596 APPLICATION OF METHODS OF BACTERIOLOGY 



Though actively motile when in the vegetative stage, it, 

 like all other motile spore-forming bacilli, loses this property 

 and becomes motionless when spores are forming. 



It is strictly anaerobic and cannot be cultivated in an 

 atmosphere in which free oxygen is present. It grows best 

 under hydrogen, and does not grow under carbonic acid. 



The media most favorable to its growth are those con- 

 taining 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 colonies appear as irregular, slightly lobu- 

 lated masses. After a short time liquefaction of the gelatin 

 occurs and the colony presents a dark, dense, lobulated and 

 broken centre, surrounded by a much more delicate, fringe- 

 like zone. 



When distributed through a deep layer of liquefied gelatin 

 that is subsequently solidified 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, concen- 

 tric arrangement of alternate clear and cloudy zones can 

 be made out. (Fig. 105.) 



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 centimeters below the surface, and causes 

 slow liquefaction at and around the track of its development. 

 During 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 centimeters below the surface, and is 



