this group. The higher imbeciles and morons, possessed of the same physical appetites as the normal, but lacking the power of inhibition, are sure to reproduce in or out of wedlock if opportunity offers. We may then summarize present knowledge with reference to these individuals as follows: 1. Among those now known as feeble-minded are two types of persons: the first, comprising perhaps one-third of the total are victims of circumstances; are usually of low grade, are short lived and present to society a problem of support. The second type, embracing some two-thirds of the total, constitute a sub-species or variation from the normal, usually of higher grade and longer life, and presenting society a problem of reproduction and conduct as well as support. 2. This second type breeds true within itself and there is reason to suspect that it acts on Mendelian lines when crossed again with the normal. Out of 324 matings, Goddard found 708 feeble-minded where the theoretical expectation was 704, and 348 normal when the expectation was 352. He well says: "Such results are difficult to account for on any other basis than that feeble-mindedness is transmitted in accordance with the Mendelian formula . . . normal-mindedness, is, or at least behaves like, a unit character" and "is dominant." 12 3. We do not know the number of the feeble-minded, but the total in the United States must be upwards of 300,000. 4. Inasmuch as the feeble-minded are differently constituted from the normal they cannot support or conduct themselves as do ordinary people, and will therefore find their way in large numbers into the charitable and penal 12 GODDARD, H. H. o. c., p. 556. institutions. Dr. Goddard estimates that perhaps 50 per cent of the inmates of reformatory and penal institutions are feeble-minded. A similar estimate is often made with reference to prostitutes. Insanity, like feeble-mindedness, is a collective term used to designate many different types of trouble. It seems to be settled that a large part of insanity is due to some disease like syphilis, or to some vice like alcoholism or worry. There is abundant reason to believe, however, that there exists a certain weak or delicate nerve structure which is frequently transmitted generation after generation. Some alienists have stated that they do not know what insanity is, but that given this neurotic type, it is perfectly sure to manifest itself in insanity, epilepsy or alcoholism. In the following charts we have illustrations of the marriage of apparently normal individuals Affected Individuals Shaded. I Insane; E Epileptic; + Dead, facts unknown. 13 DAVENPORT, C. B. Heredity in Relation to Eugenics, p. 78. 14 Ibid., p. 79. in which this neurotic taint manifests itself in later generations, as well as a case in which it was evident at first. When we recall that the cost of caring for the insane in recent years amounts to about one-sixth of the entire expenditure of the state of New York, to about onetenth of that of Pennsylvania and that the number of insane is increasing apparently at the rate of 100 per cent per decade, the importance of determining its cause needs no discussion. In 1910 there were in the United States some 187,791 insane cared for in institutions. There is some evidence that certain forms of insanity like dementia-precox, and the manic-depressive type are directly inherited and act as recessives to the normal while a rather rare form known as Huntington's chorea is a dominant. A Michigan commission has recently reported that 65.4 per cent of 4,917 insane in the state showed tainted ancestry. Guyer describes a case given in the following diagram: INHERITANCE OF INSANITY 15 Epilepsy is a mysterious condition whose causes are unknown. The number of epileptics is perhaps equal to that of the feeble-minded though much less attention has been paid to them. Their relationship to the feebleminded and the insane is obscure and yet seems to be real. Dr. D. F. Weeks, who is in charge of the Institution 15 GUYER, M. F. o. c., p. 241. for Epileptics in New Jersey, has written: "That there are five times as many epileptics as feeble-minded in those fraternities coming from matings where neither parent can be classed as normal or called mentally defective, seems to indicate that neurotic and otherwise tainted conditions are more closely related to epilepsy than to feeblemindedness." He also states that "two epileptic parents produce only defective offspring." 16 Dr. Weeks observed 15 matings where one parent was epileptic, the other feeble-minded. There were living 55 children who were old enough to be classified. Of these 28 were found to be epileptic, 26 feeble-minded and 1 insane. Further evidence is unnecessary to show us that certain types of mental defects are directly inherited. Whether there has been a real proportionate increase in the classes in recent years may be open to doubt but no one can doubt their presence in the country in very large numbers nor fail to realize the cost of their maintenance. The problem of handling them is further complicated by the fact that these characteristics seem to act usually as recessives, and may be carried to the next generation by men and women who themselves show no sign of the trouble. Evidently, too, under favorable conditions a sub-variety of the human race might easily develop. Fortunately, however, there is another side to the story. Good traits are inherited as well as bad. By the irony of fate it is often harder to see and appreciate these good features than it is to see the bad, but there are superior as well as inferior types. Longevity appears to be a family trait judging from the following tables in which the figures indicate age at death: 16 WEEKS, D. F., in Problems in Eugenics, p. 62 ff. THE INHERITANCE OF LONGEVITY 17 These two families who lived in America during the colonial times under conditions by no means exceptionally good so far as is known, whose women were mothers of large families, and yet who averaged nearly twice the length of life of Americans of today, can hardly be explained save on the basis of inherited physique. Moreover, it is possible to find families characterized by short life who have not lived under unusually bad conditions in so far as we can see. Just as color of hair and eyes, shape of skull or face and stature may be inherited so there is every reason to believe that mental characteristics may descend generation after generation. Here however we encounter great difficulties. Stature and eye color are patent to every observer regardless of the activity of their possessor. Are there different types of mental ability, let us say the mathematical, the philosophical, the executive and the musical, or does ability involve the power of success in many fields? Can we be sure that the actual career of a man is in the field in which his ability really lies? "The compass was not invented by an astronomer, Nor gunpowder by a soldier." 17 THE FOWLERS. Hereditary Descent, pp. 31-34. |