pathological disorders of the skin as reflex disturbances originating in the sexual sphere.) The influence of menstruation in exacerbating acne has been called in question, but it seems to be well established. Thus, Bulkley ("Relation between Certain Diseases of the Skin and the Menstrual Function," _Transactions of the Medical Society of New York_, 1901, p. 328) found that, in 510 cases of acne in women, 145, or nearly one-third, were worse about the monthly period. Sometimes it only appeared during menstruation. The exacerbation occurred much more frequently just before than just after the period. There was usually some disturbance of menstruation. Various other disorders of the skin show a similar relationship to menstruation. It has been asserted that masturbation is a frequent or constant cause of acne at puberty. (See, e.g., discussion in _British Medical Journal_, July, 1882.) This cannot be accepted. Acne very frequently occurs without masturbation, and masturbation is very frequently practiced without producing acne. At the same time we may well believe that at the period of puberty, when the pilo-sebaceous system is already in sensitive touch with the sexual system, the shock of frequently repeated masturbation may (in the same way as disordered menstruation) have its repercussion on the skin. Thus, a lady has informed me that at about the age of 18 she found that frequently repeated masturbation was followed by the appearance of _comedones_. FOOTNOTES: [2] A. Franklin, _Les Soins de Toilette_, p. 81. [3] W. James, _Principles of Psychology_, vol. ii. p. 347. [4] Numerous passages from the theologians bearing on this point are brought together in _Moechialogia_, pp. 221-220. II. Ticklishness--Its Origin and Significance--The Psychology of Tickling--Laughter--Laughter as a Kind of Detumescence--The Sexual Relationships of Itching--The Pleasure of Tickling--Its Decrease with Age and Sexual Activity.