APPARATUS FOR ANAEROBIC CULTURE 65 



Fl ube ^^7 culture 

 containing anaerobes. 



bell-jar can be firmly luted down with unguentum resinae. In 



the upper part of the bell-jar are two apertures furnished with 



ground stoppers, and through each of the latter passes a glass 



tube on which is a stop-cock. One 



tube, bent slightly just after passing 



through the stopper, extends nearly to 



the bottom of the chamber ; the other 



terminates immediately below the 



stopper. In using the apparatus there 



is set on the base-plate a shallow dish, 



of slightly less diameter than that of 



the bell-jar, and having a little heap 



of from 2 to 4 grms. of dry pyrogallic 



acid placed in it towards one side. 



Culture plates made in the usual way 



can be stacked on a frame of glass 



rods resting on the edges of the dish, 



or a beaker containing culture tubes 



can be placed in it. The bell-jar is 



then placed in position so that ' the 



longer glass tube is situated over that part of the bottom of 



the shallow dish farthest away from the pyrogallic acid, and 



the bottom and stoppers are luted. ' 

 The air in the bell-jar is now 

 expelled by passing a current of 

 hydrogen through the short glass 

 tube, and both stoppers are closed. 

 A partial vacuum is then effected 

 in the jar by connecting up the 

 short tube with an air-pump, open- 

 ing the tap, and giving a few 

 strokes of the pump. A solution 

 of 109 grms. solid caustic potash 

 dissolved in 145 c.c. water is made, 

 and into the vessel containing it 

 a rubber tube connected with the 

 long glass tube is made to dip, 

 and the stopper of the latter being 

 FIG. 22.-Bulloch's apparatus for opened, -the fluid is forced into the 

 anaerobic plate cultures. chamber and spreads over the 

 bottom of the shallow dish ; 



potassium pyrogallate is thus formed, which absorbs any free 

 oxygen still present. Before the whole of the fluid is forced 

 in, the rubber tube is placed in a little boiled water, and this, 



5 



