Word: emmelin
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Physiologists Emmelin & Feldberg, who describe the nettle as "one of nature's meanest masterpieces" [TIME, Dec. 29], omit to mention one curious characteristic of this labora-torial vegetable: it only stings if touched lightly. Remember...
...nettle's little stinger is one of nature's meanest masterpieces. In a recent issue of Britain's Journal of Physiology, Physiologists N. Emmelin and W. Feldberg of Cambridge University explained just how mean a nettle...
Each hair, say Emmelin & Feldberg, has a flexible bladder at its base. The hair itself is hollow and stiffened with silica. At the tip is a tiny bulb like a cork stuck on the end of a hypodermic needle. When the hair touches a victim, the bulb breaks off, exposing a point so exquisitely sharp that it slips right through the skin. Pressure on the hair shaft squeezes the bladder and injects poison into the victim's tissues. The result: a hot, burning sensation followed by a longer-lasting itching...
Patiently, Emmelin & Feldberg squeezed hundreds of nettle needles to find out what was in them. They found two separate poisons, each with a special function. Acetylcholine causes the sudden burning (as if the nettle said: "Let me alone-and quick"). The other, histamine, starts the persistent itching ("Just as a reminder not to touch me again...
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