THE TUBERCLE BACILLUS. 219 



they are easily stained with the aqueous solution of 

 fuchsine at ordinary temperatures. It is almost as 

 diflScult to decolourise them, and thus by these 

 characteristics they may be distinguished on the one 

 hand from tubercle bacilli, and on the other from all 

 other bacteria. It appears that a completely success- 

 ful culture of the leprosy bacillus has only ■ once been 

 obtained, and even in this case such varying forms 

 appeared on the peptone glycerine blood serum, that 

 it seems as though only those bacilli which had been 

 affected by unfavourable conditions (involution forms) 

 could have been present. Further, inoculation of 

 animals up to now has never succeeded in a manner 

 quite free from objections. 



