390 



BACTERIOLOGY. 



Fio. 86. 





It is strictly anaerobic and cannot be cultivated in an 



atmosphere in which oxygen is present. It grows best 



under hydrogen, 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-sodium-sulphate, sodium formate, 



etc. 



When cultivated upon gelatin plates 

 in an atmosphere of hydrogen the col- 

 onies appear as irregular, slightly lobu- 

 lated masses. After a short time lique- 

 faction of the gelatin occurs and the 

 colony presents a dark, dense, lobu- 

 lated and broken centre, surrounded by 

 a 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 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 alter- 

 in deep gelatin nate clear and cloudy zones can be made 



culture. (After ^ rpis. 86.) 



Frankel and \ & J 



pfeiffek.) In deep-stab cultures in gelatin growth 



begins after about two to three days at 



20° to 25° C. It begins usually at about one or two 



centimetres below the surface and causes slow liquefac- 



Colonies of the 

 bacillus of symp- 

 tomatic anthrax. 



