4. =Emphasize bodily and mental purity.=--All schools should teach explicitly in due season those elements of good manners and customs which have to do with health and the preservations of bodily and mental purity. They should teach habitual cleanliness of the body and particularly of the hands and face, point out the importance of this cleanliness as regards clothes, furniture and utensils, and the reasons for keeping the dwelling free from dust, dirt, insects and vermin. They should show the reasons for avoiding contact with, or close approach to, persons who are unclean or who are suffering from colds, sores, coughs, fevers, or any other illness. They should point out the dangers of losing self-control through the use, even the rare use, of alcohol or of drugs which take strong effect on the nervous system. They should discountenance rough or boisterous play between boys and girls or young men and young women, and teach each sex to avoid, in general, bodily contact with persons of the opposite sex. Delicacy and reserve are parts of good manners; but they are also highly protective qualities. On the other hand, a coarse familiarity between the sexes is not only bad manners, but a real provocation to wrong-doing, particularly when it is accompanied by an ignorance which leaves young people without protection against the love of excitement and reckless adventure. All these are elements of good manners and right habits which should be universally taught in the schools of a democracy to promote morality as well as courtesy. Some of them, but rarely all, are taught in many good homes, but for the great mass of the people the public schools inculcate them by direct teaching, and by the indirect influence of good example. To a high degree, good manners spring from and express morals. Such instruction would naturally be associated with the teaching of natural history and general hygiene.