CULTURE METHODS 29 



3. Soil extract medium Lb'hnis. 1 



Prepare a soil extract by heating 1 kg. of soil with 1 liter of 

 water in an autoclave for half an hour at 15 Ib. pressure, or heat 

 1 kg. of soil with 2 liters of water over an open flame for two 

 hours. Filter the hot solution through paper and use as directed 

 in the following formula : 



Soil extract 1000 cc. 



Potassium phosphate 5 g. 



Mannite or dextrose 10 g. 



Agar 15 g. 



Exercise 51. Preparation of Winogradsky and Omelianski's Solution for 

 Cultivating Nitrite-Forming Organisms 



Ammonium sulphate 1.0 g. 



Potassium biphosphate 1.0 g. 



Magnesium sulphate 0.5 g. 



Sodium chloride 2.0 g. 



Ferrous sulphate 0.4 g. 



Basic magnesium carbonate Excess 



Distilled water 1000.0 cc. 



Exercise 52. Preparation of Winogradsky and Omelianski's Solution for 

 Cultivating Nitrate-Forming Organisms 



Potassium biphosphate 0.5 g. 



Sodium chloride 0.5 g. 



Ferrous sulphate . 0.4 g. 



Magnesium sulphate 0.3 g. 



Fused sodium carbonate 1 .0 g. 



Sodium nitrite 1.0 g. 



Distilled water . . 1000.0 cc. 



Exercise 53. Preparation of Naegeli's Solution 



This solution has been found to be well suited for the culture 

 of yeast and of many other fungi. 



Calcium chloride 0.1 g. 



Magnesium sulphate 0.2 g. 



Dipotassium phosphate 1.0 g. 



Ammonium tartrate 10.0 g. 



Distilled water 1000.0 cc. 



1 Centralbl. f. Bakt., 2te Abt., 14 : 590. 1905. 



