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same transient feelings of relief may be procured by smoking a mixtureof opium and any aromatic herb. Forms of Exhibition. Some discre-pancy of opinion has existed upon this point ; the native practitioners inthe Carnatic gave the powdered root; Hufeland recommends a tinctureof the whole plant ; in this country an extract of the leaves, or, morelately, of the seeds, has been preferred, and 1 have been recently in-formed by Sir Henry Halford, that he has found a tincture made with theseeds,* a very efficient and unobjectionable preparation. Dr. Davy, atmy request, h is uirtde a series of experiments upon the extracts prepar-ed by Mr. Barry in vacuo, and his report upon the effects ofthat ofrtra-monium, will be found under the article Extract. Slrantonti which see.Dose. In the commencement, of the leaves powdered gr. i. of theseeds gr ss. It i- said that the lurks sometimes use the Stramonium in-stead of Opium, and the t hinese infuse the seeds into beer. Cataplasmsof the fresh bruised leivet have been very successfully used in sores ofa highly irritable and painful nature. Officikal Prefahation. Eitract.Stramonii.

DECOCTA. L.E.D. Decoctions.

These are solutions of the active.principles of vegetables, obtained bvboiling them in water. To decide upon the expediency of this form ofpreparation, in each particular case, requires a knowledge of the che-mical composition of the substance in question. In conducting the ope-ration, the following rules must be observed :

1. Those substances only should be decocted, whose medicinal powers re-side in principles which are soluble in water.

2. If the active principle be volatile, decoction must be an injurious pro-cess ; and, if it consist of extractive matter, long boiling, by favouring itsoxidizement, will render it insipid, insoluble. and inert.

3. The substances to be decocted should be previously bruised, or sliced soas to expose an extended surface to the action of the water.

4. The substances should be completely covered with water, and the ves-sel slightly closed, in order to prevent, as much as possible, the access of air:the boiling should be continued without interruption, and gently.

5. In compound decoctions, it is sometimes convenient not to put in allthe ingredients from the beginning, but in succession, accnrdin" to theirhardness, and the difficulty with which their virtues are extracted; and ifany aromatic, or other substances containing volatile principles, or oxidiz-able matter, enter into the composition, the boiling decoction should be sim-ply poured upon them, and covered up until cold.

6. The relative proportions of different vegetable substances to the wa-ter, must be regulated by their nature : the following general rule may beadmitted : of roots, barks, or dried woods from 3ij to 3vj to every pint ofwater: of herbs, leaves, or flowers, half that quantity will suffice.

7. The decoction ought to be filtered through linen, while hot, as import-ant portions of the dissolved matter are frequently deposited on cooling ■care must be also taken that the filtre is not too fine, for it frequently hap-pens, that the virtues of a decoction depend upon the presence of particles■which are suspended in a minutely divided state.

* The seeds undoubtedly contain, in an eminent degree, all the properties of theplant. It was in the seeds that Brandes first discovered the Daturia.