40 LABORATORY GUIDE IN BACTERIOLOGY 



Solution for testing the denitrification of nitrates 

 to free nitrogen (Giltay solution) 



Solution i 



Dextrose 10 grams 



Distilled water 250 c.c. 



Solution 2 



KNOj i . oo gram 



MgSO 4 2 . oo grams 



Citric acid 5 . oo grams 



KH 2 PO 4 2 . oo grams 



CaCla o . 2 gram 



Fe 2 CU o . 01 gram 



Distilled water 250 c.c. 



Make solution i neutral to phenolphthalei'n 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 



MgSO 4 0.2 gram 



K 2 HPO 4 0.5 gram 



Pepton o . 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 1 8. PREPARATION OF MISCELLANEOUS 

 MEDIA 



Blood agar. Fresh blood obtained under aseptic 

 precautions is smeared over the surface of agar, or 



