Bloodletting

Bloodletting is the deliberate withdrawal of blood from a patient to prevent or cure various illnesses.

For over 2,000 years, it served as one of the most common medical practices performed by surgeons and physicians. This long history spans from antiquity through the late 19th century in Europe. While it was once a standard treatment for almost any ailment, modern medicine has largely abandoned it. Today, the traditional practice is classified as a pseudoscience because it is not based on scientific evidence. However, modern medical procedures like phlebotomy still involve drawing blood, but for very different purposes such as laboratory analysis or blood transfusions.

The practice was rooted in an ancient medical theory regarding the four humors. These humors were bodily fluids that had to remain in a specific balance to maintain health. The four humors included blood, phlegm, black bile, and yellow bile. These fluids were thought to correspond to the four Greek classical elements: air, water, earth, and fire. Physicians believed that an imbalance, such as an overabundance of blood called plethora, caused disease. Symptoms of plethora were thought to include fever, headache, and apoplexy. To restore balance, a doctor would remove the excess blood to treat the patient.

Different methods were used to withdraw the blood depending on the goal. Phlebotomy, or venesection, involved opening one or more large external veins, like those in the neck or forearm. Arteriotomy was another method where an artery was punctured, though this was usually limited to the temples. Doctors also practiced scarification, which targeted superficial vessels. They might use a syringe, a glass cup with heated air to create a vacuum, or a specialized tool.

This tool was called a scarificator. It was a brass case containing a spring-loaded mechanism with steel blades. When triggered, the blades snapped out in a circular motion through slits in the cover.

Another common method involved using leeches to draw blood from the skin.

Medical history shows many different cultures utilized these techniques. In Ancient Egypt, evidence suggests bloodletting by scarification was an accepted practice. Some accounts suggest Egyptians may have based this on observations of hippopotamuses. In Greece, the physician Hippocrates mentioned the practice in the 5th century BC. Later, the Roman physician Galen became a major influence by advocating for physician-initiated bloodletting. Galen discovered that both veins and arteries were filled with blood. He believed blood was created and then used up rather than circulating. He also developed a complex system to decide how much blood to remove based on a patient's age, the season, and even the weather.

During the Middle Ages, bloodletting remained popular and was even guided by the stars. Bleeding charts showed specific sites on the body that aligned with the zodiac and planets. Islamic medical authors also advised bloodletting, particularly for treating fevers. By the 18th century, the practice became part of "heroic medicine," which was a collection of traumatic and destructive medical treatments. This era saw the rise of the distinction between physicians and barbers. While physicians recommended the treatment, barbers often performed the actual bleeding. This history is even reflected in the red-and-white-striped barber poles seen today. The red symbolizes blood, while the white symbolizes bandages.

The scale of bloodletting in the 19th century was immense. In the 1830s, France imported about 40 million leeches every year for medical use. England imported 6 million leeches annually from France alone during the following decade. The practice was also widespread in the United States. In 1799, George Washington was bled heavily for a throat infection. In a single ten-hour period, doctors withdrew between 124 and 126 ounces of his blood. This was roughly 3.75 liters of blood before his death. Such intense treatments were common because doctors believed it was better to provide a treatment than nothing at all.

The decline of bloodletting began with the rise of scientific medicine. In the 1830s, Pierre Charles Alexandre Louis used a method called la méthode numérique to study pneumonia patients. He demonstrated that phlebotomy was entirely ineffective for treating pneumonia and various fevers. Despite this evidence, many physicians resisted his findings because they preferred traditions validated by their own experience. Eventually, the humoral theory fell out of use. Today, we only use therapeutic phlebotomy for specific conditions like hemochromatosis or polycythemia vera. In these cases, drawing blood helps reduce the number of red blood cells in the body.