BACILLUS LEPILE AND LEPROSY 507 



inspissating, at 70 C., for three hours and, after inoculating with 

 leprous tissue, adding a 1 per cent solution of trypsin. Indirectly the 

 same result was obtained by employing culture media containing albu- 

 minous substances and inoculating with bacteria capable of producing 

 amino-acids from the medium. After leprosy bacilli had been grown 

 on this medium for several generations, they could easily be cultivated 

 on agar slants without special additions or preliminary treatment. 



In spite of extensive work upon this very important problem 

 opinions are still divided as to the specific nature of the organisms cul- 

 tivated by Clegg and by Duval. Animal experiments with these cultures 

 have remained inconclusive. The cultures after prolonged preservation 

 upon artificial media grow heavily, often lose their acid-fast charac- 

 teristics, develop into streptothrix-like or diphtheroid forms and become 

 markedly chromogenic, all these characteristics suggesting saprophytism. 



In a recent communication, Duval and Wellman 1 state their opinion 

 as follows : From 29 cases of leprosy, 22 successive cultivations of acid- 

 fast bacilli were made; in 14 of them a chromogenic organism, similar 

 to that of Clegg, was found. This grows either as a non-acid-fast strep- 

 tothrix in subsequent cultivations or as non-acid-fast diphtheroid forms. 

 From eight cases an organism distinctly different from the former was 

 cultivated which grows only on specific media and by serological tests 

 seems to give reaction which differentiates it from Clegg's organism. Du- 

 val believes that there is no reason to assume specific etiological relation- 

 ship for the first organism mentioned. In the case of the second, he 

 admits that not sufficient proof has been brought, but states his belief 

 that its etiological significance is probable. 



Pathogenicity. Innumerable attempts to transmit leprosy to ani- 

 mals by inoculation have been unsuccessful. Nicolle, 2 however, has 

 recently claimed 'successful experiments upon monkeys (macacus) in 

 whom inoculation with tissue from infected human beings was followed, 

 in sixty-two days, by the development of a small nodule at the site of 

 inoculation, in which, upon excision, leprosy bacilli were found. In 

 most cases, however, inoculation has given rise merely to a transient 

 inflammatory reaction. 



Among human beings, leprosy has been a widely spread disease since 

 the beginning of history, and much evidence is found in ancient lit- 

 erature which testifies to a wide distribution of the disease long before 

 the Christian era and throughout the Middle Ages. At the present day, 



1 Duval and Wellman, Jour, of Inf. Dis., xi, 1912. 



2 Nicolle, Sem. medicale, 10, 1905. 



