On the objective side, then, the nipple is to be regarded as an erectile organ, richly supplied with nerves and vessels, which, under the stimulation of the infant's lips--or any similar compression, and even under the influence of emotion or cold,--becomes firm and projects, mainly as a result of muscular contraction; for, unlike the penis and the clitoris, the nipple contains no true erectile tissue and little capacity for vascular engorgement.[19] We must then suppose that an impetus tends to be transmitted through the spinal cord to the sexual organs, setting up a greater or less degree of nervous and muscular excitement with uterine contraction. These being the objective manifestations, what manifestations are to be noted on the subjective side?
It is a remarkable proof of the general indifference with which in Europe even the fairly constant and prominent characteristics of the psychology of women have been treated until recent times that, so far as I am aware,--though I have made no special research to this end,--no one before the end of the eighteenth century had recorded the fact that the act of suckling tends to produce in women voluptuous sexual emotions. Cabanis in 1802, in the memoir on "Influence des Sexes" in his _Rapports du Physique et du Moral de l'Homme_, wrote that several suckling women had told him that the child in sucking the breast made them experience a vivid sensation of pleasure, shared in some degree by the sexual organs. There can be no doubt that in healthy suckling women this phenomenon is exceedingly common, though in the absence of any methodical and precise investigation it cannot be affirmed that it is experienced by every woman in some degree, and it is highly probable that this is not the case. One lady, perfectly normal, states that she has had stronger sexual feelings in suckling her children than she has ever experienced with her husband, but that so far as possible she has tried to repress them, as she regards them as brutish under these circumstances. Many other women state generally that suckling is the most delicious physical feeling they have ever experienced. In most cases, however, it does not appear to lead to a desire for intercourse, and some of those who make this statement have no desire for coitus during lactation, though they may have strong sexual needs at other times. It is probable that this corresponds to the normal condition, and that the voluptuous sensations aroused by suckling are adequately gratified by the child. It may be added that there are probably many women who could say, with a lady quoted by Féré,[20] that the only real pleasures of sex they have ever known are those derived from their suckling infants.