Various parts of the skin surface appear to have special sexual sensitiveness, peculiarly marked in many individuals, especially women; so that, as Féré remarks (_L'Instinct Sexuel_, second edition, 1902, p. 130), contact stimulation of the lips, lobe of ear, nape of neck, little finger, knee, etc., may suffice even to produce the orgasm. Some sexually hyperæsthetic women, as has already been noted, experience this when shaking hands with a man who is attractive to them. In some neurotic persons this sensibility, as Féré shows, may exist in so morbid a degree that even the contact of the sensitive spot with unattractive persons or inanimate objects may produce the orgasm. In this connection reference may be made to the well-known fact that in some hysterical subjects there are so-called "erogenous zones" simple pressure on which suffices to evoke the complete orgasm. There is, perhaps, some significance, from our present point of view, in the fact that, as emphasized by Savill ("Hysterical Skin Symptoms," _Lancet_, January 30, 1904), the skin is one of the very best places to study hysteria. The intimate connection between the skin and the sexual sphere is also shown in pathological conditions of the skin, especially in acne as well as simple pimples on the face. The sexual development of puberty involves a development of hair in various regions of the body which previously were hairless. As, however, the sebaceous glands on the face and elsewhere are the vestiges of former hairs and survive from a period when the whole body was hairy, they also tend to experience in an abortive manner this same impulse. Thus, we may say that, with the development of the sexual organs at puberty, there is correlated excitement of the whole pilo-sebaceous apparatus. In the regions where this apparatus is vestigial, and notably in the face, this abortive attempt of the hair-follicles and their sebaceous appendages to produce hairs tends only to disorganization, and simple _comedones_ or pustular acne pimples are liable to occur. As a rule, acne appears about puberty and dies out slowly during adolescence. While fairly common in young women, it is usually much less severe, but tends to be exacerbated at the menstrual periods; it is also apt to appear at the change of life. (Stephen Mackenzie, "The Etiology and Treatment of Acne Vulgaris," _British Medical Journal_, September 29, 1894. Laycock [_Nervous Diseases of Women_, 1840, p. 23] pointed out that acne occurs chiefly in those parts of the surface covered by sexual hair. A lucid account of the origin of acne will be found in Woods Hutchinson's _Studies in Human and Comparative Pathology_, pp. 179-184. G.J. Engelmann ["The Hystero-neuroses," _Gynæcological Transactions_, 1887, pp. 124 et seq.] discusses various