Powder, a form of medicine,

"which is prepared, by breaking and reducing sustances to minute particle either in a mortar, or by chemical process.

In the preparation of powders, especial care ought to be taken that no corrupted, or impure matters .be employed. Dry aromatic substances should be sprinkled, their pulverization, with a drops of water; while those moist nature, may previously be exposed to a moderate heat. Gums, and other materials that are with difficultly reduced to powder, may be mixed with drier articles, and no part should be separated for use, till the whole quantity has passed through the sieve, and the different sittings are incorporated.

If powders be long kept, and the air not carefully secluded, their virtue becomes greatly impaired. Thus, ipecacuanha, if exposed to the action of the atmosphere, at length loses its emetic property.

The dose of powders, in general, is from one scruple to a dram; though the principal ingredient often does not exceed one grain.— The usual vehicle for taking this form of medicine, is any agreeable thin liquid., or pure water ; but the more ponderous calces of metals, as well as the powders compounded of resinous matters, are more eligibly swallowed in syrups, or other thick liquor.—On the whole, medicines reduced to this impalpable state, operate both more certainly and expeditiously than pills, lozenges, or bolusses ; without clogging the stomach and bowels.