When mother boasts cheerfully, "Johnny is just crazy about his new little sister. . . . You love her, don't you, dear?" Johnny hasn't much choice but to lie like a gentleman . . . and then he begins to worry that something terrible may happen to little sister. She might get eaten by a stray tiger or fall into a tub of scalding water. . . . It doesn't often occur to that grownup to wonder why tigers and tubs of scalding water are all of a sudden wandering around the house waiting for an unwary moment.