The beliefs in the action of the devil, and in the power of the sorcerers, so deeply rooted in the imagination of the seventeenth century, were summed up in 1588 in the _Démonomanie des Sorciers_ of the famous Jean Bodin. He defined the sorcerer as one who 'by devilish and unlawful means endeavours to attain some end'; but in his book he speaks for the most part of witches. As Sprenger, the German inquisitor, remarked, 'We should talk of the heresy of the witches, and not of sorcerers, for these are of little account.' In Bodin are to be found most of the practices in black magic still flourishing at the end of the seventeenth century. Sorcerers and witches formed a sort of vast fraternity. There were entire families whose formulae and whose customers were handed down as heritable property. Jeanne Harvillier, burnt to death on April 30, 1579, may serve as type. Her mother, a witch like herself, had been burnt to death thirty years before. Such a death was the natural end to her career, an end foreseen, and one that terrified those fascinated by the strange vocation much less than one would imagine. Jeanne was born about 1528, at Verberie near Compiègne. At the age of twelve she was presented by her mother to the devil, who appeared to her in the shape of a very tall dark man. Jeanne renounced God, and consecrated herself to the 'Spirit.' 'At the same time she had carnal intercourse with him, which continued from the age of twelve to the age of fifty, when she was arrested. It sometimes happened that her husband, lying by her side, failed to perceive what was going on.' This was the _incubat_. Jeanne Harvillier was brought to justice on the charge of causing the death of men and beasts by witchcraft. She confessed to it with the greatest frankness, and told the story of her last homicide: 'She laid some powders, prepared for her by the devil, in the place where the man who had beaten his daughter was to pass.' Another man came by to whom she wished no harm, and immediately he felt a sharp pain all over his body. She promised to cure him, and in fact took her place at the bedside of the sick man and tended him with the gentleness of a sister of mercy. She fervently besought the devil to restore life to the dying man, but the devil replied that it was impossible.