ELIXIR, a Latinized form of the Arabic word al-iksīr, is related to the Greek word xerion, denoting a dry powder used for medicine and alchemical transmutation. Elixirs are potions believed to have restorative and curative powers. The term was first used by alchemists to describe the substance (also known as the philosophers' stone) that was believed to transmute base metal into gold, cure disease, and promise immortality. The term is also used in medical pharmacy to mean "a sweetened hydroalcoholic solution containing flavoring materials and usually medicinal substances" (Encyclopædia Britannica, 1964, vol. 8, p. 288). Ambrosia and nectar are related terms, especially in classical Western religion and mythology, where all three are sometimes used interchangeably for the divine drink and food of the gods. In some senses they relate to the concept of a substance that confers immortality. There is the possibility, too, that the idea of an ingestible...