The problem commences, then, with puberty. And here a warning should be uttered against that school of reformers which tends to the view that sex can be regarded as naturally and as publicly as natural history or chemistry. This attitude ignores the fact that there is such a quality as sexual appetite. And consequently, sex education should be rather a matter for individuals than for public instruction. We have remarked that the parent may not infrequently be an unfortunate educator. But where these objections do not arise, the home is an admirable atmosphere for sensible teaching. The Catholic Church possesses the invaluable medium of the Confessional, and where the Confessor can give sound sex instruction no better opportunity can be imagined. There remains the school, but even here better work will be done in the study than the classroom. The immediate problem in the early post-puberty age is the tendency towards solitary practices. It must be recognized that this is usual with all children, and that there is no evidence to show that, save in extreme exceptions, physical harm results. All attempt at _alarmist prudism_ must be abandoned. Sane instruction will tend rather to emphasize that sex abuse is due to a weakness of will-power, and that man is most manly, i.e. most removed from the animal, in the exercise of will-power. All education should contain that subject which is at present consistently ignored, namely, the art of thought-control. The child will be interested to follow certain simple rules of mental exercise, and where this is followed the liability to indulge in sex-acts diminishes. It is this element which must be emphasized, the fact, that is, that solitary practices are usually the result of an inability to exercise the will and control the mind.