Now, if the female of the species is to exercise discernment before she succours her young, if her action is to be deliberative and not impulsive, what becomes of those variations which, when happy, lead to a new development of the species, or actually to a new variety of species? Happy variations are just as odd—_qua_ type—as unhappy variations. But if the female’s instinct is to preserve life, it will preserve one just as passionately as the other. Discrimination would prove fatal to both. The very process of organic evolution, if it be a fact, therefore depends upon the lack of discrimination in the motherly instinct, and the hypothesis of organic evolution certainly assumes it. This instinct in the female to succour young life of any kind, therefore, is useful to Nature’s scheme. It is an indispensable factor in Nature’s plan. In the lower animals it is demonstrated by the ease with which a female of one species can be made to act as foster-mother to the young of another. Books on natural history mention many such cases: cats that have reared leverets and young squirrels,[204] hens that rear ducklings, and the classical natural instance of birds like the Pipit, the Water Wagtail, etc., rearing the young of the cuckoo.[205] The latter, of course, is a parasitic abuse in Nature, of the female’s undiscriminating instinct to succour; but it is nevertheless, an excellent example of the fact I have been trying to establish. It is true that in the human species this lack of discrimination in the female operates as a preserver both of desirable and undesirable varieties; but, as in all modern civilizations, the father is no longer allowed, as he was by ancient Sparta or Rome, to override the female’s lack of taste in this matter, and unsuccessful variations from type are more common than geniuses, it follows that the female’s point of view, now that it is supported by the State and public opinion, must lead to the survival of a vast number of undesirable human beings in our midst. Thus, although the human female’s instinct is seen to be a vital one, and though her lack of taste must be regarded as part of the general scheme of life, it must tend nowadays to an enormous amount of degeneration.