THE INHERITANCE OF FAMILY TRAITS 79 



Fia. 47. — The central mating is that of a pair who, though not insane, 

 have pronounced neuropathic manifestations. The mother has an insane 

 sister and the father comes of neuropathic stock. Of the 3 surviving 

 children 1 is neurotic, 1 insane and 1 epileptic. A similar mating of 

 2 neuropathic persons is seen in the parents of the father — all of their off- 

 spring are neuropathic. The shaded symbols represent neuropathic in- 

 dividuals. Cannon and Rosanoff, 1911. 



oa 



DO 



*inf I tinf iinf 



nTT 



+inf +inf 



iinf 



Fig. 47a. — Inheritance of "insanity." From the central mating of 2 

 normal persons there are derived 8 children, 3 insane. But there is the heredi- 

 tary tendency in the germ plasm of both parents. Mott, 1905. 



it is fairly open to debate whether alcoholics are not usually 

 mentally defective and the delirium tremens that develops 

 is a symptom of their mental weakness. Similarly a blow 

 is often just the stress that reveals the mental weakness; 



