122 JOHNE'S DISEASE 



tuberculin prepared at the Pasteur Institute, diagnostic 

 avian tuberculin obtained from the Royal Veterinary 

 College, and a special timothy-grass bacillus vaccine 

 prepared by ourselves. This last was made by grow- 

 ing the bacillus for about three weeks in a glycerine- 

 broth medium, which was then steamed and filtered 

 through a Doulton white porcelain filter. The sterile 

 filtrate was placed in small sterile phials without 

 previous concentration. 



The results of tests conducted with these vaccines are 

 summarized in tabular form on p. 123. Bovines Nos. i 

 2, 4, and 5 are mentioned also in Chapter IX., where a 

 full account of the pathological lesions present in each 

 animal is. given. Bovines 2, 4, and 5 are calves. 



A + sign is used to indicate a positive reaction, and 

 a — sign a negative one. On referring to the table, 

 one will notice that Vaccine No. i gave a positive 

 result with bovines Nos. i, 2, and 5, a doubtful re- 

 action with No. 4, and no reaction with the control 

 bull. It is also seen from the tuberculin tests and 

 from post-mortem examination that animals i, 2, and 

 5 had contracted tuberculosis. 



In considering the results, it must be remembered 

 that Vaccine No. i was prepared by growing the 

 specific bacillus on a medium containing the tubercle 

 bacillus, and it might be expected that tubercular 

 animals would react to the vaccine on account of the 

 substances dissolved from the tubercle bacilli in the 

 medium, in which case the positive results do not 

 prove the presence of pseudo-tuberculous enteritis. 

 That the rises of temperature with Vaccine No. i may 

 have been caused by the presence of these substances 

 is also indicated by the absence of any reaction in the 

 control bull, and also by the negative results obtained 

 with Vaccines Nos. 4 and 5, which contained no 



