The methods by which the artificial stimulation of the genital organs is effected are extremely variable. The commonest way to masturbate is with the hands, but this is by no means the invariable practice. All kinds of little artifices are employed, partly to render it possible to masturbate unobserved in the presence of others, and partly in order to increase the intensity of the stimulus. Boys sometimes manipulate their genital organs through their trouser pockets; some even make a hole in the pocket to enable them to masturbate more effectually. In other cases, children, especially girls, lean against some article of furniture--a chair or a table--apparently in a harmless manner, but really in such a way that pressure is exercised upon the genital organs, which are stimulated by pressure or friction. In some, strong mechanical stimulation is required; in others, weaker stimuli suffice, because the way has previously been sufficiently prepared by psychical processes. In female children frequently, but less often in males, masturbation is effected by rubbing the crossed thighs one against the other. We learn from many girls that they tie a knot in the nightgown or chemise, and masturbate by rubbing this against the genital organs. I must allude also to horseback riding, working the treadle of a sewing machine, cycling, the vibration of a carriage or railway train in motion; we must, however, be careful not to attach undue importance to these factors of masturbation, for in such cases much depends upon the individuality, and much also upon the external mechanical conditions--- as, for instance, on the construction of the saddle used in cycling and the like. In the case of the male genital organs, the glans penis is the most sensitive portion, and mechanical stimulation of this structure in especial is likely to induce the practice of masturbation; in the case of the female genital organs, on the other hand, it is the clitoris which is most sensitive, and of which, therefore, we have especially to think in this connexion. But there is a tendency to overestimate the proportion of cases in which stimulation of the glans penis, in the male, or the clitoris, in the female, is the exciting cause of masturbation. In a very large number of cases of masturbation, it is not the glans, but some other portion of the penis, which is the focus of stimulation. In girls, also, in numerous instances, masturbation is effected by stimulation of the labia minora, and I am inclined to believe that the importance of the labia minora is in this respect not inferior to that of the clitoris. In solitude, and above all in bed, masturbation can naturally be effected much more readily. Some little girls grasp a pillow between their legs in such a way as to give rise to a masturbatory stimulus. Others introduce cylindrical objects into the vagina, a practice much commoner among fully-grown girls than among children. Still, physicians are sometimes called on to remove such