Three Contributions to the Theory of Sex · Sigmund Freud
THE SEXUAL AIM OF THE INFANTILE SEXUALITY
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]
Text from Project Gutenberg, public domain in the United States.