QUOTE : ...the exorcist should not believe too readily that a person is possessed by an evil spirit; but he aught to ascertain by the signs by which a person possessed can be distinguished from one who is suffering from some illness; especially one of a psychological nature. Signs of possession may be the following: ability to speak with some facility in a strange language or to understand it when spoken by another; the facility of divulging future and hidden events; display of powers shich are beyond the subject's age and natural condition; and various other conditions which, when taken together as a whole, build up the evidence.