1 86 BACTERIA 



appears, lateral hair-like outgrowths are seen in the gelatine. At 

 the bottom of the crater a white crumbly mass is formed, but no 

 pellicle. On agar plates, small whitish colonies develop which 

 are elevated and round. When magnified, wavy hair-like growths 

 appear on the edge, caused by many twisted parallel chains of 

 bacilli (Fig. 53). 



In agar stab, the growth is more luxuriant near the top; lateral 

 filamentous branches are seen along the stab line. In agar 

 streak the colonies are abundant, thick and fatty; have tangled 

 edges, and the water of condensation is cloudy. In bouillon, it 



FIG. 53. Anthrax bacilli. Cover-glass has been pressed on a colony and 

 then fixed and stained. (Kolle and Wassermann.) 



forms homogeneous flocculi, which precipitate, leaving the bouillon 

 clear. A fragile pellicle is formed. In milk, it multiplies rapidly, 

 the proteids are coagulated, generally rendered acid, and later the 

 coagulum is dissolved. Potato cultures are likewise luxuriant. 

 The growth is elevated, dull in lustre, and the outline is wavy. 



Pathogenesis. The anthrax bacillus increases so rapidly, and 

 so luxuriantly, that it has been supposed to cause death merely 

 by mechanically overwhelming the animal : absorbing nutriment 

 and oxygen, and blocking capillaries. Its action is certainly not 



