602 Preparations and Compositions. Part III.

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In this way are prepared

EXTRACTUM CINCHONA RUBKiE RESINOSUM. Dub.

Resinous Extract of Red Cinchona Bark.

EXTRACTUM JALAP.E RESINOSUM. Dub.

Resinous Extract of Jalap.

Opium purificatum. Dub.Purified Opium.

Take of

Opium, cut into small pieces, one pound;Proof-spirit of wine, twelve pints.

Digest with a gentle heat, stirring now and then tilljthe opiumbe dissolved ; filter the liquor through paper, and distil ina retort until the spirit be separated : Pour out the liquorwhich remains, and evaporate, until the extract acquires aproper thickness.

Purified opium must be kept in two forms ; one soft, properfor forming into pills; the other hard, capable of being re-duced into powder.

Lond.

Very carefully separate opium from all heterogeneous matters,

- especially those adhering to it on the outside. Opium is

to be kept in two states ; one soft, fit for making pills ; and

another hard, dried in a water-bath, until it become pulve-

rizable.

All these extracts are supposed to contain the virtues ofthe substances from which they are prepared, in a very pureand concentrated form ; but this supposition is, probably inseveral instances, erroneous; and the directions for preparingthem are frequently injudicious and uneconomical.

As the changes which opium and aloes undergo by solu-tion, and subsequent evaporation, have never been ascertain-ed by careful and satisfactory experiments, well-selected piecesof these substances are to be preferred to the preparations inwhich they are supposed to be purified. As a farther proofof the superiority of good opium over all its preparations, Imay also remark, that the latter, however well prepared, soonbecome mouldy, the former never does.

Mr Phillips, however, prefers the preparing of an extractof opium, by first submitting it to the action of boiling water,as long as any portion of it continues to be dissolved, and thendigesting the residuum in rectified spirit, and mixing the wa-tery and alcoholic extracts thus obtained. He found, that 72parts of opium, dried by steam till it became pulverizable,