Note: Information is dated. Do not rely on it.Bark, Peruvian. The bark of various species of trees of the genus Cinchona, found in many parts of South America, but more particularly in Peru, and having medicinal properties. It was formerly called Jesuit's bark, from its having been introduced into Europe by Jesuits. Its medicinal properties depend upon the presence of quinine, which is now extracted from the bark, imported, and prescribed in place of nauseous mouthfuls of bark.