30 



A MANUAL OF BACTERIOLOGY 



Exercise 54. Preparation of Czapek's Nutrient Solution for the 

 Cultivation of Fungi 



Distilled water 1000.00 oc. 



Magnesium sulphate 0.50 g. 



Dipotassium phosphate . . 1.00 g. 



Potassium chloride 0.50 g. 



Ferrous sulphate ... . . . . 0.01 g. 



Sodium nitrate . . . . . . 2.00 g. 



Cane sugar 30.00 g. 



Exercise 55. Preparation of Sulphindigotate Bouillon (Weyl) for 

 Detecting Anaerobic Organisms 



To 1 liter of regular beef bouillon add 20 g. of glucose and 

 1 g. of sodium sulphindigotate. After sterilization, which should 



be done in the Arnold sterilizer, the 

 medium should be blue. The growth 

 of anaerobic organisms turns it yellow. 

 Solid media may be had by the addi- 

 tion of gelatin or agar. 



Exercise 56. Methods of Cultivating 

 Anaerobic Bacteria 



These bacteria grow in an atmos- 

 phere devoid of oxygen, obtaining 

 the oxygen necessary for their meta- 

 bolism from carbohydrates and other 

 compounds in the medium which they 

 break down. Any method of culture 

 is successful which either absorbs the 

 gaseous oxygen present or replaces 

 the air with a nonpoisonous gas. 



1. Test-tube cultures. The cultures 

 should be made in dextrose beef agar 

 or gelatin, which should be freshly 

 prepared and always boiled to expel 

 air immediately before being inocu- 

 lated. Wright's modification of Buchner's method, given on the 

 following page, is very convenient. 



Fig. 16. Novy jar for anaerohic 

 cultures 



The jar is sealed by turning the 

 stopper in the top 



