Chapter 20.—The Superstitious Nature of Human Institutions. 30.  All the arrangements made by men for the making and worshipping of idols are superstitious, pertaining as they do either to the worship of what is created or of some part of it as God, or to consultations and arrangements about signs and leagues with devils, such, for example, as are employed in the magical arts, and which the poets are accustomed not so much to teach as to celebrate.  And to this class belong, but with a bolder reach of deception, the books of the haruspices and augurs.  In this class we must place also all amulets and cures which the medical art condemns, whether these consist in incantations, or in marks which they call characters , or in hanging or tying on or even dancing in a fashion certain articles, not with reference to the condition of the body, but to certain signs hidden or manifest; and these remedies they call by the less offensive name of physica , so as to appear not to be engaged in superstitious observances, but to be taking advantage of the forces of nature.  Examples of these are the earrings on the top of each ear, or the rings of ostrich bone on the fingers, or telling you when you hiccup to hold your left thumb in your right hand. 31.  To these we may add thousands of the most frivolous practices, that are to be observed if any part of the body should jump, or if, when friends are walking arm-in-arm, a stone, or a dog, or a boy, should come between them.  And the kicking of a stone, as if it were a divider of friends, does less harm than to cuff an innocent boy if he happens to run between men who are walking side by side.  But it is delightful that the boys are sometimes avenged by the dogs; for frequently men are so superstitious as to venture upon striking a dog who has run between them,—not with impunity however, for instead of a superstitious remedy, the dog sometimes makes his assailant run in hot haste for a real surgeon.  To this class, too, belong the following rules:  To tread upon the threshold when you go out in front of the house; to go back to bed if any one should sneeze when you are putting on your slippers; to return home if you stumble when going to a place; when your clothes are eaten by mice, to be more frightened at the prospect of coming misfortune than grieved by your present loss.  Whence that witty saying of Cato, who, when consulted by a man who told him that the mice had eaten his boots, replied, “That is not strange, but it would have been very strange indeed if the boots had eaten the mice.”