24 



CLINICAL BACTERIOLOGY 



of water will absorb 



caustic soda dissolved in 15 c.c 

 1,150 c.c. of oxygen. 



3. The following is more complicated, as we require 

 coal or hydrogen gas to replace the oxygen. It is known 

 as " FrankePs method." 



A stout test-tube has inserted into its mouth a rubber 

 cork having two perforations, through which two pieces of 

 glass tubing are passed. One tube reaches into the medium j 



r? 



ES 



31 



J 



Fig. 13. — Frankel's Tube for Anaerobic Cultivation. 



the other is shorter and does not. Outside the test-tube the 

 tubes are bent at opposite angles to each other, and gradu- 

 ally taper to points. The long tube is connected with the 

 hydrogen supply, and the small tube permits of its exit. 

 The stream of gas should be kept up for several minutes at 

 least, to permeate the whole medium. The short tube 

 should now be sealed off by the blowpipe flame, the long 

 tube in the same way, and the joint at the cork covered 

 with paraffin. 



