Until the early 18th century, blood was thought of as the moist, well-tempered “sap that fills the blood vessels and is thought [by physicians] to consist of four particular humors: phlegm, yellow and black bile, and the blood proper” [1]. In the view of humoralism, the humors with their associated qualities (blood: warm, moist; yellow bile: warm, dry; phlegm: cold, moist; black bile: cold, dry) are produced by digestion (Latin coctio, literally “cooking”) of food; they are always present…