Definition. - The dried bark of Cinchona Ledgeriana Moene, Cinchona Calisaya Weddell, Cinchona officinclis L., and of hybrids of these with other species of Cinchona. It should yield not less than 5 per cent. of total anhydrous cinchona alkaloids, and at least 4 per cent. of anhydrous ether-soluble alkaloids.

Origin. - The genus Cinchona as at present constituted consists of from thirty-one to thirty-six species, all of which are native to South America. The habitat of the three follows the eastern slope of the Andes, beginning in Bolivia and extending through Peru. From about 2 south latitude in Ecuador it occupies also the eastern slope of the Western Cordilleras, until by two narrow belts it enters the highlands of New Granada, whence it spreads northeast and northward into Venezuela, reaching the vicinity of Caracas and the Caribbean Sea. Owing to the great number of hybrids the delimitation of the various species of cinchona is, at the present time, almost an impossible task.

The climate in which the most valuable species are found is, according to Karsten (1858), characterized by a rainy season lasting for nine months, heavy rains falling principally during the night, alternating with sunshine and fog during the day. During the remaining three months of the year the nightly temperature frequently sinks below freezing-point, in the day-time, however, reaching 25o C. (77o F.), producing dense fogs.

The Cinchonas are evergreen trees or shrubs, the most valuable species attaining a height of from 40 to 80 feet (12 to 24 M.). They are not met with in the valleys, but are found at altitudes varying from 330 feet (100 M.) to 11,500 feet (3500 M.). According to Weddell, the most valuable species grow at an altitude of 5300 to 7900 feet (1600 to 2400 M.). All the species are found in the primeval forests, either singly or in collections of a few specimens. The tree is cultivated in British Sikkim, Ceylon, Java, and Jamaica. It is also cultivated in South America, its original home.

Description and. Properties. - In quills or in curved pieces, varying in length, and usually 1/12 or 1/8 inch (2 or 3 Mm.), or sometimes 1/5 inch (5 Mm.) thick; the outer surface covered with a gray or brownish-gray cork, usually slightly wrinkled, marked with transverse and also intersecting longitudinal fissures (C. Calisaya), and sometimes with scattered warts and slight longitudinal ridges; inner surface light cinnamon-brown, very highly striate; fracture of the outer layer short and granular, finely fibrous in the inner layer; powder light- or yellowish-brown; odor slight, somewhat aromatic; taste bitter and somewhat astringent.