How do we know what’s wrong with our bodies? We may be aware of symptoms – of pains, twinges, immobility. We can also aware of some of our bodily fluids: our saliva, sweat, urine, menses or semen. Sometimes a fluid which is clearly abnormal emerges from an orifice or a wound. If we seek medical treatment, our blood or urine can be tested for what we now know are its constituent parts, or we can undergo a range of types of visualisation (X rays, CT scans, PET or MRI), showing us structures of which we would otherwise be unaware. Our tissue can be examined at microscopic level.
In the past, with no way of seeing into the body, an entirely different approach grew up. It was possible to get answers by touching the body from outside, but a far more comprehensive picture could be gained from the visible fluids of the body, seen as clues to the invisible fluids. What were these fluids? People often characterise the medicine of the ancient worlds, the Byzantine worlds, the medieval and early modern worlds as ‘humoral medicine’. What they usually mean is that the four humours – blood, phlegm, yellow bile and black bile – were regarded as the key constituents of the body and the main causes of disease. Influenced by what someone ate and drank, but also by their age and their environment – these four fluids were identified in the Hippocratic text On the Nature of Man as the focus of medicine. In balance lay health: in imbalance, disease. Blockages in the body could prevent the free flowing of the humours.
In the second century CE, Galen singled out On the Nature of Man among the many fourth century BCE medical writings associated with the name of Hippocrates, giving it the status of what would later be called a ‘genuine work’, seeing a section of it as a work from the hand of the great Father of Medicine himself. Whatever we now think of that claim, the four humours settled down as the centrepiece of medicine. In spring, and in the young, the hot and wet humour of blood predominates, the balance of humours shifting as the seasons turn and as the person’s life continues, until in winter the body is dominated by the cold wet humour of phlegm.
It’s a powerful model precisely because it’s so inclusive: it covers so many aspects of human experience. In some forms, it also covers character: most famously, if you are melancholic, you are constitutionally dominated by the humour of black bile – melan-chole. And this inclusiveness makes it both satisfyingly complete but also satisfyingly difficult to think with. You can do so much on your own, but you really need a physician to sort you out! That’s quite convenient for the medical profession! The four humours were tied to the four elements – earth, air, fire and water – and to the four qualities – hot, cold, wet and dry. A physician needs to take into account so many factors: the patient’s age, the season, the temperament, the diet and lifestyle of the patient, and features of the environment in which the patient lives.
But it’s also a powerful model because it is so sensory. Colour goes far beyond the basic red blood, white phlegm, and yellow or black bile. Blood itself can be different colours according to the other humours it carries. Green or yellow or purple are signs of imminent death: black is particularly bad. In looking at urine – a fluid which moved centre stage in late antiquity, as an indicator of what the humours were doing – a veritable rainbow of colours were distinguished. These colours pointed to the part affected as well as to the humoral imbalance. Clarity and murkiness were also important indicators.
Smell was important in diagnosis but also in treatment – as the humoral system developed and spread into the Arabic world, even more strong-smelling herbs like fennel, and spices like ginger and cloves and nutmeg and cardamom, were added to the arsenal of drugs. The production and balance of the humours could be altered by drinks, by food, by clysters, by enemas, or by external plasters. The aim was often to use hot and cold, wet and dry, to balance a hot humour with a cold treatment, for example. Ointments and oils applied to the body were also used. So was bathing.
Humoral medicine, then, is superficially simple. Four humours, and health as balance. But it rapidly becomes complex, requiring a physician rather than being simply for the patient to work out. I sometimes wonder just what it felt like to be a patient in this system. Were people more aware of their body’s fluids? If you believed that health was about the proper production of humours, how far would you think about the claims for which fluids the things you ate and drank were likely to produce? Is that different from us thinking about the vitamins, minerals, and calories of what we are eating? If you believed that the flow of humours could be obstructed, how would that make you think about a sudden pain in your body?