ANAEROBIC CULTURE METHODS 157 



elder pith, mushrooms, etc.) have been used similarly with 

 success (Wrzosek, Ori and others). Spongy platinum has 

 also been used similarly with satisfactory results. 



The vitality of anaerobic organisms is exhausted much 

 more quickly on media prepared on these principles than on 

 media under anaerobic conditions (Jungano and Distaso). 



Perhaps if these methods were used in conjunction with 

 anaerobic methods the vitality of the anaerobes would not 

 be impaired. 



4. Growing the anaerobe in the presence of a vigorous 

 aerobe by the use of special methods or apparatus. 



IV. Displacement of air by an indifferent gas such as 

 hydrogen, carbon dioxid, etc. 



V. A combination of two or more of the above methods. 

 The following methods are those best adapted for class 



use and can be utilized in a regular exercise as desired : 



I. EXCLUSION OF AIR 



Hesse's Method. This method may be used either with 

 a pure culture or for determining the presence of anae- 

 robes in any substance. 



Apparatus. Tubes of agar or gelatin for stab cultures; 

 sterilized oil (olive oil, vaselin or paraffin oil) ; sterile 1 c.c. 

 pipette. 



Culture. Pure culture of an anaerobe. 



Method. 1. Make a stab culture of the anaerobe, using 

 a tube containing a deep column of the medium, and thrust- 

 ing the inoculating needle to the bottom of the tube. The 

 stab culture and a test tube shake culture also may be 

 treated as follows: 



2. With the sterile pipette place a layer of sterile oil,* 

 1 to 2 cm. deep, upon the surface of the medium. 



3. Incubate at the optimum temperature. 



* Sterile melted agar or gelatin may be substituted for the 

 sterile oil. 



