THE BACILLUS LEPRM 465 



tures of this organism precisely as tuberculin is prepared. Neither 

 nastin nor leprolin have been successful clinically judging from avail- 

 able information. 



Pathogenesis. Human. McCoy and Goodhue 1 have summarized 

 observations of the infectiousness of lepers in the leper settlement in 

 the Hawaiian Islands as follows: of 119 men, practically all Hawaiians 

 living in the same house with lepers, 5 (4.40 per cent.) developed 

 leprosy; of 106 women, practically all Hawaiians, living in the same 

 house with lepers, 5 (4.71 per cent.) developed leprosy; of 12 women, 

 all Caucasians, nurses and members of religious orders, living among 

 lepers, none contracted the disease; but of 23 Caucasian males, three 

 contracted leprosy. The shortest period in which the disease appeared 



FIG. 63. Lepra 'bacilli in liver. (Kolle and Hetsch.) 



after exposure was three years (2 cases) ; the longest seventeen years. 

 Arning 2 inoculated a condemned criminal with leprosy bacilli derived 

 from a leper and the criminal developed leprosy. Several other 

 investigators have made similar experiments, a few of which have 

 resulted positively. The majority of such attempts have been fail- 

 ures, and the consensus of opinion is that the few positive results are 

 to be explained by the existence of leprosy in the early stages. 



The earliest lesion appears to be an ulcer at the junction of the 

 bony and cartilaginous septum of the nose. When the bacilli are car- 

 ried to any tissue in the body they excite the usual inflammatory 

 reaction which, however, is continued to excessive tissue proliferation. 

 Granular tissue containing bloodvessels is formed, providing a good 

 vascular supply, so that proliferation continues until a fair-sized 



1 Public Health Bull., 1913, No. 61. 2 Centralb!. f. Bakt., 1889, v, 672. 



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