164 GENERAL MICROBIOLOGY 



B. subtilis, or an equal depth of liquefied agar or gelatin and 

 inoculate this when solid with the aerobe. 



The growth of the aerobe will use up all the oxygen that 

 reaches it and will not allow any to pass through to the 

 medium below, which will consequently remain in an 

 anaerobic condition. 



Giltner's H-tube Method. The use of Giltner's H-tube 

 allows the anaerobe in a certain medium to be grown on one 

 side of the H either as a stab culture or a streak, while the 

 aerobe in the same or a different medium, liquid or solid, 

 may be grown on the other side. Rubber stoppers, fitted 

 to mouths of both tubes, are superimposed on cotton plugs. 

 The aerobe soon exhausts the oxygen from the tube, allow- 

 ing the anaerobes to develop. 



This is the method recommended for determining the 

 presence of and isolating Bad. abortus from infected mucous 

 membranes and tissues. This organism when first isolated 

 from tissues is a partial anaerobe, i.e., when an agar shake 

 culture is made in an ordinary test tube the colonies develop 

 in a zone about 0.5 cm. in width about 1.5 to 2 cm. below the 

 surface of the agar. 



By the use of the H tube, surface colonies of this organism 

 may be readily obtained for study. 



Novy Jar Method. This same principle may be applied 

 by the use of separate tube or plate cultivations of anaerobes 

 and aerobes in a Novy jar or similar apparatus; the aerobic 

 organisms should be offered a large surface for growth in 

 each case, 



IV. DISPLACEMENT OF AIR BY INDIFFERENT GASES 



The special tubes, flasks and jars adapted to cultivation 

 of anaerobes in a vacuum are equally applicable in this 

 method. 



The gas generally employed is hydrogen. It is preferable 

 to other gases not only because it is easily prepared, but that 

 it has no injurious effects on the organisms. 



