzling only to some extent as one stimulus for its suppression seems to want another applied to the same place.

THE MASTURBATIC SEXUAL MANIFESTATIONS[13]

It is a matter of great satisfaction to know that there is nothing further of greater importance to learn about the sexual activity of the child after the impulse of one erogenous zone has become comprehensible to us.  The most pronounced differences are found in the action necessary for the gratification, which consists in sucking for the lip zone and which must be replaced by other muscular actions according to the situation and nature of the other zones.