190 ACQUIRED CHARACTERS sec. 



of Eoth already mentioned, a paper in other respects note- 

 worthy, which contains numerous instances in favour of 

 pathological inheritance, and in which the question of heredity 

 in general is profoundly discussed. 



I would here add a few words on the inheritance of but 

 one kind of diseases, namely, mental diseases. That mental 

 diseases are inherited to a considerable degree no one wdll 

 deny. 



But it is quite beyond doubt that among such hereditary 

 mental diseases are some which can only have arisen from 

 external influences on the nervous system, not through direct 

 modification of the germ. 



The restless chase of life especially which is so character- 

 istic of our time leads in certain classes of the population 

 to an over- excitement of the nervous system which often 

 expresses itself in actual mental disease, and which — the over- 

 excitement as well as the actual disease — is certainly inherited. 

 Wliere disease commences cannot be determined, for by the 

 nature of the case it is impossible to define the boundary 

 between the two. Every over -excitement of the nervous 

 system is morbid, even when it is confined within the limits 

 of the socially permissible. The brain -workers especially, 

 whose life is often a struggle with their nerves, know the 

 truth of tliis, at least those wdio accept the conclusions of 

 physiological inquiry. 



But the question may be asked, Whether the cultured classes 

 generally of the present day, using the term in a wide sense, 

 are to be regarded as perfectly normal with respect to their 

 nervous system ? The same question may be asked of their 

 children, even before the latter have begun to expose them- 

 selves to the abnormal conditions which have injuriously 

 affected their parents and ancestors. Our peasants and their 

 children, on the other hand, enjoy traditionally sound nerves. 



As among single classes, so also among different nations 



