154 PATHOGENIC BACTERIA. 



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 tlu- blowpipe. After this the tube can be warmed and 

 the melted gelatin or agar-agar rolled on its sides, as sug- 

 gested by Esmarch, if desired. 



Better than any of the preceding is the method of 

 Frinki-1, which removes the air and replaces it by hy- 

 drogen. Frankel prepares an ordinary Esmarch tube, 

 removes the cotton stopper, and replaces it by a carefully 

 sterilized rubber cork containing two tubes (Fig. 37). The 



