Virtually nothing is known of the first physician named Hippocrates, but there are considered to have been several, all of them teachers at the famous medical school on the Mediterranean island of Cos. It was in the 5th century B.C.E., however, that Hippocrates’ name and image began to emerge as a leader in medical research and thought.
Hippocrates is generally credited with turning away from divine notions of medicine and using observation of the body as a basis for medical knowledge. Prayers and sacrifices to the gods did not hold a central place in his theories, but changes in diet, beneficial drugs, and keeping the body "in balance" were the key.
Central to his physiology and ideas on illness was the humoral theory of health, whereby the four bodily fluids, or humors, of blood, phlegm, yellow bile, and black bile needed to be kept in balance. Illness was caused when these fluids became out of balance, sometimes requiring the reduction in the body of a humor through bloodletting or purging.
The Hippocratic Corpus, or the collected writings attributed to Hippocrates, contains about sixty works on a variety of medical topics, including diagnosis, epidemics, obstetrics, pediatrics, nutrition, and surgery. There are assumed to be several authors, however, probably scattered over several centuries, and different treatises often give contradictory advice.
This first Greek edition of Hippocrates’ complete works benefited from Aldus Manutius’ careful editing, which made its text the standard for the Greek Corpus for over a century.
Phaedrus: "Hippocrates the Asclepiad says that the nature even of the body can only be understood as a whole."
Socrates: "Yes, friend, and he was right:-still, we ought not to be content with the name of Hippocrates, but to examine and see whether his argument agrees with his conception of nature."
Phaedrus: "I agree."
Socrates: "Then consider what truth, as well as Hippocrates, says about this or about any other nature. …"