ANAEROBIC CULTURE METHODS. 49 



the third. At the end of one hour turn the stopper 

 of the jar, which automatically seals it. The same 

 process can be carried out by using an ordinary large 

 tube with a rubber stopper perforated with two holes 

 for glass tubing. After the hydrogen has been passed 

 in for an hour, seal in the flame the glass tubing, clos- 

 ing first the exit tube. 



Place the jar in the incubator at 37°C. 



Another method of producing anaerobiosis, which is 

 much employed is that of Buchner. It consists in the 

 absorption of the oxygen by the use of freshly prepared 

 pyrogallate of potash. This may be carried out in 

 large jars, or in large test tubes. 



3. Treat the agar and gelatine cultures made, by 

 Buchner's method. 



(a) In the bottom of the large test tubes furnished, 

 place one-half inch layer of sand, and then add 1 

 gramme pyrogallic acid. 



(6) Now place in this test tube one of the inoculated 

 tubes and add lOcc. of 1% caustic potash solution, 

 taking care not to soil the inoculated tube. 



(c) Immediately plug firmly the large test tube with 

 a rubber cork. Pour melted wax or paraffin about the 

 edges of the cork, to secure perfect sealing. 



The oxygen is quickly absorbed and the bacteria 

 develop in an atmosphere of nitrogen. 



Place the agar tubes in the incubator at 37°C. and 

 keep the gelatine tubes at 20°C. 



