CULTIVATION WITHOUT OXYGEN. 



219 



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 COj, and a trace of ammonia. 



Fig. 42. 



Frankel's method for the cultivation of anaerobic bacteria. 



Method 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. 



