Galen: Encyclopedia II - Galen - Work and impact

Galen - Work and impact

Galen transmitted Hippocratic medicine all the way to the Renaissance. His On the Elements According to Hippocrates describes the philosopher's system of four bodily humours, which were identified with the four classical elements. He created his own theories from those principles. In turn, he mainly ignored Latin writings of Celsus.

Amongst Galen's own major works is a seventeen-volume On the Usefulness of the Parts of the Human Body. He also wrote about philosophy and philology. His collected works total twenty-two volumes.

Galen's own theories, in accord with Plato's, emphasized purposeful creation by a single Creator ("Nature" - Greek phusis) - a major reason why later Christian and Muslim scholars could accept his views. His fundamental principle of life was pneuma (air, breath) that later writers connected with the soul. Pneuma physicon (animal spirit) in the brain took care of movement, perception, and senses. Pneuma zoticon (vital spirit) in the heart controlled blood and body temperature. "Natural spirit" in the liver handled nutrition and metabolism.

Galen expanded his knowledge partly by experimenting with live animals. One of his methods was to publicly dissect a living pig and cut its nerve bundles one at a time. Eventually he cut a laryngeal nerve (now also known as Galen's Nerve) and the pig stopped squealing. He tied the ureters of living animals to show that urine comes from the kidneys. He severed spinal cords to demonstrate paralysis.

From the modern viewpoint, Galen's theories were partially correct, partially flawed. He demonstrated that arteries carry blood, not air and made first studies about nerve functions, and the brain and heart. He also argued that the mind was in the brain, not in the heart as Aristotle had claimed.

However, much of Galen's understanding is flawed from the modern point of view. He did not recognize blood circulation and thought that venous and arterial systems were separate. This view did not change until William Harvey's work in the 17th century. Since most of his knowledge of anatomy was based on dissection of pigs, dogs, and Barbary apes, he also assumed that rete mirabile, a blood vessel plexus of ungulates, also existed in the human body. He also resisted the idea of tourniquets to stop bleeding and vigorously propagated blood letting as a treatment.

Galen's authority dominated medicine all the way to the 16th century. Experimenters' disciples did not bother to experiment and studies of physiology and anatomy stopped - Galen had already written about everything. Blood letting became a standard medical procedure. Vesalius presented the first serious challenge to his hegemony.

Much of medieval Islamic medicine drew on the works of the ancient Greeks, especially those elucidated by Galen, such as his expanded humoral theory. Most of Galen's Greek writings were first translated to the Syriac language by Nestorian monks in the university of Gundishapur, Persia. Muslim scholars primarily in Baghdad translated the Syriac manuscripts into Arabic, along with many other Greek classics. They became some of the main sources for Arabian scholars such as Avicenna, Rhazes, and Maimonides. Galen was known in Arabic as Jalinos, and many people with that name today are considered to be descendents of him.

Adapted from the Wikipedia article "Work and impact", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki