The author maintains that unsatisfactory results are obtained in
determinations of starch when the method employed is based upon the
inversion of sugar, formed as an intermediate product, since maltose,
dextrose, and levulose are partly decomposed by boiling with dilute
acids. He proposes to replace the methods hitherto employed by one
which depends upon the formation of a barium salt of starch, to which
he assigns the formula BaO.C_{24}H_{40}O_{20}. This salt is sparingly
soluble in water and insoluble in dilute alcohol.
In making a determination a weighed quantity of starch is saccharified
with water, then mixed with an excess of normal baryta solution,
dilute alcohol added to make up to a certain volume, and, after the
precipitate has settled, the excess of baryta is titrated back with
acid.
[Illustration: Titrating apparatus]
The author also describes the apparatus he employs for storing and
titrating with baryta solution. The latter is contained in the bottle,
A, and the drying tube attached to the neck of the same is filled with
quicklime. The burette, B, which is in direct connection with the
bottle, may be filled with the solution by opening the stop cock, and
the small drying tube, _n_, is filled with dry KOH, thus preventing
the entrance of any CO_{2}. Numbers are appended which seem to testify
to the excellence of the method employed. The author finally gives a
detailed account of the entire analysis of various cereals.--_A.R. in
Jour. Soc. Chem. Indus._
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