CULTURE MEDIA 35 



Medium 84 

 Peptone-sucrose Solution for Gum 



Peptone 1.0 gm. 



Monopotassium phosphate (KH2PO4) 2.0 gm. 



Magnesium sulphate (MgS04-7H20) 0.1 gm. 



Calcium chloride (CaCl2) 0.1 gm. 



Sucrose 20 . gm 



Distilled water 1,000.0 cc. 



MEDIA FOR CELLULOSE-DECOMPOSING ORGANISMS 



Medium 85 



Ammonium Sulphate-cellulose Solution^-^ 



Ammonium sulphate ((NH4)2S04) 1.0 gm. 



Dipotassium phosphate (K2HPO4) 1.0 gm. 



Magnesium sulphate (MgS04-7H20) 0.5 gm. 



Calcium carbonate (CaCOs) 2.0 gm. 



Sodium chloride (NaCl) trace 



Distilled water 1,000 . cc. 



^ Ammonium chloride (NH4CI), diammonium phosphate ((NH4)2HP04), 

 potassium nitrate (KNO3), or sodium nitrate (NaNOs) may also be used. 

 2OMELIANSKY, W., Centr. Bakt., II Abt., 8: 226, 1902. 



Fill large test tubes about one-third full. Add two or three 

 strips of filter paper to each tube, part of the paper protruding, 

 above the surface of the medium. When nitrates are used, the 

 calcium carbonate may be left out. 



Medium 86 

 Silica-gel Cellulose 



Prepare a series of silica-gel plates according to Souleyre 

 method. 



Silica Gel according to Souleyre^ 

 (Modified) 



To 40 cubic centimeters of 20 per cent tartaric acid, 1 cubic 

 centimeter of 60 per cent phosphoric acid and 1 cubic centimeter 

 sulphuric acid (1:1), add 100 cubic centimeters of potassium silicate 

 solution (specific gravity, 1.057).^ Let stand until clear, then 

 filter off the clear solution. This is designated as solution A. 



3 Souleyre, M., Compt. rend. d. la Soc. Biol., 93: 306, 1925. 

 ^ 7.6 grams potassium silicate made up to 100-cubic centimeters solution 

 gives specific gravity = 1.057. 



