66 LABORATORY BACTERIOLOGY 



EXERCISE XXVIII 



PREPARATION OF CULTURE MEDIA 



100. In this exercise some of the more specialized media 

 used in determining certain of the physiologic and biocheraic 

 properties of bacteria are added. A few media required by 

 certain pathogenic bacteria, either for their artificial cultivation 

 or to aid in their differentiation, are also included. There are, 

 however, many other media often referred to in the literature 

 of this subject as being of more or less importance, but those 

 mentioned in this exercise seem to be more commonly used. 

 While it is not expected that the regular student will be able to 

 prepare all of these media, it is essential that the methods of 

 preparing them should be fully understood. If, however, any 

 student desires, he has the privilege of making all of them. For 

 convenience of reference the media are arranged in groups with 

 the minimum number of tubes of each to be prepared. 



101. Work for this Exercise. — Prepare after the methods 

 already given (Exercises III., IV., and X.) the media in Group A. 



102. Groups of Culture Media. — These are arbitrarily ar- 

 ranged for convenience of reference. 



Group A. — (Media commonly used.) 



(iq) Small test tubes of bouillon. 



(ip) Small and (15) large test tubes of agar. 



(10) Small and (15) large test tubes of gelatin. 



(10) Small test tubes of milk. 



(10) Small test tubes of potato. 



Group B. — (Media used to determine the power of bac- 

 teria to produce acids and alkalies.) 



(10) Small test tubes of litmus milk. 



(10) Small test tubes of sugar-free bouillon. 



