118 JOHNE'S DISEASE 



Case IV. was retested after six weeks. A special 

 vaccine was given : Fifty milligrammes of avian 

 tubercle bacilli grown on the surface of glycerine- 

 broth, and made into an emulsion with 2 c.c. of physio- 

 logical salt solution, were injected into the jugular 

 vein. *' The temperature at the time of injection was 

 io2-6° F., and by midnight it had risen to 105° F. On 

 the following day the morning and afternoon tempera- 

 tures were 104-2° and 103-6° F. respectively." This 

 may be taken as a positive result, and the animal was 

 afterwards found to be suffering from Johne's disease. 



Case VIII. was retested after eight weeks. "A 

 very good reaction was provoked on this occasion." 



Case XL was retested after the same lapse of time, 

 and ** a good general reaction was again produced." 



Case XVI., which gave a marked reaction on the 

 first test, on being retested after about nine weeks, 

 gave what the authors considered was a " slight " reac- 

 tion. Certainly the second set of figures in this case 

 would not be sufficiently definite for a practitioner 

 to risk the slaughter of a valuable animal. On post- 

 mortem examination this case showed no decided 

 macroscopic lesions, but gave *' a decidedly positive 

 result with regard to the presence of acid-fast bacilli." 



Case XVII. had been previously tested by a 

 veterinary surgeon with avian tuberculin, with a 

 negative result. 



We consider that the results obtained by these 

 workers afford further proof that the avian tuberculin 

 test is not a reliable means of diagnosing cases of 

 Johne's disease, for in spite of the large doses of 

 vaccine that were given, the majority of the cases 

 failed to react, a result which is in agreement with 

 that obtained by other investigators. 



M'Fadyean, Sheather, and Edwards have also tried 



