‡ Physicians in the Middle Ages believed that four principal humors—blood, phlegm, yellow bile, and black bile—controlled body functions and that a person’s temperament resulted from the humor that was most prevalent in the body. Sanguine people were controlled by blood, phlegmatic people by phlegm, choleric people by yellow bile (also known as “choler”), and melancholic people by black bile (also known as “melancholy”).
