should be called in question, but the wisdom and good sense of the speaker. We ought to expect a head-master to possess both an adequate acquaintance with the nature of the phenomena of auto-erotism and homosexuality, and a reasonable amount of tact in dealing with boys; he may then fairly be trusted to exercise his own judgment. It may be doubted whether boys should be made too alive to the existence of sexual phenomena; there can be no doubt about their teachers. The same is, of course, true as regards girls, among whom the same phenomena, though less obtrusive, are not less liable to occur. As to whether masturbation is more common in one sex than the other, there have been considerable differences of opinion. Tissot considered it more prevalent among women; Christian believed it commoner among men; Deslandes and Iwan Bloch hold that there are no sexual differences, and Garnier was doubtful. Lawson Tait, in his _Diseases of Women_, stated his opinion that in England, while very common among boys, it is relatively rare among women, and then usually taught. Spitzka, in America, also found it relatively rare among women, and Dana considers it commoner in boys than in girls or adults.[307] Moll is inclined to think that masturbation is less common in women and girls than in the male sex. Rohleder believes that after puberty, when it is equally common in both sexes, it is more frequently found in men, but that women masturbate with more passion and imaginative fervor.[308] Kellogg, in America, says it is equally prevalent in both sexes, but that women are more secretive. Morris, also in America, considers, on the other hand, that persistent masturbation is commoner in women, and accounts for this by the healthier life and traditions of boys. Pouillet, who studied the matter with considerable thoroughness in France, came to the conclusion that masturbation is commoner among women, among whom he found it to be equally prevalent in rich and poor, and especially so in the great centres of civilization. In Russia, Guttceit states in his _Dreissig Jahre Praxis_, that from the ages of 10 to 16 boys masturbate more than girls, who know less about the practice which has not for them the charm of the forbidden, but after 16 he finds the practice more frequent in girls and women than in youths and men. Näcke, in Germany, believes that there is much evidence pointing in the same direction, and Adler considers masturbation very common in women. Moraglia is decidedly of the opinion, on the ground of his own observations already alluded to, that masturbation is more frequent among women; he refers to the fact--a very significant fact, as I shall elsewhere have to point out--that, while in man there is only one sexual centre, the penis, in woman there are several centres,--the clitoris, the vagina, the uterus, the breasts,[309]--and he mentions that he knew a prostitute, a well-developed