THE BACILLUS FOR SMALL ANIMALS 159 



rapidly disappears, leaving a loose fibrous tissue. On 

 the other hand, where the injections have been re- 

 peated, a large proportion of the parenchyma may be 

 replaced by this loose fibrous tissue, and a general 

 fatty condition of the remaining liver substance may 

 supervene. 



The intestines, when examined at different levels, 

 show a complete absence of pathological changes, and, 

 so far, it has been found impossible to demonstrate the 

 presence of acid-fast bacilli in this situation. 



In animals that receive several injections at long 

 intervals, the axillary glands may be very congested, 

 and may show small haemorrhages, while acid-fast 

 bacilli are often present. 



As only a comparatively small number of bacilli 

 seem to be excreted by the kidney, but, on the other 

 hand, are rapidly absorbed by the hver, it was thought 

 that many might pass through the bile-ducts into the 

 intestines. 



In order to prove this the following experiments 

 were performed : 



Two rabbits were inoculated intravenously with 

 30 milligrammes of the bacilli, one being killed twenty- 

 four hours, and the other forty-eight hours, after the 

 inoculation. A few drops of the urine and bile were 

 placed on to separate tubes of the special medium 

 necessary for the growth of Johne's bacillus, and incu- 

 bated at 39° C, while the remainder of each of the 

 fluids was centrifuged, and the deposit examined 

 microscopically for bacilli. A careful examination of 

 the deposits failed to reveal the presence of any micro- 

 organisms, and the cultures appeared to be sterile at 

 the end of three weeks. However, a week later 

 several minute colonies were visible in the tube con- 

 taining the bile from the rabbit killed forty-eight hours 



