GENUS BACILLUS 337 



of animals. In the hanging drop the bacilli are observed to 

 be actively motile, and in stained preparations flagella may 

 be demonstrated. Spores are formed. They are elliptical in 

 shape, usually thicker than the bacilli, lying toward one ex- 

 tremity. This gives to the bacilli containing spores a some- 

 what spindle shape. 



Staining 1 . It stains readily with the ordinary aniline 

 dyes. It stains feebly by Gram's method. 



Cultivation; This organism grows readily on the ordi- 

 nary cultural media in the absence of oxygen. It grows more 

 vigorously, however, in media containing from 1 to 2% of 

 glucose, or 5% of glycerine. It must be cultivated under 

 strict anaerobic conditions. 



Agar. In agar stick cultures growth, occurs along the 

 needle track some distance below the surface after 24 to 48 

 hours. It has a peculiar disagreeable odor. A few gas bub- 

 bles form in the agar. 



Gelatin. At room temperature colonies appear in from 

 24 to 48 hours. They are round or oval with somewhat dense 

 centers about which fine radiating filaments form an opaque 

 halo. The gelatin is liquefied. 



Bouillon. Bouillon in the fermentation tube, containing 

 l c / ( glucose, becomes deeply clouded in the closed branch with 

 the formation of a considerable quantity of gas. 



Life conditions and properties. The bacillus of symp- 

 tomatic anthrax is an obligatory anaerobe and can not be 

 cultivated under aerobic conditions. It grows best at a tem- 

 perature of about 37 C. although it multiplies more slowly 

 at room temperature. This organism produces, according to 

 Leclainche and Vallee, 1 a soluble toxin, which they found to be 

 formed in considerable quantities in broth containing blood 

 and various animal fluids. According to these authors the 

 best medium for obtaining the toxin is the bouillon of Martin 2 

 made of equal parts of veal infusion and a peptone solution 



1 Leclainche and Vallee. Ann. de 1'Inst. Pasteur, Vol. XIV (1900) 

 p. 202. 



2 Martin. Ann. de 1'Inst. Pasteur, Vol. XII (1898) p. 26. 



