166 JOHNE'S DISEASE 



tubercle bacilli are found to disappear the more 

 rapidly. This might be expected, but, on the other 

 hand, in animals immunized with dead Johne's bacillus, 

 and then inoculated with one of the two living bacilli 

 as before, it is again the human tubercle bacillus that 

 first disappears. 



If, as is thought by some authors (Wolff- Eisner, etc.), 

 the tuberculin reaction be due to the action of the 

 specific lysin on the tubercle bacilli, or particles of 

 them, then one would expect the rise of temperature 

 in the tuberculin test to take place at an earlier hour 

 than in animals suffering from Johne's disease, and 

 treated with a diagnostic vaccine prepared from Johne's 

 bacillus. The contrary, however, seems to take place, 

 since the tuberculin reaction appears about the ninth 

 hour to the eighteenth hour, whilst, as we have seen, 

 the reaction in the case of Johne's disease usually 

 takes place before the ninth hour. It is, however, 

 possible that the comparatively early disappearance of 

 tubercle bacilli is not due to lysis, but to the fact that 

 they are more toxic than Johne's bacillus to the cells, 

 which break down more quickly, and liberate the 

 bacilli, these subsequently becoming disseminated 

 throughout the animal body. It is also well known 

 that in an encapsulated caseous nodule tubercle bacilli 

 are usually not numerous, whilst we have seen that 

 Johne's bacillus is often present in enormous numbers. 

 The same appears, in a general way, to be true as 

 regards the destruction of the bacilli in subcutaneous 

 abscesses. 



That (lysed ?) Johne bacilli are as toxic as the 

 (lysed?) tubercle bacilli is proved by the general dis- 

 turbance caused in animals by the inoculation of a 

 diagnostic vaccine. The same is shown by experi- 

 ments performed on rabbits that have been immunized 



