39Q THE POPULAR SCIENCE MONTHLY. 



It is now impossible to deny the heredity of mental troubles, as 

 well of those in the case of which we do not know the accompany- 

 ing anatomical lesions as of those with which we think we are 

 better acquainted, as in general paralysis and senile dementia. 

 Still less doubtful is it that our cases are most frequently not of 

 direct and identical heredity, but usually of what we call col- 

 lateral and dissimilar heredity. The son may not inherit from 

 his father, and if the nephew inherits, he will generally seem to 

 be afflicted with a different mental affection from that of his 

 uncle. It must, therefore, be understood that what is meant by 

 heredity in mental diseases does not necessarily correspond with 

 the definition of normal biological heredity. 



This frequent dissimilarity in the inheritance of madness be- 

 comes more clearly denned when we regard the alliances of the 

 psychopathic family. Nervous troubles very different in their 

 manifestations are frequently met with in families of insane. 

 Prichard has given the name of moral insanity to a mental trou- 

 ble which prompts to abnormal or mischievous acts while con- 

 sciousness of their moral nature is wanting. This kind of insanity 

 differs from the impulsive insanity, in which the patient is urged 

 to violent, harmful, or criminal acts by a force which, though in- 

 vincible, leaves him able to appreciate more or less sanely the 

 character of those acts. 



Vice and crime are, furthermore, often hereditary, like in- 

 sanity. More frequently they are met in families combined with 

 the most various mental disorders insanity, imbecility, idiocy, 

 etc. The combination of insanity and crime is observed not only 

 in the same family, but often, too, in the same person. Physi- 

 cians of penitentiaries have long insisted on the frequency of 

 mental disorders among the convicts, and have become convinced 

 that the causes of what is called prison-madness are inherent in 

 the prisoners and not in the prison. It has, moreover, been re- 

 marked that debauchery and instinctive perversions are often 

 met with in the hereditary antecedents of insane persons. 



Not criminality only has family connections with insanity, but 

 the artistic temperament and genius are frequently associated 

 with it. An old writer has said that there never was a great 

 genius who had not some tinge of insanity. Numerous men, illus- 

 trious under different titles, have been attacked with various 

 mental troubles, or have belonged to families in which such trou- 

 bles were common. The frequency of such associations suggested 

 to Moreau de Tours his saying that genius is a nervous disorder. 

 Further, while great men are rarely exempt from a trace of folly, 

 madmen have no less frequently had a share of genius. Thus we 

 sometimes find in the asylums calculators and musicians of re- 

 markable aptitude in their respective lines. M. H. Nordau (De- 



