The marquis himself lived in equal terror. He knew what was going on, and took things philosophically. Here is a sketch of a dinner at his house. 'The marchioness put Sainte-Croix on her right; the marquis was at the sideboard end of the table. The latter was very carefully served by a domestic specially attached to his person, to whom he always said: "Don't change my glass, but rinse it every time you give me anything to drink."' When the evening was over, the marquis retired to his room; Sainte-Croix and the marchioness went to the lady's room, and Briancourt went upstairs with the children. With the horrors of crime there were thus mingled scenes of burlesque. Accommodating as her husband was, the marchioness began to poison him; then, struck with remorse, she called in to attend him one of the most famous physicians of the time, Dr. Brayer. 'She wished to marry Sainte-Croix,' writes Madame de Sévigné, 'and with that intention often gave her husband poison. Sainte-Croix, not anxious to have so evil a woman as his wife, gave counter-poisons to the poor husband, with the result that, shuttlecocked about like this five or six times, now poisoned, now unpoisoned, he still remained alive.' Brinvilliers emerged from this violent treatment with a weakness in the legs. Afterwards he always carried theriac about with him, that being regarded as an antidote; he took it from time to time, and gave doses to his people. Briancourt, however, succeeded in escaping from the service of his formidable mistress, and, under the baleful impression of what he had seen in the world, he retired to Aubervilliers, where he lived in solitude, giving lessons in the establishment of the Fathers of the Oratory there. Seven or eight months had passed when the marchioness came to see him; then she sent from time to time to ask how he was doing. It was at Aubervilliers that one evening, on July 31, 1672, he received from his late mistress a very urgent note, begging him to go immediately to Picpus, where she had an important communication to make to him. There had just happened an event which was to entail incalculable consequences: on July 30 Sainte-Croix died in his mysterious dwelling in the cul-de-sac of the Place Maubert. A widespread legend makes Sainte-Croix' death the result of a chemical experiment; it is said that the glass mask with which he covered his face to protect it from the poisonous vapours had broken. But he really died a natural death after an illness of some months, in the course of which he was visited by several persons who have left their testimony in regard to the matter. In the legendary laboratory of the cul-de-sac there was found indeed a furnace of 'digestion.' Sainte-Croix 'philosophised' there, that is, worked at the philosopher's stone, and more particularly at solidifying mercury, that eternal dream of the alchemists. Madame de Brinvilliers soon learned of the death of her lover. Her first cry was, 'The little box!' II. HER TRIAL