It may be remarked that the frequency of the association between lactation and the sexual sensations is indicated by the fact that, as Savage remarks, lactational insanity is often accompanied by fancies regarding the reproductive organs.
When we have realized the special sensitivity of the orificial regions and the peculiarly close relationships between the breasts and the sexual organs we may easily understand the considerable part which they normally play in the art of love. As one of the chief secondary sexual characters in women, and one of her chief beauties, a woman's breasts offer themselves to the lover's lips with a less intimate attraction than her mouth only because the mouth is better able to respond. On her side, such contact is often instinctively desired. Just as the sexual disturbance of pregnancy is accompanied by a sympathetic disturbance in the breasts, so the sexual excitement produced by the lover's proximity reacts on the breasts; the nipple becomes turgid and erect in sympathy with the clitoris; the woman craves to place her lover in the place of the child, and experiences a sensation in which these two supreme objects of her desire are deliciously mingled.
The powerful effect which stimulation of the nipple produces on the sexual sphere has led to the breasts playing a prominent part in the erotic art of those lands in which this art has been most carefully cultivated. Thus in India, according to Vatsyayana, many authors are of the opinion that in approaching a woman a lover should begin by sucking the nipples of her breasts, and in the songs of the Bayaderes of Southern India sucking the nipple is mentioned as one of the natural preliminaries of coitus.
In some cases, and more especially in neurotic persons, the sexual pleasure derived from manipulation of the nipple passes normal limits and, being preferred even to coitus, becomes a perversion. In girls' schools, it is said, especially in France, sucking and titillation of the breasts are not uncommon; in men, also, titillation of the nipples occasionally produces sexual sensations (Féré, L'Instinct Sexuel, second edition, p. 132). Hildebrandt recorded the case of a young woman whose nipples had been sucked by her lover; by constantly drawing her breasts she became able to suck them herself and thus attained extreme sexual pleasure. A. J. Bloch, of New Orleans, has noted the case of a woman who complained of swelling of the breasts; the gentlest manipulation produced an orgasm, and it was found that the swelling had been intentionally produced for the sake of this manipulation. Moraglia in Italy knew a very beautiful woman who was perfectly cold in normal sexual relationships, but madly excited when her husband pressed or sucked her breasts. Lombroso (Archivio di Psichiatria, 1885, fasc. IV) has described the somewhat similar case of a woman who had no sexual sensitivity in the clitoris, vagina, or labia, and no pleasure in coitus except in very strange positions, but possessed intense sexual feelings in the right nipple as well as in the upper third of the thigh.
It is remarkable that not only is suckling apt to be accompanied by sexual pleasure in the mother, but that, in some cases, the infant also appears to have a somewhat similar experience. This is, at all events, indicated in a remarkable case recorded by Féré (L'Instinct Sexuel, second edition, p. 257). A female infant child of slightly neurotic heredity was weaned at the age of 14 months, but so great was her affection for her mother's breasts, though she had already become accustomed to other food, that this was only accomplished with great difficulty and by allowing her still to caress the naked breasts several times a day. This went on for many months, when the mother, becoming again pregnant, insisted on putting an end to it. So jealous was the child, however, that it was necessary to conceal from her the fact that her younger sister was suckled at her mother's breasts, and once at the age of 3, when she saw her father aiding her mother to undress, she became violently jealous of him. This jealousy, as well as the passion for her mother's breasts, persisted to the age of puberty, though she learned to conceal it. At the age of 13, when menstruation began, she noticed in dancing with her favorite girl friends that when her breasts came in contact with theirs she experienced a very agreeable sensation, with erection of the nipples; but it was not till the age of 16 that she observed that the sexual region took part in this excitement and became moist. From this period she had erotic dreams about young girls. She never experienced any attraction for young men, but eventually married; though having much esteem and affection for her husband, she never felt any but the slightest sexual enjoyment in his arms, and then only by evoking feminine images. This case, in which the sensations of an infant at the breast formed the point of departure of a sexual perversion which lasted through life, is, so far as I am aware, unique.
Jonas Cohn (Allgemeine Æsthetik, 1901, p. 11) lays it down that psychology has nothing to do with good or bad taste. "The distinction between good and bad taste has no meaning for psychology. On this account, the fundamental conceptions of æsthetics cannot arise from psychology." It may be a question whether this view can be accepted quite absolutely.