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tubes with constricted necks are commonly employed for 

 this purpose. The air is pumped out, after the medium is 

 inoculated, and the tube is then sealed in a llame. 



The absorption of oxygen can be accomplished by 

 means of an alkaline solution of pyrogallic acid. In 

 Buclmer's method the inoculated tube is placed within a 

 larger tube, which is closed with a rubber stopper, and 

 which contains on the bottom the pyrogallate solution. 



The displacement of air by some inert gas, as hydro- 

 gen, is frequently made use of in cultivating anaerobic 

 bacleria. Special tubes, as those of Li bonus, have been 

 introduced for this purpose. A current of hydrogen is 

 passed through the inoculated tube until all the air has 

 been displaced, after which it is sealed in a ilame. Plate 

 cultures in hydrogen can be readily obtained with Botkin's 

 apparatus a bell jar inverted over liquid paraffin, or 

 mercury. 



Cultures of anaerobic bacteria can be readily obtained 

 by inoculating glucose gelatin tubes, colored with litmus, 

 and placing them in the incubator. Although the con- 

 tents of the tubes are liquid, and apparently the air has 

 free access, yet energetic growth takes place. These cul- 

 tures preserve their vitality for a considerable period of 

 time and have the additional advantage of being readily 

 accessible. 



The most convenient method for obtaining cultures in 

 a vacuum, or in an atmosphere of any desirable gas, is to 

 use some form of bottle in which the ordinary culture tubes 

 can be placed, and the exhaustion or displacement of air 

 carried out. Fig. 1 shows such a bottle, which is provided 

 with a special stopper through which a current of gas, as 

 hydrogen, carbonic acid, etc., can be passed. The bottle is 

 sealed air-tight by merely turning the stopper through 

 ninety degrees. Fig. 2 shows a simple and eilicient form 

 of bottle in which the same result is obtained by means of 

 two glass stop-cocks. 



Ordinary test-tubes containing glucose gelatin, bouil- 



