Leech

Leech: what was it used for?

Bloodletting where the lancet could not go: for inflammations, fevers, and congestion.

Leech: what does modern science say?

Its saliva contains hirudin, an anticoagulant; leeches are used again after reconstructive surgery, and the FDA cleared them as a medical device in 2004. John Haycraft found in 1884 that the leech’s saliva stops blood from clotting; the substance, hirudin, is now made by recombinant techniques for anticoagulant drugs. Plastic surgeons returned to the living leech in the 1970s to drain congested blood from reattached fingers and grafted flaps, and the United States cleared it as a medical device in 2004. The wild leech is protected across Europe.

Leech: what did the older authorities say?

François Broussais

The French army physician reported in 1816 that the fever patients in his wards at the Val-de-Grâce were all cured within days by bleeding and by leeches on the abdomen or the anus, repeated as often as the symptoms grew worse.

The leech-mania

Broussais’s theories made France, which had once exported its surplus leeches, the largest consumer in the world, using fifty to a hundred million a year and importing over fifty-seven million in 1832 alone; the Manchester Royal Infirmary used fifty thousand in 1831, and the harvest across Europe brought local populations almost to extinction.