So the American share market seems to be behaving like Desperate Dan, the Wild West hero of The Dandy, the comic produced by DC Thomson of Dundee that sold two million copies a week in the Fifties, and only finished printing six years ago. For those not entirely up to speed with the popular culture of a generation or more ago, he was the strongest man in the world, able to lift a cow with one arm, knocking out a buffalo with his fist, and blowing a hole in the bar-room floor when he sneezed.