ANAEROBIC CULTURES 



247 



strokes of the air pump, aspirate a small quanity of 

 gas, so creating a slight vacuum. Then shut off the 

 stop-cock and disconnect the air pump. 



9. Fill the 10 c.c. bulb pipette with water; insert its 

 point into the rubber tubing on the long tube b as far as 

 the screw clamp. Open the screw clamp and run in 

 water until stopped by the internal pressure. Shut 

 off stop-cock. (The water dissolves the soda and 



FIG. 137. Bulloch's jar. 



pyrogallic acid converting the latter into alkaline 

 pyro. and so bringing its latent capacity for oxygen 

 into action) . 



10. Reverse the tubes from the tubulures so that 

 they meet, out of harm's way, over the top of the 

 bell glass ; again see that all joints are tight and trans- 

 fer the apparatus to the incubator. 



This last method is the most satisfactory for anae- 

 robic cultivations, as by its means complete anaerobi- 

 osis can be obtained with the least expenditure of time 

 and trouble. 



