LEPROSY 133 



(4) ' Leprosy is not directly originated by the use of any 

 particular article of food, nor by any climatic or telluric 

 conditions, nor by insanitary surroundings ; neither does it 

 peculiarly affect any race or caste. 



(5) ' Leprosy is indirectly influenced by insanitary sur- 

 roundings, such as poverty, bad food, or deficient drainage 

 or ventilation, for these, by causing a predisposition, in- 

 crease the susceptibility of the individual to the disease. 



(6) ' Leprosy in the great majority of cases originates de 

 novo, that is, from a sequence or concurrence of causes 

 and conditions, dealt with ia the report, and which are 

 related to each other ia ways at present imperfectly 

 known,' 



Occurrence and Distribution.— During the Middle Ages this 

 disease was prevalent in England, and many leper houses, 

 or hospitals, were established all over the country, some of 

 the largest being at Burton, Thetford, St. Giles's (London), 

 Sherburn, etc. It is probable that many other skin 

 diseases were misdiagnosed as leprosy. It became finally 

 extinct in the eighteenth century. Doubtless its extinction 

 was largely due to its tendency to die out under favourable 

 circumstances.* Endemic leprosy still exists in Iceland, 

 Norway, Spain, India (100,000), Japan, the Cape, the West 

 Indies, and the Sandwich Islands. Generally speaking, it 

 shows signs of decline rather than increase. 



Pathogenesis. — One of the different forms of the same 

 disease generally predominates — either the nodular or 

 ' tubercular ' (lepra tuberculosa), in which the new forma- 

 tion has its seat in the skin or mucous membrane ; or the 

 anaesthetic (lepra ansesthetica), in which the nerves are 

 chiefly affected. In the skin variety the hands and face 

 are mostly affected, and larger or smaller swellings appear 



* For furtiier information see the ' Decline and Extinction of 

 Leprosy in the British Islands ' (Newman), p. 109. 



