A STUDY OF HEREDITY IN INSANITY IN THE LIGHT 

 OF THE MENDELIAN THEORY. 



By a. J. ROSANOFF, M. D., 



AND 



FLORENCE I. ORR, B. S., 

 Kings Park State Hospital, Kings Park, N. Y. 



From the earliest times physicians have recorded observations 

 of the transmission of nervous diseases by heredity. 



In modern times the accumulation of large amounts of mate- 

 rial in the shape of clinical statistics published by hospitals has 

 established beyond question the fact that heredity plays an essen- 

 tial part in the etiology of certain neuropathic conditions. Table 

 I shows some statistical figures selected at random. 



TABLE I. • 



Figures such as these are for all forms of insanity, including 

 those which occur on a basis of exogenous causes ; yet even as 

 they are, .their significance becomes quite apparent when they are 

 compared with figures representing the frequency of a neuro- 

 pathic family history among normal subjects : 3 per cent accord- 

 ing to Jost, 7.5 per cent according to Nacke,^ 



Aside from statistical data, studies of individual cases have 

 revealed, on the one hand, the facts of atavistic and collateral 

 heredity, and on the other hand, the fact of the frequent failure 

 of transmission of neuropathic traits. In other words, there 



* Cited by Kraepelin, Psychiatric, 7th ed., Vol. I, p. 116. 



