SOLUTION FOR HYDROGEN SULPHID FORMATION 1 17 



Medium 58 



Sulphate Reduction 



Iron lactate (Fe(C 3 H 5 O 3 )2 + 3H 2 O) 5.0 gm. 



Ammonium sulphate ((NH 4 ) 2 SO4) 2.0 gm. 



Dibasic potassium phosphate (K2HPO4) 0.5 gm. 



Water 1000.0 c.c. 



To prepare a solid medium add the above ingredients to 

 15 per cent, gelatin. Heat the medium in a steamer until 

 the precipitate has settled, and filter. Sterilize at a low 

 temperature, about 10 pounds' pressure for fifteen minutes, 

 or in the steamer for twenty minutes for three consecutive 

 days. 



Medium 59 



Solution for Hydrogen Sulphid Formation from Protein 

 and from Sulphur 



(a) Iron ammonium-sulphate (FeSO 4 (NH 4 )2(SO 4 ) + 



6H 2 O) i gm. 



Bouillon. . . . 1000 c.c. 



(b) Iron-ammonium sulphate (FeSO 4 (NH 4 ) 2 (SO 4 ) + 



6H 2 O) i gm. 



Sulphur flowers (S) i gm. 



Bouillon. . . . 1000 c.c. 



In the presence of the proper organisms, hydrogen sulphid 

 formation will be noted in solution (b) long after solution 

 (a) has been reduced. 



Beijerinck, W. M., Centbl. Bakt. (etc.), Abt. 2, Bd. i, p. 5, 1895. 



