NERVOUS DISEASES 281 



points to the position which many hold, which is well argued 

 for by Rohde (1895), that what is really inherited is a constitu- 

 tional peculiarity (arising originally as a germinal variation) 

 which may express itself in general neurasthenia, easy ex- 

 haustibility, deficient control, etc., or — under sufficient provo- 

 cation — in some specific form of acute neurosis. After a careful 

 survey Rohde concludes that the only nervous disorders which 

 are transmissible are those which have a germinal origin ; and 

 another authority, Dr. T. S. Clouston, says, " A neurotic 

 heredity is seen to resolve itself into general morbid tendencies 

 rather than direct proclivities to special diseases." What is 

 inherited is a predisposition, not a disease ; and, fortunately, 

 the predisposition may never realise itself. 



What we have just said does not imply that persistent nerve- 

 fatigue and neurasthenia in parents may not favour the outcrop 

 of neurosis in the offspring, for the abnormal nervous condition 

 in the parent may, through nutritive disturbances, affect the 

 germ-plasm in a generally deleterious way (as Weismann expressly 

 says), and the development of the nervous system of the 

 unborn child may be affected disadvantageously by the abnormal 

 condition of an over-fatigued mother. 



It is exceedingly probable that many neuroses are due to 

 primary defects in the development of some of the nerve-centres 

 or of the cells that compose these. Thus, a weakening in the 

 developmental power of certain rudiments in the inheritance, 

 which might well arise as a germinal variation, and which might 

 by hypothesis be inherited, would account for the recurrence 

 of certain forms of nervous disease generation after generation, 

 e.g. for a similar breakdown at adolescence or in senescence. 



(2) On the other hand, there are some cases — a small 

 minority — which suggest that a specific predisposition may be 

 heritable. Thus, some of the records of inherited nervous 

 disorders disclose an appalling exactness in their mode of 

 expression, though it is probable that this is due in part to 



