[Blood as a clinical sign in the corpus hippocraticum]

Blood as a clinical sign has a key role throughout the Corpus Hippocraticum: as the most prominent and visible of the four fluids which make up the humoral system, it recurs quite often as a crucial cue for prognosis. This paper collects and classifies some of the most important loci in the Corpus which are devoted to describe and interpret the different qualities of human blood and the ways it can be altered and corrupted; this recollection clearly shows the systematic character of the Hippocratic treatment of blood and its function within the whole theoretical building of CH. The status of blood within the evolution of medical theories in the Antiquity is also scrutinized, especially as far as the polemics on encephalocentrism vs haemocentrism is concerned. The nature of observations about the manifestation of pure and altered blood sheds light on the epistemological status of clinical observation within the clinical methods of the Hippocratic school.