igii] Ernest D. Clark 203 



described. One-half gram portions of the dry substance were dis- 

 solved in 10 c.c. volumes of distilled water. The fluids were tested 

 by the reagents and with the results indicated in the appended 

 summary :^ 



Polysaccharid. Redncing Subsiance. 



lodine Solution Fehling Solution 



Reprecipitated prodiict i Purple Reduction 



Reprecipitated product 2 Blue Reduction 



Reprecipitated product 3 Blue Reduction 



Reprecipitated product 4 Blue Reduction 



Second series. In the first series of experiments with the alco- 

 hohc filtrates from the soluble starch precipitates the alcohol was 

 removed by evaporation at ordinary steam-bath temperature. Fear- 

 ing that this temperature had caiised some degree of hydrolysis, we 

 sought, in the second series of tests, to prevent such a change by 

 evaporating the alcohoHc filtrates at 40°. We took up each residue 

 in 10 c.c. of water at 40° and tested the Solution by the methods and 

 with the resuhs indicated below : 



Polysaccharid. Redncing- substance. 



lodine Solution Fehling Solution 



Filtrate from reprecipitated product i. . .Reddish brown Very strong reduction 



Filtrate from reprecipitated product 2. . . Yellow brown Very strong reduction 



Filtrate from reprecipitated product 3. . .Reddish brown Strong reduction 



Filtrate from reprecipitated product 4. . .Reddish brown Strong reduction 



Soluble starch preparations 3 and 4 generally showed the least 

 reducing power and also the weakest reddish colorations with iodine 

 in all of these experiments. The same was true of the materials in 

 the alcoholic filtrates from the reprecipitated soluble starch of these 

 two preparations. The acidity of each of these preparations (3 

 and 4), in terms of n/ioo sodium hydroxide Solution, was very 

 slight. Preparation 2, however, had nearly as low an acidity as 

 that of Preparations 3 and 4, but showed in almost every case, 

 properties very much like those of Preparation i, which had an 

 acidity fifteen times as great as that of Preparation 2. It will be 

 remembered that Preparations i and 2 were made from commercial 

 potato starch. The process employed in the preparation of our 

 specimen of the latter is unknown to us. That the method of pre- 

 paring raw starch has some efTect on the properties of the Lintner 



8 



The blank tests were negative in every case. 



