The Library and Lighthouse of Alexandria

There was a poetic justice to the fact that the city of Alexandria became the leading light in medicine during the third century BC, given that the land to which the city belonged had been famed far and wide for the same reason during earlier centuries.

Homer reveals the regard in which the Greeks held Egyptian medicine more than 400 years before the founding of Alexandria. In the Odyssey, he speaks of Egypt as the “land where the teeming soil bears the richest of yield of herbs in all the world: many health itself when mixed in the wine, and many deadly poison. Every man is a healer there, more skilled than any other men on earth — Egyptians born of the healing god himself.” Some three centuries later, the Greek historian, traveler, and raconteur Herodotus wrote that in Egypt “the art of medicine is divided so that each physician treats just one illness and no more. Doctors are everywhere, as there are specific physicians for the eyes, the head, the teeth, the abdomen, and still others for illnesses that are invisible.”

Homer and Herodotus were, alas, a bit too sanguine. While the ruling classes of pharaonic Egypt were indeed able to call upon an array of doctors and dentists to cure their ills, the ordinary people suffered from a wide variety of debilitating ailments that went completely unremedied. Archaeological investigations have revealed evidence of untreated schistosomiasis, tuberculosis, cancer, and hernias among the Egyptian peasantry, to name just a few of the burdens under which they labored.

Even for the rich and powerful who had access to it, Egyptian medicine was fundamentally different in concept from what we think of as the practice of medicine today. Like so much in Egyptian life, diseases and their cures were intimately bound up with the gods; disease was something visited on the individual by the gods, curing it a matter of placating or otherwise satisfying the divine victimizer. Preserved Egyptian “medical” texts reveal that the doctors there were also priests, chanting prayers and incantations that were considered at least as important as any physical cures they might attempt. For example, a priest would say the following prayer to Isis, goddess of magic, wisdom, and healing, as he removed a simple bandage placed over a wound: “Oh, Isis, great in sorcery, may you loosen me, may you save me from all evil, bad, red things…”

But of course there were bandages involved as well, along with many other forms of non-spiritual treatment, including a cornucopia of herbal concoctions. Egyptian medicine was doubtless efficacious enough in its way in many areas, a product of happy accidents and perhaps occasional bouts of more concerted experimentation over the course of several millennia. Yet an increasingly entrenched priesthood seems to have arrested its progress well before the time of Homer; the surviving texts we have at our disposal reveal little obvious change in the practice of Egyptian medicine between 1800 BC and AD 200. It became static, a matter for religious dogma rather than logical inquiry.

It was thus left to the Greeks to separate medicine from religion for the first time. While we can see the first signs of their beginning to do so as far back as 550 BC, the man whom we most associate with the movement today — in fact, the most famous man of medicine in history, the canonical “Father of Medicine” — was born in approximately 460 BC. His name was Hippocrates, and he lived out the entirety of his more than eighty years on the Greek island of Kos. He had no need to go anywhere else, for Kos was already well-known at the time of his birth as a sort of spa island, a place where wealthy travelers came to take the waters and relax. Hippocrates served as their consulting physician when he wasn’t researching and writing.

What’s become known as the Hippocratic corpus is vast, encompassing some sixty different texts of many types and styles — so much so that historians now suspect that most of them were not written by Hippocrates at all, but rather by his students and fellow doctors on Kos. One of the most famous of these Hippocratic texts does much to illustrate the new attitudes that its real or apocryphal author embodied. It deals with what the Greeks called “the sacred disease,” which we now refer to as epilepsy. If any disorder can convince an observer that it stems from a god or other supernatural being, it must be this one, what with the bizarre seizures it produces, where some external spirit seems literally to have seized control of the sufferer’s body. Yet Hippocrates rejected that explanation in no uncertain terms.

It is thus with the disease called “sacred”: it appears to me to be nowise more divine nor more sacred than other diseases, but has a natural cause like other afflictions. Men regard its nature and cause as divine from ignorance and wonder. And this notion of its divinity is kept up by their inability to comprehend it. Neither truly do I count it a worthy opinion to hold that the body of man is polluted by a god, the most impure by the most holy; for it would be likely to be purified and sanctified rather than polluted by a god.

Those who first referred this malady to the gods appear to me to be just such persons as the conjurers, mountebanks, and charlatans now are. Such persons, then, using the divinity as a pretext and screen for their inability to afford any assistance, have given out that the disease is sacred.

This disease is formed from those things that enter and go out of the body, and is not more difficult to cure than other diseases; neither is it more divine than they.

The importance of this assertion that epilepsy, like all diseases and disorders, has a natural rather than a supernatural cause can hardly be overstated. Charles-Edward Winslow, a significant voice in epidemiology during the twentieth century of our epoch, wrote that “if disease is postulated as caused by gods or demons, scientific progress is impossible. The assumption of natural causation was the essential first step.” This assumption — the assumption that all things have a rational cause that is of this world, and can thus be understood by us humans, who are of the same world — is a prerequisite of science.

Nevertheless, Hippocratic medicine wasn’t quite scientific in the full, modern sense of that term. It was rather deeply rooted in abstract Greek philosophy, whose golden age coincided with the life of Hippocrates. His contemporary Plato emphasized the need for order and balance in all things. In fact, Plato believed that the universe itself was a balancing act between four basic elements: air, water, earth, and fire.

Hippocratic medicine applied Plato’s macrocosmic theory to the microcosm that is the human body. Hippocrates imagined four “humors” in the body which were connected to the four basic elements: blood (air), phlegm (water), black bile (earth), and yellow bile (fire). While a certain amount of variation in the humoric balance was acceptable — indeed, this was the reason that different people evinced different physical and mental qualities and capabilities — it was possible for the humors to get too far out of balance, with disease or other undesirable conditions, from obesity to insomnia, being the result. One endeavored to treat not the symptoms of humoric imbalance but rather their root cause, attempting to bring the humors back into the proper balance by a variety of means that added to the quantity of one of them and/or subtracted from the quantity of another. The most infamous of these is the practice of “bleeding” patients to get rid of what was thought to be an excess of blood in the system, although it should in all fairness be noted that bleeding was more favored by later practitioners of humorism than it was by Hippocrates himself.

Before we rush to mock any of this too enthusiastically, we should give it its due as the revolution in thought that it was. Hippocrates’s achievement in moving medicine from the domain of the gods to that of rational men is still widely celebrated, as it should be. The Hippocratic Oath which is taken by most medical doctors today is an updated version of one found in the Hippocratic corpus. Both emphasize that the proper role of the physician is not to play god by attempting to heal the patient on his own, but rather to do everything possible to help the patient’s body — that amazing self-righting machine — to heal itself. Both emphasize the need for humility in the would-be healer, and both emphasize that, above all else, a doctor’s imperative is to “do no harm” to a patient who might very well heal on her own with no intervention whatsoever. (This phrase does not appear in those exact words in the ancient version of the oath, but the spirit of it is certainly there; another Hippocratic text instructs physicians to “practice two things in your dealings with disease: either help or do not harm the patient.”)

Hippocrates understood well that too much treatment can be worse than too little. The general practitioners of today tell us that as many as 75 percent of the patients who come to see them don’t require any physical intervention at all. They present with the symptoms of poor lifestyle choices, or with minor afflictions which will cure themselves, or with no real afflictions of any kind, and they require only verbal intervention, in the form of advice and reassurance. Much of the Hippocratic physicians’ advice to their patients would ring all too familiar to the general practitioners of today: “Get more exercise”; “Eat more vegetables”; “Drink less wine”; “Try to reduce your stress level”; etc. An ounce of prevention was better than a pound of cure: “Live a healthy life,” said Hippocrates, “and you are not likely to fall ill, except through epidemic or accident.”

There is much wisdom in all of this. And it should be noted as well that Hippocratic medicine was by no means completely indifferent to empirical observation. There are extensive patient case studies in the Hippocratic corpus, the first and last of their kind for the next 1700 years or so. Each of these records what transpired with one patient; about 60 percent of the patients they describe die of their conditions in the end, giving ample reason to believe in the reports’ honesty.

The case studies thus serve to underline the reality that there are occasions in medicine when everything will not be okay, when radical outside intervention is required if a patient is to have a chance of living. It’s these occasions that tend to point out the weaknesses of humorism; often the only recourse left to the Hippocratic doctor is a referral to the local temple.

Surgery beyond the lancing of boils and the setting of bones was almost an unknown art on Kos. Hippocrates did correctly identify the brain as the seat of consciousness, and also knew that the heart was a pump for the blood; many of those who came after him, including no less august a personage than Aristotle, would reverse the two. Nevertheless, Hippocrates’s knowledge of internal anatomy can most generously be described as limited. Tellingly, no mention of human dissection is to be found anywhere in the extensive Hippocratic corpus.

There were reasons for this beyond the predilections of Hippocrates himself, reasons bound up with longstanding Greek attitudes toward the body. Perhaps even more so than we do today, the Greeks believed that a human corpse should be treated with respect, even reverence, lest it become a source of spiritual pollution. The Greek philosopher Teles put it simply: writing of his people, he noted that “we shrink both from looking at and touching corpses.”

During times of war, hatred of the enemy could and often did cause the Greeks to violate their taboos against mistreatment of the dead. And yet they believed that to do so even under these extenuating circumstances was to risk the wrath of the gods. Greek mythology and literature abound with stories of those who failed to show the dead the respect they were due, always with grave consequences. The climax of the Iliad depicts the Greek hero Achilles’s desecration of the body of his fallen Trojan counterpart Hector as the livid gods look on and plan his comeuppance:

This Achilles — first he slaughters Hector,
he rips away the noble prince’s life
then lashes him to his chariot, drags him round
his beloved comrade’s tomb. But why, I ask you?
What good will it do him? What honor will he gain?
Let him beware, or great and glorious as he is,
we mighty gods will wheel on him in anger — look,
he outrages the senseless clay in all his fury!

And then there is Sophocles’s tragic play Antigone, telling of the refusal of Creon of Thebes to allow Polynices, a rebel against his city, to be buried after he is killed in battle. “You keep up here a corpse belonging to the gods down there, robbed of its due, its offerings and its rites,” says the Theban prophet-in-residence. “And so the destroyers, the late-avenging Furies of Hades and the gods lie in wait for you, to trap you in the evils you’ve unleashed yourself!” And sure enough, Creon’s blasphemy brings bitter recompense to himself and his city.

If merely neglecting to bury a corpse could have such consequences, one can understand why the even more extreme physical violation that is human dissection should have been absolutely out of the question in the Greek world. The best that a curious mind could hope to do was to cut into animals. “One must refer to the parts of animals which have a nature similar to the nature humans possess,” noted Aristotle. The prohibition against human dissection would never be lifted during the entirety of Greek and Roman antiquity, except in one very specific place and time: Alexandria during the first half of the third century BC.

In the abstract, this unique chance to dissect human cadavers was down to the unique culture of Ptolemaic Egypt; in the specific, it was down to the direct intervention of that land’s first two monarchs. In fact, it is claimed by some ancient sources that not only did Ptolemy I and II make corpses available for dissection, but they also handed over living criminals to be tied down naked on a table and vivisected without benefit of anesthetic, all so that doctors could observe their organs still in action, as it were. If the veracity of this horrifying story is by no means absolute, neither is it terribly difficult to believe in the context of the times. Let it serve as a potent reminder, should we need one, that the milieu of Ptolemaic Egypt was a very different one from our own with very different values, however much high-minded talk about philosopher kings and the like it chose to indulge in.

Many historians attribute the first flowering of Greek philosophy and rational inquiry to the democratic systems of government in Athens and some of the other city-states, which promoted open debate and the free exchange of ideas. And yet democracies can be a double-edged sword in this respect, because they are by definition beholden to the values of the masses who make up their bodies politic, as Socrates learned to his cost when he was tried and executed by a jury of his peers in Athens. In Alexandria, however, the king’s word was law. For all their proud Greekness, the Ptolemies demonstrated a willingness to fly in the face of Greek cultural prejudices when it suited them, such as when they chose to marry their sisters in the Egyptian pharaonic tradition. Why not in this area as well, when doing so could do so much to advance the cause of Knowledge to which they were so dedicated as philosopher kings?

I’ve dwelt on this subject at such length not in order to be sensationalist or grisly, but rather because it has so much to tell us about the early Alexandrian spirit. The cosmology of the ancient world had previously consisted of divinities who were beyond human understanding and a natural world which could be comprehended, with humans themselves perched somewhat uneasily between the two, neither fully fish nor fully fowl; thus the discomfort with human corpses, those contrary reminders that people were made of the same muscle, sinew, and bone as the creatures to be found on their dinner plates. Alexandrian medicine brought people fully down to earth, as it were, by making it absolutely clear that our bodies at least truly were of the world around us rather than somehow outside of it. The idea that all things are at least theoretically understandable — that no understanding is or ought to be unattainable or forbidden, that nothing is sacred in the sense of being out of bounds for rational investigation — lies at the heart of the scientific impulse, which flared brighter in the Alexandria of the third century BC than at any other time or place in the ancient world.

Two names are indelibly associated with this revolutionary if brief-lived new way of studying the human body: Herophilos and Erasistratus. Although their stays in Alexandria may very well have overlapped, they were of different generations. Herophilos was the older of the pair, arriving in Alexandria at a very early date and dying not long after the passing of Ptolemy I; Erasistratus came along later and died some three decades after Herophilos, not long before the passing of Ptolemy II. But they were united by their advocacy for a bottom-up rather than top-down approach to medicine — a position which ironically owed much to Aristotle, despite the wise philosopher’s confusion about such seemingly basic issues as the functions of the brain and the heart. “First the phenomena must be grasped,” Aristotle had written, “and then their causes discussed.” This was the polar opposite of Hippocrates’s approach.

Herophilos was born in approximately 335 BC in Chalcedon, a rather obscure Greek town in Asia Minor, then went to Kos to begin his study of medicine; Hippocrates himself was long dead by the time Herophilos arrived, but the school of medicine he had founded was still going strong there. Its influence on Herophilos remained pronounced enough even after he came to Alexandria that a debate still rages over whether he saw his work there as building upon the Hippocratic tradition in some sense or as replacing it with an entirely new, better edifice of understanding. Such debates are ultimately irresolvable, given that only fragments of Herophilos’s original writings remain to us, along with commentaries upon them by other, later ancient scholars with agendas and prejudices of their own.

A few more traces of Erasistratus’s life have been preserved. It seems he was most likely born on the Greek island of Keos in about 305 BC, probably to a prominent family; one ancient source claims him to have been a grandson of Aristotle, although most modern historians tend to doubt this. He was trained in medicine in the town of Knidos in Asia Minor, then traveled farther east while still a young man to the city of Seleucicia, where he practiced medicine very successfully in the court of Seleucus I, formerly one of Alexander the Great’s Bodyguards, now the monarch of the Seleucid Empire. And then Erasistratus made his way to Alexandria, his reputation surely preceding him. Although we have even fewer fragments of his writings than we do of the writings of Herophilos, we do know that he left no doubt whatsoever that his work should be seen as a definitive break with the humoric theories of Hippocrates. Just as Hippocrates had replaced religious explanations for ill health with philosophical ones, he was now replacing the philosophical with the natural, the phenomenological — or, as we might prefer to call it, the scientific. He pointedly rejected any form of “mysticism,” a category in which he placed the Hippocratic tradition alongside other, still more dubious theories of health and sickness.

Having dwelt so long upon what their work signified for humanity’s relationship to the world around it, I shouldn’t neglect to mention some of what Herophilos and Erasistratus actually found inside the human bodies they dissected.

Herophilos’s investigations of the brain were the first and last of their kind in the ancient world. He mapped its hemispheres and ventricles in careful detail. Some of the names he put to what he found inside the skull are still used by neurosurgeons today. Perhaps the most charming of them is the styloid process, a slender outcropping at the base of the temporal bone that got its name from its resemblance to the pen (styloi) he was using at the time to make his notes. Another structure, one which reminded him of a wine press, has since been named the torcular Herophili (“Herophilos’s press”) in honor of him.

Herophilos discovered nerves, and even surmised that they functioned as the conduits for signals between the brain and the rest of the body, all despite living thousands of years before the invention of electrical wiring would provide an obvious, easily graspable analogy for their purpose. More remarkably still, he intuited and described the distinction between motor and sensory nerves. He then went on to map with an admirable degree of accuracy all those sections of the nervous system that are visible without a microscope. He bestowed his most often heard gift upon our modern language for the body when he noted that the tangle of nerves and blood vessels at the back of the eye resembles a fishing net; today we call that part of the eye the retina, from the Latin rete, meaning “net.”

Herophilos also examined in meticulous detail the heart, the lungs, the liver, the stomach, the intestines… all of the major organs of the body, including the male and female reproductive organs. He made countless more discoveries along the way, from the duodenum — another modern name which he provided — to the ovaries and Fallopian tubes.

Both Herophilos and Erasistratus studied the process of respiration carefully, developing a detailed if inevitably flawed theory of its functioning and purpose. Ditto the process of vascular circulation. Erasistratus compared the pumping action of the heart to a blacksmith’s bellows — an apt analogy, all things considered. Herophilos and Erasistratus were the first to draw a distinction between arteries and veins, both of which systems they mapped with as much accuracy as one could possibly ask for given the tools at their disposal. They believed that arteries carried pneuma, which was either the vital spirit of life or blood infused with same, while veins carried ordinary or spent blood. Although this description doesn’t corral every detail — how could it so long before the discovery of oxygen? — it’s more or less spot-on as a broad overview of the cardiovascular system. Erasistratus conjectured, correctly, that blood vessels became too small to see at their extremities, almost two millennia before Antony van Leeuwenhoek would view capillaries under a microscope for the first time. Still more incredibly, he theorized, again correctly, that these capillaries were a means of interconnection between the systems of arteries and veins.

Both men were fascinated with the pulse, rightly sensing that it could tell them much about the health and even state of mind of the living subjects they examined; Herophilos went so far as to design and build his own water clock for measuring it. A precious fragment of his writing on this subject has survived: “[One] pulse seems to differ from [another] pulse in volume, in size, in speed, in vehemence, and in rhythm. From the fact that they differ in these respects, the pulse clearly at times becomes ‘fitting’ [i.e., in physiological harmony with body and environment], at times not fitting.”

Reading somewhat between the lines of what little we know about these two men, we can surmise that Erasistratus was more of a clinician than his older counterpart, more involved with seeing patients and applying his research to the curing of their ills. He and his followers cut cancerous tumors out of their patients’ bodies, marking some of the first attempts to surgically treat the disease that has killed more human beings down through history than any other.

Indeed, Alexandria became known all over the world as the premier center for cutting-edge medical treatments of all types. Long after the deaths of both Herophilos and Erasistratus, thousands of well-heeled sufferers would continue to visit the city in search of advice, healing, and last-minute death-defying miracles — this last for the most part fruitlessly, no doubt; in ancient times as today, there was only so much that even the cleverest doctor could do. Still, Alexandria was the only place in the world where most types of surgery were even attempted. For in other places the Hippocratic tradition continued to hold sway, with its attitude toward the body as too sacrosanct for the surgeon’s knife to cut into too deeply, even in the name of healing.

Although we know little of the specific cures and treatments that were employed at Alexandria, we can assume that they must have been more efficacious in many cases than the Hippocratic methods; why else would so many patients have streamed into the city? And yet in the long run it would be the school of Hippocrates rather than that of Herophilos and Erasistratus that survived — survived, in fact, for thousands of years to come. Even in Alexandria itself, the men of medicine who came after Herophilos and Erasistratus would continue to employ the knowledge those two had collected for a considerable length of time after their passing, but would add surprisingly little to this intellectual inheritance.

The reasons for this have much to do with Alexandrian social tensions which we’ll explore in more detail in later chapters. For now, though, let it be noted that Ptolemaic Egypt, like so many societies, grew more conservative as it aged, and the later members of its ruling dynasty grew less committed to the fearless pursuit of knowledge at all costs than their forefathers had been. The old prohibitions against violating the dead reasserted themselves; the later doctors of Alexandria were not provided with cadavers for dissection. For a time, they tried to maintain their empirical focus despite this lack, writing with palpable longing of the precious opportunity that had been accorded to their illustrious predecessors. But gradually the humoric approach to medicine that reigned supreme elsewhere took over once again even in Alexandria.

The second most famous ancient man of medicine is Galen, a Greek who lived and worked in Rome and, for a time, Alexandria as well during the second century AD. Like Hippocrates, Galen was astonishingly prolific, so much so that one has to suspect that much of what was published under his name was really the work of his followers. As little as 30 percent of his original corpus has come down to us, but that alone amounts to some 3 million words, or about 12,000 pages.

A brilliant man in his own right with an ego to match, evincing a withering scorn for virtually all of his contemporaries in medicine, Galen nevertheless slavishly deferred to Hippocrates, expressing no doubts whatsoever about the veracity of his theory of humorism. He believed Hippocrates to be a direct descendant of the mythological hero Heracles, who was himself a son of Zeus, making the good doctor literally divine. Hippocrates was in Galen’s view the personification not just of medical wisdom but of all the nobler virtues: humility, piety, justice, patriotism. Galen saw himself as a sort of prophet of this deity, interpreting and disseminating his message, clarifying its details by conducting extensive research of his own — although, what with the prohibition against human dissection being as strong as ever, none of it was conducted on human cadavers. And then, too, if ever his own observations appeared to contradict the theories of Hippocrates, it was of course the former that must be in error.

This unstinting worship of Hippocrates often placed Galen in strident disagreement with the writings of Herophilos and especially Erasistratus. It’s thus ironic to note that most of the details we have of those men’s lives and work have come to us courtesy of Galen — for, despite his disagreement with so many of their most fundamental conclusions, he was enough of a scholar to realize that their explorations of the physical body made them a unique and invaluable resource. And so, thanks to the fact that the original texts of Herophilos and Erasistratus are long lost, Galen in turn has become a unique and invaluable resource for us today as we try to understand the first incarnation of a recognizably modern approach to medicine.

Galen enjoyed immense esteem during his life; as a young man, he was the official physician of the gladiators who fought in the Coliseum, and when he died he was serving as the personal doctor of Emperor Septimius Severus. His public reputation combined with his prolificacy were enough to let his interpretation of Hippocratic medicine go unchallenged through the remainder of classical times and well beyond them. He was embraced by the burgeoning Muslim world while Europe was mired in the Middle Ages, and after the Renaissance he made his way back to Europe, where his writings were given additional luster as the forgotten wisdom of the ancients, profound in a way that more recent teachings could never be. The humors became an inescapable part of Renaissance consciousness — you’ll find them all over the plays of Shakespeare, for example — and the lancet, the small double-edged blade used for bleeding patients, became the universal symbol of the physician. Instead of debating the results of experiments, men of medicine wrestled over translations and interpretations of Galen’s holy texts, their unimpeachable source of received wisdom. When confronted with discrepancies between the things that Galen described and those they observed in their patients, doctors decided that the human body itself must have changed during the intervening years. It would take until the nineteenth century for the stranglehold of Hippocrates, as channeled through Galen, to be comprehensively broken and for the accepted best practices of medical research to return to something resembling the model of Herophilos and Erasistratus.

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(A full listing of print and online sources used will follow the final article in this series.)