Personal hygiene means a sound body and mind. It means the preservation of health, which was humanity’s effort since time immemorial. Personal hygiene is as old as civilization. The Bible devotes many a chapter to personal hygiene. The ancient Greeks spent a considerable part of the day in exercise, games, etc., in the interest of personal hygiene. The celebrated Roman baths were established in the interest of the hygienic development of the body. The Roman maxim was, “mens sana in corpore sano.” As far as humanity is concerned, the most important part in the science of sexuality is the hygiene of the vita sexualis. Preventive medicine will score its greatest successes in the field of sexual diseases. If the rules of personal hygiene are followed they may prevent many an anomaly which, when once established, is seldom amenable to treatment. Especially does the principle, “prevention is the best cure,” hold good in the anomalies of anaesthesia. In almost ninety-nine cases out of a hundred these anomalies are contracted through the patient’s own recklessness and fault. If the patient could be guarded against sexual excesses, the main cause of impotence in all its ramifications would be removed. But the necessity of avoiding certain things requires a proper insight into the nature of these things. To be good requires a proper knowledge of the evil. “We cannot,” says Hain Friswell (Essays on English writers), “be good by pretending not to know evil. When women go mad, the most innocent, the youngest, the most purely educated often utter the most horrid and obscene language; a proof that to them evil has been known; how acquired, how taught, it is vain to ask. What the teacher ought to seek is, not to blot out and veil iniquity, since that will always be visible, but to make the heart strong enough to cast out the evil.” To accomplish this end proper instruction in matters of sex is a condition sine qua non. The instruction should begin before the sexual idea has an emotional garb. When the habit of masturbation has once been contracted, it is very hard to break it; when promiscuous life has been tasted, all knowledge of its dangers will seldom protect the individual from continuing such a life.[BJ]