The Absorption of the Atmospheric Oxygen 263 



through tube d, both tubes are withdrawn. It is well to 

 place one Petri dish containing alkaline pyrogallic acid in 

 the rack to absorb any oxygen not successfully displaced. 



3. The Absorption of the Atmospheric Oxygen. This 



method was first suggested by Buchner, whose idea was to 

 absorb the atmospheric oxygen by alkaline pyrogallic acid 

 and permit the bacteria to develop in the indifferent nitro- 

 gen. Various methods have been suggested for achieving 

 this end, Buchner's own method consisting in the use of two 

 tubes, a small one to contain the culture (Fig. 68) and a larger 

 one to contain the absorbing fluid. A fresh solution of pyro- 

 gallic acid and sodium hy- 

 droxid were poured into 

 the large tube, the smaller 

 tube placed within it, upon 

 some appropriate sup- 

 port, and the whole tightly 

 corked. 



Nichols and Schmitter,* 

 at the suggestion of Carroll, 

 have modified the method 

 by connecting the tube con- 

 taining the inoculated cul- 

 ture medium with a U- 

 shaped tube, to the other 

 end of which is attached 

 a tube to contain the pyro- 

 gallic acid solution. The 

 apparatus will at once be 

 understood by a glance at ] 

 the cut (Fig. 67). The mode 

 of employing it is as follows : ' ' After inoculating the culture- 

 tube the plug is pushed in a little below the lips of the tube ; 

 the ends of the U tube and the test-tubes are coated exter- 

 nally with vaselin, the rubber tubes are adjusted on the 

 U tube and a connection made with the culture-tube so that 

 the glass ends meet. One or two grams of pyrogallic acid 

 are put in the empty test-tube and packed down with a 

 little filter-paper over it; ten or twenty cubic centimeters, 

 respectively, of a 10 per cent, solution of sodium hydroxide 

 are then poured into the tube and the second connection 

 made before the acid and alkali react to any extent." 

 * "Jour, of Medical Research," July, 1906, p. 113. 



66. Bodkin's apparatus for 

 making anaerobic cultures. 



