In ancient Greece, physicians used to believe that four humors, or juices, of the body were ways for the human body to maintain health. These were fluids of the nose and pancreas, as well as bile and blood. An excess of any of these was believed to cause disease, so when the nose ran, it was an indication of excess bodily fluids being released. The old practice of bloodletting, the release of a large portion of the body's blood, became a common remedy to illnesses.
By the 18th and 19th centuries, this practice had went to extremes. When the doctor prescribed this treatment, the actual procedure was performed by local barbers. After the patient had their blood drained, if they were not yet cured, more blood would be released. Obviously, this would result in death. The used bandages would then be hung on a post or pole outside the building, where they would blow around the pole in the wind, leaving red stripes like a candy cane.
In time, this became a symbol for barber shops. The red stripes were meant to signify blood, the white stripes signified the bandages. In relatively recent years, the blue stripes were added and some believe these may represent the blue colour of veins, perhaps matched with the red colour of arteries. The brass basin on top of the barber pole represented a container for leeches, which were sometimes used in place of bloodletting, and the bottom bowl was that which held the patient's blood.
Kind of makes you cringe at the thought of a two-bit shave with a straight-razor.
Seeley's Essentials of Anatomy and Physiology, 7th Edition - VanPutte, Regan and Russo
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