Next time you glance at the wall clock in the gym to check your heartrate or notice the arm-squeezing machine at the doctor’s office extracting your pulse, think back to these innovators from 2300 years ago who had at their disposal only their powers of observation/reasoning and the very limited technology of the time — a water clock or clepsydra.
Luckily for us, Alexandria, a city named for Alexander the Great, in northern Egypt, attracted the era’s greatest scholars. Among these were mathematicians and physicians. Among the latter were two of note whose works have been lost, Herophilos (335–280 BC) and Erasistratus (304 BC – 250 BC), from Chalcedon and Ceos, respectively. These two men were pioneers in human anatomy. Uncommon at the time, they used dissection, if not vivisection, to learn about human physiology.
Elsewhere in the Greek world, human dissection is thought to have been taboo. Animals were okay, but humans — dei advertant. It is said (note the weasel words) that the Ptolemies facilitated not just dissection of the dead, but vivisection, by supplying the scientists with criminals from the royal prisons. (Even if this is not true, the Ptolemies did support their work.) Why it suddenly became permissible for Greeks to defile dead bodies, when it had not been earlier, and only in the Hellenistic capital of Alexandria, has puzzled scholars. Maybe it was a result of philosophical teaching about the nature of the soul or an increased emphasis among philosophical schools on empirical research. Perhaps its appearance uniquely in Alexandria was connected with the Egyptian practice of embalming. Longrigg reviews such ideas in his article:
Anatomy in Alexandria in the Third Century B.C. James Longrigg The British Journal for the History of Science, Vol. 21, No. 4 (Dec., 1988), pp. 455-488.
We know of these great early doctors thanks to the records and quotations of others, including Galen, Rufus of Ephesus, Soranus, the AD first century Anonymous Londinensis [note the “-ensis”, a suffix of connection denoting “belonging,” according to Gonzales Lodge’s The Vocabulary of High School Latin], which contains material from Aristotle’s pupil Meno, and Celsus’ De medicina. Their work improved the understanding of heart, brain, eye, liver, vascular, nervous, and reproductive systems, according to Greek Rational Medicine, also by Longrigg (Routledge: 1995).
Herophilus for the Latinists, or Herophilos, otherwise, improved on existing theories of the human sexual reproduction, explaining the structures of the male and female systems if not the exact nature of the fluids involved. He understood pulses and is the first known physician to have clocked the pulse to assess fevers, noticing both its strength and speed. He distinguished between veins and arteries, and found both sensory and motor nerves. Then came Erasistratus who improved Herophilus’ analyses of the vascular and nervous systems, understood the structure and function of the heart, and may possibly have identifying the coordinated function of the four heart valves, although he should not be credited with discovering the circulatory system. Erasistratus also explained the structure of the brain, agreeing with his predecessor that nerves started there.
Erasistratus was influenced by contemporary philosophical theories of matter as a result of which he developed a theory of corpuscles in a vacuum along with the idea of suction. His scientific principles led to a mechanistic understanding of the digestive system, that included an accurate description of the muscles, which has survived. He thought that the food once digested passed nutrients to all parts of the body through a system of pores, vessels, and veins.
So long ago, yet so close to what we know today, thanks mostly to their own amazing brains.