SOLUTION FOR NITRATE REDUCTION 107 



Medium 35 

 Starch Nitrate Agar 



Agar ....................................... ... 10 gm. 



Potassum nitrate (KNO 3 ) ........................ i gm. 



Starch (C 6 HioO 5 ) n .............................. 5 gm. 



Bouillon ....................................... 1000 c.c. 



After colonies develop, treat one series of plates with a 

 weak solution of potassium iodid (KI) in dilute HC1. The 

 treatment should result in the development of a character- 

 istic blue halo about the colonies that reduce nitrate to 

 nitrite. 



Hoffmann, C., Centbl. Bakt. (etc.), Abt. 2, Bd. 34, p. 386, 1912. 



Medium 36 

 Solution for Nitrate Reduction 



Dibasic potassium phosphate (K2HPO4) ......... 0.5 gm. 



Potassium nitrate (KNO 3 ) ..................... 10.0 gm. 



Ethyl alcohol (C 2 H 5 OH) ....................... 5.0 c.c. 



Tap-water ................................... IOOG.O c.c. 



Beijerinck, M. W., Centbl. Bakt. (etc.), Abt. 2, Bd. 25, p. 35, 1910. 



Medium 37 

 Solution for Nitrate Reduction 



Dibasic potassium phosphate (KaHPC^) ......... 0.5 gm. 



Potassium nitrate (KNOs) ..................... 2.5 gm. 



Filter-paper in strips .......................... 20.0 gm. 



Tap-water ................................... 1000.0 c.c. 



Iterson, C. V., Centbl. Bakt. (etc.), Abt. 2, Bd. n, p. 689, 1904. 



