Leeches and Bloodletting

As a child, playing through freshwater streams and ponds in eastern Europe, I would encounter frogs and leeches which I collected using grandma's fine stockings from which I fashioned a "minciog," a type of fishing net with a wire handle I made from grandpa's metal scraps in the tool shed (she had no idea and neither did grandpa) and placed them in grandma’s milk glass bottle (she also did not know about the secondary use of her milk bottles). I would bring them to the farm and leave the bottles at night by the water pump where the ground and rocks were always wet.

I would place a thick piece of foil with holes for breathing on the large mouth of the milk bottle and then a small rock on top of it, to make sure that the numerous leeches would not escape during the night. Without fail, all the leeches I had collected the previous day were gone in the morning. Their disappearance, a mystery to me, did not deter me from trying again to trap more, sometimes using my legs as bait when grandma stocking tore. If you had asked me then what I was going to do with them, had they not escaped, I had no idea. I just enjoyed the thrill of finding them, catching them, and bringing them home to grandma's house.

In my quest for fun and discovery of various creatures in the village streams, I caught frogs, fish, and leeches. But, like most five and six-year-olds, I had no idea that leeches were used for medicinal purposes, i.e., bloodletting. And grandma was too busy to tell me, she allowed me roam around the village with my friend Stella, so long as I was not in her way all day.

Later in life I learned that medicinal leeches had been used so heavily during the Victorian era that they almost disappeared as a species. Some European governments took measures to prevent the extinction of leeches by banning overharvesting, exports, and by regulating leech collecting. However, despite these measures, by early 1900s the leech became endangered and was believed to be extinct in several countries. As they became scarcer, intrepid doctors invented artificial bloodletting kits.

Americans tried to breed their own European versions and in 1835 there was a $500 reward offered to anyone who could breed European leeches in America but it was a total failure.

Breeding leeches commercially was not very attractive since leeches only need blood meals every six months and it takes them two years to reach reproductive age. Used leeches were dumped in ponds but there was no guarantee that they would survive although they could naturally live to be ten years old.

Using their 100 teeth, leeches would clamp down on their prey or on a patient and draw about a tablespoon of blood before they were full and could be easily detached from the skin. Millions of blood-sucking leeches were used by doctors in Europe for the treatment of just about any disease imaginable.

The leech collectors suffered a lot of blood loss and fatigue, in addition to infections from organisms in the leeches’ gut and even infectious diseases such as syphilis if the animal happened to regurgitate previously ingested blood from another diseased patient. (History, Nat Geo, 2024)

Offering one’s body as bait in order to collect a parasitic worm was considered “employment hazardous and wearisome” by poet William Wordsworth.

Hirudo medicinalis, as the leech is known scientifically, can grow up to seven inches long. When the leeches were not able to reduce the cholera epidemic raging in Europe and the U.S., their medicinal use fell out of favor as a cure-all treatment.

The leech is still useful in modern medicine in transplants and plastic surgery and the parasitic worms are actually bred in laboratories.