The eugenic significance of assortative mating is obvious. Marriage of representatives of two long-lived strains ensures that the offspring will inherit more longevity than does the ordinary man. Marriage of two persons from gifted families will endow the children with more than the ordinary intellect. On the other hand, marriage of two members of feeble-minded strains (a very common form of assortative mating) results in the production of a new lot of feeble-minded children, while marriage contracted between families marked by criminality or alcoholism means the perpetuation of such traits in an intensified form. For alcoholism, Charles Goring found the resemblance between husband and wife in the following classes to be as follows: Very poor and destitute .44 Prosperous poor .58 Well-to-do .69 The resemblance of husband and wife, in respect of possession of a police record, he found to be .20. Of course alcoholism and criminality are not wholly due to heredity; the resemblance between man and wife is partly a matter of social influences. But in any case the existence of assortative mating for such traits is significant. 3. Preferential mating occurs when certain classes of women are discriminated against by the average man, or by men as a class; or _vice versa_. It is the form of sexual selection made prominent by Charles Darwin, who brought it forward because natural selection, operating solely through a differential death-rate, seemed inadequate to account for many phases of evolution. By sexual selection he meant that an individual of one sex, in choosing a mate, is led to select out of several competitors the one who has some particular attribute in a high degree. The selection may be conscious, and due to the exercise of aesthetic taste, or it may be unconscious, due to the greater degree of excitation produced by the higher degree of some attribute. However the selection takes place, the individual so selected will have an opportunity to transmit his character, in the higher degree in which he possesses it, to his descendants. In this way it was supposed by Darwin that a large proportion of the ornamental characters of living creatures were produced: the tail of the peacock, the mane of the lion, and even the gorgeous coloring of many insects and butterflies. In the early years of Darwinism, the theory of sexual selection was pushed to what now seems an unjustifiable extent. Experiment has often failed to demonstrate any sexual selection, in species where speculation supposed it to exist. And even if sexual selection, conscious or unconscious, could be demonstrated in the lower animals, yet the small percentage of unmated individuals indicates that its importance in evolution could not be very great.[96] [Illustration: HOW BEAUTY AIDS A GIRL'S CHANCE OF MARRIAGE