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Preparations and Compositions. Part III.

this swells exceedingly in drying, and would otherwise runover.

Mr Chaptal found, that by exsiccation in a red heat, alutnof his own manufacture lost 0.67, Roman alum O.50, Englishalum 0.47, and Levant alum only 0.40. These differencesarise principally from different proportions of water of crys-tallization, but also from an excess of alumina, which the lastcontains.

According to Kirwan, crystallized alum consists of 17.66acid, 12 alumina, and 70.24 water, and alum desiccated at700°, of 36.25 acid, and 63.75 basis, by which it would ap-pear, that at that heat it loses not only all its water, but als»more than half its acid.

Dried alum is only applied externally, as a gentle escharo-tic to fungous ulcers.

Chap. V.—METALLINE PREPARATIONS.

ANTIMONY.

SULPHURETUM ANTIMONII PR.S3PARATUM. Ed.

Prepared Sulphuret of Antimony.Sulphuret of antimony is prepared in the same way as carbo-nate of lime.

Dub.

Reduce it to powder, and separate for use the impalpableparticles, in the manner directed for the preparation ofchalk.

By reducing the sulphuret of antimony to the state of animpalpable powder, it is both rendered much more active,and is prevented from irritating the stomach mechanically, ofwhich there would be some danger, from the sharpness of itsspiculae. Even in this state, however, it is not a very certainremedy. In general, it operates as a mild sudorific or ca-thartic ; but sometimes, if it meet with much acid in thestomach, it becomes more active, producing vomiting and hy-percatharsis. Therefore, it seems prudent to evacuate theprimae vite before it be exhibited, and to combine it with anabsorbent earth.