Edward Stone (natural philosopher) piece of bark from a willow tree and was struck by its extremely bitter taste. Knowing that the bark of the Peruvian cinchona tree − from which quinine (used in the treatment of malarial fevers) is derived − has a similarly bitter taste, he surmised that the willow might also have therapeutic properties. Stone's interest in willows was due to the ancient "doctrine of signatures" – whereby the cause of a disease offers a clue to its treatment. According to Stone: "As this tree delights in a moist or wet soil, where agues chiefly abound, the general maxim that many
Cinchona South America, the species had geographically distinct distributions. The introduction of several species into cultivation in the same areas in India and Java, respectively, by the English and Dutch East India Companies led to the formation of hybrids. Linnaeus described the genus based on the species "Cinchona officinalis." Nearly 300 species have been described and named in the genus but a revision of the genus in 1998 identified 23 distinct species. The febrifugal properties of bark from trees now known to be in the genus "Cinchona" were used by many South American cultures but malaria was an Old World disease