Oxidizers in the Hydrolysis of Starch and Dextrins. 385 



boiling water and boiled a few minutes. The solution was 

 then allowed to cool to 40°-45° C. Meanwhile 10 cm3 of fil- 

 tered saliva were neutralized with 0*1 per cent hydrochloric 

 acid. A blue litmus strip, which had been dipped in acetic 

 acid and wished, was used as indicator. The saliva was added 

 to the starch solution at the proper temperature. In three or 

 four minutes the solution became entirely clear, and was at 

 once brought to a boil and boiled for ten minutes. 



The addition of the alkali was to hinder the action from 

 going beyond the first step of digestion. The boiling at the 

 end destroyed any further action of the saliva. Starch cellu- 

 lose is said to produce a feeble red or brownish color with 

 iodine,* hence the possible utility of this method lay in the 

 absence of cellulose from the starch solution, since the cellu- 

 lose is digested by the saliva. 



Solutions were made up according to each of these formulae. 

 The amorphous ainylodextrin was made from impure starch, 

 the other two solutions from pure potato starch, specially pro- 

 cured. Table IV shows the relative sharpness of the different 



Table IV. 



Volume 125 cm3 . 



n/lOIsol. Potassium iodide. Starch sol. . Color, 



drops. cm 3 . 



1 :._. 



2 faint change 



3 . . _...__ decided change 



4 light yellow 



5 decided yellow 



1 lgrm. " 



1 1 crystal " " 



1 .. 1 ordinary pale purplish 



2 " stronger faint " 



1 1/5 amorphous 



amylodextrin flash of blue 



o a a a 



2 1*5 " good blue 



a a 



1 1 crystal 1-5 " 



1 . 1 KI starch 



2 " deeper blue 



1 1-5 amidulin slight change 



3 " very faint pink 



2 3 " no change 



3 3 " pale blue 



2 5 " stronger " " 



* Beilsteiu I, 1082, line 17. 



