CULTIVATION OF ANAEROBIC BACTERIA. 217 



Esmarch used a regular "Esmarch tube," into the 

 central cavity of which melted sterile gelatin was poured 

 to exclude the air. 



Buchner invented a method by which, by the use of 

 pyrogallic acid, the oxygen was absorbed from the atmo- 

 sphere in which the culture was kept, and the growth 

 allowed to continue in the nitrogen and carbonic acid 

 which remained (Fig. 36). His method was to place the 

 tube which had been inoculated in a much larger outer 

 test-tube containing alkaline pyrogallic acid. The large 



Fig. 35. — Hesse's 

 method of making 

 anaerobic cultures. 



Fig. 36. — Buchner's 

 method of making an- 

 aerobic cultures. 



Fig. 37. — Frankel's meth- 

 od of making anaerobic cul- 

 tures. 



tube was closed with a rubber cap, and the absorption of 

 the oxygen allowed to progress. 



Gruber, instead of absorbing the oxygen as Buchner 

 does, prefers to use an air-pump and exhaust the contents 

 of the tube. He uses a tube having a slender neck and 

 a perforated rubber stopper. After the inoculation is 

 made the air is pumped out and the slender neck sealed 

 in the blowpipe. After this the tube can be warmed and 



