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
Jesuit's bark long conflict over the good or harm effected by Peruvian Bark". The Spanish Jesuit missionaries in Peru were taught the healing power of the bark by natives, between 1620 and 1630, when a Jesuit at Loxa was indebted to its use for his cure from an attack of malaria ("Loxa Bark"). It was used at the recommendation of the Jesuits in 1630, when the Countess of Chinchon (Cinchon; the derivative is Cinchona, the appellation selected by Carl Linnaeus in 1742; Clements Markham preferred Chinchona), wife of the new viceroy, who had just arrived from Europe, was taken ill with malaria