The witches, who entered into their unholy compact with Satan at the Sabbat, were there invested with various tremendous and abominable powers. Unlike sorcerers and magicians, who occasionally used their black art to good purposes, witches could work nothing else but evil. They were particularly fond of interfering with procreation, where both men and women, because of the connection with original sin, were most vulnerable. They produced sterility in the one sex, impotence in the other.[213] Indeed it could be taken practically for certain that these two evils were invariably due to witchcraft. Witches also produced abortion and interfered with the flow of the mother's milk.[214] They sometimes offered up infants at their birth to demons; were vampires and sustained themselves by sucking children's blood.[215] They were able to transform men and women into beasts, to create tempests and thunder-storms.[216] Indeed they went about the world doing all manner of noxious damage, ranging in seriousness from the breaking of crucifixes to the destruction of human life. In their peregrinations they were much assisted by their being able to transform themselves into the likeness of animals, particularly of cats, so that it was very difficult to keep them out of any dwelling-house they cared to visit.[217] Indeed so powerful and versatile were witches supposed to be, not only by vulgar report, but according to authoritative statement, that it may seem difficult to understand how it could be imagined that any human agency could ever get the better of them.
But something had to be done. The evil tended to grow so disastrously, in this helped as a matter of fact--as in the case of sorcery--by the Church's decision that the magic arts were no mere delusion but reality, and that while the practiser of them was a heretic, to believe that he or she was no charlatan but genuinely in league with the Devil was sound doctrine. In this way were men and women encouraged, whenever ill-fortune befell them, to find a facile explanation for unmerited calamity in such an intrinsically innocent incident, for example, as that of a sinister-looking old woman with a hooked nose having peered in at their cottage window. The simple fact of being found wandering alone in fields or woods after nightfall constituted legitimate evidence before the Inquisition. Or again, if an old woman said to someone who had injured her, 'You will repent of this,' and some misfortune subsequently occurred to the latter, the old woman might easily on such trivial grounds be suspect.[218]