Medical invention: Doctors unveil the latest in mechanical parasites.
"Leech" is derived from an old English word meaning "physician," and in the practice of Dr. Gregory Hartig, based in Madison, Wisconsin, that makes sense. After performing a reconstructive surgery, Hartig still sometimes prescribes leeches. From prehistory to the present, the bloodsucking worms have been applied to treat everything from cancer to broken bones. Modern research has shown that leeches help blood circulate and prevent clots. The problem, according to Hartig, is that many patients don't like the idea of carnivorous parasites biting into their flesh and slurping down their blood.