284 Heredity and Eugenics 



of the children are hable to go insane; and that nervous 

 breakdowns of these 1)^65 never occur if both parents be 

 of sound stock. 



E^'en the condition of general nervousness is an indica- 

 tion of a nervous weakness that is, apparently, due to the 

 absence of a determiner. Thus when a person belonging to 

 a neurotic strain marries a normal person whose father 

 died of apoplexy, some neurotic and feeble-minded children 

 may appear in the offspring. 



Finally, a study of families with special abilities reveals 

 a method of inheritance quite like that of nervous defect. 



[N]f® 0f® 



d) [i] d) (N) ^ ^ [N]f(N) \k} (t) 6 In] (^ (^ [^ [^ 



(§e®^ 



Fig. 95. — Pedigree of a family in wliich ihe fatlier's parents (upper left) are 

 bolti ner\-ous (N) and have four nervous children. The mother is nervous; so were 

 her father and four of her brothers and sisters, while one is insane. Of the three 

 grandchildren one is insane (I) , one epileptic (E) , and one extremely nervous (N) . — 

 Cannon and Rosanoff. 



If both parents be color artists, or have a high grade of 

 vocal ability or are litterateurs of high grade, then all of 

 their children tend to be of high grade also. If one parent 

 has high ability, while the other has low ability but has 

 ancestry with high abihty, part of the children will have 

 high ability and part low. It seems like an extraordinary 

 conclusion that high ability is inherited as though due to 

 the absence of a determiner in the same way as feeble- 

 mindedness and insanity are inherited. We are reminded 

 of the poet: "Great wits to madness sure are near allied." 

 Evidence for the relationship is given by pedigrees of men 



