Leigh Ann Wynn, age 15, of Tacoma, Wash., for her question:

WHERE DO WE GET QUININE?

Quinine is an alkaloid derived principally from the bark of the cinchona tree. It was probably discovered by Jesuit missionaries in Peru, who introduced the drug to Europe about 1640. We now obtain it from Indonesia and also use synthetic quinine drugs. Quinine is a remedy for malaria and is also effective in reducing fever.

The increase in its use through the years threatened to exhaust the South American trees and efforts to cultivate cinchona trees in other countries finally succeeded in the Dutch East Indies (now Indonesia) in the late 19th century.

Production from the cultivated trees was so much superior in both quality and quantity to that of the native South American trees that the Netherlands East Indies soon had a practical monopoly on the market.

At the outbreak of World War II, the Japanese invasion of the Indies cut off more than 90 percent of the world supply of quinine. During the war substitutes were developed.

Natural quinine is still in demand, however, because some malarial organisms are resistant to the synthetics.