40 LABORATORY GUIDE IN BACTERIOLOGY 



Solution for testing the denitrification of nitrates 

 to free nitrogen (Giltay solution) — ■ 



Solution I 



Dextrose lo grams 



Distilled water 250 c.c. 



Solution 2 



KNO3 1 . 00 gram 



MgSO^ 2 . 00 grams 



Citric acid S . 00 grams 



KH2PO4 2 , 00 grams 



CaCU 0.2 gram 



FejCls o . 01 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 autoclave. 



Synthetic agar for quantitative examination of soil — 



Dextrose 10 grams 



MgSOi 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 



