Andean Indians have long chewed leaves of the coca plant to decrease hunger and increase their stamina for work. Chewing the leaves produces no “high.” Cocaine was first extracted from coca in the 19th cent. and was at first hailed as a miracle drug. By the 1880s in the United States it was freely prescribed by physicians for such maladies as exhaustion, depression, and morphine addiction and was available in many patent medicines. After users and physicians began to realize its dangers and various regulations were enacted, its use decreased, and by the 1920s the epidemic had abated. Another epidemic...