462 Proceedings Columbia Biochem'ical Association [April-July 



and sodium selenate (0.05-0.1 percent) induced slight effects on 

 ptyalin. In the presence of 0.05 percent sodium selenite and, more 

 markedly, in the presence of 0.05 percent sodium selenate, the activ- 

 ity of amylase seemed sHghtly increased. The results obtained for 

 peptolysis showed that selenious or selenic acid could replace hydro- 

 chloric acid in the process. Selenious acid was slightly inhibitive, 

 while selenic acid resembled sulfuric acid in the marked Inhibition 

 shown towards proteolysis. Sodium selenite (neutralized) and 

 sodium selenate (o.oi to 0.02 percent) had little or no effect on pep- 

 tic activity. Higher concentrations produced inhibition, this being 

 more marked with sodium selenite than with sodium selenate, 

 Potassium selenocyanate, even in minute amounts, inhibits peptic di- 

 gestion, due, in part, probably, to mechanical interference by the 

 brick red precipitated selenium, which completely Covers the Sub- 

 strate (fibrin) ; or, possibly, to the presence of the Compound that 

 results from the acid decomposition of potassium selenocyanate. 

 Slight amounts of sodium selenate and potassium selenocyanate had 

 tio effect on tryptic activity. Neutralized sodium selenite inhibited 

 even in small quantities. 



Sodium selenate and potassium selenocyanate (0.05-0.5 percent) 

 had no influence on rennin. Coagulation was retarded by conc. of 

 neutralized sodium selenite above 0.2 percent. Sodium selenite and 

 sodium selenate had but slight effect on the souring of milk. Potas- 

 sium selenocyanate showed an inhibitory effect, the amount of in- 

 hibition being directly proportional to the conc. of the salt. 



Sodium selenate and potassium selenocyanate had no effect on 

 pancreatic lipase. Sodium selenite showed slight inhibition, the 

 effect produced being proportional to the conc. Selenium dioxid 

 and selenic acid markedly increased hydrolysis (acid content). 



Selenium dioxid in conc. of 0.5 percent had a marked inhibition 

 on alcoholic fermentation. In a 2.5 percent sol., fermentation still 

 occurred but was suppressed entirely in a 3 percent sol. Sodium 

 selenite (alkalin) inhibited the evolution of carbon dioxid. Selenic 

 acid, even in a conc. of 0.04 percent, exercised an inhibitory influ- 

 ence over zymase. Very little carbon dioxid was evolved in a 0.2 

 per Cent sol., while sol. containing 0.5 percent or more gave no evi- 

 dence of carbon dioxid formation. Sodium selenate accelerated 



