‘Uroscopy’ (the examination of urine) was a standard diagnostic tool for most early modern physicians. Having just come from inside the patient’s body, urine was understood to contain vital information about what was happening in there.
According to early modern medical theory, every human body contained a mixture of four liquids known as the humours: blood, black bile, yellow bile, and phlegm. Health was preserved by keeping these humours in proportion to one another; humoral imbalance led to disease. So if you had too much black bile in your body (a cold, dry, heavy humour), you might be consumed by dark, heavy thoughts, or suffer from constipation.
A healthy body prevented imbalance by getting rid of excess humours via all of its exit routes (the nostrils, the mouth, the bladder, and so on). Urine was understood to contain excreted humours, so its colour and quality showed what kind of state they were in. Physicians looked at, smelled (and reportedly sometimes tasted) their patients’ urine, and consulted colour-coded uroscopy wheels to help them to interpret its contents. So if you have to give a urine sample this Christmas, remember it could be worse!
Featured image: (C) Museum of London. Reproduced with Museum’s permission. https://collections.museumoflondon.org.uk/online/object/119061.html