“A cure-all remedy” in times past was to apply leeches to suck out the blood. Most households kept a supply on hand. In 1837, one London hospital used 96,000 leeches on 50,557 patients.
If you have ever been attacked by a blood-sucking leech, you will know that a surprising and possibly disturbing element is that only after the parasite released its hold did you realize you were its victim.
Since Roman times, physicians have used the leech’s ability to draw blood painlessly. Until well into the nineteenth century, it was thought that the most effective treatment was to reduce its volume. The cure often provide worse than the complaint. Some patients were bled white, killing them.
British and French doctors were leading advocates of leeching. After about 1820, Britain exhausted its supply of native leeches, and had to import replacements. At that time, chemists and barbers sold leeches for home use, and many families kept their leech applied to a black eye or other disfiguring bruise can be a swift cure.
Leeches are worms found in water throughout the world and on land in tropical forests. Not all leeches depend on blood for food, but all will latch on to a vertebrate animal if given the chance.
Once it finds its victim, a leech grips swiftly with its suckers. Retractable jaws inside the sucker surrounding the mouth soon break the skin. A proboscis, similar to mosquito’s draws off the blood. A feed may last from ten minutes to more than an hour, during which the leech changes its threadlike shape to something looking more like a fat slug.
When it is satisfied, it falls away, leaving a human victim with an itchy wound that may continue to bleed for several hours. This – and the painless nature of the blood-sucking – is due to an anti clotting substance called hirudin, which the leech injects with its saliva.
Leeching lost fashion in the 1860s, except in some parts of Europe and Asia, but researchers remained interested in the anti clotting properties of leech saliva. Now, extracts or hirudin are used to treat people at risk of a blockage in their blood circulation.
Since the 1980s, some surgeons have used live leeches, because of a discovery that leech saliva not only thins the blood but dilates veins. Surgeons attempting to rejoin tiny veins in accident victims or to repair surface blood vessels in delicate cosmetic operations sometimes apply leeches to open these channels wider.
If, after swimming or during a country walk, you find a leech clinging to you, a lighted match, alcohol vinegar or salt will induce it to relax its hold. Pull it off gently to prevent its sucker and proboscis breaking away and possibly causing infection. A styptic pencil will help to stop the bleeding.