PLATE V 



ILLUSTRATIONS OF BIOLOGICAL REDUCTIONS OF SELENIUM COMPOUNDS 



Fig. 1. — B. coli grown on a sodium selenite culture medium. The colonies 

 appear as red spots. 



Fig. 2. — Another culture of B. coli grown on a slant. 



Fig. 3. — Section of the liver of a dog that had been subcutaneously treated 

 with 2 mg. selenium dioxid per kilo of body weight. The chocolate 

 red granules represent deposited selenium. 



Fig. 4. — Stab cultui*e of streptococcus pyogenes. 



