It is, moreover, clear that the action of the thumbsucking child is determined by the fact that it seeks a pleasure which has already been experienced and is now remembered. Through the rhythmic [sucking] on a portion of the skin or mucous membrane it finds the gratification in the simplest way. It is also easy to conjecture on what occasions the child first experienced this pleasure which it now strives to renew. The first and most important activity in the child's life, the sucking from the mother's breast (or its substitute), must have acquainted it with this pleasure. We would say that the child's lips behaved like an erogenous zone, and that the excitement through the warm stream of milk was really the cause of the pleasurable sensation. To be sure, the gratification of the erogenous zone was at first united with the gratification of taking nourishment. He who sees a satiated child sink back from the mother's breast, and fall asleep with reddened cheeks and blissful smile, will have to admit that this picture remains as typical of the expression of sexual gratification in later life. But the desire for repetition of the sexual gratification is separated from the desire for taking nourishment; a separation which becomes unavoidable with the appearance of the teeth when the nourishment is no longer sucked in but chewed. The child does not make use of a strange object for sucking but prefers its own skin because it is more convenient, because it thus makes itself independent of the outer world which it cannot yet control, and because in this way it creates for itself, as it were, a second, even if an inferior, erogenous zone. The inferiority of this second region urges it later to seek the same parts, the lips of another person. ("It is a pity that I cannot kiss myself," might be attributed to it.)
Not all children suck their thumbs. It may be assumed that it is found only in children in whom the erogenous significance of the lip-zone is constitutionally reënforced. Children in whom this is retained are habitual kissers as adults and show a tendency to perverse kissing, or as men they have a marked desire for drinking and smoking. But if repression comes into play they experience disgust for eating and evince hysterical vomiting. By [virtue] of the community of the lip-zone the repression encroaches upon the impulse of nourishment. Many of my female patients showing disturbances in eating, such as hysterical globus, choking sensations, and vomiting, have been energetic thumbsuckers during infancy.
In the thumbsucking or pleasure-sucking we have already been able to observe the three essential characters of an infantile sexual manifestation. The latter has its origin in conjunction with a bodily function which is very important for life, it does not yet know any sexual object, it is autoerotic and its sexual aim is under the control of an erogenous zone. Let us assume for the present that these characters also hold true for most of the other activities of the infantile sexual impulse.
THE SEXUAL AIM OF THE INFANTILE SEXUALITY
The Characters of the Erogenous Zones.—From the example of thumbsucking we may gather a great many points useful for the distinguishing of an erogenous zone. It is a portion of skin or mucous membrane in which the stimuli produce a feeling of pleasure of definite quality. There is no doubt that the pleasure-producing stimuli are governed by special determinants which we do not know. The rhythmic characters must play some part in them and this strongly suggests an analogy to tickling. It does not, however, appear so certain whether the character of the pleasurable feeling evoked by the stimulus can be designated as "peculiar," and in what part of this peculiarity the sexual factor exists. Psychology is still groping in the dark when it concerns matters of pleasure and pain, and the most cautious assumption is therefore the most advisable. We may perhaps later come upon reasons which seem to support the peculiar quality of the sensation of pleasure.
The erogenous quality may adhere most notably to definite regions of the body. As is shown by the example of [thumbsucking], there are predestined erogenous zones. But the same example also shows that any other region of skin or mucous membrane may assume the function of an erogenous zone; it must therefore carry along a certain adaptability. The production of the sensation of pleasure therefore depends more on the quality of the stimulus than on the nature of the bodily region. The thumbsucking child looks around on his body and selects any portion of it for pleasure-sucking, and becoming accustomed to it, he then prefers it. If he accidentally strikes upon a predestined region, 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.