four temperaments

thumb|16th-century German illustration of the four humors: Flegmat (phlegm), Sanguin (blood), Coleric (yellow bile) and Melanc (black bile), divided between the male and female sexes Humorism, the humoral theory, or humoralism, was a system of medicine detailing a supposed makeup and workings of the human body, adopted by Ancient Greek and Roman physicians and philosophers.

Humorism began to fall out of favor in the 17th century and it was definitively disproved with the discovery of microbes.