A parasitic, fresh water-dwelling animal. Leeches attach themselves to another animal's skin, which they bite through. The leech feeds on its unwitting host's blood. The leech's saliva contains an anti-coalgelent to prevent the host's blood from clotting. Leeches have several modern and historical medical applications.

leapfrog attack = L = leech mode


1. n. (Also `leecher'.) Among BBS types, crackers and warez d00dz, one who consumes knowledge without generating new software, cracks, or techniques. BBS culture specifically defines a leech as someone who downloads files with few or no uploads in return, and who does not contribute to the message section. Cracker culture extends this definition to someone (a lamer, usually) who constantly presses informed sources for information and/or assistance, but has nothing to contribute. 2. v. [common, Toronto area] To instantly fetch a file (other than a mail attachment) whether by FTP or IRC file req or any other method. Seems to be a holdover from the early 1990s when Toronto had a very active BBS and warez scene.

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.

In addition to their medical use, the leech was also used in Victorian times by sailors, who used them to detect impending storms.

A contraption existed where twelve leeches were placed in bottles, with small plates attatched at the top which, when knocked slightly, would ring a bell. The theory was that when a storm approached, the leeches would react to the change in air pressure, and instinctively attempt to seek cover by climbing out of the bottle. They would then knock the plate, ringing a bell.

The idea was eventually scrapped because of the fact that the leeches had to be fed periodically, and also because the sailors were reluctant to place their lives in the "hands" of a bunch of parasites.
Hirudo medicinalis

The medicinal leech of Europe, perhaps twelve centimeters long on average. It is now rare in nature because of over-collecting and destruction of habitat. It has been introduced into northeastern United States, but is uncommon there. They are hermaphroditic.

This humble and somewhat repulsive animal played an important part in the history of Europe and of European culture as exported elsewhere, and for a long time was important for its production of hirudin,a powerful anti-coagulant.

These are freshwater animals. (Some leeches of other species can be found in marine or terrestrial habitats.) A leech attaches itself to its prey by a posterior sucker, then applies the anterior sucker to the skin and makes a wound, often with the aid of little saw-toothed jaws inside the mouth. It fills its digestive tract with blood, sometimes taking an amount equivalent to 10 times its own weight, then drops off. Hirudin is manufactured by the animal to prevent the coagulation of the blood during the process of drawing it as well as while it is being digested.

European physicians developed the idea that illness was caused by an imbalance of substances (called by them "humors") in the body, which imbalance could be corrected by allowing leeches to draw large amounts of blood from the sick. (This notion goes back as least as far as to Galen (130 AD).) It is probable that George Washington died from excessive "bleeding;" nor was he the only victim. From this practice physicians came popularly to be called "leeches."

Though bleeding is no longer used therapeutically in Europe, hirudin is still important as an anti-coagulant in some kinds of heart surgery. Further, because of the peculiar construction of hirudo's nervous system, it is an important animal for research purposes.

Hirudo medicinalis is difficult to cultivate in the laboratory. For a time researchers turned to Haementeria ghilianii, a giant South American leech. Hirudin can now be made artificially.

(PHYLUM, Annelida; CLASS, Hirudinea; ORDER, Gnathobdellae)

Leech (?), n.

See 2d Leach.


© Webster 1913.

Leech, v. t.

See Leach, v. t.


© Webster 1913.

Leech, n. [Cf. LG. leik, Icel. lik, Sw. lik boltrope, stende liken the leeches.] Naut.

The border or edge at the side of a sail.

[Written also leach.]

Leech line, a line attached to the leech ropes of sails, passing up through blocks on the yards, to haul the leeches by. Totten. -- Leech rope, that part of the boltrope to which the side of a sail is sewed.


© Webster 1913.

Leech, n. [OE. leche, laeche, physician, AS. lce; akin to Fries. ltza, OHG. lahhi, Icel. laeknari, Sw. lakare, Dan. laege, Goth. lkeis, AS. lacnian to heal, Sw. laka, Dan.laege, Icel. laekna, Goth. lkinn.]


physician or surgeon; a professor of the art of healing.

[Written also leach.] [Archaic]


Leech, heal thyself. Wyclif (Luke iv. 23).

2. Zool.

Any one of numerous genera and species of annulose worms, belonging to the order Hirudinea, or Bdelloidea, esp. those species <-- formerly! -->used in medicine, as Hirudo medicinalis of Europe, and allied species.

In the mouth of bloodsucking leeches are three convergent, serrated jaws, moved by strong muscles. By the motion of these jaws a stellate incision is made in the skin, through which the leech sucks blood till it is gorged, and then drops off. The stomach has large pouches on each side to hold the blood. The common large bloodsucking leech of America (Macrobdella decora) is dark olive above, and red below, with black spots. Many kinds of leeches are parasitic on fishes; others feed upon worms and mollusks, and have no jaws for drawing blood. See Bdelloidea. Hirudinea, and Clepsine.

3. Surg.

A glass tube of peculiar construction, adapted for drawing blood from a scarified part by means of a vacuum.

Horse leech, a less powerful European leech (Haemopis vorax), commonly attacking the membrane that lines the inside of the mouth and nostrils of animals that drink at pools where it lives.


© Webster 1913.

Leech, v. t. [imp. & p. p. Leeched (?); p. pr. & vb. n. Leeching.]


To treat as a surgeon; to doctor; as, to leech wounds.



To bleed by the use of leeches.


© Webster 1913.

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