This question cannot be answered in other than most general terms. The author has known one case of a young man who, for several years, practiced masturbation several times a day, so far depleting his powers that he could not walk erect, his muscles were flabby, his testes were very soft and small, his eyes shifty, his hands clammy and his mind incoherent in its working. He seemed to be a candidate for the asylum and would probably have gone there if radical means had not been adopted to break him of the habit. He was broken, however, absolutely, and never performed the act after his nineteenth birthday. Within three years he had completely recovered his virility. He had nearly doubled in weight and in lung capacity and a large part of his increased weight was in great bulk of muscle of high tonicity--muscle which he had gained by heavy physical work upon a ranch. His sexual organs had completely regained their tonicity and without doubt, their virility. He had so far recovered mentally that he finished a course of professional study and entered with great success upon the practice of his chosen profession. On the other hand, a middle-aged man consulted the author regarding the sterility of his wife. After examination, it was found that the husband had practiced masturbation about twice a week from the age of puberty to his twenty-fourth year, when he was married. He assured the author that at the time of his marriage his testicles were, as far as he had known, similar to the testicles of other young men, and that during his married life he had never had intercourse with his wife more frequently than once in a month, but that during that time he had noticed a gradual atrophy of the testes. At the time of the examination only small atrophied remains of these testes could be discovered. The sterility of the wife was due, without any question, to the absolute impotence of the husband, and so far as the history of the case would suggest, there was no other assignable cause of this impotence than the eight years of masturbation. From these two cases, it must be evident that no rules can be laid down. In one case the subject recovered fully from a case of extreme masturbation; in the other-case, a habit that would not be called extreme resulted in impotence. It must be evident that the practice is a dangerous one after puberty, as no individual can tell to which of the above cases his may be similar. 10. _Granting that masturbation is harmful through loss of semen, is there any compensation for this loss of semen in case of intercourse with a woman?_