ANTHRAX 63 



the most important feature in cultures of the anthrax bacillus 

 is the development of spores, which are oval, highly refractile 

 bodies, and 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. Thus it happens that in films of a cultiva- 

 tion of the anthrax bacillus which have been stained with such 

 a dye as weak 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 

 decolorized by a very rapid immersion in very dilute sul- 

 phuric acid (i per cent.) or in methylated spirit, and examined 

 microscopically. If the red colour has been entirely removed 

 from the bacilli, but is still present in the spores, the films 

 are ready to be counterstained by methylene blue ; if not, they 

 must be dipped in the acid or spirit once more and re- 

 examined. When this process is successful, the spores are 

 stained red, and the bacilli blue (Plate I., Fig. 4). 



The presence of spores enables us to isolate the bacilli from 

 most of the organisms with which they are likely to be con- 

 taminated, by a very simple process. The spores resist the 

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

 reason, and a suitable temperature will kill off all the non- 

 sporing organisms and spare the spores. The latter may 

 then be inoculated at a suitable temperature, and will develop 

 into bacilli. This process, however, is not applicable to the 

 examination of the blood or morbid effwsions, as the bacillus 

 of anthrax does not form spores in the living body. In this 

 it differs from the tetanus bacillus, in which the process may 

 be applied direct to the material from the body. 



INVESTIGATION OF A SUPPOSED CASE OF MALIGNANT PUSTULE. 



Requisites. i. Several glass pipettes; if cultures are not 

 required, one will be enough. 



2. Clean slides and cover-glasses. 



3. Bunsen burner or spirit-lamp. 



4. LofBer's methylene blue; also the materials for Gram's 

 staining. 



