The Editor: Feeblemindedness 



35 



The smoke of controversial battle 

 must not obscure from the public the 

 fact that as to the hereditary nature of 

 much if not most feeblemindedness 

 there is no doubt. This alone would 

 sutticc to justify a eugenic campaign. 

 The further question of how it is inher- 

 ited is purely a technical one. Neverthe- 

 less, it is one which has great importance, 

 to society as well as to the professional 

 genetist. What, then, is the layman to 

 think about the way in which this 

 condition is transmitted? 



It seems iinpossible to overlook the 

 ease with which the puzzle can be 

 explained by the hypothesis that feeble- 

 mindedness is due to not one but many 

 unit characters, which in general, btit 

 not always, cling together in a group, 

 when transmitted. When they stick 

 together in one group, they produce the 

 appearance of a single unit character, 

 and thus yield the approximate Men- 

 delian proportions which Goddard 

 found when he tabulated his matings, 

 and which his predecessors also found 

 in their researches. But when some 

 other factor comes into play, this group 

 may be broken up and only a part of 

 the units passed on to a given individual. 

 They may be enough in number to 

 produce obvious feeblemindedness ; they 

 may be so few that the individual who 

 receives them appears, in any ordinary 

 environment, to be little inferior to his 

 comrades.* 



NEED FOR MORE RESEARCH. 



If this hypothesis be the true explana- 

 tion of the behavior of feeblemindedness 

 in heredity, the antagonism between 

 the biometrists with their insistence on 

 continuity and the Mendelians, with 

 their insistence on the unit character, 

 is only apparent. Neither side at 

 present accepts such a .solution, but it 

 seems probable that the further prose- 



cution of genetic studies will result in a 

 more general acceptance of the idea 

 that supposed unit characters arc multi- 

 ple and that visible traits are complex 

 in nature. , 



But as I have already said, we must 

 not get so much interested in a question 

 of secondary importance as to forget the 

 point of first importance — namely, that 

 feeblemindedness is a widespread defect, 

 largely due to heredity, which threatens 

 to lower the intellectual level of the 

 whole race unless careful selection in 

 mating keeps it from infecting more 

 sound stock each year. As feeble- 

 mindedness involves a lack of self- 

 control and an inability to understand 

 ethical questions, the possessor of it 

 can not be expected voluntarily to take 

 any steps which will prevent the trans- 

 mission of his defect. With society 

 is the responsibility for protecting itself. 



But, the opponents of eugenics object, 

 Nature will take care of the whole 

 matter. These diseased conditions of 

 the germ-plasm "run out;" the stream 

 always tends to purify itself. "A 

 study of the charts here presented," 

 Dr. Goddard remarks, "will hardly be 

 found reassuring in this direction." 

 In the absence of any interference, the 

 niunber of feebleminded usually becomes 

 larger with each generation; if they are 

 of the very lowest grade, it is true that 

 they leave no descendants, but among 

 the morons the taint is more likely to 

 spread than not. And even in cases 

 where it seems to have died out, where 

 no feeblemindedness appears for three 

 or four generations, we can not be sure 

 that the condition has not become 

 merely latent. The genetist, indeed, 

 who has seen exactly analogous cases 

 in his breeding experiments, will feel 

 quite sure that it is merely latent, ready 

 to appear again when the proper mating 

 is made. There is no safeguard for 

 society in a dependence on some 



1912) that feeblemindedness is a survival of the mentalily that characterized the ape-man: that 

 the condition has been carried down unchanged in the stream of germ-plasm ever since. 



*' For a clear statement of this hypothesis see "Nature of Mendelian Units" by G. N. Collins, 

 Journal of Heredity, V, 10, 425, October, 1914. This hypothesis will also harmonize the con- 

 flicting views on albinism in man, where the same statistics are interpreted by biometricians to 

 show continuity and by Mendelians to show segregation of a unit character. See the statement 

 of the two sides of the case in the Journal of Heredity, V, 11, November, 1914: "Albinism 

 in Man" (a review of the work of the Galton Laboratory) by A. E. Hamilton and "The Laws 

 of Naudin-Mendel " by Dr. E. Apert. 



