MAINTENANCE AND PRESERVATION OF CULTURES 109 



6. Azotobacter Agar {Mannitol) 



K2HPO4 1.0 g 



MgSO* 0.2 g 



NaCl 0.2 g 



FeSO* Trace 



Agar 15 g 



Soil extract 100 ml 



Tap water 900 ml 



Dissolve, add mannitol 20 g 



Adjust pH to 8.3, autoclave. 



7. Beef Liver for Anaerobes 



Ground beef liver 500 g 



Tap water 1,000 ml 



Peptone 10 g 



K2HPO4 Ig 



Soak liver in 1 liter of water overnight in refrigerator; skim off fat. Autoclave 10 

 min at 15 lb. Strain through cheesecloth; save the meat. Add peptone and K2HPO4 

 to broth, and heat to 100°C. Adjust pH to 9.0, filter through paper, and make up to 

 1 liter with tap water. 



Place a small amount of CaCOs in each tube; add meat to depth of 3^^ in.; cover 

 with broth to total depth of 2 in. Autoclave. 



8. Blood Agar 



Heart infusion agar (Difco) 40 g 



Distilled water 1,000 ml 



Heat to 100°C; adjust pH to 7.4. Tube, and autoclave, but do not slant. Melt 

 blood base agar, cool to 45°C, add 0.5 ml of sterile blood aseptically, mix, and slant, 



80. Blood Glucose Agar 



Same as formula 8 with addition of 0.5-0.75 ml of sterile 10 per cent glucose solution 

 per tube, besides blood. 



9. Bordet-Gengou Medium 

 Potato infusion 100 ml 



Prepare by dicing 12.5 g of potato in 100 ml of distilled water, let stand overnight 

 at 60°C, filter through cheesecloth, and restore volume. 



Agar 1.5 g 



NaCl 0.55 g 



Proteose peptone 1.0 g 



Heat to 100 C, adjust pH to 7.4, and add 



Glycerol 1.0 ml 



