Medicine: Of Sheep & Men

Scrapie is a disease of the nerves and muscles of sheep, so named because bleating victims rub themselves against fence posts or wire to relieve the itching that goes with it, and in doing so scrape off valuable wool. In later stages the animals get the shakes and staggers, so the French call the disease la tremblante. Last week veterinary researchers were engaged in a transatlantic argument over whether scrapie is hereditary or infectious, or—as would be scientifically most exciting—whether it has features of both. Medical investigators from New York to New Guinea...