John closes his second book with a chapter on natural scientists and medical men, for he seems to apply the term _physici_ in both senses, although towards the close of the chapter he also employs the word _medici_. He begins by saying that it is permissible to consult concerning the future anyone who has the spirit of prophecy or who from scientific training knows by natural signs what will happen in the bodies of animals, or who “has learned experimentally the nature of the time impending,” provided only that these latter men say and do nothing prejudicial to the Christian faith. But sometimes the _physici_ attribute too much to nature,[493] and John has heard many of them disputing concerning the soul and its virtues and operations, the increase and diminution of the body, the resurrection, and the creation, in a way far from accord with the Christian faith. “Of God Himself too they sometimes so speak, ‘As if earth-born giants assailed the stars.’”[494] John recognizes, however, their knowledge of animals and medicine, although he finds their theories sometimes in conflict. As for practicing physicians, he dares not speak ill of them, for he too often falls into their hands, and he grants that no one is more necessary or useful than a good doctor. John makes considerable use of the _Natural History_ of Pliny and of Solinus, and sometimes for occult or marvelous phenomena, as when he cites Pliny concerning men who have the power of fascination by voice and tongue or by their glances, and adds the testimony of the Physiognomists.[495] [Sidenote: Summary.]