n44-4 MANUAL OF METHODS FOR PURE CULTURE STUDY 



Manual to include all the media employed by bacteriologists. In 

 selecting the ones to include two principles have been kept in mind : 

 first to include only those known to be in fairly common use among 

 American bacteriologists; second, reaUzing that this is a Manual for 

 Pure Culture Study of Bacteria, not to list media that are used purely 

 for counting bacteria or for the diagnosis of disease. The media 

 given here are employed either for maintaining pure cultures or for 

 the identification of species. 



For the purposes of this Manual these media may be classified as 

 follows: A. Cultivation and storage media; B. General differential 

 media — i.e. media employed in tests for determining the identity of 

 saprophytic aerobes, in general; C. Media for special groups of 

 aerobes — i.e. media employed in the identification of bacteria of 

 certain narrow groups, such as the colon-typhoid group; D. Media 

 for anaerobic bacteria. 



The media included in this leaflet under the heading "C" have 

 been arranged into three groups the first of which is denoted "Basal 

 Media". The basal media may be considered as formulae to which 

 substances under investigation (e. g., sugars) may be added. The 

 selection of any of these basal media depends upon the group of 

 bacteria to be studied. 



Special reference is made here to Levine and Schoenlein's Com- 

 pilation of Culture Media, 1930. In the case of the formulae taken 

 from this source, the number therein assigned to the medium is given 

 at the head of each formula under the designation "L&S No " 



Attention is called to the fact that many of these media are now 

 on the market in dehydrated form. Use of such dehydrated media is 

 entirely permissible, and often convenient. 



A. Cultivation and Storage Media 



Beef -extract broth ordinarily has the following composition : 



Beef-extract 3 g. 



Peptone 5 g. 



Distilled water 1000 ml. 



Concerning the peptone called for in the above formula, no definite 

 specifications can yet be given. Various commercial products are 

 available, no one of which is superior for all bacteriological purposes. 

 In the case of reports on standard methods (e.g., those of the Ameri- 

 can Public Health Assoc.) emphasis is laid on one brand of peptone 



