In the fourth century BCE the most important locus of medical thought and practice was not the island home Cos of Hippocrates, but the great center of Greek learning at Alexandria, founded in 331 BCE by Alexander the Great and governed by a dynasty stemming from his general Ptolemy. The Ptolemaic rulers gave lavish financial support to the library and museum at Alexandria which consequently attracted researchers in all fields, including philosophy, mathematics, history, poetry and medicine. Medical research in the Alexandrian museum became world renowned. Two of its most influential investigators were Herophilos of Chalcedon (fl. circa 280 BCE) and Erasistratos of Iulis (fl. 250 BCE). Most of our knowledge of these two is derived from later commentators, such as Celsus and Galen in the Roman period.

Herophilos’ most important contribution to clinical medicine was his development of the theory of the diagnostic value of the pulse. Although the pulse is referred to occasionally by earlier writers (for example by Aristotle in his Inquiry Concerning Animals 521a5f), it was Herophilos’ teacher, Praxagoras, who first restricted the pulse to a distinct group of vessels and held that it could be used as an indicator of disease. Herophilos corrected his master’s teaching on several points, maintaining that the pulse is not an innate faculty of the arteries, but one they derive from the heart, and distinguishing the pulse not merely quantitatively, but also qualitatively from palpitations, tremors and spasms, which are muscular in origin.

Erasistratos, Herophilos’ rival at Alexandria, made remarkable progress in anatomy. Erasistratos described the brain more accurately than Herophilos. He distinguished the cerebrum from the cerebellum, and he determined that the brain was the originating point for all nerves. He distinguished sensory from motor nerves and he was the first to dispel the notion that nerves are hollow and filled with pneuma (air); but are solid, consisting of marrow of the spinal kind. In his account of the heart and its function, he distinguished between pulmonary and systemic circulation.

Jacques-Louis David, 1774 “Erasistratus Discovering the Cause of Antiochus’ Disease”

Antiochus, son of Seleucus I Nicator, King of Syria, was dangerously ill, and, when other physicians failed to help him, Erasistratos was called in. While he was examining the patient, Stratonice, a young woman, one of the elderly king’s wives, entered the room. From the quickening of the sick man’s pulse and from the flush which spread over his cheeks, the doctor recognized that the illness was mental rather than physical--that a passion for his inaccessible step-mother was at the root of the trouble.

Dissection and Vivisection