344 



ANTHRAX 



individuals from one another after division. A whole colony may, 

 in fact, be one long thread. Such colonies are very suitable 

 for making impression preparations (vide p. 140) which preserve 



FIG. 104. Anthrax bacilli arranged in chains, 

 from a twenty-four hours' culture on agar at 

 37 C. 



Stained with fuchsin. x 1000. 



permanently the appearances 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 consist- 

 ing of a chain of bacilli lying end to 

 end, and similar to those observed in 

 the blood (Fig. 104). 



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 charac- 

 teristically wreathed appearance at the 

 margin, the colonies sometimes give off 



radiating spikelets irregularly jointed, nodulated, and whorled, 

 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. 



FIG. 105. Stab culture of 

 the anthrax bacillus in 

 peptone - gelatin ; seven 

 days' growth. It shows 

 the " spiking," and also, 

 at the surface, com- 

 mencing liquefaction. 

 Natural size. 



