Thomas, Lewis, 1913–93, American physician and biologist, b. Flushing, New York. In his youth he often accompanied his physician father on his rounds and decided early on to be a doctor or a writer. He graduated from Princeton, and obtained his medical degree from Harvard in 1937. He held various professorships and research posts and was dean of the medical schools of New York Univ. (1966–69) and Yale (1972–73). He served as president (1973–80) then chancellor (1980–83) and president emeritus (from 1983) of Memorial Sloan-Kettering Cancer Center in New York City. He is mostly widely known, however, for his lucid essays that combine his fascination for the living world with his thoughts on biology and philosophy. His collections of his essays include The Lives of a Cell (1974), The Medusa and the Snail (1979), and Late Night Thoughts on Listening to Mahler's Ninth Symphony (1983).