LEVINE, BIOCHEMICAL STUDIES OF SELENIUM 387 



chloric. Oxalic, citric, tartaric, malic and salicylic acids, benzaldehyde, 

 cinnaniic aldehyde, and salicyl aldehyde reduce neither in acid nor in 

 alkaline mixtures. 



The results show that monosaccharides readily reduce an alkaline solu- 

 tion of sodium selenite. The pentoses give readier and more profuse 

 reduction than the hexoses and the reducing disaccharides. Of the 

 pentoses, xylose yields most profuse reduction. Among the hexoses, 

 levulose and galactose reduce more readily than dextrose, and galactose 

 less readily than levulose. Among the disaccharides only those having a 

 free carbonyl group reduce. Maltose and lactose show reduction, but 

 sucrose does not. Eaffinose, cellulose, starch, dextrin, glycogen, inulin 

 also do not reduce. 



In order to test the influence of acidity or alkalinity upon the re- 

 duction of sodium selenite, nineteen reagents were made up. One 

 consisted of sodium selenite neutralized with sulfuric acid. x\nother 

 consisted of sodium selenite, which reacts alkaline. To nine other sele- 

 nite solutions were added sodium hydroxid, potassium hydroxid and Eo- 

 chelle salts, sodium bicarbonate, sodium carbonate, and sodium citrate, 

 sodium tetraborate, sodium silicate, disodium hydrogen phosphate. Eight 

 reagents were acidified by the addition of one of the following : potassium 

 bisulfate, sodium dihydrogen phosphate; hydrochloric, nitric, sulfuric, 

 phosphoric, citric, or tartaric acid. When these reagents were heated 

 none reduced, even on complete evaporation, except the one containing 

 citric acid and the one containing tartaric acid. These two reagents also 

 deteriorated after standing several months. Experiments with these 

 reagents were carried on at 37.5° C. and at 100° C. Solutions (0.5 

 per cent) of arabinose, rhamnose, xylose, glucose, fructose, galactose, su- 

 crose, maltose, lactose, glycogen, starch, dextrin, inulin, rafiSnose, mucic 

 acid, lactic acid, formic acid, acetone and formaldehyde were used. 

 Three cubic centimeters of the solution to be tested were mixed with 

 two cubic centimeters of the selenite reagent and toluol added. The 

 tubes were incubated at 37.5° C, and examined from time to time. 

 Controls were run with the Fehling and the Fehling-Benedict reagents. 



The reagents containing sodium hydroxid and potassium liydroxid 

 (selenite and Fehling) were the first to show reduction at 37.5° C. The 

 Fehling reagent reduced more quickly than the Fehling-Benedict. Gly- 

 cogen, starch, dextrin, inulin and raffinose reduced acidified solutions of 

 sodium selenite only at the end of four days. Alkaline solutions were not 

 affected. Formic acid, lactic acid, formaldehyde reduced in acid solutions 

 only. Acetone profusely reduced acid solutions, and very faintly reduced 

 alkaline solutions. The reagent acid with nitric showed no reduction, 



