Page:EB1922 - Volume 31.djvu/34

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in institutions, but morons possess sufficient intelligence to struggle along in the lowest social grade and in the poorest-paid employments, and just these grades of society which produce an enormous crowd of children which in former times died out but which our philanthropists now endeavour to keep alive at the expense of taxes levied on the better grades of society.

The gradual lowering of the grade of mental capacity in the whole population which must result from these conditions is not the full extent of the evil. Not only are the morons defective in intelligence, they are also defective in self-control which is the basis of all morality. American investigators have applied the Simon-Binet tests in certain large American cities to the delinquents who appear before police-courts: and their results point to the conclusion that a large proportion of the thieves, prostitutes and habitual drunkards are mental defectives. In one case, to give one example, it was found that 50% of prostitutes were indubitably feeble-minded and this proportion was arrived at when a large number of doubtful cases had been put down as normal.[1] There seems to be no tendency such as Lombroso postulated in these unfortunates to commit crime for its own sake; their crimes are simply due to an inability to control the tendency to the gratification of their own desires and passions, irrespective of the consequences to others and to themselves.

Dr. Goddard points out that there are two totally different kinds of inebriates to be met with, viz. (i) ordinary people who have lapsed into drinking habits but who are quite capable, if they become sufficiently frightened, of being completely cured, and (2) morons, ready to repent with tears and to sign any pledge, but certain within a week to plunge again into intemperance.

These conclusions which run counter to so many popular prejudices have naturally awakened much criticism and opposition. It should be stated that Dr. Goddard's work has been repeated at various places in the United States, and that similar results have been obtained, but it is to be feared that in many cases his extreme care and the constant repetition of his investigations which he practised have been omitted. Hence Dr. Heron[2] and Prof. Pearson[3] have pointed out that the methods of ascertaining the degree of mental defect were often extremely unsatisfactory and unconvincing and Goddard's methods of ascertaining the feeble-mindedness of the parents and other relatives of feeble-minded children have been criticized as being based on impressions which the investigators derived from mere gossip. On the face of it there is much in this objection, but on the whole Goddard's answer to it is satisfactory. He says first that the investigators were carefully trained so that their judgment could be relied on, and secondly that when different investigators examined the same case, at considerable intervals, they arrived at concordant results. From the point of view of students of heredity it is of far greater importance that the inheritability of mental defect should have been established in the carefully standardized investigations of Dr. Goddard than that obvious blunders should have been demonstrated in many of the parallel investigations carried out elsewhere.

A school of English social reformers of which Dr. Saleeby has been a prominent member have endeavoured to account for most of these cases of mental defect by the action of what they term racial poisons. They maintain that alcohol, when drunk in immoderate amounts, and the toxins of the venereal disease syphilis both attack the germ cells carried in the parents' bodies and not only tend to cause the production of diseased and defective children but that these children if they survive and reproduce likewise give rise to imperfect offspring. Now it is conceded on all hands that the toxins of syphilis do in certain cases penetrate the placenta, and interfere with the growth of the embryo; nay more, that the embryo itself may become infected. As a result horribly malformed and diseased infants are born, but when these survive they appear to get rid of the syphilitic infection before the completion of adolescence, and there is no reliable evidence that their germ cells are defective or diseased.

With regard to alcohol it seems clear that immoderate in- dulgence in alcohol about the time of conception and during pregnancy tends to produce children with weakened constitutions, but again there is little or no evidence that their germ cells are weakened. It is true that one investigator (Stockard) [4][5] claims to have proved that by making guinea-pigs inhale the vapour of absolute alcohol for several hours daily he succeeded in causing them to produce weakened offspring. In these young guinea-pigs injuries to the eyes and nervous system were prominent, and these weaknesses were transmitted in increased degree to subsequent generations without further exposure to the influence of alcohol. The stock died out in the fourth or fifth generation. It would, however, be exceedingly rash to generalize from these experiments. Pearl[6] repeated them, using the domestic fowl instead of the guinea-pig, and found that the chicks produced by alcoholized parents were on the whole hardier than those whose parents were left untouched. The present writer has repeatedly introduced large quantities of absolute alcohol by subcutaneous injection into the bodies of white mice, so that they passed into a state of complete insensibility, yet even after repeated treatment of this kind they recovered and became the parents of offspring which were apparently quite healthy. Finally, considering the enormous extent to which alcohol has been consumed by the British nation during the last 300 years it is obvious that if any permanent injury had been done to the germ cells, it should be now a diseased and crippled nation instead of a virile people such as it sufficiently proved itself to be in the World War of 1914-8. That the causes of mental defect cannot be found in the alcoholism of the parents was definitely proved by Goddard. Of 300 children born of defective parents not alcoholic 99% were mentally defective; and of 130 children born of alcoholic defectives 985% were defective.

Mental defect must be assigned to the same cause as that which produces other types of Mendelian recessive. It is the common experience of all who have bred large numbers of animals or cultivated large numbers of plants, that from time to time Mendelian recessives turn up, and no more definite cause for their appearance has ever been suggested than that of "accidents of division" in the ripening germ cells. These recessives in many cases show varying degrees of defect which closely recall the grades of mental defect met with amongst the feeble-minded. For instance, in the cultures of the fruit-fly Drosophila ampelophila made by Prof. Morgan and his pupils various grades of blindness have appeared. The normal pigment necessary to the function of vision is of a dark red colour: complete albinos in which the eyes are white frequently occur, and also various imperfect grades of red classified by Morgan as cherry, eosin, etc. The occurrence of these defectives in the fruit-fly is certainly not attributable either to syphilis or to alcohol, and there is no more reason to attribute the occurrence of mental defectives in the human race to these causes than there is to assign these "race-poisons" as causes of the defectives in the fruit-fly.

As the results of the inquiry into the nature of human heredity are so startling and seem to involve such grave consequences it is obviously the first step in eugenic endeavour to make them as widely known as possible, so as to prepare public opinion for the practical steps which sooner or later must be taken. With this object the Eugenics Record Office was established in America by the Carnegie trustees and placed under the able presidency of Dr. Davenport. In England Sir Francis Gallon by a bequest in his will founded a chair of Eugenic Research in University

  1. Report of the Massachusetts Commission for the Investigation of the White Slave Traffic so-called.
  2. David Heron, Mendelism and the Problem of Mental Defect: I. A Criticism of Recent American Work, Biometric Laboratory Publications (Questions of the Day), No. 7.
  3. Karl Pearson and Gustav Jaederholm, Mendelism and the Problem of Mental Defect: II. The Continuity of Mental Defect, ibid., No. 8. Mendelism and the Problem of Mental Defect: HI. The Graduated Character of Mental Defect, etc., ibid., No. 9.
  4. C. R. Stockard and Dorothy Craig, "An Experimental Study of the Influence of Alcohol on the Germ-Cells," Archiv für Entwicklungsmechanik, vol. xxxv. (1913).
  5. C. R. Stockard and George N. Papamcolaou, "Further Studies of the Modification of Germ-Cells," Jour. Exp. Zool., vol. xxvi. (1918).
  6. R. Pearl, " The Experimental Modification of Germ-cells," pt. .i., Jour. Exp. Zool., vol. xxii. (1917).