Galen

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Galen, the most outstanding physician of antiquity after Hippocrates. His anatomical studies on animals and observations of how the human body functions dominated medical theory and practice for 1400 years. Galen was born of Greek parents in Pergamum, Asia Minor, which was then part of the Roman Empire. A shrine to the healing god Asclepius was located in Pergamum, and there young Galen observed how the medical techniques of the time were used to treat the ill or wounded. He received his formal medical training in nearby Smyrna and then traveled widely, gaining more medical knowledge. About 161 he settled in Rome, where he became renowned for his skill as a physician, his animal dissections, and his public lectures. About 169, the Roman emperor Marcus Aurelius appointed Galen as the physician to his son Lucius Aelius Aurelius Commodus. Most of Galen's later life was probably spent in Rome.

Galen dissected many animals, particularly goats, pigs, and monkeys, to demonstrate how different muscles are controlled at different levels of the spinal cord. He noted the functions of the kidney and bladder and identified seven pairs of cranial nerves. He also showed that the brain controls the voice. Galen showed that arteries carry blood, disproving the 400-year-old belief that arteries carry air. Galen also described the valves of the heart and noted the structural differences between arteries and veins, but fell short of conceiving that the blood circulates. Instead, he held the erroneous belief that the liver is the central organ of the vascular system, and that blood moves from the liver to the periphery of the body to form flesh.

Galen was also highly praised in his time as a philosopher. In his treatise On the Uses of the Parts of the Body of Man he closely followed the view of the Greek philosopher Aristotle that nothing in nature is superfluous. Galen's principal contribution to philosophic thought was the concept that God's purposes can be understood by examining nature.

Galen's observations in anatomy remained his most enduring contribution. His medical writings were translated by 9th-century Arab thinkers and became highly esteemed by medical humanists of Renaissance Europe. Galen produced about 500 tracts on medicine, philosophy, and ethics, many of which have survived in translated form.

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