ISOLATION OF BACTERIA IN PURE CULTURE 195 



A number of procedures may be used to greatly facilitate 

 the above methods of isolation by taking advantage of the 

 different physiological properties of different organisms in a 

 mixture such as ability to form spores, different resistance 

 to antiseptics, special food requirements and pathogenic 



Fig. 133.— Photograph of microscope with Barber's isolation apparatus 

 set up to use. 



properties, (a) If material contains resistant spores it may 

 be heated to temperatures high enough to kill all of the organ- 

 isms except the spores (80° for half an hour, for example) 

 and then plated out. Or (6) an antiseptic which restrains 

 the growth of some organisms and not others may be placed 



