Thanks to a nationwide search for an antidote, a snake handler is expected to survive an attack by a 12-foot king cobra that bit him in front of visiting children. George VanHorn, 51, was upgraded from very critical to serious condition Friday after many hours at "death's door," a hospital spokesman said. He was struck Wednesday at his Reptile World Serpentarium in St. Cloud, about 30 miles south of Orlando. VanHorn milks the snakes and sells the venom to medical laboratories for research. Shipments of king cobra antivenin from across the country began arriving at the hospital within hours. Many of the 100 vials were provided by a network of zoo curators and herpetologists.