A certain vizier had a stupid son, whom he sent to a learned man, desiring him to instruct him, in hopes that his capacity might improve. After having instructed him for some time without any effect, he sent a person to the father with this message: “Your son has no capacity, and has almost distracted me. When nature has given capacity, instruction will make impression; but if iron is not of a proper temper, no polishing will make it good. Wash not a dog in the seven seas, for when he is wetted he will be dirtier. If the donkey that carried Jesus Crist was to be taken to Mecca, at his return he would still be a donkey.”