At this period of life, no uncertain advice should be given by the physician. Support and guidance are required from him, and his counsel must be strong, positive, and clear. The patient must be taught that chastity, properly understood, is health. He must learn that the indications of sex in early manhood are a notice that the new faculties must be restrained--not exercised; that they give a warning to guard against self-abuse and abuse of the other sex; that the great danger to be dreaded is stimulation; that everything that can excite, whether external or internal, must be studiously avoided. The vital fact must be announced and powerfully brought home to him--that if he will keep the mind pure, Nature will keep the body healthy. This mental strength is his one great concern, to be secured in every possible way. There must be no doubt in medical advice; it must ring like the words of true science spoken by our distinguished surgeon to his students:[43] ‘Many of your patients will ask you about sexual intercourse, and some will expect you to prescribe fornication. I would just as soon prescribe theft or lying or anything else that God has forbidden.... Chastity does no harm to mind or body; its discipline is excellent; marriage can be safely waited for, and among the many nervous and hypochondriacal patients who have talked to me about fornication, I have never heard one say that he was better or happier for it.’[44] The radical importance of the medical advice given to youth will therefore be evident to all parents who perceive the full bearing of the truths contained in the preceding pages. No lesser consideration, no false feeling of reserve, should ever prevent the parent from knowing to which class of physicians the medical guidance of his son be intrusted.