ANAEROBIC CULTURE METHODS 



67 



potash solution* are put in the larger tube, which is tightly plugged 

 with an india-rubber stopper. The oxygen is quickly absorbed by the 

 pyrogallic acid, and the organisms develop in the remaining con- 

 stituents of the atmosphere nitrogen, small amount of, Co 2 , and a 

 trace of NH 3 . 



CXXVII. KASPAREE'S METHOD FOR LIQUID MEDIA. 



A special flask is necessary for this method, with a small tube 

 terminating in a bulb blown into its neck about f ths of an inch 

 above the top of the liquid medium, which is prepared as follows : 



1. Fill the flask with bouillon almost to the neck, then add 3 c.c. 



FIG. 11 



FIG. 18. 



Buchner's Tube for Anaerobic 

 Cultures. 



Kipp's Hydrogen Apparatus. 



of liquid paraffin, and sterilize the whole in the steam sterilizer in the 

 usual manner. This expands the bouillon, causing the paraffin to rise 

 in the neck of the flask and overflow into the side tube and bulb. 

 After sterilization is completed, only a thin layer of the paraffin 

 remains on the top of the bouillon, and during heating a large portion 

 of the air absorbed by the bouillon is driven out ; its re-absorption 

 while the flask is cooling is prevented by the thin paraffin film. 



2. Before inoculation pierce the thin paraffin film on the top of 



* A normal solution of caustic potash contains as many grammes to the litre as 

 the number of its molecular weight 56 '1 grammes to the litre of water. 



