154 



BIOLOGY AND TECHNIQUE 



In using the Novy jar, the inoculated plates are set upon a wire 

 frame resting about an inch above the bottom of the jar. The cover 

 is then tightly set in place and the air in the jar exhausted by means of a 

 suction pump. The arrangement of the double stop-cock in the top 

 renders it possible now, by simply turning this, to admit hydrogen from 

 a Kipp generator into the jar. The process of alternate exhaustion and 



admission of hydrogen may be 

 several times repeated. 



A combination of air exhaus- 

 tion, oxygen absorption, and hy- 

 drogen replacement may be prac- 

 ticed in jars such as that shown 

 in Fig. 39. Tubes or plates after 

 inoculation are placed in this jar, 

 on a raised wire frame. Dry py- 

 rogallic acid is placed in the 

 bottom of the jar and the cover 

 tightly fitted. An opening in 

 the side of the jar connects its 

 interior with a bottle containing 

 sodium or potassium hydrate so- 

 lution. Through the stopper of 

 this bottle pass two glass tubes, 

 one of them of such length that 

 it can be pushed down into the 

 alkaline solution, or puUed up- 

 ward above the level of the fluid. 

 This tube connects the jar with 

 the bottle. The other glass tube 

 is short, passing just through the 

 stopper and at the top made in 

 the form of a T, one arm of the T 

 being connected with a Kipp hydrogen generator, the other with a 

 suction-pump. 



After the jar has been sealed, the glass tube connecting the jar and 

 the bottle is raised above the level of the fluid in the bottle and, the con- 

 nection to the hydrogen generator being closed, the air in the jar is 

 exhausted with the suction-pump. Connection to the suction may then 

 be closed, and the other arm of the T being open, hydrogen is allowed to 

 flow into the jar. Alternate suction and hydrogen replacement may be 



Fig. 38.- 



-Jak fob Anaerobic Cul- 

 tivation. 



