It has already been stated that the immediate physical results of self-abuse are small evils indeed compared with the corruption of mind which comes from perverted sex ideas. They are, however, by no means negligible; and are, in some cases, very serious. The great prevalence of self-abuse among boys, combined with the inevitable uncertainty as to the degree of a boy's freedom from, or indulgence in, this vice, makes it very difficult to institute a reliable comparison between those who are chaste and those who are unchaste. Greater significance attaches, I think, to a comparison in individual cases of a boy's condition during a period of indulgence in masturbation and his condition after its total, or almost total, relinquishment. I have no hesitation in saying that the difference in a boy's vitality and spiritual tone after relinquishing this habit is very marked. The case _D_ quoted in Chapter I. is, in this respect, typical. In my pamphlet, _Private Knowledge for Boys_, I have quoted a striking passage from Acton on the Reproductive Organs, in which he contrasts the continent and the incontinent boy. But in the case of men like Dr. Acton--specialists in the diseases of the male reproductive organs--it must be remembered that it is mostly the abnormal and extreme cases which come under their notice: a fact which is liable to affect their whole estimate. The book can be recommended to adults who wish to see the whole subject of sex diseases dealt with by a specialist who writes with a high moral purpose. My own estimate is given in the pamphlet already referred to. After quoting Dr. Acton's opinion, I add:--