CULTIVATION WITHOUT OXYGEN. 



223 



The larger tube is then tightly plugged with a rubber 

 stopper. The oxygen is quickly absorbed by the pyro- 

 gallic acid, and the organisms develop in the remaining 

 constituents of the atmosphere, viz., nitrogen, a small 

 amount of CO 2 , and a trace of ammonia. 



FIG. 40. 



Frankel's method for the cultivation of anaerobic bacteria. 



^[ethod of C. Frdnkel. Carl Frankel suggests the 

 following as a modification of or substitute for the tube 

 of Liborius : the tube is first inoculated as if it were 

 to be poured as a plate or rolled as an ordinary Esmarch 

 tube. The cotton plug is then replaced by a rubber 

 stopper, through which pass two glass tubes. These 

 must all have been sterilized in the steam sterilizer 



grammes to the litre as the number of its molecular weight 56.1 

 grammes to the litre of water. 



