160 JOHNE^ DISEASE 



after inoculation, and, on staining, bacilli with all the 

 characters of Johne's bacillus were found. 



A similar series of experiments, consisting in feeding 

 rabbits with pure cultures of Johne's bacillus, were 

 then carried out, but no bacilli could be found in the 

 bile or urine, and cultures made from these fluids 

 remained sterile. 



The Intraperitoneal Inoculation of Rabbits. — The intra- 

 peritoneal inoculation of loo to 200 milligrammes 

 of Johne's bacillus is easily tolerated by rabbits, and 

 seems to produce no ill-effect upon the general health ; 

 there is no rise of temperature or loss of appetite 

 or weight, and no deaths directly due to the bacilli 

 have been noted. If small quantities of the fluid con- 

 tents of the peritoneal cavity are pipetted off a few 

 hours after making the injection, and a microscopical 

 examination made, there is evidence of leucocytosis, 

 and the bacilli are found to be phagocytosed, only 

 a few remaining free after twenty-four hours. Johne's 

 bacillus, however, has a very great resisting power, 

 and may be found well stained and well formed inside 

 the phagocytes for several weeks. 



In animals killed four weeks after inoculation all 

 that can be seen on post-mortem examination is a very 

 small amount of thick stringy pus in the peritoneal 

 cavity. Rabbits inoculated into the peritoneal cavity 

 and kept for two or three months are of special interest, 

 as they are the first animals in which any evidence of 

 nodular formation has been found. Usually these 

 nodules are not numerous, and are limited to the 

 abdominal cavity. They vary in size from a match- 

 head to a bean, and are indistinguishable from an 

 ordinary caseous tubercular mass. The nodules occur 

 on the under surface of the diaphragm, on the peri- 

 toneal covering of the liver and spleen, and in the 



