Claudius Galen was a Greek physician who went to Rome and revived the ideas of Hippocrates and other Greek doctors. Galen favoured the observations of Hippocrates and other Greek doctors who lived at the time of Hippocrates. He put great emphasis on clinical observation – examining a patient very thoroughly and their symptoms. Galen also accepted the view that disease was the result of an imbalance between blood, phlegm, yellow bile and blood bile. Galen also believed in the healing power of nature and he developed treatments to balance of the four humours. Galen believed in the use of opposites – if a man appeared to have a fever, he treated it with something cold; if a man appeared to have a cold, he would be treated with heat. People who were weak were given hard physical exercises to do to build up their muscles and people who had breathing problems due to a weak chest were given singing exercises.
Galen extended his knowledge of anatomy by dissecting pigs and apes and studying their bone structure and muscles. In "On Anatomical Procedures", Galen advised his students to dissect apes and take whatever opportunities that existed to study the human body. Galen also studied how the body worked, concentrating on the movement of blood and the working of the nervous system. Later, he experimented with the spinal cords of pigs.
Galen’s influence was great. Protected by the emperors, he could work free from his jealous rivals in Rome. Galen also believed that his knowledge should be shared and he was a writer of many books. These books were still being used in the Middle Ages and, for many medical students, they were the primary source of information on medicine.
He advanced the study of anatomy and physiology by careful dissection and observation. He had a private income. He was a skilled surgeon, capable of operations also a philosopher and logician.
He left a huge mass of writing behind,