examinate that she would become his subject, and give her soul unto him; the which she at first refused to assent unto; but after by the great persuasions made by the said Demdike, she yielded to be at his commandment and appointment; whereupon the said wicked spirit then said unto her, that he must have some part of her body to suck upon; the which she denied then to grant unto him; and withal asked him, what part of her body he would have for that use: who said he would have a place of her right side near to her ribs, for him to suck upon; whereunto she assented."
This form of sucking the blood was the act by which the witch swore fealty, so to speak, to the evil one. The instrument that thus partook of the spirit through the blood was thenceforth the witch's evil spirit, or familiar. It was this being, known by numerous names, in the likeness usually of an animal, that performed for the witch many of the tasks that are beyond mortal powers. It was currently believed, however, that the animal form of a familiar was always incomplete in one respect: it lacked a tail. This fact is referred to in Macbeth in the phrase, "Like a rat without a tail," which means in the form or likeness of a rat without a tail. Contemporary writings give many lists of familiars by name,