HIDDEN FEEBLEMINDEDNESS 



One Person in Fourteen of the American Population Probably Carries the Trait in 

 a Recessive Form, Although Normal to all Appearances — One-Fourth 

 of Offspring will be Feebleminded if Mating is Made 

 with Another Carrier 



E. M. East 

 BitsscY Institution, Forest Hills. Mass. 



THE increase in the number of 

 feebleminded in the United States 

 during the past few years has 

 been such that the heredity of 

 the trait, and the classification and 

 treatment of those so afflicted, have 

 been the subject of much careful study. 

 The result of this activity has been 

 very creditable. Thanks to the re- 

 searches of Goddard, the method of 

 inheritance of feeblemindedness is as 

 clear as that of any other heritable 

 variation in the hiunan race. Owing 

 to the ingenious psychological methods 

 of Binet and Simon, the grade of 

 mentality can be determined reasonably 

 well. Even our slowly moving legisla- 

 ti\^e bodies have been somewhat dis- 

 turbed by the facts and have passed a 

 considerable number of laws designed 

 to cut off this defective germplasm, 

 either through segregation of the sexes 

 during the reproductive period or by 

 sterilization. 



One can have only words of com- 

 mendation for the serious efforts to face 

 the problem; nevertheless, in the nu- 

 merous papers on feeblemindedness that 

 have been published during the last 

 decade, not a single author appears to 

 have appreciated the real menace. Our 

 modern Red Cross Knights have 

 glimpsed but the face of the dragon. 



Goddard has shown that feeble- 

 mindedness is transmitted as a Mendel- 

 ian recessive. In other words feeble- 

 minded individuals may be produced 

 in three ways. If feebleminded mates 

 with feebleminded all of the offspring 

 will be feebleminded. If a feeble- 

 minded individual mates with one carry- 

 ing the trait in his or her germcells, on 

 the average one-half of the offspring 



will be feebleminded. It is these two 

 types that segregation or sterilization 

 will affect. But these are not the only 

 sources of feeblemindedness, and per- 

 haps they are not the most dangerous. 

 If two carriers of feeblemindedness 

 mate, one-quarter of their offspring will 

 exhibit the trait and one-half of them 

 will transmit it. Let us endea\'or to 

 see what this means. 



THE NUMBER AFFECTED 



It appears that in our present popula- 

 tion of 100,000.000 or thereabouts, 

 there are 300,000 persons who are 

 feebleminded through an hereditary 

 defect, a ratio of 3 per 1,000. This is 

 an estimate to be sure, but it is so 

 conservative that it probably veils the 

 true state of affairs. 



Now how many of these defectives 

 have been the result of a mating 

 wherein at least one of the parents was 

 feebleminded? This question is a dif- 

 ficult one and can only be answered 

 with a rough approximation. The best 

 estimate that I can make from a careful 

 examination of the meagre statistics at 

 present available is 100,000. The dose 

 must not be too bitter, however, so let 

 us double this estimate. This leaves 

 100,000 feebleminded persons that must 

 have been produced by the mating of 

 two transmitters of feeblemindedness 

 who did not show defective mentality 

 themselves, unless an unprecedented 

 percentage of origin de novo be assumed. 



These 100,000 defectives were pro- 

 duced during a period in which there 

 were rather less than 20,000,000 married 

 couples of reproductive age. They 

 were produced by parents both of which 

 carried feeblemindedness. But only 



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