Exclusion of Atmospheric Oxygen 221 



test-tube, a kink is given each rubber tube and the fluid contained 

 in the bulbous part of the pipet becomes hermetically sealed. 



In all cases where the presence of suspected micro-organisms is to 

 be demonstrated, it is necessary to make both aerobic and anaerobic 

 cultures. For routine work of this kind, this method of Wright is 

 probably the most convenient yet suggested. 



