Bloodletting (or blood-letting) is the withdrawal of blood from a patient to prevent or cure illness and disease. Bloodletting, whether by a physician or by leeches, was based on an ancient system of medicine in which blood and other bodily fluids were regarded as "humours" that had to remain in proper balance to maintain health. It is claimed to have been the most common medical practice performed by surgeons from antiquity until the late 19th century, a span of over 2,000 years. In Europe, the practice continued to be relatively common until the end of the 18th century. The practice has now been abandoned by modern-style medicine for all except a few very specific medical conditions. It is conceivable that historically, in the absence of other treatments for hypertension, bloodletting sometimes had a beneficial effect in temporarily reducing blood pressure by reducing blood volume. However, since hypertension is very often asymptomatic and thus not diagnosable without modern methods, this effect was unintentional. In the overwhelming majority of cases, the historical use of bloodletting was harmful to patients. Today, the term phlebotomy refers to the drawing of blood for laboratory analysis or blood transfusion. Therapeutic phlebotomy refers to the drawing of a unit of blood in specific cases like hemochromatosis, polycythemia vera, porphyria cutanea tarda, etc., to reduce the number of red blood cells. The traditional medical practice of bloodletting is today considered to be a pseudoscience. Passages from the Ebers Papyrus may indicate that bloodletting by scarification was an accepted practice in Ancient Egypt. Egyptian burials have been reported to contain bloodletting instruments. According to some accounts, the Egyptians based the idea on their observations of the hippopotamus, confusing its red secretions with blood and believing that it scratched itself to relieve distress. In Greece, bloodletting was in use in the fifth century BC during the lifetime of Hippocrates, who mentions this practice but generally relied on dietary techniques. Erasistratus, however, theorized that many diseases were caused by plethoras, or overabundances, in the blood and advised that these plethoras be treated, initially, by exercise, sweating, reduced food intake, and vomiting. Herophilus advocated bloodletting. Archagathus, one of the first Greek physicians to practice in Rome, also believed in the value of bloodletting. "Bleeding" a patient to health was modeled on the process of menstruation. Hippocrates believed that menstruation functioned to "purge women of bad humours". During the Roman Empire, the Greek physician Galen, who subscribed to the teachings of Hippocrates, advocated physician-initiated bloodletting. The popularity of bloodletting in the classical Mediterranean world was reinforced by the ideas of Galen, after he discovered that not only veins but also arteries were filled with blood, not air as was commonly believed at the time. There were two key concepts in his system of bloodletting. The first was that blood was created and then used up; it did not circulate, and so it could "stagnate" in the extremities. The second was that humoral balance was the basis of illness or health, the four humours being blood, phlegm, black bile, and yellow bile, relating to the four Greek classical elements of air, water, earth, and fire respectively. Galen believed that blood was the dominant humour and the one in most need of control. In order to balance the humours, a physician would either remove "excess" blood (plethora) from the patient or give them an emetic to induce vomiting, or a diuretic to induce urination. Galen created a complex system of how much blood should be removed based on the patient's age, constitution, the season, the weather and the place. "Do-it-yourself" bleeding instructions following these systems were developed. Symptoms of plethora were believed to include fever, apoplexy, and headache. The blood to be let was of a specific nature determined by the disease: either arterial or venous, and distant or close to the area of the body affected. He linked different blood vessels with different organs, according to their supposed drainage. For example, the vein in the right hand would be let for liver problems and the vein in the left hand for problems with the spleen. The more severe the disease, the more blood would be let. Fevers required copious amounts of bloodletting. The Talmud recommended a specific day of the week and days of the month for bloodletting, and similar rules, though less codified, can be found among Christian writings advising which saints' days were favourable for bloodletting. During medieval times bleeding charts were common, showing specific bleeding sites on the body in alignment with the planets and zodiacs. Islamic medical authors also advised bloodletting, particularly for fevers. It was practised according to seasons and certain phases of the Moon in the lunar calendar. The practice was probably passed by the Greeks with the translation of ancient texts to Arabic and is different than bloodletting by cupping mentioned in the traditions of Muhammad. When Muslim theories became known in the Latin-speaking countries of Europe, bloodletting became more widespread. Together with cautery, it was central to Arabic surgery; the key texts Kitab al-Qanun and especially Al-Tasrif li-man 'ajaza 'an al-ta'lif both recommended it. It was also known in Ayurvedic medicine, described in the Susruta Samhita. Even after the humoral system fell into disuse, the practice was continued by surgeons and barber-surgeons. Though the bloodletting was often recommended by physicians, it was carried out by barbers. This led to the distinction between physicians and surgeons. The red-and-white-striped pole of the barbershop, still in use today, is derived from this practice: the red symbolizes blood while the white symbolizes the bandages. Bloodletting was used to "treat" a wide range of diseases, becoming a standard treatment for almost every ailment, and was practiced prophylactically as well as therapeutically. Diagram of scarificator, showing depth adjustment A number of different methods were employed. The most common was phlebotomy, or venesection (often called "breathing a vein"), in which blood was drawn from one or more of the larger external veins, such as those in the forearm or neck. In arteriotomy, an artery was punctured, although generally only in the temples. In scarification (not to be confused with scarification, a method of body modification), the "superficial" vessels were attacked, often using a syringe, a spring-loaded lancet, or a glass cup that contained heated air, producing a vacuum within (see fire cupping). There was also a specific bloodletting tool called a scarificator, used primarily in 19th century medicine. It has a spring-loaded mechanism with gears that snaps the blades out through slits in the front cover and back in, in a circular motion. The case is cast brass, and the mechanism and blades steel. One knife bar gear has slipped teeth, turning the blades in a different direction than those on the other bars. The last photo and the diagram show the depth adjustment bar at the back and sides. Leeches could also be used. The withdrawal of so much blood as to induce syncope (fainting) was considered beneficial, and many sessions would only end when the patient began to swoon. William Harvey disproved the basis of the practice in 1628, and the introduction of scientific medicine, la méthode numérique, allowed Pierre Charles Alexandre Louis to demonstrate that phlebotomy was entirely ineffective in the treatment of pneumonia and various fevers in the 1830s. Nevertheless, in 1838, a lecturer at the Royal College of Physicians would still state that "blood-letting is a remedy which, when judiciously employed, it is hardly possible to estimate too highly", and Louis was dogged by the sanguinary Broussais, who could recommend leeches fifty at a time. Some physicians resisted Louis' work because they "were not prepared to discard therapies 'validated by both tradition and their own experience on account of somebody else's numbers'." Bloodletting was used to treat almost every disease. One British medical text recommended bloodletting for acne, asthma, cancer, cholera, coma, convulsions, diabetes, epilepsy, gangrene, gout, herpes, indigestion, insanity, jaundice, leprosy, ophthalmia, plague, pneumonia, scurvy, smallpox, stroke, tetanus, tuberculosis, and for some one hundred other diseases. Bloodletting was even used to treat most forms of hemorrhaging such as nosebleed, excessive menstruation, or hemorrhoidal bleeding. Before surgery or at the onset of childbirth, blood was removed to prevent inflammation. Before amputation, it was customary to remove a quantity of blood equal to the amount believed to circulate in the limb that was to be removed. There were also theories that bloodletting would cure "heartsickness" and "heartbreak". A French physician, Jacques Ferrand wrote a book in 1623 on the uses of bloodletting to cure a broken heart. He recommended bloodletting to the point of heart failure (literal). Bloodletting was also popular in the young United States of America, where Benjamin Rush (a signatory of the Declaration of Independence) saw the state of the arteries as the key to disease, recommending levels of bloodletting that were high even for the time. George Washington asked to be bled heavily after he developed a throat infection from weather exposure. Within a ten-hour period, a total of 124–126 ounces (3.75 liters) of blood was withdrawn prior to his death from a throat infection in 1799.