40 THE TREND OF THE RACE 



influence on the mentality of the individual concerned, it is a 

 priori very improbable that the inheritance of mental defect is 

 adequately describable in simple Mendelian terms. Most of the 

 charts which group human beings categorically as feeble-minded 

 or normal, as we class mice as gray or albino, take no account of 

 the varied manifestations of mentality which really occur. They 

 are liable to give a false or misleading appearance of simplicity 

 which in fact has no existence. 



Whether the inlieritance of mental defect follows simple or 

 complex Mendelian formulas, or whether, indeed, it may not take 

 place according to the older conceptions of blending inheritance, 

 makes comparatively little difference in the practical treatment of 

 hereditarily defective persons. The fact that defective mentality 

 is strongly transmitted is established beyond the possibility of 

 sane objection, and the particularly disastrous results that are 

 pretty sure to follow from the mating of two mental defectives 

 have certainly been made sufficiently impressive by the work of 

 recent investigators. 



EPILEPSY 



Although Morel questioned its hereditary transmission, there 

 is now a general consensus of opinion that epilepsy is often 

 inherited. This dreaded malady occurs in a variety of forms 

 (petit mal, grand mal, Jacksonian epilepsy, etc.) and is frequently 

 associated with other forms of defect such as feeble-mindedness 

 and insanity. Many cases are doubtless to be attributed to 

 trauma, disease and alcohol, although a part of such cases prob- 

 ably have a basis in inheritance as well. Concerning the propor- 

 tion of cases attributable to heredity I can do no better than to 

 quote from Barr {Menial Defectives, p. 212) "Hammond in a study 

 of 171 epileptics, finds heredity a cause in 45, — 21 of these proving 

 direct; Echeverria gives 26 per cent of 306 as descendants of 

 epileptic parents. Delasiauve found the same in 33 out of 300 

 cases, and Herpin 10 in 68 cases. . . . Hamilton states that fully 

 50 per cent of his 980 cases are attributable to heredity. Gowers 



