It may perhaps be necessary to remark that by sterilization is here meant, not castration, but, in the male vasectomy (and a corresponding operation in the female), a simple and harmless operation which involves no real mutilation and no loss of power beyond that of procreation. See on this and related points, Havelock Ellis, Studies in the Psychology of Sex, Vol. VI, "Sex in Relation to Society," chap. xii.

The term "feeble-minded" may be used generally to cover all degrees of mental weakness. In speaking a little more precisely, however, we have to recognize three main degrees of congenital mental weakness: feeble-mindedness, in which with care and supervision it is possible to work and earn a livelihood; imbecility, in which the subject is barely able to look after himself, and sometimes only has enough intelligence to be mischievous (the moral imbecile); and idiocy, the lowest depth of all, in which the subject has no intelligence and no ability to look after himself. More elaborate classifications are sometimes proposed. The method of Binet and Simon renders possible a fairly exact measurement of feeble-mindedness.

Mott (Archives of Neurology and Psychiatry, Vol. V, 1911) accepts the view that in some cases feeble-mindedness is simply a form of congenital syphilis, but he points out that feeble-mindedness abounds in many rural districts where syphilis, as well as alcoholism, is very rare, and concludes by emphasizing the influence of heredity; the prevalence of feeble-mindedness in these rural districts is thus due to the fact that the mentally and physically fit have emigrated to the great industrial centres, leaving the unfit to procreate the race.