We now come to the most dangerous part of the house—in fact, one of the most hazardous environments anywhere: the stairs. No one knows exactly how dangerous the stairs are, because records are curiously deficient. Most countries keep records of deaths and injuries sustained in falls, but not of what caused the falls in the first place. So in the United States, for instance, it is known that about twelve thousand people a year hit the ground and never get up again, but whether that is because they have fallen from a tree, a roof, or off the back porch is unknown.
