196 PRACTICAL BACTERIOLOGY. 



addition, there are numerous other dififerences to be 

 observed between them ; the anthrax bacillus is 

 thicker than the hay bacillus, and forms longer rod- 

 lets ; it is always non-motile, whilst the hay bacillus 

 always passes through motile stages, especially after 

 budding has taken place. In addition, the appear- 

 ance of their colonies in the various cultures is very 

 different. 



The anthrax bacillus is easily stained -with any of 

 the usual staining reagents ; gentian violet gives the 

 prettiest effect. Gram's method may be used, and 

 ■with special advantage, when sections and blood pre- 

 parations are to be doubly stained. If from a young 

 agar-agar culture a small portion be taken, and a dry 

 cover-glass preparation be made with it, the thread, 

 after suitable staining, may be seen to hang together, 

 although the separate cells are clearly to be distin- 

 guished. If, on the other hand, a blood preparation is 

 stained, the threads are seen to be much shorter, and 

 between the cells composing them greater gaps occur, 

 which do not have parallel but lenticular walls, as the 

 shorter walls of the cells are concave. The impression 

 cover-glass preparations taken from plate cultures 

 must be well dried before they are fixed. When they 

 are cold they may then be carefully stained. If the 

 staining solution is heated, the colonies, especially if 

 they are a little old, become easily loosened from the 

 cover-glass. Spores may be easily rendered visible if 



