In some instances, the epidermis is covered with whitish gray lichens.1 The greater number of the pieces are flat, but some are partially quilled, as if taken from half the circumference of the branches to which they belong. Under the epidermis, which is of a rust-grey hue, and cracked with furrows almost penetrating to the bark, there is an intermediate layer, which is dark-coloured or brownish-red, compact, brittle, and seemingly resinous, but less bitter than the inner bark: and within it the internal part is woody, fibrous, and of a rust-red, sometimes yellowish colour. The fracture, examined by a lens, consists of close, longitudinal, parallel, needle-form fibrillae of pale red or red fawn colour, with a deep red agglomerated powder in the interstices. The powder is of a deeper colour than the internal part of the bark, namely, a dull brownish-red hue.

1 Flora Peruv. ii. 53. t. 196.

2 The other synonymes of this kind are the following:-,

Cascarilla mariquita de Loxa.

--- del rey.

--roxa verdadera Huanuco.

Qualities.-Red cinchona bark has a weak peculiar odour, not unlike that of tan, or earthy; and its taste is bitter and slightly aromatic, but more austere than that of the barks of the other species. The aqueous infusion has a pale ruby colour, a slight degree of bitterness, and a decided astringency. It lets fall a sediment of a brighter hue than that of the dry powder. It reddens litmus paper2, is slowly precipitated by the solution of galls, the supernatant liquor being perfectly colourless; and a very light, flocculent, ruby-coloured precipitate is produced by the solution of gelatine. It is scarcely altered by tartarized antimony, more so by the acetate of lead: the pro-tosulphate of iron makes it assume a deep olive-green colour, but little is precipitated. The ethereal tincture is of the same colour, and exhibits the same appearances, as that of the former species, when treated in a similar manner. The alcoholic is of a very deep brownish-red colour; when diluted with water, a red flocculent matter falls down; and it precipitates the solutions of sulphate of iron, and of tartarized antimony, the former of a black colour, and the latter red.

Its virtues depend on two alkaline substances; one the cinchonia already described, the other quina, about to be described in the account of the next species; and both are combined with kinic acid;-the cinchonia is in greater quantity than the quina.

1 Guibourt divides the red barks into quinquina rouge verruqueux. and q. rouge non verruqueux.

2 Fourcroy found in it a portion of citric acid, some muriate of ammonia, and muriate of lime.

According to the experiments of Pfaff, many specimens afford only 1.7 per cent. of cinchonia, and 0.44 of sulphate of quina; others so much as 3.17 of the former, and 0.15 of the latter. Pelletier and Caventou found 0.8 of cinchonia, and 1.7 of quina!1

This bark was intoduced by Don Sebastian Josef Lopez Ruiz, in 17782; and is considered by Zea and Mutis as the least directly febrifuge of the three kinds which are described in this work. It possesses powerful astringent properties; consequently its use is contra-indicated in inflammatory and bilious affections: but the Spanish physicians regard it as highly beneficial as an external application in suppurating and sphacelating ulcers. An extract prepared from it is much used in Spain, in putrid fevers.

3. Cinchona cordifolia. Mutis.5

Officinal. Cinchonae cordifoliae cortex, Lond. Edin. Dub. Heart-leaved Cinchona. The Yellow Bark of the shops.

Syn. Quinquina jaune, Quinquina Calisaya (F.), Gelbe Chinarinde, Rieber-rinde, Konigs- China ( G.), Gul Kinabark ( Swed.), China (I.), Quina amarilla (S.).

This source of yellow bark is far from being certain. Mutis affirms that it is the produce of C. lancifolia.4 It is the produce of Bolivia in Upper Peru, and the province of La Paz. It is exported from Buenos Ayres, as well as from Lima. The tree which is said to afford this bark in the British pharmacopoeias is found on the mountains of Loxa, in the kingdom of Quito, and those of Santa Fe de Bogota, growing along their skirts, and on the plains, under the 4th degree of north latitude, on heights betwixt 900 and 1440 toises; flowering from May to September. It is a spreading tree, rising fifteen to twenty feet high, on a single, erect, round stem of no great thickness; and covered with a smooth bark, externally of a brownish-grey colour. The younger branches are quadrangular, smooth, leafy, sulcated, and tomentose: the leaves, which are about nine inches in length, are opposite, petiolate, spreading, of an oblong oval, cordate or egg-shape, entire, shining on the upper surface, ribbed and pubescent on the under; with the petioles flat on one side, and roundish on the other, about a thumb's breadth in length, and of a purple colour; but the leaves of the species vary even more than those of C. lancifolia.

The flowers appear in large terminal, brachiate, leafy panicles, supported on long, compressed, tetragonous peduncles. The calyx is five-toothed, downy, and of a dull purple colour : the corolla internally tomentose; the tube of a diluted red colour; the limbs shaggy, white above and purplish below; and the segments spreading, with reflected tips. The filaments are short, supporting linear anthers, bifid at the base, which reach as far as the upper part of the tube of the corolla. The germen is tomentose, and changes to an oblong narrow capsule, about one inch and a half in length, marked with ten striae, of a reddish-brown colour, and crowned with the calyx.

1 Geiger.

2 From some remarks of Ruiz, there is reason for thinking that the red bark is the bark of the same tree which yields the pale bark, but taken from larger branches.

3 Synonymes. C. pubescens, Vahl. C. otata, Flor. Peruv. C. hirsuta, Flor. Peruv. But Lambert affirms that it is totally different from the C. hirsuta of the Flora Peruviana. See Illustrations of the Genus Cinchona, 4to. 1821, p. 4.

4 Lambert's Illustrations, p. 53.