48 LABORATORY GUIDE IN BACTERIOLOGY 



the autoclav at 120° for 5 minutes, and connection is 

 made through the flask (g) and the tube (h) with the 

 aspirator. Now aspirate some air through the flask, 

 disconnect at /, and set aside. Observe the results. Why 

 does no growth take place ? Remove the cotton filter 

 (d), and drop it into a flask containing sterile broth; 

 place in the thermostat for 18-24 hours; note and 

 examine the conditions then present. 



