The last part of de Haen's work relates to the discovering and treating of magical diseases, to explain which seems to have been the chief purpose of the author in composing his book. Much caution, he observes, and attention are necessary on this head; and the physician should not readily admit the imputation of witchcraft. No absence of the ordinary symptoms, no uncommon alteration of the course of the distemper, are sufficient to infer this conclusion, because these may arise from unknown natural causes. What then are the marks of certain incantations? De Haen holds the following to be indisputable: "if, in any uncommon disease, there shall be found, in the stuffing of the cushions, or cielings of the room in which the patient lies, in the feather or the chaff of his bed, about the door, or under the threshold of his house, any strange characters, images, bones, hair, seeds, or roots of plants; and if upon the removal of these, or upon conveying the patient into another apartment, he shall suddenly recover; or if the patient himself, or his friends, shall be so wicked as to call a wizzard to their aid, by whom the malady shall be removed; or if insects and animals which do not lodge in the human body; if stones, metals, glass, knives, plaited hair, pieces of pitch, be ejected from particular parts of the body, of greater size, and weight and figure, than could be supposed to make their way through these parts, without much greater demolition and delaceration of the passages; in all these cases, the disease is unquestionably magical." The author proceeds to enquire whether the physician may presume to remove the instruments of incantation in order to relieve the patient without incurring the accusation of impiety by interfering with the implements and furniture of the devil; and concludes very formally that, after approaching them with all due ceremony and respect, after imploring with suitable devotion and ardour, the protection and direction of heaven in such a perilous undertaking, he may attempt to intermeddle, and may occasionally expect a successful issue. Such are the views, reasonings, and conclusions of, at the time, one of the first physicians and philosophers of Germany;--views and reasonings which would have been received with eagerness and applause two hundred years ago, but which the philosophy and improvements of later times seem to have banished to the abodes of ignorance and barbarity.