Erasippus

Erasippus was a Greek physician and anatomist who lived in Alexandria during the Hellenistic period, around the 3rd century BC. He is considered, along with Herophilus of Chalcedon, to be one of the founders of the Alexandrian medical school and a pioneer of anatomical study.

Erasippus is credited with making significant contributions to the understanding of human anatomy and physiology through his dissections, which were reportedly performed on condemned criminals. He distinguished between nerves and tendons, and described the brain's cerebrum and cerebellum. He also studied the heart and circulatory system, correctly identifying the function of the heart valves and differentiating between arteries and veins, though he incorrectly believed that arteries contained air.

Erasippus opposed the then-prevalent humoral theory of disease, proposing instead that illnesses were caused by alterations in the blood. He also emphasized the importance of hygiene and diet in maintaining health.

While none of his original writings survive, his anatomical and physiological discoveries are known through the writings of Galen, Celsus, and other later medical authors who referenced and built upon his work. Erasippus's focus on empirical observation and anatomical dissection marked a significant shift in medical understanding and laid the groundwork for future advancements in the field.