EXPERIMENTS WITH PURE CULTURES 147 



mucosa. Those from the gland grew tubercle bacilli ; 

 the rest remained sterile. The fact that this animal 

 accidentally contracted tuberculosis, while it resisted 

 the inoculation of the culture of Johne's bacillus, 

 demonstrates, with other experiments, a comparatively 

 low virulence for Johne's bacillus. 



Bovine No. 3. — This was a red and white male calf 

 which was received at the Institution when three days 

 old. Taken for about three weeks, the temperature 

 remained normal for a young animal, and repeated 

 examination of the faeces failed to reveal any acid- 

 fast bacilli. On December i, 1910, the calf was in- 

 oculated intraperitoneally with ^ c.c. of a thick 

 emulsion of Johne's bacillus, the growth being the 

 second subculture distant from the primary culture 

 from the gland. No immediate symptoms followed, 

 and the temperature remained normal. Daily exami- 

 nation of the faeces, however, from December 29 to 

 January 11, showed an increasing number of short, 

 thick, acid-fast bacilli with rounded ends. Though 

 these did not resemble Johne's bacilli as found in pure 

 culture or in lesions, we decided to kill the calf and 

 examine the intestine. This was done on January 11, 

 191 1, and the post-mortem showed no pathological 

 lesions. A few acid-fast bacilli were found in the 

 mucous membrane and in sections of the bowel, but 

 they appeared to be in the crypts of the membrane, 

 and were probably not Johne's bacilli. We consider 

 the result of this experiment negative, the calf being 

 killed before the disease had had time to develop. 



Bovine No. 4. — This was a brown male calf, and 

 when received at the Institution (January 7, 191 1) was 

 two days old. The faeces showed no acid-fast bacilli, 

 and the temperature remained normal up to Feb- 

 ruary 21, when the calf was inoculated into the peri- 



