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.CHO. 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.
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. 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.