Sir

In her review of Mark Honigsbaum's book The Fever Trail (Nature 418, 820–821; 2002), Sandra Knapp asks how the Cinchona tree's properties came to be discovered, given that malaria did not exist in the New World until the Europeans arrived there. The book does not answer this question.

Several species of the Cinchona tree (which was called “quina-quina” by the Indians) grow on the warm, moist slopes of the Andes above 1,500 metres, where the Anopheles mosquito does not survive. The quina-quina trees were thought by some people to be poisonous, owing to the bitter taste of the bark. Yet plants that are unpleasant to the taste or even harmful if taken unwisely may be used, in the right form and dosage, as medicines.

Therefore it is plausible to suppose that the bark of quina-quina trees has also been used therapeutically by South American Indians since pre-Columbian times for chills and fevers. (One legend tells of an Indian who, burning with fever, drank from a jungle pool despite the bitter taste that revealed it was contaminated by the neighbouring quina-quina trees, and whose fever then abated.) The Jesuits probably learned about the anti-fever properties of this bark from the Indians and tried it, successfully, to treat malaria — hence the remedy's popular name of 'Jesuit's bark'.

According to a story that is widely accepted in Western countries, the use of the bark for malaria is a case of serendipity (see R. M. Roberts, Serendipity: Accidental Discoveries in Science, 6–10; Wiley, New York, 1989). The Countess of Chinchon (1576–1639), wife of the Viceroy of Peru, was said to have been cured of malaria by taking an extract from the bark of a Peruvian tree. She was also said to have carried some bark back with her to Spain in 1638, thereby introducing its use in Europe. This part of the story, at least, is false, because the Countess died in Cartagena de Indias, Colombia, without ever returning to Spain — though she was immortalized by Linnaeus when he gave the tree its botanical name.

In 1633, the monk Calancha, who accompanied the Spanish conquistadors, introduced the use of the remedy Cinchona to Europe (for more information, see R. B. Silverman, The Organic Chemistry of Drug Design and Drug Action, 1–2; Academic, San Diego, 1992).