INHERITANCE OF MENTAL DEFECTS AND DISEASE 43 



are considered in which there are some epileptic offspring. In 

 many feeble minded stocks the proportion of epilepsy that ap- 

 pears is quite small. On the other hand most pedigrees which 

 include a considerable number of epileptics contain also more or 

 less feeble-mindedness. 



In many pedigrees epilepsy shows a marked association with 

 other neuropathic traits. As Weeks observes, "That there are 

 more than five times as many epileptics as feeble-minded persons 

 in these fraternities coming from matings where neither parent can 

 be classed as normal, or called mentally defective, seems to indi- 

 cate that neurotic or otherwise tainted conditions are more closely 

 related to epilepsy than to feeble-mindedness." 



From the available data it is far from evident that epilepsy 

 is inherited as a single Mendelian character. "It will be seen 

 from the present evidence," Weeks admits, "that epilepsy cannot 

 be considered as a Mendelian factor when considered by itself, but 

 that epilepsy and feeble-mindedness are Mendelian factors of the 

 recessive type in that their germ cells lack the determiner for 

 normality," however we are to imagine such an entity to occur. 

 The statement of Davenport and Weeks concerning epilepsy and 

 feeble-mindedness that "each is due to the absence of a proto- 

 plasmic factor that determines complete nervous development," 

 and the further conclusion that "when both parents are either 

 epileptic or feeble-minded all their offspring are so likewise," 

 indicate that both these defects are due to the loss of the same 

 factor. If so, epilepsy and feeble-mindedness should be heredi- 

 tarily equivalent, which we have seen they are not. If they 

 depend on the loss of different factors we should expect them to 

 behave as independent characters in which case it would be per- 

 fectly possible for the mating of a feeble-minded and an epileptic 

 to produce normal children; in fact we should expect most 

 children to be normal. Neither of the authors mentioned seems 

 to be sufficiently impressed with the dilemma into which their 

 interpretations land them. There are indications that epilepsy is 

 often recessive and that it is frequently inherited in an alternative 

 manner, but we must be guarded on both these points. Davenport 



