heredity is so mixed that this ideal is not always practicable; and if any two persons wish to abandon it, society is hardly justified in interfering, unless the case be so gross as those which we were discussing in the first part of this chapter. Progress in this direction is to be expected mainly from the enlightened action of the individual. Much more progress in the study of heredity must be made before advice on marriage matings can be given in any except fairly obvious cases. The most that can now be done is to urge that a full knowledge of the family history of an intended life partner be sought, to encourage the discreet inquiries and subtle guidance of parents, and to appeal to the eugenic conscience of a young man or woman. In case of doubt the advice of a competent biologist should be taken. There is a real danger that high-minded people may allow some minor physical defect to outweigh a greater mental excellence.
There remains one other non-coercive method of influencing the distribution of marriage, which deserves consideration in this connection.
We have said that society can not well put many restrictions on