COMPOSITION OF CULTURAL MEDIA AND SUBSTRATES USED 

 IN BACTERIOLOGY 



Any classification of media and substrates used in bacteriology must of 

 necessity be artificial and arbitrary in form. In the classification here adopted 

 an effort has been made to bring closely related media together, although it is 

 realized that in some cases even the primary divisions tend to separate media 

 having much the same essential composition and used for much the same 

 purposes. 



The 7 primary divisions which have been adopted are as follows: 



PRIMARY CLASSIFICATION OF MEDIA 



Ai. Liquid media Group I (Med. 1-1394) 



A2. Solid media. 



Bi. Initially liquid. 



Ci. Reversible. Reversibly liquid and solid. Liquefiable by heat. 



Di. Solidified by the addition of agar-agar. . Group II (Med. 1395-2198) 

 D2. Solidified by the addition of gelatin. . Group III (Med. 2199-2371) 

 D3. Solidified by the addition of other materials 



Group IV (Med. 2372-2382) 

 C2. Irreversible. Not reversibly liquid and solid. 



Di. Solidifying agent organic Group V (Med. 2383-2466) 



D2. Solidifying agent inorganic Group VI (Med. 2467-2485) 



B.. Initially solid Group VII (Med. 2486-2543) 



GROUP I. LIQUID MEDIA 



The term "Liquid Medium" is here de- 

 fined to include all media containing suffi- 



SUBGROUP I-A 



cient water and so lacking in viscosity as to rr^u j. i • xu u x • i • i 



* , • , The water used in the bacteriological 



be readily poured from one vessel to another. 



A liquid medium is considered one which 



laboratory as a medium or in the prepara- 



, ,, ,, ,. ,.^ , , , tion of media may be either distilled or a 



does not set or solidify when cooled to ^^tural water. In theory distilled water is 



o? wateT''^*"'' ""^ ^°'''*' ^° •'" preferred, although distilled water 



mi. ,' -n J.- I-1- -1 1- J X 1 unless carefully prepared may contain gas- 



i he classihcation 01 liquid media adopted „ j. n- ■ -i- i- u -n • j. 



, . ., ^ , , , ! eous or metallic impurities which will inter- 



is based primarily upon whether the nitro- j-^j.^ ^^^-^ j^^ ^^^ 



gen supplied is inorganic or organic. Distilled water' for the bacteriological 



Subgroups of liquid media laboratory. 



Ai. Water only Subgroup I-A Surface and ground water for media. 



A2. Water with other constituents 



Bi. All constituents of medium inorganic 1, Molisch's Basal Nutrient Solution 



Subgroup I-B (Med. 2 to 113) 



B2. One or more constituents organic Constituents: 



Subgroup I-C (Med. 114 to 1394) 1. Sea water 1000.0 cc. 



