CULTURE MEDIA 43 



Medium 100 

 Sodium Citrate for the Colon Aerogenes Group^ 



Sodium chloride (NaCl) 5.0 gm. 



Magnesium sulphate (MgS04-7H20) 0.2 gm. 



Monoammonium phosphate (NH4H2-POi) 1.0 gm. 



Dipotassium phosphate (K2HPO4) 1.0 gm. 



Sodium citrate (S^^HaO) 2 . 77 gm. 



Distilled water 1,000.0 cc. 



1 KosER, S. A., J. Bad., 9: 63, 1924. 



Bacterium coli of fecal origin is unable to utilize citrate, while 

 the B. aerogenes-cloacae types all utilize citrate. 



Medium 101 

 Ferric Ammonium Citrate-nitrate Solution 



Ammonium sulphate ((NH4)2S04) 0.5 gm. 



Sodium nitrate (NaNOs) 0.5 gm. 



Dipotassium phosphate (K2HPO4) 0.5 gm. 



Magnesium sulphate (MgS04-7H20) 0.5 gm. 



Calcium chloride (CaCla) 0.2 gm. 



Ferric ammonium citrate 10.0 gm. 



Distilled water 1,000.0 cc. 



The ferric ammonium citrate should be sterilized separately 

 and added to the salt solution when cool. If a solid medium is 

 wanted, add 1.5 per cent of agar. 



The decomposition of the organic radical is accompanied by 

 the precipitation of the iron; thus in an agar medium brown 

 zones are formed around the colonies. 



Medium 102 

 Corn Mash 



Corn meal (not degerminated) 50 to 80 gm. 



Tap water 1,000 cc. 



Mix the corn meal with cold water. Steam for 2 to 3 hours 

 and tube in long test tubes. Sterihze for 2 hours at 120°C. 



Medium 103 



Sheep- or Beef-brain for Anaerobic Bacteria 



1. Boil sheep brain with equal volume of water. 



2. Decant water (save) and press brain through a potato ricer. 



