Striking with cruel randomness across an increasingly elderly population, Alzheimer's disease afflicts some 4 million Americans, most of them over the age of 65. They may range from a former President to a neighbor next door, but the ailment is always the same: it clutters the brain with tiny bits of protein, slowly robbing victims of their mental power until they are no longer able to do even the simplest chores or recognize their closest friends and kin. So far, medical science has been stymied, unable to treat the disease or slow its fatal progression.
Last week scientists offered what could...