Oxidizers in the Hydrolysis of Starch and Dextrins. 393 



two drops for the amidulin reading and one drop for the iodine 

 reading, the absolute values in A are 49*36 and 49'28 with a 

 difference of 0*08 ciu3 of iodine solution. The abundant pro- 

 duction of a red color is as important as the loss of iodine. 



In B with antimony there is a similar loss of iodine and 

 production of a red color, but it is no more striking than with 

 arsenic, and the loss is no greater. It is noticeable, however, 

 that toward the end the tartar emetic fades the iodine some- 

 what more slowly than arsenious acid and hence the red some- 

 times appears a little sooner and lingers somewhat longer. 



Titrations without dilution and with increasing amounts of 

 amidulin present were now made. The colors mentioned were 

 all permanent, and the last color mentioned was as nearly as 

 possible of the same shade of purple. 







Table XII. 





i/10 As 2 3 . 



n/10 I sol. 



JSTo extra dilution. 

 KHC0 3 Amidulin. 



Color. 



cm 3 . 



cm 3 . 



cm 3 . 



cm 3 . 





10 

 10 



9-85 

 j 9-86 

 ( 9-88 



5 



5 



yellow 



deep purplish red 



deep blue, purplish 



10 



( 9-91 

 1 9-94 

 ( 9-96 



it 



10 



deep red 



deep reddish purple 



deep blue, purplish 



10 



j 9 89 

 \ 9-91 



a 



15 



deep purplish red 

 deep blue, purplish 



10 



j 9*90 

 ( 9-93 



u 



20 



deep red 



deep blue, purplish 





( 9-94 



a 



25 



very deep red 



10 



\ 9-96 

 ( 9-98 







deep purplish red 

 deep blue, purplish 



There is apparent in this table a loss of iodine increasing 

 very slightly with the increase of amidulin, somewhat irregular 

 because of possibly much varied conditions, such as volume, 

 rapidity of running in the iodine, amount of stirring, etc. 

 The conditions with 10 cm3 of amidulin present seem to have 

 been exceedingly favorable for the development of the phe- 

 nomena under consideration, as the red produced was very 

 abundant and the loss of iodine was nearly as much as with 

 25 cm3 of amidulin present. 



That the erythrodextrin of the impure starch is identical 

 with the erythrodextrin of saliva digestion of starch was 

 proven in the following manner. A solution of impure starch 

 was dialyzed for twelve days. The product which came 

 through became colored a faint brown upon adding iodine. 

 This was due to its extreme dilution. On concentration it 

 gave a rich red with iodine. 



