Plato, indeed, in spite of his idealism, is often very practical, and on the question of marriage his doctrine is most sound. The simple law of marriage is this: A man _must_ marry before he is thirty-five; if not, he shall be fined and lose all his privileges. Mankind are immortal because they leave children behind them; and for a man to deprive himself of immortality is impiety. He who obeys the law shall be free and pay no fine; but the disobedient shall pay a yearly fine, in order that he may not imagine that his celibacy will bring him ease or profit: moreover, he shall not share in any of the honours which the State gives to the aged. Marriage is to be regarded as a duty, and ‘every man shall follow, not after the marriage which is most pleasing to himself, but after that which is most beneficial to the State.’ This cannot be effected by definite regulations, but we should ‘try and charm the spirits of men into believing’ that their children are of more importance than themselves, and that a child’s disposition will depend upon the happy blending of its parents. Plato realises that children are the State’s vital interest, and his concern for them extends to the period before birth. Husband and wife are to consider how they are to produce for the State the best and fairest specimens of children which they can. If proper attention is given to anything, success is certain; and the eugenic system is to be under the definite control of a committee of women, who shall meet every day and spend a third part of the day in ensuring that the regulations for perfect births are duly carried out. Their care is to be expressly extended to the future mothers, for the period of a child’s life before birth is equally decisive, and the young wife must be carefully tended, kept from excessive pleasures or pains, and be encouraged to cultivate habits of gentleness, benevolence, and kindness. Then comes the proper management of infants, and Plato is very convinced of the importance of constant motion for the young child, who in a Greek household was often closely bandaged in swaddling clothes and left to its own resources. He anticipates Aristippus, who, holding that pleasure was the chief end of life, found the best definition of pleasure to be ‘a gentle motion,’ and he is prepared to make his ideal state for infants at least a pleasant one. The first principle in relation both to the body and soul of very young children is that nursing and moving about by day and night is good for them all, and that the younger they are the more they will need it. Infants should live, if it were possible, as if they were always rocking at sea. Exercise and motion in the earliest years greatly contribute to create a part of virtue in the soul: the child’s virtue is cheerfulness, and good nursing makes a gentle and a cheerful child.