It has been held that Erasistratus lived in Alexandria and the he practiced medicine there in the third century BC about 400 years before Galen. His works are lost for fragments quoted by other writers,
Erasistratus made numerous physiological and anatomical discoveries, perhaps using – like his contemporary Herophilus – an exceptional combination of human and animal dissection to explore the structure and workings of the human body.
Among his achievements, two in particular won high praise from later authors. First he described the heart valves, noting the irreversibility of the flow through the valves and detailing the heart’s pumping action. He supplied an excellent description of the bicuspid and tricuspid valves and their function in determining one-way flow through the heart.
Second, his account of the brain includes descriptions of its four ventricles, the convolution of the cerebrum and the cerebellum and the origin of the nervous system in the brain.
Erasistratus believed that all tissue in the body contains veins arteries and nerves and these vessels serve as channels by which various substances fundamental to the functioning of the body conducted to its various organs.
Erasistratus rejected the widespread Hippocratic theory of humoral medicine. Instead, he attributed disease to ‘plethora’ an excess of blood that produces inflammation and blocks the flow of pneuma.
Erasistratus of Ceos (325 BC – 250 BC)
