We'll admit to being a little freaked out when, in early October, a mysterious jellylike substance was discovered at the Science Museum of Minnesota. The nation was, after all, in the grip of terrorism-induced hysteria, and it seemed plausible at the time that some malefactor had set his or her sights on downtown St. Paul. Even as moon-suited firefighters and bomb-squad technicians gingerly removed the goo--discovered on a plate, near a briefcase purportedly abandoned by a dark-complexioned man--we wondered whether we were about to be besieged by anthrax or some equally malignant but heretofore unknown spore. It was certainly a relief--though, oddly, also something of a letdown--when the jellylike substance turned out to be...jelly.