METHODS USED IN CULTIVATION OF BACTERIA 179 



Barber Single Cell Apparatus, and no description that could be given 

 in a text book would be of sufficient value to be allowed to take 

 up space. 



ANAEROBIC METHODS 



We have seen in a preceding chapter (p. 28) that many bacteria, 

 the so-called anaerobes, will develop only in an environment from 

 which free oxygen has been excluded. 



FIG. 15. DEEP STAB 

 CULTIVATION OF AN- 

 AEROBIC BACTERIA. 



FIG. 16. DEEP STAB 

 CULTIVATION OF AN- 

 AEROBIC BACTERIA. 



The exclusion of oxygen for purposes of anaerobic cultivation 

 may be accomplished by a variety of methods, depending upon a 

 few simple principles which have been applied, either separately 

 or in combination, by many workers. 



The earliest methods depended upon the simple exclusion of air 

 by mechanical devices. In other methods, the oxygen of the air 

 is displaced by inert gases (hydrogen), and others again depend 



