are analogies that cannot be denied when human attractions and chemotropism are compared. I may refer as an instance to the relation between Edward and Ottilie in Goethe's "Wahlverwandtschaften."
Mention of Goethe's romance leads naturally to a discussion of the marriage problem, and I may here give a few of the practical inferences which would seem to follow from the theoretical considerations of this chapter. It is clear that a natural law, not dissimilar to other natural laws, exists with regard to sexual attraction; this law shows that, whilst innumerable gradations of sexuality exist, there always may be found pairs of beings the members of which are almost perfectly adapted to one another. So far, marriage has its justification, and, from the standpoint of biology, free love is condemned. Monogamy, however, is a more difficult problem, the solution of which involves other considerations, such as periodicity, to which I shall refer later, and the change of the sexual taste with advancing years.
A second conclusion may be derived from heterostylism, especially with reference to the fact that "illegitimate fertilisation" almost invariably produces less fertile offspring. This leads to the consideration that amongst other forms of life the strongest and healthiest offspring will result from unions in which there is the maximum of sexual suitability. As the old saying has it, "love-children" turn out to be the finest, strongest, and most vigorous of human beings. Those who are interested in the improvement of mankind must therefore, on purely hygienic grounds, oppose the ordinary mercenary marriages of convenience.
It is more than probable that the law of sexual attraction may yield useful results when applied to the breeding of animals. More attention will have to be given to the secondary sexual characters of the animals which it is proposed to mate. The artificial methods made use of to secure the serving of mares by stallions unattractive to them do not always fail, but are followed by indifferent results. Probably an obvious result of the use of a substituted stallion in impregnating a mare is the extreme nervousness
