The Witch of Prague by F. Marion Crawford

Unorna was superstitious, as Keyork Arabian had once told her. She did not thoroughly understand herself and she had very little real comprehension of the method by which she produced such remarkable results. She was gifted with a sensitive and active imagination, which supplied her with semi-mystic formulae of thought and speech in place of reasoned explanations, and she undoubtedly attributed much of her own power to supernatural influences. In this respect, at least, she was no farther advanced than the witches of older days, and if her inmost convictions took a shape which would have seemed incomprehensible to those predecessors of hers, this was to be attributed in part to the innate superiority of her nature, and partly, also, to the high degree of cultivation in which her mental faculties had reached development.

Keyork Arabian might spend hours in giving her learned explanations of what she did, but he never convinced her. Possibly he was not convinced himself, and he still hesitated, perhaps, between the two great theories advanced to explain the phenomena of hypnotism. He had told her that he considered her influence to be purely a moral one, exerted by means of language and supported by her extraordinary concentrated will. But it did not follow that he believed what he told her, and it was not improbable that he might have his own doubts on the subject -- doubts which Unorna was not slow to suspect, and which destroyed for her the whole force of his reasoning. She fell back upon a sort of grossly unreasonable mysticism, combined with a blind belief in those hidden natural forces and secret virtues of privileged objects, which formed the nucleus of mediaeval scientific research. The field is a fertile one for the imagination and possesses a strange attraction for certain minds.