304-250 BC

Erasistratus was a Greek anatomist who practiced medicine in Alexandria, Egypt. He advanced the understanding of the nervous and circulatory systems and also proposed a pneuma theory that provided life forces to the nervous and circulatory system.

Erasistratus was the first to distinguish the cerebrum from the cerebellum. He determined, further, that the brain was the origin for all nerves and distinguished sensory from motor nerves, linking both to the brain.

Cardiovascular medicine was also greatly expanded due to Erasistratus’ research. He described the valves of the heart and was among the first to distinguish between veins and arteries. He also concluded that the heart was not the center of sensations, but instead it functioned as a pump.

Some consider Erasistratus to be the first to study the rhythms of the heart. He is also credited with having developed the first lie detector test as he noticed his patients heart rates tended to increase when the were lying to him.

Finally, Erasistratus proposed a detailed version of pneuma theory describing the course of nervous and animal spirits through the body. He considered atoms to be the essential body element, and that the atoms were vitalized by external air (pneuma) that circulated through the nerves. He also thought that the nerves moved a “nervous spirit” from the brain. He believed that the arteries were filled with pneuma carrying the “animal spirit” from the heart. Using this theory he tried to counter the humor theory of Hippocrates that was in current use.

Writings about Erasistratus

Brain, Peter (1986) Galen on Bloodletting: A Study of the Origins, Development and Validity of His Opinions. Cambridge University Press.

Wright, John P. and Paul Potter (2000) Psyche and soma: physicians and metaphysicians on the mind-body problem from antiquity to enlightenment. Oxford: Clarendon Press.