Exact investigation is now showing that feeble-mindedness is passed on from parent to child to an enormous extent. Some years ago Ashby, speaking from a large experience in the North of England, estimated that at least seventy-five per cent of feeble-minded children are born with an inherited tendency to mental defect. More precise investigation has since shown that this estimate was under the mark. Tredgold, who in England has most carefully studied the heredity of the feeble-minded, [29] found that in over eighty-two per cent cases there is a bad nervous inheritance. In a large number of cases the bad heredity was associated with alcoholism or consumption in the parentage, but only in a small proportion of cases (about seven per cent) was it probable that alcoholism and consumption alone, and usually combined, had sufficed to produce the defective condition of the children, while environmental conditions only produced mental defect in ten per cent cases. [30] Heredity is the chief cause of feeble-mindedness, and a normal child is never born of two feeble-minded parents. The very thorough investigation of the heredity of the feeble-minded which is now being carried on at the institution for their care at Vineland, New Jersey, shows even more decisive results. By making careful pedigrees of the families to which the inmates at Vineland belong it is seen that in a large proportion of cases feeble-mindedness is handed on from generation to generation, and is traceable through three generations, though it sometimes skips a generation. In one family of three hundred and nineteen persons, one hundred and nineteen were known to be feeble-minded, and only forty-two known to be normal. The families tended to be large, sometimes very large, most of them in many cases dying in infancy or growing up weak-minded. [31]
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]
It is not only in themselves that the feeble-minded are a burden on the present generation and a menace to future generations. In large measure they form the reservoir from which the predatory classes are recruited. This is, for instance, the case as regards prostitutes. Feeble-minded girls, of fairly high grade, may often be said to be predestined to prostitution if left to themselves, not because they are vicious, but because they are weak and have little power of resistance. They cannot properly weigh their actions against the results of their actions, and even if they are intelligent enough to do that, they are still too weak to regulate their actions accordingly. Moreover, even when, as often happens among the high-grade feeble-minded, they are quite able and willing to work, after they have lost their "respectability" by having a child, the opportunities for work become more restricted, and they drift into prostitution. It has been found that of nearly 15,000 women who passed through Magdalen Homes in England, over 2500, or more than sixteen per cent—and this is probably an under-estimate—were definitely feeble-minded. The women belonging to this feeble-minded group were known to have added 1000 illegitimate children to the population. In Germany Bonhoeffer found among 190 prostitutes who passed through a prison that 102 were hereditarily degenerate and 53 feeble-minded. This would be an over-estimate as regards average prostitutes, though the offences were no doubt usually trivial, but in any case the association between prostitution and feeble-mindedness is intimate. Everywhere, there can be no doubt, the ranks of prostitution contain a considerable proportion of women who were, at the very outset, in some slight degree feeble-minded, mentally and morally a little blunted through some taint of inheritance. [34]
Criminality, again, is associated with feeble-mindedness in the most intimate way. Not only do criminals tend to belong to large families, but the families that produce feeble-minded offspring also produce criminals, while a certain degree of feeble-mindedness is extremely common among criminals, and the most hopeless and typical, though fortunately rare, kind of criminal, frequently termed a "moral imbecile," is nothing more than a feeble-minded person whose defect is shown not so much in his intelligence as in his feelings and his conduct. Sir H.B. Donkin, who speaks with authority on this matter, estimates that, though it is difficult to obtain the early history of the criminals who enter English prisons, about twenty per cent of them are of primarily defective mental capacity. This would mean that every year some 35,000 feeble-minded persons are sent to English prisons as "criminals." The tendency of criminals to belong to the feeble-minded class is indeed every day becoming more clearly recognized. At Pentonville, putting aside prisoners who were too mentally affected to be fit for prison discipline, eighteen per cent of the adult prisoners and forty per cent of the juvenile offenders were found to be feeble-minded. This includes only those whose defect is fairly obvious, and is not the result of methodical investigation. It is certain that such methodical inquiry would reveal a very large proportion of cases of less obvious mental defect. Thus the systematic examination of a number of delinquent children in an Industrial School showed that in seventy-five per cent cases