22 LABORATORY MANUAL OF MICROBIOLOGY 



Medium 46 



Urea Soil Extract^ 



Urea (CO(NH2)2) 50.0 gm. 



Dipotassium phosphate (K2HPO4) 0.5 gm. 



Soil extract (stock) 100 . cc. 



Tap water 900 . cc. 



iLoHNis, F. Centr. BakL, II Abt., 14: 714-723, 1905. 



Medium 47 



Urea Bouillon Gelatin or Agar 



Urea (CO(NH2)2) 20.0 gm. 



Gelatin 120 to 150.0 gm. 



or 



Agar 15.0 gm. 



Bouillon 1,000.0 cc. 



Reaction about pH 7.5. 



MEDIA FOR NITRIFYING BACTERIA 



Medium 48 



Ammonium Sulphate Solution^ 



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



Dipotassium phosphate (K2HPO4) 1.0 gm. 



Sodium chloride (NaCl) 2.0 gm. 



Magnesium sulphate (MgS04-7H20) 0.5 gm. 



Ferrous sulphate (FeS04-7HoO) trace 



Magnesium carbonate (MgCOs) excess 



Distilled water 1,000 . cc. 



2 WiNOGRADKSY, S. Lafar's "Handb. techn. mylol.,'' 3: 132-181, 1904. 



In order to prevent any loss of ammonia, it is desirable to 

 sterilize the magnesium carbonate separately. When cool add 

 an excess of the magnesium carbonate to each flask. 



Medium 49 



Magnesium Ammonium Phosphate Solution 



Magnesium ammonium phosphate (MgNH4P04- 



6H2O) 2.0 gm. 



Dipotassium phosphate (K2HPO4) 1.0 gm. 



Sodium chloride (NaCl) 2.0 gm. 



Magnesium sulphate (MgS04-7H20) 0.5 gm. 



Ferrous sulphate (FeS04 -71120) trace 



Magnesium carbonate (MgCOs) 5.0 gm. 



Tap water 1,000.0 cc. 



