Masturbation is sometimes practised in very early childhood, being then commonly due to local irritation of some kind, as for instance when threadworms find their way into the vagina. Itching results, leading the child to rub the genital organs. This rubbing produces a pleasurable sensation, and gives rise to repeated masturbation. But in adolescent girls at the time of the menarche, a vague impulse arises to handle the genital organs, depending upon cerebral processes which are themselves the result of sexual sentiments, of reading, or of conversations with sexually instructed female friends. This vague impulse may lead to masturbation, and will do so earlier and more surely if the girl is a neuropsychopath by inheritance. The local influence of menstrual congestion, however, also plays a part in provoking the impulse toward masturbation, since at every period a hyperæsthetic state recurs in the genital organs. Girls thus addicted have sometimes a very striking general appearance. They are pale, with a weary expression of countenance, their eyes are dull-looking and darkly ringed, their movements are sluggish, they like to spend a long time in bed—signs, however, which I by no means wish to adduce as characteristic of onanists. Temperament and mode of life are decisive in determining the greater or less frequency of the habit of masturbation in young girls. Girls of a passionate temperament, those also who from early childhood have been accustomed to mix much with young persons of the opposite sex, and those, finally, in whom from conversation on the subject with female friends or from the perusal of erotic literature, sexual enlightenment has occurred at an early age, experience the awakening of the sexual impulse earlier and with greater force, than phlegmatic girls, than those who have grown up apart from boys, and than those who have been strictly and carefully brought up. Masturbation may arise either instinctively or from instruction. In young girls masturbation is usually effected by friction of the clitoris; less often by intra-vaginal manipulation, since this is liable to lead to injury to the hymen. For the former purpose the finger may be used; or some other article, such as a knot tied in the nightgown, or a rounded projection on some article of furniture; in one case the friction was effected by the naked heel. If two female onanists come together, they practice tribadism, presently to be described. Opportunity for this practice occurs especially in institutions in which young girls occupy a common dormitory, and sleep together without adult supervision.