The Absorption of the Atmospheric Oxygen 217 



better to adapt the principle to some larger piece of apparatus that 

 can contain a number of tubes or Petri dishes at a time. For this 

 purpose the jar invented by Novy or the apparatus of Botkin can 

 be used. 



The Novy jar receives as many inoculated tubes as it will contain 

 and has its stopper so replaced that the openings in the neck and 

 stopper correspond. Hydrogen gas is passed through until the air 

 is displaced. This usually takes several hours, as the cotton stop- 

 pers retain the air in the test-tubes and prevent rapid diffusion. 

 When the air is all displaced, the stopper is turned so that the tubes 

 are closed. If it be desired to 

 expedite matters a pump can be 

 used to withdraw the air, after 

 which the hydrogen is permitted 

 to enter. 



Botkin's apparatus is intended 

 for cultures in Petri dishes. It 

 consists of three parts a deep 

 dish of glass (7>), a stand to sup- 

 port the Petri dishes to be ex- 

 posed (c), and a bell-glass (a) to 

 cover the stand and fit inside of 

 the dish. The prepared dishes 

 are stood uncovered in the rack, 

 which is then placed in the dish 

 forming the bottom of the appa- 

 ratus, and into which liquid par- 

 affin is poured to a depth of about ,.,. 



. i rp,, i n i . tig. 65. Botkin's apparatus for mak- 



2 inches. The bell-glass cover is ing anaerobic cultures. 



now stood in place and hydrogen 



gas is conducted through previously arranged rubber tubes (d, e)'. 



As soon as the air is displaced 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withdrawn.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 atmos- 

 pheric oxygen by alkaline pyrogallic acid and permit the bacteria 

 to develop in the indifferent nitrogen. 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 and a 

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

 gallic acid and sodium "hydroxid were poured into the large tube, 

 the smaller tube placed within it, upon some appropriate support, 

 and the whole tightly corked. 



Nichols and Schmitter, * at the suggestion of Carroll, have modified 

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



