Peruvian Bark. The U. S. P. recognizes several species, inclusive of Cinchona calisaya, C, Ledgeri-ana, C. officinalis, and Red Cinchona, C. succirubra. Few other national standards discriminate, simply designating "Cinchona Species." Quinine is the important constituent of cinchona, but in this country the whole bark is much used as a tonic and there has from time to time been much written upon the different species of bark and the relative content of tannin, etc., acting as disturbing agents in the fluid preparations thereof. We have the fluidextract (average dose, 15 minims), the tincture (average dose, 1 fluidrachm), the compound tincture (cinchona, bitter orange peel, and serpentaria, average dose, 1 fluidrachm), and Huxham's Tincture of Bark (made of red cinchona).

About thirty alkaloids have been separated from cinchona. The several fluid preparations vary, depending upon the alkaloidal constituents most largely represented; but these differences are of little practical importance, the preparations of bark being now used simply as bitter tonics. The detan-nated tincture is to be preferred.

Cinchona is an astringent bitter, and a stomachic tonic; but its continued use sets up gastric catarrh, interferes with digestion, and induces constipation. Nevertheless there are cases in which cinchona, especially in connection with acids, serves admirably as a tonic. In my view, relaxed and atonic conditions are the ones indicating cinchona; and it is useful in convalescence from septic infections and other debilitating and exhausting diseases.

Nevertheless, cinchona is not adapted as a general tonic bitter, and it has been largely displaced by more available agents. For a general discussion of the bitters, see "Gentian"; and for the pharmacology and general therapeutics of cinchona, see "Quinine."