The Arizona bark scorpion may be small, but its sting delivers a neurotoxin that can kill or render critically ill a young child. A study in the May 14 New England Journal of Medicine finds that an antivenom drug commonly used in Mexico for such stings neutralizes the toxin, eliminates symptoms and reduces the need for sedation in children who have been stung. More than 200 children in Arizona and a handful in New Mexico become critically ill from Arizona bark scorpion stings each year, but there is no U.S.–approved remedy for the stings. Children are rushed to intensive care...