In addition to these species, Dr. Lindley recognises in his Flora 3Iedica ' the following C. lucumerfolia, PSvoA (C. stupea). A species said to furnish a part of the Leas Bark.
C. lanceolata 'FL Per.' Ruiz suspects this species to be the true source of the Caliaaya Bark. It is found in the districts of Muria, Panas, Pillao, and Cuchero.
C. rotundifolia, Ruiz and Pave)), MSS. From a specimen in Mr. launbert'a Museum. Found at Loxa in Quito.
C. cordifolia, Mutis, MSS. Found in the mountains of New Gra nada, at an elevation of from 5000 to 8000 feet above the sea.
C. hirsu.ta, FL Per.' It is probable this species yields some of the fine Yellow Bark of the shops. It is found in high and cold places near Pillow and Acomayo.
C. villosa, Pavon (C. Ilumboldgiana, Lambert). Found at S. Jaen de Loxa.
C. oblongifolia, Lambert. Although nothing is known of this plant beyond the specimens in the Lambortian Museum, the London College of Physicians, in their Pharmacopwia ' of 1836 recognised it as yield ing one of the barks of commerce.
a acutifoua, 'FL Per.' It is found in the lower groves of the Peruvian Andes, in Claicoplaya, by the river Taso. It yields very poor bark.
C. stenocarpa, Lambert. From Jaen, in the mountains of Lout.
C. cava, Pavon. From Quito.
Whatever may be the botanical history of the different kinds of bark, on their arrival in Europe they are known by names which have reference rather to their physical appearance or the place whence obtained, than to the botanical characters of the trees which furnish them. In England they are classed under three heads—pale, yellow, and red barks. Of each there are several varieties, which comprehend however, various barks, not the produce of any of the genuine apeciea of Cinchona above enumerated, but obtained from species of Exo stemma, Buena, and Slrychnoa (according to Mr. Burchell). These last, called false or spurious Cinchona barks, are all distinguished from the true Cinchona barks by the abseuce of Cinchonia, Quiuia, and •Aricina (or Cusco-Cinchonia, a principle found in the Cusco or Arica Bark, referred to the Cinchona rubiginosa, Bergen). Several of these spurious barks are employed in fever and other diseases, but they are chiefly used to adulterate the more valuable kinds of Cinchonas.
Even when there is no intermixture of these inferior sorts, a variable ness in quality occurs in the bark of the same species, according to its place of growth. The finer kinds are known by experienced persons by a glance of the eye ; but it is extremely difficult to indicate, by any description, the marks by which they are guided. All kinds arrive in Europe in the same package, either a chest or serene, which is formed of pieces of wood rudely fastened together, and covered with the hides of animals. They are afterwards sorted, and bring very different prices in the markets, according to the degree of estimation in which each kind is held. We shall describe the beat kind only of each ; but we must remark, that much prejudice exists on this point, and some times excellent kinds are rejected, while inferior sorts are prized. To meet these prejudices, the barkers employ various artifices, more or less injurious. The most useful classification of barks is that proposed by Geiger, which has reference to the relative proportions of their alkaloids :-1. Those in which Cinchonia predominates : chiefly pale or brown barks.-2. Those in which Quinia predominates, of which there is only one—the yellow bark of English commerce, called China regia Vera, China Calisaya.-3. Those in which Cinchonia and Quiuia exist in nearly equal proportions, red barks, and the yellow bark of continental writers; the China of Carthagena of the French, China flara dura, Quinn amarilla. This last is also called orange bark (Quinn aurantiaca of Mutis), which is not the yellow bark of English commerce, though by some it is erroneously so considered ; and hence the frequent error in the British Pharmacopeeias of referring yellow bark to the C. cordifelta (Mutis).
Of the Pale Barks three varieties are known in English 1. Crown or Loxa Bark.-2. Gray, Silver, or Huanuco Bark.-3. Ash Bark. These are always quilled, and never in flat pieces. The powder, which gives the name, varies from gray to fawn-colour.