204 Lintner Soluhle Starch [Dec. 



soliible starch prodticed from it is indicated by the differences to 

 which allusion has just been made. 



6. Comparative properties o£ Lintner soluble starch and 

 soluble starch prepared with the aid o£ saliva. The prepa- 

 ration of Lintner soluble starch is an unusually tedious process. 

 The final product is obviously a mixture of substances. It seemed 

 probable that soluble starch, made through the almost instantaneous 

 action of pt3^alin or diastase and obtained in a comparatively pure 

 form, would be as satisfactory for ordinary use as the Lintner 

 product. 



We prepared soluble starch for such a comparative study as 

 follows: A thick paste was made by pouring 15 c.c. of cold water 

 holding 4 grams of potato starch into a casserole containing 185 

 c.c. of water at 95° C, which was thoroughly stirred as mixture 

 occurred. The fluid was promptly cooled to 40° C, then 5 c.c. 

 of filtered saliva were added and the mixture thoroughly stirred. 

 In two or three minutes the paste was completely liquified. The 

 whole volume was then poured into one liter of 95 per cent. alcohol. 

 All the soluble starch was apparently precipitated by this treat- 

 ment, but to insure that result, a few drops of 10 per cent. sodium 

 Chloride Solution were added. The soluble starch was filtered 

 off and redissolved in 50 c.c. of water at 95° to destroy any con- 

 tained ptyalin. Solution occurred immediately. The Solution was 

 cooled at once and reprecipitation in alcohol was promptly effected. 

 The product was redissolved in cold water and reprecipitated several 

 times in this way, and then dried in the open air before a fan. 



Comparative tests of the responses to treatment with iodine Solu- 

 tion, and reducing action upon the Fehling and Fehling-Benedict 

 reagents yielded results which showed that this preparation of 

 soluble starch was practically the same in these respects (and 

 almost if not quite as pure) as all of our Lintner products. It was 

 much more readily soluble than the Lintner products. The saving 

 of time, energy and material in such a simple process, and the 

 greater solubility of the resultant product, Warrant preference for 

 a method of this kind in the preparation of soluble starch for ordi- 

 nary usage. The impurities which may be introduced with the 

 enzyme are negligible in all but exceptional cases. 



