I’m reading Rose George’s new book, Nine Pints: A Journey through the Money, Medicine, and Mysteries of Blood, which is written in an appealingly conversational style and which pumps out a steady flow of startling and irresistible stories about transfusion, menstruation, hemophilia, and blood-borne disease. I’m an every-eight-weeks blood donor myself (O-positive, CMV-negative), so I was riveted by George’s accounts of whole-blood and plasma donation. For sheer eye-widening, jaw-dropping amazingness, though, it’s hard to top Chapter 2: “That Most Singular and Valuable Reptile,” which is all about leeches.
Leeches are not, of course, reptiles; the chapter title comes from a treatise published by one George Horn in 1798, during the full flowering of medical leech mania, when it was believed that relieving the body of excess blood was the cure for just about every ailment from headaches to syphilis to cholera. Leeches are bloodsucking aquatic annelid worms of the order Hirudinea (hirudo is Latin for “leech”); the ones used for medical purposes have, George tells us, “ten stomachs, thirty-two brains, nine pairs of testicles, and several hundred teeth that leave a distinctive bite mark” that resembles “either a wound made by a circular saw or a Mercedes-Benz logo.” They’re still being bred for specialized medical purposes, especially skin grafts; George describes her visit to Biopharm, in Wales, whose bland name masks its function as a medical leech farm.
Leech, designating the animal, has been an English word since about 900. That’s also when leech had a second meaning: “physician.” Leeches used leeches, but the two words evolved separately. George writes:
Doctors were called leeches, but because of an etymological coincidence, not for their fondness for prescribing worms. (Leeches were named for the Old English word laece, meaning “worm,” and derived from Middle Dutch; doctors were also called laece, but derived from the Old Frisian laki, meaning “a physician.”) This name for physicians lasted until the Renaissance and bequeathed to us such wonderful book titles as Leeching, Wortcunning, and Starcraft of Early England.
The Online Etymology Dictionary goes into more detail about leech=physician:
from Proto-Germanic *lekjaz “enchanter, one who speaks magic words; healer, physician” (source also of Old Frisian letza, Old Saxon laki, Old Norse læknir, Old High German lahhi, Gothic lekeis “physician”), literally “one who counsels,” perhaps connected with a root found in Celtic (compare Irish liaig “charmer, exorcist, physician”) and Slavic (compare Serbo-Croatian lijekar, Polish lekarz), from PIE *lep-agi “conjurer,” from root *leg- (1) “to collect, gather,” with derivatives meaning “to speak (to ‘pick out words’).”
“Leech” has been used figuratively to mean “human parasite” since the late 1700s.
Here are some more leech facts from George’s book:
- “Dogs are often leeched to relieve swollen or infected ears, a problem particularly common in French bulldogs.”
- An attached leech can bite in six seconds; a handled leech is slower: 12 to 15 seconds.
- A biting leech injects a local anesthetic as well as “the best anticoagulants known to exist” – “vastly more efficient” than the next-best, heparin.
- The 21st century has its own version of leech mania: “hirudotherapy,” which promises to cure diseases caused by “insufficient micro-circulation.” (The British Association of Hirudotherapy – www.bah.today – offers “online self-healing in leech therapy.”) The actress Demi Moore claimed in 2008 that “highly trained medical leeches” had fed on her to “detoxify my blood.” Rose George briskly dispenses with that assertion: “This is scientific nonsense.”
Leech application in a hirudotherapy clinic in Talinn, Estonia.
- A 19th-century family doctor felicitously named William Merryweather believed that leeches could predict weather. He called leeches “my little comrades,” and built a leech-driven device he called the Tempest Prognosticator. (His first choice of name had been “the Atmospheric, Electro-Magnetic Telegraph, conducted by Animal Instinct.”) He brought the machine to the Great Exhibition in London in 1851 where, alas, it failed.