334 



ANTHRAX 



described. On examining such with a high power, the wreaths 

 are seen to be made up of bundles of long filaments lying 

 parallel with one another, each filament consisting of a chain 



FIG. 100. Anthrax bacilli, arranged in chains, 

 from a twenty-four hours' culture on agar 

 at 37 C. 



Stained with fuchsiu. x 1000. 



of bacilli lying end to end, and similar 

 to those observed in the blood (Fig. 

 100). 



On gelatin plates, after from twenty- 

 four to thirty-six hours at 20 C., the 

 same appearances manifest themselves, 

 and later they are accompanied by 

 liquefaction of the gelatin. In gelatin 

 plates, however, instead of the char- 

 acteristically wreathed appearance at 

 the margin, the colonies sometimes 

 give off radiating spikelets irregularly 

 nodulated, which produce a star-like 

 form. These spikelets are composed 

 of spirally twisted threads. 



From such plates the bacilli can be easily isolated, and the 

 appearances of pure cultures on various media studied. 



In bouillon, after twenty-four hours' incubation at 37 C., 

 there is usually the appearance of irregularly spiral threads sus- 

 pended in the liquid. These, on being examined, are seen 



FIG. 101. Stab culture of 

 the anthrax bacillus in 

 peptone-gelatin ; seven 

 days' growth. It shows 

 the "spiking," and also, 

 at the surface, com- 

 mencing liqiiefaction. 

 Natural size. 



