Erasistratus of Ceos was a Greek physician and anatomist active in the first half of the 3rd century BCE. A student of Theophrastus in Athens, he later moved to Alexandria, where he served at the royal court and founded his own influential medical school. He is considered a founder of systematic human anatomy. In Alexandria, he conducted detailed dissections of human bodies, a rare practice at the time.
His investigations led to major discoveries. He distinguished the brain's cerebrum and cerebellum, described its folds, and identified sensory and motor nerves. He also produced advanced studies of the heart and blood vessels. None of Erasistratus's own writings survive intact. His ideas are known only through fragments and reports by later medical authors like Galen. His lost works included titles such as On Fevers, On Paralysis, and a major theoretical text called General Principles.
Erasistratus stands as a central figure in the history of science. His empirical approach to dissection set a new standard for anatomical knowledge. While his theories of the body's workings, which explained it as a system of vessels carrying pneuma, were later rejected, his anatomical observations remained the basis of the field. His school rivaled that of Herophilus in Alexandria for centuries, and his emphasis on diet and mechanical causes for disease influenced more rationalist medical traditions.
Also published as PDF.