TUBERCULAR DISEASE. 205 



tendent of the Asylum for Idiots at Darenth, who, 

 in the course of his extended inquiries into the 

 causes of idiocy, found that phthisis, either alone or 

 in combination with some other degenerate condition, 

 as insanity, epilepsy, or drunkenness, was present in 

 50 per cent, of the parents of all idiots admitted 

 into his asylum ; and as two-thirds of these idiots 

 are themselves scrofulous, it is clear that phthisis 

 in the parent not only deepens to scrofula in the 

 child, but to that lowest of all types of humanity, 

 the scrofulous idiot. 



As to the very close relationship existing between 

 insanity and the phthisical type of the tubercular 

 diathesis, there is not room for the smallest doubt. 

 That the phthisical and insane diatheses are inter- 

 changeable is proved to the asylum physician every 

 day. Lugol found insanity so common amongst the 

 parents of scrofulous and phthisical persons, that 

 he treated of hereditary scrofula descending from 

 paralytic, epileptic, and insane parents. Schroeder 

 van der Kolk, a quarter of a century ago, showed that 

 phthisis and insanity are interchangeable. So long 

 ago as 1863 Dr. Clouston described a form of 

 insanity peculiar to those of the phthisical diathesis 

 and their descendants, and said he could count 

 hereditary predisposition in 7 per cent, more of such 

 cases than of the insane generally. After twenty- 

 seven years' study and observation he remains of 

 the same opinion. Speaking of phthisis and insanity, 

 he says : " It is surprising how often both diseases 



