THE BA CILL US OF SYMPTOM A TIC ANTHRAX. 449 



single colonies appear as discrete globules that cause 

 rapid liquefaction of the gelatin, and ultimately coalesce 

 into irregular, lobulated, liquid areas. In some of the 

 larger colonies an ill-defined, concentric arrangement of 

 alternate clear and cloudy zones can be made out. 

 (Fig. 97.) 



In deep stab-cultures in gelatin growth begins after 

 about two or three days at 20° to 25° C. It begins 

 usually at about one or two centimetres below the sur- 

 face, and causes slow liquefaction at and around the 

 track of its development. During the course of its 

 growth gas-bubbles are produced. 



In deep stab-cultures in agar-agar at 37° to 38° C. 

 growth begins in from twenty-four to forty-eight hours, 

 also at about one or two centimetres below the surface, 

 and is accompanied by the production of gas-bubbles. 

 There is produced at the same time a peculiar, penetrat- 

 ing odor somewhat suggestive of that of rancid butter. 

 Under these conditions spores are formed after about 

 thirty hours. 



It grows well in bouillon of very slightly acid reac- 

 tion under hydrogen, but does not retain its virulence 

 for so long a time as when cultivated upon solid media. 

 In this medium it develops in the form of white flocculi 

 that sink ultimately to the bottom of the glass and leave 

 the supernatant fluid quite clear. If the vessel be now 

 gently shaken, these delicate flakes are distributed homo- 

 geneously through it. In bouillon cultures there is 

 often seen a delicate ring of gas-bubbles around the 

 point of contact of the tube and the surface of the 

 bouillon. There is produced also a peculiar, penetrat- 

 ing, sour or rancid odor. 



It grows best at the body temperature — i.e., from 37° 



