54 THE TREND OF THE RACE 



the parents was not excluded in the statistics and the "sane" 

 offspring may have been neuropathic in other ways. 



Heron's data on this point are meagre and do not furnish 

 information as to the age of the sane offspring, so it is not certain 

 that they reached the period at which insanity would be devel- 

 oped. Goring gives three matings between insane parents, with 

 19 offspring, all sane, but we know little of their age beyond the 

 fact that they were convicts. 



Several writers have brought forward evidence that particular 

 types of insanity tend to run in famiHes. Berze reports a case 

 of dementia pr^ecox in a father and three sons; a case of a man, 

 his daughter and her two children and several other instances with 

 two or more in each family. Dr. Schuster from a statistical 

 investigation of cases in the London County Asylums concludes 

 that "a periodically insane son or daughter is more likely to be 

 associated with a periodically insane mother or father than with 

 one differently affected," and a similar association occurs between 

 insane brothers and sisters. In delusional insanity "The tend- 

 ency for the afliiiction to run in families is very marked" and "in 

 the incidence of the primary dementia of adolescence there is a 

 strong correlation between members of the same co-fraternity." 



Strohmayer finds that manic-depressive insanity frequently 

 reappears in much the same form. "Es gibt kaum ein Krank- 

 heitsbild, wo so einmutig die Macht des Erbfaktors anerkannt 

 wird, wie beim manisch-depressiven Irresein. Alle Autoren heben 

 den auffallend grossen Prozentsatz des durch Geisteskrankheit 

 direkt odcr indirekt belasteten Kranken dieses Schlages hervor. 

 Die Angaben schwanken zwischen 75 und 85%. Ebenso stim- 

 men alle Beobachter darin iiberein, das innerhalb des manisch- 

 depressiven Gebeites die gleichartige verbliiffend iiberweigt." 

 , Many alienists from Morel to the present time have empha- 

 sized the extreme variability of the manifestations of mental 

 defect and disease, and have found little tendency for the same 

 type of insanity to repeat itself in successive generations. That 

 particular forms of insanity are rarely transmitted as such is a 

 doctrine which has been rather more frequently espoused ia 



