CULTIVATION OF LEPROSY BACILLUS. 413 



organs on media containing amcebge and cholera vibrios and on ordinary 

 laborator)^ media were negative. 



White rats Xos. 4603. 4604 and 4605 Avere inoculated subeutaneoiisly 

 with a suspension of Bacillus F, lesions were produced on the site 

 of inoculation consisting of a small, indurated nodule which disap- 

 ])eared after three weeks. Microscopical preparations made from the 

 scrapings of the nodules and stained by the Ziehl-Neelson method 

 sliowed large numbers of acid-fast bacilli. Cultures made from the 

 nodules on media containing amoebae and cholera vibrios and ordinary 

 laboratory media were negative. 



Twelve monkeys were inoculated subcutaneously and intraperitoneally 

 with various amounts of Bacillus F. At the pi'esent time, thi'ee months 

 later, there is no evidence of external lesions. 



Upon failing to recover the bacillus from the internal organs of these 

 experimental animals, a series of guinea pigs was inoculated sul)cu- 

 taneously with the s])lenic pulp of guinea pigs Xos. 4o97 and 4.")!)y. 

 Altogether six animals were inoculated. They tlied three weeks Uiter 

 Avith the same symptoms as those inoculated with the culture of the 

 microorganisms. Cultures from the organs in these animals also re- 

 mained sterile, and smear preparations examined microscopically showed 

 no acid-fast bacilli. The splenic pulp of these animals inoculated sub- 

 cutaneously into a thii'd series produced identical lesions with fatal 

 results. Cultures made from the organs I'emained sterile and no acid- 

 fast bacilli were found in the smears. 



DISCUSSIOX OF RESULTS. 



Attempts have been made by me to cultivate the leprosy bacillus fi-oni 

 the spleens of lepers and from cutaneous nodules in cases of leprosy in 

 ten instances. In eight out of the ten instances an acid-fast bacillus 

 was observed to multiply in successive transplants of the cultures of 

 amoebae to which the leprosy material had been added. Control ])lates 

 of the amffiba cultures without the addition of leprosy material showed 

 no acid-fast organisms present. By heating such an amceba-cholera- 

 leprosy culture a half hour at 60° C. and incubating, isolated colonies 

 of the leprosy bacillus were obtained which grew readily in pure culture 

 when transplanted to the ordinary laboratory media (nutrient agar, 

 bouillon, coagulated egg medium, etc.). 



Guinea pigs inoculated subcutaneously with the pure culture devel- 

 oped in some instances lesions at the site of inoculation which bear a. 

 certain resemblance to the leprous lesions of man, botli luacroscopically 

 and when sectioned and examined under the microscope. The ai-id- 

 fast organisms were found at the site of inoculation and in some in- 

 stances also in the spleen. Tu one instance the acid-fast organism was 



