I’m sitting alone in Girvan, Scotland, on one of the longest days of the year, looking at the late sun and thinking about the women who all of a sudden caught fire. There were a good number of them. Enough, in the 1700s, to constitute a chapter in the medical literature. The most-quoted British case is Grace Pitt, a 60ish female whose charred corpse was discovered one morning in 1744—like “a log of…