Leeching

Basic Information

Leeching, also known as hirudotherapy¹, is a form of bloodletting accomplished by applying leeches to the patient. Historically, it was a component of medical philosophies and practices based on humorism. Humorism stated that illness and ailments were caused predominantly by an imbalance of the four major fluids in the body, one of which was blood. If a disease was caused by "too much" blood, or by "bad blood", it could be removed or filtered by attaching a leech to the body (sometimes to specific parts of the body, based on the nature of the disease). The saliva of a leech also has natural anticoagulant properties, which might potentially be helpful for patients with abnormally thick or quick-clotting blood.²³

Once a leech locks its mouth on you, expect it to drink for 20 minutes or more. When it eventually lets go, it will leave a small Y-shaped incision that will bleed for potentially up to 10 hours. Yanking the leech off early is likely to be harmful to both the leech and the patient.

The doctor who applies leeches is sometimes called a leech, but that's kind of a slang usage⁴. If you prefer a classier (and somehow more ridiculous) title, that might be a barber-chirurgeon. The brave soul who walks into the swamp to catch leeches in the wild on their own legs is known as leech-collector, and it was a legit profession back in the day. Leeching as a medicine goes back 2,500 years or more, and reached its peak as recently as the mid 19th Century.

Wild leeches are quite capable of carrying blood-borne illnesses or parasites that could infect the patient, but that wasn't really understood prior to the development of germ theory. Excessive blood loss is obviously dangerous as well. In many cases leeching did more harm than good.

Leeches also have a minor application in modern medicine, particularly in the fields of grafting and re-attachment surgery where they are used to establish drainage and therefore blood circulation in tissue where the veins have been damaged and so do not allow blood to return to the heart effectively. Leech drainage thus clears "stagnant" blood for the dead end tissue and allows fresh blood to enter. Other swellings related to blood congestion such as varicose veins can also be reduced like this.

Sources

Bibliography

1. Wikipedia

2. Video: Worst Jobs of the Middle Ages

3. Ripley's Believe It Or Not on the leech-craze of the 19th Century

Game and Story Use

• Those tiny Y-shaped wounds could be clue. Was the victim a believer in quackery? Were they exsanguinated by a vampire, or a bucket of leeches?
  • Would be an interesting way to kill someone - perhaps "poetic justice" for a tax collector, debt collector, loan shark or similar "bloodsucker".
  • Is that huge Y-shaped wound a sign that the cadaver had been opened by a coroner before you got to the scene, that the deceased had recently undergone open-heart surgery, or they were attacked and killed by a giant leech monster? (Should be fairly easy for anyone with any skill points invested in medicine or related sciences to tell a bite from a surgical incision, but some players don't spend points on anything that isn't directly combat related).
• A vampire or similar undead might use leeches as a snack, or might apply leeches to their undead body to help promote/simulate circulation to keep themselves looking more lifelike. This too could be a clue, or a red-herring.
  • One of the larger species of leech could perhaps be used to extract blood by a vampire somehow unable to feed directly (say due to a curse or, I don't know, some kind of electronic chip in his head…).
• A magically preserved leech could work as part of a healing charm - much like the bloodflies in Planescape Torment.
• A leech mouthed hybrid might make a suitably non-glamorous sort of vampire.
• For reference, the leech anticoagulant is called hirudin and is indeed used medically for a variety of applications - it also has significant anti-inflammatory properties. However, the pharmaceutical grade material is usually made be recombining the appropriate genes into a microorganism and then culturing and expressing as harvesting from leeches is not practicable on an industrial scale.
• Fantasy leeches might supply enough saliva to use as a blade poison, making wounds from a slashing-weapon bleed far more severely than they otherwise would. Alternatively magic or alchemy might prepare a poison from leeches that removes the target's ability to clot their blood …
• Historical users didn't really understand the concept of the circulation of blood until quite late in the day - a culture that did might use leeches more effectively. Besides local drainage, leeching might be effectively used to remove infected blood and/or slow the spread of sepsis from a wound.
  • Example of this hypothetical use being found in A Song of Ice and Fire / Game of Thrones Qyburn attempts to use leeches to draw off the poison from Gregor Clegane's wounds following his duel with Oberyn Martell. He observes that they all die and tries something else.
• A fantasy or historical hypochondriac might well be obsessed with being bled regularly, possibly to the detriment of their health. Not thinking of any characters from any currently popular novel series turned TV-shows. Whether fantasy or historical fiction come to think of it…
• Leeches fattened on livestock (…or slaves…) might be cooked as some sort of bizarre snack food. Like a sort of blood-pudding…

Footnotes

1. from the leech's taxonomic family name hirudo. More likely to be applied to more modern, scientific uses.

2. I am not a medical professional, and this page is not medical advice. Please don't do anything foolish because you read leeches were cool on arcanawiki.

3. There is, actually, an anticoagulant derived from leech saliva licenced for medical use - this does not make it a good idea to mess about with leeches.

4. Although in Old English laece meant both the creature and the one who used it to practice his laececraft.