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发布时间：2006-06-21 21:04     点击：

Questions 41-50; 　　The healing power of maggots is not new. Human beings have discovered it several times. The Maya are said to have used maggots for therapeutic purposes a thousand years ago. As early as the sixteenth century, European doctors noticed that soldiers with maggot-infested wounds healed well. More recently, doctors have realized that maggots can be cheaper and more effective than drugs in some respects, and these squirming larvae have, at times, enjoyed a quiet medical renaissance. The problem may have more to do with the weak stomachs of those using them than with good science. The modern heydey of maggot therapy began during World War I, when an  American doctor named William Baer was shocked to notice that two soldiers who had lain on a battlefield for a week while their abdominal wounds became infested with thousands of maggots, had recovered better than wounded men treated in the military hospital. After the war, Baer proved to the medical establishment that maggots could cure some of the toughest infections.

　　In the 1930s hundreds of hospitals used maggot therapy. Maggot therapy requires the right kind of larvae. Only the maggots of  blowflies (a family that includes common bluebottles and greenbottles) will do the job; they devour dead tissue, whether in an open wound or in a corpse. Some other maggots, on the other hand, such as those of the screw-worm eat live tissue. They must be avoided. When blowfly eggs hatch in a patient's wound, the maggots eat the dead flesh where gangrene-causing bacteria thrive. They also excrete compounds that are lethal to bacteria they don't happen to swallow. Meanwhile, they ignore live flesh, and in fact, give it a gentle growth-stimulating massage simply by crawling over it. When they metamorphose into flies, they leave without a trace - although in the process, they might upset the hospital staff as they squirm around in a live patient. When sulfa drugs, the first antibiotics, emerged around the time of World War II, maggot therapy quickly faded into obscurity.

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