Not only is feeble-mindedness inherited, and to a much greater degree than has hitherto been suspected even by expert authorities, but the feeble-minded thus tend (though, as Davenport and Weeks have found, not invariably) to have a larger number of children than normal people. That indeed, we might expect, apart altogether from the question of any innate fertility. The feeble-minded have no forethought and no self-restraint. They are not adequately capable of resisting their own impulses or the solicitations of others, and they are unable to understand adequately the motives which guide the conduct of ordinary people. The average number of children of feeble-minded people seems to be frequently about one-third more than in normal families, and is sometimes much greater. Dr. Ettie Sayer, when investigating for the London County Council the family histories of one hundred normal families and one hundred families in which mentally defective children had been found, ascertained that the families of the latter averaged 7.6 children, while in the normal families they averaged 5. Tredgold, specially investigating 150 feeble-minded cases, found that they belonged to families in which 1269 children had been born, that is to say 7.3 per family, or, counting still-born children, 8.4. Nearly two-thirds of these abnormally large families were mentally defective, many showing a tendency to disease, pauperism, criminality, or else to early death.[32]
Here, indeed, we have a counterbalancing influence, for, in the large families of the feeble-minded, there is a correspondingly large infantile mortality. A considerable proportion of Tredgold's group of children were born dead, and a very large number died early. Eichholz, again, found that, in one group of defective families, about sixty per cent of the children died young. That is probably an unusually high proportion, and in Eichholz's cases it seems to have been associated with very unusually large families, but the infant mortality is always very high.
This large early mortality of the offspring of the feeble-minded is, however, very far from settling the question of the disposal of the mentally defective, or we should not find families of them propagated from generation to generation. The large number who die early merely serves, roughly speaking, to reduce the size of the abnormal family to the size of a normal family, and some authorities consider that it scarcely suffices to do this, for we must remember that there is a considerable mortality even in the so-called normal family during early life. Even when there is no abnormal fertility in the defective family we may still have to recognize that, as Davenport and Weeks argue, their defectiveness is intensified by heredity. Moreover, we have to consider the social disorder and the heavy expense which accompany the large infantile mortality. Illegitimacy is frequently the result of feeble-mindedness, since feeble-minded women are peculiarly unable to resist temptation. A great number of such women are continually coming into the workhouses and giving birth to illegitimate children whom they are unable to support, and who often never become capable of supporting themselves, but in their turn tend to produce a new feeble-minded generation, more especially since the men who are attracted to these feeble-minded women are themselves--according to the generally recognized tendency of the abnormal to be attracted to the abnormal--feeble-minded or otherwise mentally defective. There is thus generated not only a heavy financial burden, but also a perpetual danger to society, and, it may well be, a serious depreciation in the quality of the community.[33]