If a man had a sore leg, and he should go to an honest, judicious chirurgeon, and he should only bid him keep it warm, and anoint it with such an oil, (an oil well known) that would do the cure; haply he would not much regard him, because he knows the medicine, beforehand an ordinary medicine; but if he should go to a surgeon that should tell him, your leg will gangrene within three days, and it must be cut off, and you will die, unless you do something that I could tell you, what listening there would be to this man?