Galen

Galen of Pergamum (ad 129–216), the most influential and prolific of all the physicians of antiquity, produced a philosophically sophisticated synthesis of earlier medical theories of the body that was dominant until the seventeenth century. The son of a rich architect, he began his medical career in ad 145–6; due to his family's wealth, he was able to train in his home town of Pergamum, and then at Smyrna and Alexandria for the unusually long period of ten years. From ad 157 he worked as physician to the gladiators in Pergamum, where he claims to have significantly reduced the death rate, before moving to Rome in ad 162. He left Rome in ad 165, alleging that other physicians in Rome were jealous of his success. His abrupt departure is, however, more likely to have been due to an attempt to avoid the smallpox epidemic which hit Rome soon after. On his return in ad 169 he became doctor to the emperor Marcus Aurelius and his family, although he managed to avoid accompanying the imperial household on a dangerous campaign in Germany by claiming that he could not go on religious grounds.

His work claimed to continue the tradition of Hippocrates, the fifth-century (bc) doctor to whom a large and disparate corpus of ancient Greek medical texts was attributed. Galen attacked other doctors of the time for failing to understand what Hippocrates really meant, but this is merely rhetoric; the ‘Hippocrates’ Galen gives us is one created in the image of Galen. Galen's very personal judgements of which treatises in the Hippocratic corpus were the ‘genuine works’ of Hippocrates have influenced all subsequent work on that corpus.

Galen's model of the body combined ideas from Hippocratic medicine, Plato, and Aristotle. The scientific logic is Aristotelian. The notion of three body systems – governed by the heart, the brain, and the liver respectively — comes from Plato, the fourth-century (bc) Athenian philosopher whose dialogue, the Republic, divides the soul into three parts, namely reason, ‘spirit’ or emotion, and desire. From some Hippocratic texts, Galen adopted the idea of four humours, or body fluids, the balance between which is necessary for health, and used these as the basis of a more far-reaching system in which each humour can be tied to a quality, a season, and a period of life. Blood, the warm and moist fluid, is associated with spring and predominates in childhood; yellow bile is warm and dry, and is associated with summer and youth; black bile, thought to be cold and dry, is associated with autumn and adulthood; phlegm, cold and moist, is the humour of winter and of old age. Healing for Galen involved the application of general principles to specific, individual cases. The maintenance of the correct balance amongst the four humours in any individual body constitutes health, while imbalances can be corrected by attention to air, food and drink, exercise, sleep, repletion and evacuation, and emotion.

In the Galenic body, heat plays a central role: the three ‘faculties’ of the body are, in ascending order of importance, the nutritive, the vital, and the logical faculties. In the nutritive sphere, food is partially cooked by the stomach, and then moved in the form of chyle to the liver where it is heated further. The portal vein then carries chyle to the liver, where further heat refines it into blood and adds the ‘natural spirit’. The liver draws in the chyle by ‘attraction’, and other parts of the body then attract to themselves for nourishment most of the ‘venous blood’ which the liver makes. Some fluid, however, travels on, by way of the vena cava, to the heart, where in a further stage of cooking it takes in ‘vital spirit’ to become lighter and thinner, as ‘arterial blood’. This transmits to other parts of the body the vital faculty, which gives warmth and the power of growth and can be measured through the pulse. The brain gives the blood psychic pneuma, which is distributed through the body by means of the nerves; with the brain is associated the logical faculty — the power of thought, will, and choice. In the Galenic body, veins, arteries, and nerves are thus separate systems with different functions. Veins originate in the liver, and carry food to nourish the body, while arteries proceed from the heart and carry vital spirit, although they also contain some blood.

Galen believed that medicine required both practical and theoretical elements. He claimed that he dissected every day, sometimes in public, even asking members of the audience to nominate the part to be dissected; his experiments on the spinal cord, in which he demonstrated that muscles are controlled by nerves, are still famous. However, these experiments were performed on animals, particularly pigs and apes, rather than on humans. Some parts of the Galenic body, which were questioned — and their existence eventually disproved — in the Renaissance, derive from incorrect analogies between animals and humans. The ‘rete mirabile’ at the base of the skull is one example. Other errors, such as the ‘invisible pores’ which Galen insisted must be present in the interventricular septum of the heart, were logically necessary to his model of the body.

Galen was a highly prolific writer, whose works included not only philosophically and logically argued treatises on the body but also texts on the practical side of being a doctor in the Roman world. He insisted that his enemies spread malicious rumours about him, including the slander that his extraordinary success in prognosis was due to magical rather than medical skills. On one famous occasion, described in his treatise On Prognosis, he detected that a woman's pulse rate increased when the name of the man she loved was mentioned. Galen himself attributed his prognostic skills to following Hippocratic principles based on reading bodily signs and being aware of all relevant features of the patient's life.

Helen King