The female protagonist of my current novel is a bit of a healer. She has learned all she can about medicine from people who are willing to share what they know and from the books she has to hand. Since she’s betrothed to the son of an earl, she lives in a large household and can see how the sick are looked after. She can also practise on them if the circumstances allow.
In reality, however, physicians were unlikely to share what they knew beyond their families and apprentices, and a woman who was to be married to the son of an earl would see very little of the father-in-law’s household.
There was a vast gulf between those who studied medicine in the universities and those who practised it in towns and villages. Universities trained up men to serve in royal and noble households. They read and discussed ancient and modern writings about medicine as part of their studies, but it’s questionable how much practical training they received.
Practical medicine was left to physicians, midwives, surgeons, apothecaries, dentists and barbers. You didn’t have to be literate to be a good physician. All you had to do was to watch and learn from someone who knew more than you did.
A physician’s main aim in caring for the sick would have been to ensure that their humours were in balance with one another.
The skin wasn’t considered to be an impenetrable barrier to the natural elements: earth, air, water and fire. These four interacted with the body. Each of them also had properties relating to heat and moisture. Earth was dry and cold, air hot and wet, water wet and cold, and fire hot and dry. As well as the external agents, the body was affected internally by blood, phlegm, yellow bile and black bile. These were the humours and a person could only be well if they were kept in balance. There were four of them to match the number of external elements, not because it made any real sense medically.
If someone was thought to have too much of a particular humour, they would be purged. Excessive heat could be removed by the use of cooling herbs. Fiery spices could drive out the cold. The idea of the humours came from Ancient Greece. Aristotle particularly valued hot, thin, clear blood, which he said led to courage and intelligence.
Phlegm was any colourless or white secretion that wasn’t semen or milk. It was mostly associated with the brain, but it was also connected with blood.
Yellow and black bile were said to come from the gall bladder, but were essentially the same thing. They were believed to purify the blood when they were functioning properly.
Blood was considered to be both a single substance and something that was mixed with the other three humours.
It’s not surprising, then, that blood-letting could be considered a cure for certain conditions. Nor is it surprising that the patient’s blood, urine or faeces were examined more closely than the patient himself. The only way a physician could discover what was wrong with his patient was by looking at what the patient secreted to learn what he could about the balance of the humours.
Medieval Bodies by Jack Hartnell
Medieval and Early Renaissance Medicine by Nancy G. Siraisi