Smart (and disloyal) individuals will desert a failing enterprise before it is too late. This observation was made long ago about rats, which would remain on board devouring a ship’s stores in the hold until the ship foundered in a storm or ran aground; then they would disappear so as not to be drowned. The transfer to human desertion was made before 1600; in some cases it was a ship they abandoned, in others a house about to collapse. “It is the Wisdome of Rats that will be sure to leave a House somewhat before its fall,” wrote Francis Bacon (Essays, 1597).