1 88 ESSENTIALS OF BACTERIOLOGY 



Form. Large slender rods, which swell up at one end or in 

 the middle for the spore (Fig. 95). 



Properties. They are motile, and liquefy gelatin quite 

 rapidly. 



A rancid odor is developed in the cultures. 



Cultures. The growth occurs slowly, and only in an atmos- 

 phere of hydrogen, being anaerobic; grows best at 38 C.; 

 under 15 C. no growth. 



Glucose-gelatin. In a few days little round colonies develop, 



Fig. 95. Bacilli of symptomatic anthrax, with spores ( X 1000) (Frankel 

 and Pfeiffer). 



which, under low power, show hairy processes around a com- 

 pact center. 



Stab-cultures in Full Test-tubes. The first growth in the 

 lower portion of the tube not very characteristic. Gases 

 develop after a few days, and the gelatin becomes liquid. 



A gar at brood temperature, in twenty-four to forty-eight 

 hours, an abundant growth with a sour odor and abundant 

 gas-formation. 



