RE: Black bile
Black bile (kole melaina), together with blood, phlegm, and yellow bile, was one of the four humors that were responsible for health and disease according to Hippocratic medicine. Phlegm was most probably what we call mucus, yellow bile what we call bile, and black bile was an imaginary humor that probably owed its existence to the observation that sometimes, following gastrointestinal or urinary hemorrhages, vomit, feces, and urine may become black. We do not know exactly how the idea of black bile arose. As systematic dissections were not practiced, ancient notions of the composition of the body were based on observations made in the kitchen, at the sacrificial altar, on the battlefield, and on examination of wounds and body effluents. Occasionally, black material was observed in the conditions mentioned above (old coagulated blood also often looks quite black) and, most likely, as it could not have been identified with any of the other three humors, another one, a black one, was imagined and called "black bile." For a bibliography of original sources, see my History of Medicine, Volume II (Greek Medicine), pp. 272ff. Plinio Prioreschi