The Greatest Benefit to Mankind. Roy Porter

The arteries stemmed from the heart; the veins, by contrast, Praxagoras believed, arose from the liver, their function being to carry the blood, created from digested food, to the rest of the body. The combining of blood and pneuma generated innate heat.

      Herophilus practised medicine in Alexandria under the first two Ptolemies, apparently dissecting human cadavers in public. He wrote at least eleven treatises. Three were on anatomy: it was he who discovered and named the prostate and the duodenum (from the Greek for twelve fingers, the length of gut he found). He also wrote on the pulse as a diagnostic guide, on therapeutics, ophthalmology, dietetics and midwifery, and a polemic ‘Against Common Notions’.

      Continuing Praxagoras’ differentiation between veins and arteries, Herophilus pointed out that the coats of the arteries were much thicker than those of the veins. Unlike Praxagoras, however, he held that the arteries were filled not with air but with blood. His most striking dissection feat was the delineation of the nerves. Demonstrating their source in the brain enabled him to conclude that they played the part preceding thinkers had ascribed to the arteries: transmitting motor impulses from the soul (intelligence centre) to the extremities. Rebutting Aristotle, he thus established the importance of the brain, distinguishing the cerebrum from the cerebellum and displaying the nerve paths from the brain and spinal cord. His description of the rete mirabile, the network of arteries at the base of the brain, shows he dissected animals as well as human corpses, since it does not exist in humans.

      Herophilus also devoted attention to the liver and to ‘veins’ ending in glandular bodies which, he believed, nourished the intestines but did not pass to the liver. These ‘veins’ must have been the lacteals or chyle-vessels, whose function was explained by Aselli some two thousand years later. Praxagoras’ interest in the pulse was taken up by Herophilus. Identifying pulsation as derived from the heart, he developed a speculative classification of different classes of pulse, on the basis of magnitude, strength, rate and rhythm, and is reputed to have tried to calculate pulse by means of a portable water clock.

      Erasistratus is far more nebulous and controversial. He supposedly studied medicine in Athens before settling in Alexandria, where he experimented on living animals and perhaps humans. His main discoveries concerned the brain which, like Herophilus but unlike Aristotle, he regarded as the seat of intelligence. He too distinguished the cerebrum from the cerebellum, described the cerebral ventricles within the brain, and distinguished between motor and sensory nerves. Nerves were hollow tubes containing pneuma (‘spirit’ or air), which transmitted sensation, enabling muscles to produce motion.

      In a tradition going back to Alcmaeon, he also believed that pneuma alone – not blood – was contained in the arteries: it was taken in through the lungs, piped to the heart (which he compared to a blacksmith’s bellows) and then pumped out to fill the arteries. Blood by contrast was formed in the liver and carried by the veins. Why then was it blood that spurted from a cut artery? It was drawn in, Erasistratus reasoned, because nature abhorred a vacuum.

      Erasistratus has been portrayed as an early mechanist, because of his model of bodily processes: digestion for instance involved the stomach grinding food. Yet this may be a caricature created by Galen for polemical purposes. Even Galen applauded his remarkable investigations of brain anatomy, while being scathing about his other views, particularly the idea that the arteries contained air alone. Erasistratus was clearly a radical; for want of evidence, he is also a riddle.

      In the following centuries medicine, like philosophy, split into sects: Hippocratics, Herophileans and Erasistrateans were later challenged by the Pneumatists, who regarded pneuma as a fifth element which flowed through the arteries, sustaining vitality. All such sects were later given the label of ‘rationalist’, to signal their antagonism to the Empirics, a band of physicians led by Heraclides of Tarentum (fl. 80 BC), who spurned medicine based on speculation about hidden disease causes in favour of one grounded on experience. What mattered, Empirics claimed, was not cause but cure, and so they collected case histories and remedies. Knowledge, they held, could be better gained at the bedside than by dissection; what counted was which drugs worked. Hence theory must bow to experience – a claim later opponents, principally Galen, rejected as shallow.

      MEDICINE IN THE ROMAN ERA

      Greek medicine spread throughout the Mediterranean, not least to Italy, where the southern cities shared Greek culture – doctors at Elea, Tarentum and Metapontum were like their colleagues in Athens or Alexandria. Rome was different. No-nonsense Roman tradition held that one was better off without doctors. Romans had no need of professional physicians, insisted authors like Cato (234–149 BC), for they were hale and hearty, unlike the effete Greeks. ‘Beware of doctors’, he cried; they would bring death by medicine. ‘It is our duty, my young friends’, reflected Cicero (106–43 BC), ‘to resist old age; to compensate for its defects by a watchful care; to fight against it as we would fight against disease; to adopt a regimen of health; to practise moderate exercise; and to take just enough food and drink to restore our strength and not to overburden it.’

Romans enjoyed bad-mouthing Greek physicians: according to Pliny (AD C. 23–79), who deplored the recent influx of ‘luxury’ and worthless Greek physicians, an inscription, echoing Alexander, was now sprouting up on monuments in Rome: ‘It was the crowd of physicians that killed me.’^*

      Romans liked to think healing should take place in the family, under the care of the paterfamilias, who would dispense herbs and charms. Cato, who dosed his family on cabbage soup, derided Greek physicians as the antithesis of Roman virtue: they were frauds who cheated patients and ‘have sworn to kill all barbarians with their drugs’. Prejudices such as these may explain the tardy emergence of native Italian physicians.

      The contrast drawn by Cato and Pliny between homespun healing and hellenistic speculation was xenophobic prejudice. The real difference was not between Greece and Rome, but between rustic medicine and that of the big city. Greek medicine arrived with city life as Rome was hellenized. For long professional doctors (medici) in Italy were immigrants; the first noted Roman practitioner, Asclepiades (c. 120–30 BC), was a native of Bithynia in Asia Minor. Modified by his pupil, Themison of Tralles (fl. 70 BC), his doctrines gave rise to the Methodist sect. Its physiology was based not upon the Hippocratic four humours but upon corpuscular theory. In the body the proper arrangement of atoms and their intermediate pores produced health; any obstruction or undue looseness led to disease, so health was the balance between tension and relaxation. This atomist physiology enabled the doctor to reduce diagnosis to the ‘common conditions’ – the constricted, the lax and the mixed – deducible from visible symptoms. Hence the Asclepiadean or Methodist doctor did not need intimate familiarity with the life history of his patients: plain symptoms were sufficient. Cure was by opposites, enlarging narrow pores and reducing large ones, for which Asclepiades promoted massage, exercise and cold-water bathing. His slogan cito, tute et jucunde – swiftly, safely, sweetly – is reflected in his rejection of heroic bleeding, his preference for gentle medicines, his prescription of wine and his stress on convalescence. Self-styled Asclepiadeans nourished for three centuries, though their rejection of philosophical reasoning riled Galen, who sneered at their pre-packed therapies.

      More light on the infiltration of Greek medicine into Rome is offered by the physician Scribonius Largus (c. AD 1–50). Born in Sicily, he probably learned his craft from hellenistic practitioners on the island, and in AD 43 he accompanied the Emperor Claudius on his campaign to subdue Britain. His sole surviving medical text is a Latin handbook of drug recipes, the Compositiones. It contains 271 recipes for conditions from headache to gout, all claimed of proven value. In his preface, Scribonius set out his views on medical ethics, becoming our earliest witness to the use of the Hippocratic oath. How widespread was his endorsement of a professional ethic is unclear, for no other ancient writer made such an open commitment.

      The early empire brought the first surviving survey of medicine in Latin. An encyclopaedic compilation, Celsus’ Artes [The Sciences] originally contained at least twenty-one books, of which only the eight devoted to medicine survive in full. No professional physician but