40 LABORATORY GUIDE IN BACTERIOLOGY 



Solution for testing the denitrification of nitrates 

 Jto free nitrogen (Giltay solution) — 

 Solution I 



Dextrose lo grams 



Distilled water 250 c.c. 



Solution 2 



KNO3 1 . 00 gram 



MgS04 2 . 00 grams 



Citric acid 5 . 00 grams 



KH2PO4 2 .00 grams 



CaCIa o,.2 gram 



FcjCk o.oi gram 



Distilled water 250 c.c. 



Make solution i neutral to phenolphthalein with 



10 per cent NaOH or KOH solution. Mix solutions 



I and 2 and make up to 1,000 c.c. Dissolve 20 grams 



agar in the solution, tube, and sterilize in the autocla,ve. 



Synthetic agar for quantitative examination of soil — 



Dextrose 10 grams 



MgS04 0.2 gram 



K2HPO4 0.5 gram 



Pepton 0.05 gram 



Agar . 20 grams 



Distilled water 1,000 c.c. 



Pepton solution for ammonification — 



Distilled water 1,000 c.c. 



Pepton 10 grams 



Dissolve and sterilize in the autoclave. 



EXERCISE 18. PREPARATION OF MISCELLANEOUS 

 MEDIA 



Blood agar. — Fresh blood obtained under aseptic 

 precautions is smeared over the surface of agar, or 



