Note 61 — Chapter XXIII
Reading edition
More than a score of species of the tree from which this bark is obtained grow in the higher eastern slopes of the Andes, but a very large part is obtained from the tree, Cinchona calisaya. The medicinal substance, quinine, is extracted from the bark, and in the past half-century it has become the specific for malarial fevers. So great is the demand for it, that the cinchona-tree is now cultivated in India, Java, and Mexico.