CULTIVATION WITHOUT OXYGEN. 



205 



stopper. The oxygen is quickly obsorbed 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. 38. 



Frankel's method for the cultivation of anaerobic bacteria. 



Method of C. Frdnkel. Carl Frankel suggests the 

 following : 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 before using. 

 On the outer side of the stopper these two tubes are 

 bent at right angles to the long axis of the test-tube into 

 which they are to be placed, and both are slightly 



