BACILLUS OF SYMPTOMATIC ANTHRAX. 409 



FIG. 90. 



It forms spores, and when in this stage is seen to be 

 slightly swollen at or near one of its poles, the location in 

 which the spore usually appears. (Fig. 89, 

 B.) It is conspicuously prone to undergo 

 degenerative changes, and involution forms 

 are commonly seen, not only in fresh cul- 

 tures, but in the tissues of affected ani- 

 mals as well. 



Though actively motile when in the 

 vegetative stage, it loses this property and 

 becomes motionless when spores are form- 

 ing. 



It is strictly anaerobic and cannot be 

 cultivated in an atmosphere in which oxy- 

 gen is present. It grows best under hy- 

 drogen, and does not grow under carbonic 

 acid. 



The media most favorable to its growth 

 are those containing glucose (1.5 to 2 per 

 cent.), glycerin (4 to 5 per cent.), or some 

 other reducing body, such as indigo-so- 

 dium-sulphate, sodium formate, etc. 



When cultivated upon gelatin plates 

 in an atmosphere of hydrogen the col- 

 onies appear as irregular, slightly lobu- Colonies of the 

 lated masses. After a short time lique- bacillus of symp- 



n ,. n .1 i .. 1,1 tomatic anthrax, 



faction of the gelatin occurs and the in deep gelatin 

 colony presents a dark, dense, lobulated culture. (After 



,, . FRANKEL and 



and broken centre, surrounded by a P FE IFFER.) 

 much more delicate fringe-like zone. 



When distributed through a deep layer of liquefied 

 gelatin that is subsequently caused to solidify, colonies 

 develop at only the lower portions of the tube. The 



