Clockwise from top left, Paul McCartney, Ringo Starr, John Lennon and George Harrison in 1965.
Clockwise from top left, Paul McCartney, Ringo Starr, John Lennon and George Harrison in 1965. (By Robert Freeman -- Associated Press; Copyright Apple Corps Ltd.)
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Monday, February 4, 2008

Study Questions Plague's Power

The Black Death ravaged Europe in the middle of the 14th century, killing as much as half of the population in some areas. Many experts have thought the plague was so deadly that it killed indiscriminately, taking the strong as often as the weak, but new research is challenging that notion.

Sharon N. DeWitte of the University at Albany and James W. Wood of Pennsylvania State University analyzed 490 skeletons that had been excavated from the East Smithfield cemetery in London, which was established exclusively to bury victims of the plague.

The researchers determined the health of the victims by examining defects in their bones, features that can indicate other health or nutritional problems. The researchers compared the skeletons with those of 291 similar individuals buried at a Danish cemetery shortly before the plague began.

Although healthy people did die from the plague, which is caused by the bacterium Yersinia pestis, the researchers found that the epidemic was more likely to kill people made vulnerable because they were already ill or malnourished, according to a report published last week in the Proceedings of the National Academy of Sciences. Although this finding seems unsurprising, some global epidemics, such as the 1918 flu, have taken an unusually high toll among young, healthy people.

"Black Death did kill people who were otherwise healthy," DeWitte said. "But we found quantitative evidence against the assumption that the Black Death killed indiscriminately. This runs contrary to what a lot of people thought."

-- Rob Stein

How Plant Digests Bugs Is Detailed

Pity the fly on the pitcher plant. Having landed on the tropical plant's vaselike structure, which looks no more dangerous than a partially unfurled leaf, the insect tumbles down the six-inch chute and lands in a pool of liquid.

Not just any liquid, it turns out, but a brew of digestive juices that gradually dissolves the hapless bug.

Scientists have wondered for at least a century what chemicals are in the pitcher plant's juice -- and how it turns insects, with their tough exoskeletons, into mushy dietary supplements. Now a team from Japan has done the first thorough analysis of that fluid, answering some old questions and raising a few new ones.

The carnivorous plants, which live mostly in the Asian tropics but have also become popular houseplants in the West, rely on occasional insect snacks to stay nourished, since they mostly grow in nutrient-depleted soil. Charles Darwin himself was fascinated by the plants, and wrote a book about them in 1875.

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