Cabanis seems to have realized the significance of this connection as the basis of the sympathy between mother and child, and more recently Lombroso and Ferrero have remarked (La Donna Delinquente, p. 438) on the fact that maternal love has a sexual basis in the element of venereal pleasure, though usually inconsiderable, experienced during suckling.  Houzeau has referred to the fact that in the majority of animals the relation between mother and offspring is only close during the period of lactation, and this is certainly connected with the fact that it is only during lactation that the female animal can derive physical gratification from her offspring.  When living on a farm I have ascertained that cows sometimes, though not frequently, exhibit slight signs of sexual excitement, with secretion of mucus, while being milked; so that, as the dairymaid herself observed, it is as if they were being “bulled.”  The sow, like some other mammals, often eats her own young after birth, mistaking them, it is thought, for the placenta, which is normally eaten by most mammals; it is said that the sow never eats her young when they have once taken the teat.

It occasionally happens that this normal tendency for suckling to produce voluptuous sexual emotions is present in an extreme degree, and may lead to sexual perversions.  It does not appear that the sexual sensations aroused by suckling usually culminate in the orgasm; this however, was noted in a case recorded by Fere, of a slightly neurotic woman in whom intense sexual excitement occurred during suckling, especially if prolonged; so far as possible, she shortened the periods of suckling in order to prevent, not always successfully, the occurrence of the orgasm (Fere, Archives de Neurologie No. 30, 1903).  Icard refers to the case of a woman who sought to become pregnant solely for the sake of the voluptuous sensations she derived from suckling, and Yellowlees (Art.  “Masturbation,” Dictionary of Psychological Medicine) speaks of the overwhelming character of “the storms of sexual feeling sometimes observed during lactation.”

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.