INHERITANCE OF MENTAL DEFECTS AND DISEASE 53 



tion. It certainly seems remarkable that many kinds of germinal 

 defect would give rise to the same sort of neuropathic disorder. 

 If so, one person might lack something necessary to normality 

 and another person might lack something else, and yet the union 

 of these persons might supply all that was needed to make a 

 normal product. This would be clearly possible if the defects in 

 question were completely recessive. One might expect, therefore, 

 in view of the varied nature of hereditary insanity, that two 

 insane, or at least two neuropathic persons might occasionally, if 

 not frequently, produce a normal individual. The probability of 

 such an occurrence would obviously depend upon the number of 

 affected units in the germ plasm of the two persons, and the 

 genetic similarity of the two types of hereditary defect. It would 

 be of especial interest to compare the matings of similar neuro- 

 pathic defectives on the one hand and dissimilar types on the 

 other. Whether or not the latter types especially may not yield 

 normal offspring we are not at present sufficiently assured. Mat- 

 ings of neuropathic and neuropathic, it is true, will produce a 

 large proportion of neuropathic offspring. In the three cases of 

 this kind given by Cannon and Rosanoff the parents were simply 

 designated neuropathic, a term used to cover hysteria, feeble- 

 mindedness, epilepsy, convulsions or other pronounced manifes- 

 tations, and the children of these matings which were all marked 

 neuropathic showed insanity, epilepsy, convulsions and neuro- 

 pathic states not further specified. In a paper by Rosanoff and 

 Orr 17 such matings are recorded, resulting in 75 children of whom 

 II died, in infancy, 54 of the remaining 64 are given as "neuro- 

 pathic," 10 being designated normal. In these 10 the authors 

 state that in 2 cases " the neuropathic constitution is not insan- 

 ity," and that the 8 others "have not reached the age of in- 

 cidence." 



There are several cases in which insane parents have been 

 reported to have produced sane offspring. Pearson's family 

 records give 66 per cent, insane offspring when both parents are 

 insane. Only those children were classed as sane who reached an 

 age of 50 years without developing insanity. Acquired insanity of 



