296 METHODS OF IDENTIFICATION AND STUDY 



in the fermentation tubes. Obvious growth in the 

 closed branch as well as in the bulb or in the inverted 

 gas tube as well as in the bulk of the medium will 

 indicate that it is a facultative anaerobe ; whilst growth 

 only occurring in the bulb or in the closed branch 

 shows that it is an obligate aerobe or anaerobe respec- 

 tively. This method, however, is not sufficiently 

 accurate for the present purpose, and the examination 

 of an organism with respect to its behaviour in the 

 absence of oxygen is carried out as follows : 



Apparatus Required: 



Buchner's tubes. 



Bulloch's apparatus. 



Exhaust pump. 



Pyrogallic acid. 



Dekanormal caustic soda. 

 Media Required: 



Glucose formate agar. 



Glucose formate gelatine. 



Glucose formate bouillon. 



METHOD. 



i. Prepare four sets of cultivations: 



(A) Sloped glucose formate agar, and incubate 

 aerobically at 3 7 C. 



Sloped glucose formate gelatine, and incubate aero- 

 bically at 20 C. 



(B) Sloped glucose agar to incubate anaerobically 

 at 37 C. 



Sloped glucose formate gelatine to incubate 

 anaerobically at 20 C. 



(C) Sloped glucose formate agar to incubate anaero- 

 bically at 37 C. 



Glucose formate bouillon to incubate anaerobi- 

 cally at 37 C. 



(D) Sloped glucose formate gelatine to incubate 

 anaerobically at 20 C. 



Glucose formate bouillon to incubate anaerobi- 

 cally at 20 C. 



