this is my brain on leeches
I just want to bring you along for a reprise of the journey of how I read
’s Leeches and the Legitimizing of Folk-Medicine, because man was it fun for my brainDokukin tried hirudotherapy1 at the behest of his mother back in Russia, where it remains common practice
why?
According to Despite the ‘Yuck Factor,’ Leeches Are Big in Russian Medicine (NYTimes) - often the venom, a natural anticoagulant, is used “as a low-cost substitute for blood thinners like warfarin… Left to pay out of pocket at clinics or commercial drugstores, patients gravitate toward cheaper options, like leeches.”
And yeah, obviously USAmericans have problems with expensive healthcare too, but “Medicinal leeches cost 90 cents each in Russia, compared with $15.50 for leeches sold by Leeches USA, a medicinal leech supplier based in Westbury, N.Y.”2
Despite leeches’ having gained FDA approval as a medical instrument in 2004, a frustrating lack of clinical evidence persists.
what other living creatures has the FDA approved as medical devices? Maggots3, for sure, but are there others?
Regulatory responsibility for both medical maggots and medicinal leeches was transferred to the Center for Biologics Evaluation and Research (the Center within the FDA that regulates biological products for human use under applicable federal laws) on December 30, 2024. Which kinda implies that those were the only living creatures regulated elsewhere by the FDA at the time.
CBER’s Biologics Product Categories doesn’t seem to have a section for living creatures (leeches come under Blood & Blood Products), but they do have an entire Xenotransplantation category.
(hat tip to Dr. Phlox)
The medicinal leech, Hirudo medicinalis, is a remarkable creature.
did we really name a whole species just after what value it can provide for us? seems rude
A closer look at Hirudo medicinalis reveals what is essentially a highly optimized tube.
honestly, same.
This tube is replete with two sets of specialized suckers at each end of the leech’s body. The posterior sucker — the larger and more muscular of the two — aids in movement, vaulting the animal forward by gripping the terrain ahead.
excuse me did you just say it moves around by using its butt sucker to shove itself off the ground
This anterior region also houses five pairs of eyes
like horseshoe crabs! the number, that is, not the location.
The leech’s mouth contains three saw-like jaws arranged in a Y-shape, each bearing approximately 100 sharp teeth. These jaws create a characteristic bite — an inverted Y inside a circle — that is a telltale sign of leech feeding.
…like an old subway token?
(don’t image search ‘leech bite mark’. don’t make yourself sad, don’t set yourself on fire.)
[in 1870,] American physician John King remarked that leeches were better suited for [delicate tissues, such as] ‘hemorrhoidal tumors, prolapsed rectum, inflamed vulva … watching that they do not creep out of reach within any of the internal cavities of the body.’
Nope nope nope (peeks between fingers)
Indeed, Napoleon Bonaparte would employ leeches to treat his hemorrhoids during military campaigns.
ah yes, I heard about this via a Tolstoy discussion
“Such was the zeal for leeching,” write historians of science Kirk, Pemberton, and Serviant-Fine, “that nineteenth-century Parisian hospitals maintained large quantities of leeches in purpose-built pools.”
by 1827, France was importing 33 million leeches per year with an estimated value of Fr. 1,009,000 francs… Yet by the turn of the century, leech mania had waned.
like tulip mania.
The British clinician Charles Hare wrote in his book, appropriately titled Good Remedies, Out of Fashion, that bloodletters are "no more found in the Post Office Directory, than …the Dodo or the Ichthyosaurus." Indeed, by the 20th century, the leech had gone from inspiring patterns on textiles and poetry to a largely obscure medical relic.
It takes around two years for leeches to mature to the point of medical use. In this period, they are fed on sheep's blood up until about six to nine months before application, at which point they are starved to ensure their guts are empty.
like escargot.
In 1840, a French surgeon, Baron Charles Louis Heurteloup, developed a spring-loaded version, especially designed for veins around the eyes.
I’d rather have the leech.
the very least we can do is show greater curiosity about the potential of leechcraft.
okay, so at this point I was getting curious about leeches in general, and went down a bit more of a rabbit hole and found this article from the Guardian - 10 stomachs, 32 brains and 18 testicles – a day inside the UK's only leech farm:
The leeches that I have driven several hundred miles to encounter are freshwater, bloodsucking, multi-segmented annelid worms with 10 stomachs, 32 brains, nine pairs of testicles, and several hundred teeth that leave a distinctive bite mark.
this is false - leeches don’t really have 32 brains, just 32 ganglia to control their individual segments. They do seem to have 9 pairs of testes, though. and doesn’t that spermatic duct look kinda prettily fern-like?
Their most annoying talent, he says, is for escape, even from Biopharm’s tanks. He has often arrived home to find some attached to his ankles. “I’m usually surprised if I don’t find 10 leeches in the footwell of my car. They stick to your shoe and then they dry out.” He says this, and I look at my feet.
and I sometimes find ants on my body at very confusing moments after I’ve been sitting outside in the morning, but at least they don’t use their posterior sucker to vault themselves forward by gripping the terrain ahead.
Single-use only: all leeches employed in hospital settings must be exterminated with alcohol solution once they have fed and dropped off.
This seems ungrateful, but a filled leech is a biohazard. Leeches can transfer blood from one person to another. “They’re worse than that,” says Carl. “They’re a needle that can walk.”
The hypothetical Kant of Hirudinidae4 is rolling over in his grave.
ps I’m not sure why we’re so worried about radioactive shrimp given that they’re already on cocaine
“Hirudotherapy is when medical-grade leeches are used in surgery to reattach body parts, like fingers or soft tissues like muscles.” - Sydney Children’s Hospitals Network (emphasis mine)
at least back in 2017
“Maggot therapy is essentially a controlled wound myiasis (maggot infestation)… Maggot therapy dressings contain the medical grade larvae on the wound during the period of debridement, and facilitate easy and controlled removal when the patient and therapist determine they have completed their work.”
turns out there exists one Dr. Jessica Leech who lectures on Kant at King's College London, Department of Philosophy (not to be confused with University College London, where Bentham’s body lives) (I originally saw Bentham at UCL during my first trip to London many years ago, and then decades later I turned a corner at an exhibit in an NYC museum and saw him again - felt like, hey buddy, fancy seeing you here! small world, ain’t it!)