THE LEPROSY BACILLUS 405 



terium. In order to explain these varied findings, it has 

 been surmised that the B. leprce is really a strep tothrix, 

 that it is acid-fast only under certain conditions, viz. in 

 the body or in media containing fat, and that under 

 cultivation the streptothrix may break up into non-acid- 

 fast diphtheroid bacilli or into acid-fast leproid bacilli. On 

 the other hand, Fraser and Fletcher 1 made 373 inocula- 

 tions from thirty-three non-ulcerating cases of leprosy on 

 a variety of culture media with entirely negative results. 

 More work is therefore required before it can be definitely 

 stated that the leprosy bacillus has been cultivated. 



A certain number of positive results of the inoculation 

 of leprous material into the lower animals have been 

 recorded. Nicolle 2 has reported the successful inoculation 

 of a macaque monkey, but most of the attempts have 

 ended in failure ; positive results are open to criticism 

 and may be fallacious, for lepers not infrequently suffer 

 from coincident tuberculosis, and the animals therefore 

 may have been infected with tuberculosis. Japanese 

 dancing mice are also stated to be slightly susceptible. 

 The local lesion induced in animals may be simply inflam- 

 matory, produced by the leprous material acting as a 

 foreign body, and the bacilli may be diffused without 

 proliferating. Human beings have also been inoculated, 

 but the positive results obtained are all open to objection. 



The differentiation of leprosy from tuberculosis, although 

 the bacilli are so similar, does not in the majority of cases 

 present much difficulty. The large number of bacilli 

 present in the lesions, and particularly in the skin, forms 

 a marked distinction from tuberculosis. The Bacillus 

 leprce also stains more readily, and with watery solutions 

 in a shorter time, than does the Bacillus tuberculosis, 

 though this distinction is hardly marked enough for 



1 Lancet, Sept. 27, 1913. 



2 Comp. Rend. Acad. Sc., 1905. 



