These familiar spirits often assumed the form of animals, and a black
dog or cat was considered as a figure in which the attendant devil was
secretly hidden. These subordinate devils were called Imps. Impure and
carnal ideas were mingled with these theories. The witches were said
to have preternatural teats from which their familiars sucked their
blood. The devil also engaged in sexual intercourse with the witch or
wizard, being denominated _incubus_, if his favourite were a
woman, and _succubus_, if a man. In short, every frightful and
loathsome idea was carefully heaped up together, to render the
unfortunate beings to whom the crime of witchcraft was imputed the
horror and execration of their species.