384 



L. D. BUSHNELL 



tion at D was given a slight bend to break the sealed tip. (If 

 the tip has not been sealed too close to the lower part of the con- 

 striction it is very easily broken.) When the tip is broken there 

 is an immediate fall of the mercury in the pump and a correspond- 

 ing rise of the mercury column in the manometer tube. The gas 

 is pumped out of the culture bottle and collected in a container 

 over the mercury pump. The pumping is continued until the 

 mercury column in the manometer tube becomes stationary. 



-'=,»•"-/ 



• ^/"V 



Fig. 1. Showing Arrangement of 

 Cultures in the Incubator 



Fig. 2. Showing Details op the 



Connection Between the Cul- 



titre Bottle and the 



Mercury Pump 



This is usually very close to the theoretical vacuum, and required 

 about fifteen or twenty minutes. By this means it was possible 

 to obtain the dissolved gases as well as those which had collected 

 above the liquid. The liquid boiled vigorously at 37°C. and the 

 water vapor probably aided in washing the gases out of the 

 bottle. 



After the gas had all been forced into the collecting bottle the 

 connection between this bottle and the gas analysis apparatus 



