ANTHRAX. 67 



Here the bacilli are frequently arranged in long chains 

 which have an appearance which has been compared to 

 that of a bamboo ; chains occur in the blood or in the 

 inflammatory exudate, but are usually much shorter 

 than those seen in cultures. But the most important 

 feature in cultivation of the anthrax bacillus is the 

 development of spores which are oval highly refractile 

 bodies, which lie in or near the centre of the bacilli, one 

 in each. These spores are possessed of tough capsules, 

 which resist the action of the ordinary stains much in 

 the same way as the tubercle bacillus does. Thus it 

 happens that in films of a cultivation of the anthrax 

 bacillus which have been stained with such a dye as 

 methylene blue the spores are readily seen as colourless 

 and refractile oval areas in the centre of the bacilli, the 

 latter being stained blue. The spores themselves may 

 be stained by a modification of the process used for the 

 tubercle bacillus. The films are first stained by heated 

 carbol-fuchsin, which penetrates slowly through the 

 capsule ; they are then decolorised by a very rapid 

 immersion in dilute sulphuric acid and examined micro- 

 scopically. If the red colour has been entirely removed 

 by the spirit they are ready to be counterstained by 

 methylene blue ; if not they must be dipped in the spirit 

 once more and re-examined. When this process is 

 successful the spores are stained red and the bacilli 

 blue. 



The presence of spores enables us to isolate the bacilli 

 from most of the organisms with which it is likely to be 

 contaminated by a very simple process. The spores 

 resist the action of heat just as they resist stains, and 

 for the same reason, and suitable temperature will kill 

 off all the non-sporing organisms and spare the spores. 

 The latter may then be inoculated at a suitable tem- 



F 2 



