174 GODDARD— HEREDITY OF FEEBLE-MINDEDNESS. [April 19, 



defect or feeble-mindedness, the distinction being that feeble- 

 mindedness is an arrest of development whereas insanity is a degen- 

 erative process, the victim not simply stopping where he is but 

 losing a part of the mentality that he once had. In the early years 

 of childhood, it is practically impossible to differentiate between 

 these two. The result is that we are apt to call everything feeble- 

 mindedness which occurs in the early years. And we have assigned 

 as a cause of the feeble-mindedness whatever physical condition 

 seems to be uppermost. For example, if we have a case of imbe- 

 cility which also has hemiplegia, we classify it as a case of hemi- 

 plegic feeble-mindedness and assume, as a rule, that the cause which 

 has resulted in the brain lesion producing the hemiplegia, has also 

 caused the mental defect. 



The thesis to be maintained in this paper is that this is not neces- 

 sarily the case but rather that our whole problem will be simplified 

 if we recognize some more heads of classification in this particular. 

 To put the matter in another form, we may say that as the result of 

 our study into the heredity of feeble-mindedness, we have come to 

 the conclusion that the human family is divisible not only into the 

 sane and insane, the healthy and diseased ; but further, the sane and 

 healthy group is subdivided possibly into many groups or strains; 

 and that the mental capacity or possibilities varies widely in the 

 different strains, but is fairly constant in each strain and is trans- 

 mitted regularly, that is to say, so long as any given strain is kept 

 pure, we will have the same mental capacity and possibilities genera- 

 tion after generation ; that variations occur here as they do in the 

 plant and lower animal world; that inbreeding and crossbreeding 

 produce new combinations just as they do in plants or animals. To 

 illustrate, we have only to call to mind almost any line of animal 

 breeding. There is the genus horse, with various species, and within 

 the species there are so-called strains. Every breeder knows that 

 those strains will be transmitted and that they must be reckoned 

 with in all attempts to breed horses for particular purposes or with 

 particular characteristics. The same thing is true of dogs. No 

 trainer would attempt to train a bull dog to retrieve or to point. 

 Furthermore coming closer to our special problem, every trainer 



