William Harvey

Harvey, William (1578–1657), British physician who pioneered modern medicine, discovering the circulation of blood. In On the Movement of the Heart and Blood in Animals (1628) he argued that the heart acts as a pump and that the blood circulates endlessly about the body; that there are valves in the heart and veins that cause blood to flow in one direction only; and that the necessary pressure comes from the lower left-hand side of the heart. His theories were not fully confirmed until the early 19th century. He also made important studies of the development of the embryo.

See also: Circulatory system; Heart.