"Take of heart-leaved cinchona, bruised, ten drachms; distilled water, a pint. Boil for ten minutes in a lightly-covered vessel, and strain the liquor while it is hot."

Decoctum Cinchonae lancifolia2, Lond. Edin. Decoction of Lance-leaved Cinchona.

Decoctum Cinchonae, Dub. Decoction of Cinchona.

1 Decoctum Lichenis, P. L. 1809-1824. 2 Decoctum Cinchonae, P. L. 1788- 1824.

"Take of lance-leaved cinchona bark, in coarse powder, an ounce; water, enough to leave a pint after it is strained."

Decoctum cinchonae oblongifoliae, Lond. Decoction of Oblong-leaved Cinchona.

This decoction is to be prepared in the same manner as that of heart-leaved cinchona.

Syn. Decoction de Quinquina (F.), Chinadekokte (G.), Decotto di China. (J.)

Cinchona bark is one of those substances which suffers by long coction with water; and therefore the Colleges have properly limited the time of boiling to ten minutes, and ordered the vessel to be covered, and the liquor to be strained while it is hot. As the strained decoctions cool, they become turbid, and let fall a reddish or yellowish powder, according to the kind of bark employed; this, however, must not be rejected, but diffused through the clear decoction when it is about to be used in compounding extemporaneous mixtures, or when the dose is to be taken. When the decoction is made with the lance-leaved cinchona, it contains kinates of cinchonia with a small proportion of kinate of quina; and on these salts its peculiar properties depend. When the yellow bark is used, the active principle is chiefly kinate of quina; both contain tannin and kinate of lime. The decoction of the red bark contains acidulous kinates of quina and of cinchonia, with more tannin than exists in the other two decoctions.

By long boiling, says Pelletier, the tannin and starch form a compound insoluble in cold water, and which is, therefore in conjunction with colouring matter, kinate of lime, etc. precipitated as the decoction cools, and carries down also a portion of the cinchonia and quina; to remedy which Pelletier recommends a larger quantity of water to be used, and the decoction to be filtered and evaporated. This, however, is a tedious process; and, as sulphates of cinchonia and quina are very soluble, we are of opinion that the addition of f 3j. of diluted sulphuric acid to the water for making the decoction will better answer this intention.

This decoction is more bitter, but less aromatic, than the infusion. It is affected by the same re-agents, and used in the same cases, and in similar doses, as the infusion. (See Infusum Cinchona.)