Back before the time when barbers were barbers and doctors were doctors, and there were electric razors and swivel chairs, barbers had another, darker role to play besides shaving beard bristles and cutting overgrown hair. Back then they also hacked people's arms open [All right, so they didn't hack people's arms open. They made incisions in the arms. But that just doesn't make it any less freaky, does it? ] .

To understand this horrifying practice, we must first go back further in time to the golden age of the Greeks. Hippocrates, the father of modern medicine , was the first to conceive the notion that disease had a rational cause and therefore a rational cure. From borrowed knowledge he gathered from China and India, he stitched together the concept that bodies had four types of humours: blood, phlegm, black bile, and yellow bile. He extrapolated from this knowledge his theory that disease caused imbalance in these fluids - others had thought that it was the imbalance of these humours that caused disease. Hippocrates reckoned that it was the bad diet, absence of exercise, poor air and injuries that were responsible for illnesses. (He was right about this.