C 335 BC-280 BC

Herophilus was an anatomist and physician who spent the majority of his life learning, teaching, living, and writing in Greek-ruled Alexandria, Egypt. He was among the first to dissect the human body. Dissections of human cadavers were banned in most places in ancient times, except for Alexandria. Herophilus recorded his findings in over nine works that were kept at the library in Alexandria for almost 700 years until a massive fire destroyed all of his writings in 391 CE.

In his book, On Pulses, Herophilus wrote about his ideas on the flow of blood from the heart through the arteries and in his book on midwifery he described the duration and phases of childbirth. He carried out public dissections, so his students could understand what he was doing and why.

Herophilus revised the humor theory of Hippocrates. In his own theory he argued against the notion that the veins were filled with a mixture of blood, air, and water, rather he showed, through his dissections that it was pure blood in the veins.

His work on blood and its movements eventually led Herophilus to study and analyze the brain. He proposed that the brain housed the intellect rather than the heart. He was the first person to separate the functions of the cerebrum and the cerebellum. He located animal spirits in the cerebrum.

Herophilus conducted detailed studies of the network of nerves located in the cranium. He described the optic nerve and the oculomotor nerve for sight and eye movement. This led him to further dissect the eye, and in so doing to discover the cornea, the retina, the iris, and the chorioid coat.

Further study of the cranium led Herophilus to describe the calamus scriptorius an area of the fourth ventricle in the human brain. He believed this was the seat of the human soul or psyche.

In his detailed studies of the nervous system, Herophilus also differentiated between nerves and blood vessels and found there to be differences between motor and sensory nerves. He believed that the sensory and motor nerves shot out from the brain and that the neural transmissions occurred by means of a substance, called pneuma, that flowed through the arteries along with the blood. He theorized, according to humor theory, that diseases were due to an imbalance of humors that kept the pneuma from reaching the brain.

Herophilus also differentiated between arteries and veins. He noticed that as blood flowed through arteries, they pulsed or rhythmically throbbed. He worked out standards for measuring a pulse and used these standards to aid him in diagnosing sicknesses or diseases. He devised a water clock to measure the pulse.

Finally, Herophilus discovered and named various parts of the body, including a part of the sinus, torcular Herophili, and the duodenum, a part of the small intestine that measured the breadth of twelve fingers, hence its name--twelve.

In his book entitled Midwifery, Herophilus discussed phases and duration of pregnancy as well as causes for difficult childbirth.

Herophilus believed that exercise and a healthy diet were integral to the well being of a person, affecting many aspects of personal functioning. He said it this way: “When health is absent, wisdom cannot reveal itself, art cannot manifest, strength cannot fight, wealth becomes useless, and intelligence cannot be applied.”

Writings of Herophilus

On Pulses


Writings about Herophilus

Herophilus, Encyclopedia of World Biography Supplement Vol. 25 Michigan: Thomson Gale.

Hornblower, S.& Spawford, A. (1999). Herophilus. In The Oxford Classical Dictionary. New York: Oxford University Press, 699.

Hunt, J. (1868). On the localisation of the functions of the brain with special reference to the faculty of language, Anthropological Review, 1868, 6, 329-345.

von Staden H. (ed. trans.) (1989) Herophilus: The Art of Medicine in Early Alexandria. Cambridge University Press, 1989

Wills, A. (1999) Herophilus, Erasistratus, and the birth of neuroscience. The Lancet. November 13, 1999.