tions. It would
probably be an improvement to use 10 per cent. solutions for many of the
dextrins, as they are when low in starch extremely thin.

The hygroscopic nature of dextrins renders them unsuitable for foreign
work, but when the quantity of starch is appreciable, better results are
obtainable. A large percentage of unaltered starch is usually
accompanied with a small percentage of sugar, and no doubt this is the
explanation of this fact. An admixture containing natural gum of course
behaved better than when no such gum is present. Bodies like "arabol"
made up with water and containing gelatin are very hygroscopic when dry,
although as sold they lose water on exposure to the air. Gum substitutes
consisting entirely of some form of gelatin with water, like fish glue,
are also somewhat hygroscopic when dried. The behavior of these
artificial gums and dextrins on exposure to a warm moist atmosphere can
be determined in the same apparatus as described for gums.

The process we have adopted for estimating the glucose starch and
dextrin in commercial gum substitutes is based on C. Hanofsky's method
for the assay of brewers' dextrins (this Journal, 8, 561). A weighed
quantity of the dextrin is dissolved in cold water, filtered from any
insoluble starch, and then the glucose determined directly in the clear
filtrate by Fehling's solution. The real dextrin is determined by
inverting a portion of the filtered liquid with HCl, and then
determining its reducing power. The starch is estimated by inverting a
portion of the solid dextrin, and determining the glucose formed by
Fehling. After deducting the amounts due to the original glucose and the
inverted dextrin present, the residue is calculated as starch. A
determination of the acidity of the solution is also made with decinormal
soda, and results returned in number of c.c. alkali required to
neutralize 100 grammes of the dextrin. Results we have obtained using
this method are embodied in the following table:

ANALYSIS OF GUM SUBSTITUTES

----+---------+---------+--------+----------+-------+-------+---------
No.| Glucose.| Dextrin.| Starch.| Moisture.| Gum, | Ash. |Acidity.
| | | | | &c. | |
----+---------+---------+--------+----------+-------+-------+---------
| | | | | | | cc.
1 | 8.92 | 81.57 | 1.99 | 10.12 | None | 0.207 | 57.3
2 | 7.