98 MARRIAGE AND HEREDITY 



course. Cases are known of father and son both 

 given to seeing phantoms ; and in the Middle Ages 

 " possession by devils," which was no doubt a form 

 of hallucination, was said to run in families. One of 

 the commonest experiences of the mad doctor of the 

 present day is to find people possessed by an idea 

 that somebody is going to kill or poison them ; and a 

 large proportion of such cases are hereditary — accord- 

 ing to Esquirol, nearly one-third. In a still greater 

 degree are the violent forms of mania hereditary, the 

 proportion as given by the writer just quoted being 

 nearly one-half. The royal families of Europe, who are 

 extensively allied by marriage, have unfortunately 

 contracted the taint of insanity, and a large proportion 

 of cases have occurred among them since that of our 

 own George III. And what is true of insanity in the 

 main is of course true of all the minor morbid affections 

 to which the brain or the nervous system is liable. 



Let us now see what part heredity plays in the 

 sentiments and passions, and in the mental capacity 

 generally. The Borgias, the Stuarts, the family of 

 Charles-Quint, the houses of Cond<^ and Guise, to re- 

 de suicide. Uii autre a la fleur de I'age est pris de melaucholie et 

 se noie voloutairement ; son fils d'une bonne sante, riche, pere de 

 deux enfants bien doues, se noie volontairenient au meme age." — 

 Moreau's Psychologic Morhide, 



