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A Moment of Science

A Mechanical Leech?

There aren't too many of us who think leeches are cool--but they are still used in medicine, and now there is even a mechanical leech.

Like earthworms, leeches are segmented worms.

What has thirty-two brains and three jaws, each with one hundred teeth?


The correct answer is a leech, and the fact is that they’re still used in medicine today. Bloodletting went out with the nineteenth century, but in the 1980s, with the development of microsurgery, leeches made a comeback.

Reconstructive surgery performed to reattach limbs or to transfer tissue from one part of the body to another also involves “replumbing” the blood vessels that nourish the repositioned tissue or bone.

The problem is that sometimes the veins can’t remove the blood fast enough from the area and so the blood begins to clot. If additional surgery fails to correct the situation, they bring in the leeches.

Three Things

The leeches do three things. They attach to the wound and suck out blood; they provide their own anesthetic so that the bite doesn’t hurt; and they secrete an anticoagulant that keeps the blood flowing for hours. This gives the body time to form new veins that can handle the blood flow.

Researchers in Madison, Wisconsin have come up with a machine that acts as a leech. But unlike leeches, their machine can be sterilized and doesn’t move from one body part to another, and doesn’t fall off when it’s gorged itself.

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