People in the seventeenth century, following the teachings of Galen in the sixteenth century and in a tradition stretching back to Greek and Roman times, believed that the state of the human body was controlled by the four ‘Humours’:

Choler (yellow bile), Melancholy (black bile), Phlegm and Blood.

This theory was closely related to the theory of the four elements, earth, fire, water and air; earth predominantly present in the black bile, fire in the yellow bile, water in the phlegm, and all four elements present in the blood

In the body, the ebbs and flows of hot and cold, moist and dry humours were constantly reshaping the health of mind and body, and imbalance generated ill health.  The task of Physic (and indeed of healthy living in general) was to monitor and regulate these ebbs and flows, taking into account a person’s predominant humour or complexion, their habits of life (food, drink, exercise, study, sleep, sex), their age, the time of year, and so forth and to correct excess and deficit in order to arrive as near as possible to an ideal balance.

Thus where cold and moist humours predominated, medication and diet aimed to reinforce the warm and dry; hot and spicy foods, for example or particular herbs classified as hot.  Where the inner system seemed turbulent and generated an excess or corrupted form of a particular humour, the balance would be restored by attempting to take it out: purges, vomits and bleeding were central to medical practice in treating both mind and body.

The balance of the humours was influenced by the air, by the senses and by mood, as well as by diet; the reason for attending to all these different aspects was thus strictly speaking physical, even if they appear to be aimed at psychological rather than bodily conditions.

For example, it was believed that Melancholia comes from ‘an evil melancholy humour’.  If cold humour perturbs the brain, he should be purged and the feet kept warm.

Blood was believed to be produced exclusively by the liver.  Excess of yellow bile was thought to produce aggression, and excess anger reciprocally gave rise to liver derangement and imbalances in the humours.  The word “melancholy” derives from Greek μέλαινα χολή (melaina kholé) meaning ‘black bile’, from the belief that an excess of black bile caused depression.  Phlegm was thought to be associated with apathetic behaviour, as preserved in the word “phlegmatic”.

The phlegm of humourism is not the same thing as phlegm as it is defined today.  Modern medicine realised that two of these groups were imaginary.  Phlegm or pituitary secretion, which was believed in the seventeenth century to be the cause of tumours, of chlorosis, of rheumatism, and cacochymia¹the abundance and excess of any ill humor, provided it is only one in excess simply does not exist.

The following table shows the four humours with their corresponding elements, seasons, sites of formation, and resulting temperaments alongside their modern equivalents.

A knowledge of these associations will help you to describe the way people thought in the seventeenth century.  It also helps to explain some of the medical and herbal practices.