INTRODUCTION

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