170 STUDIE8 IX [MMUNITY. 



that, in general, the injection of acid-fast bacilli in guinea-pigs, 

 whether they be saprophytic or pathogenic for cold-blooded ani- 

 mals, or of the homogeneous culture of Arloing, gives rise to sen- 

 sitizers which are active not only against the homologous bacteria, 

 but also against other acid-fast bacteria, whether saprophytic or 

 pathogenic These sensitizers are particularly active against the 

 bacilli of human, bovine or avian tuberculosis. There arc certain 

 exceptions, however, to this rule which are brought out by my 

 experiments. Acid-fast Toblcr No. I has no sensitizer for acid- 

 fast Tobler No. V; Bacillus Tobler No. II has no sensitizer for 

 fish tuberculosis, and Tobler No. V none against avian tuberculosis. 

 I have not studied these exceptions any further, but have contented 

 myself with calling attention simply to the general uniformity of 

 this immunity against tubercle bacilli, which was formerly pointed 

 out by Klcmperer in guinea-pigs following the injections of sapro- 

 phytic acid-fast bacilli. 



It seems to me wise, before drawing any conclusions from my 

 results as to the relationship between the different acid-fast bacilli, 

 to continue these experiments and particularly to follow more 

 closely the time of occurrence of the antibodies in the immunized 

 animals. 



