In 1669, Madame de Brinvilliers succeeded in introducing a wretch named Jean Hamelin, commonly known as La Chaussée, into her brother the councillor’s household as a footman. The two brothers lived in the same house, and La Chaussée had every facility for giving poison to both. One day when he was waiting at table, the dose he put into the glass he was handing was so strong that the civil lieutenant rose up in great agitation, crying, ‘Ah, wretch, what have you given me? I think you want to poison me!’ And he bade his secretary taste the stuff. The latter took some on a spoon and declared that he detected a strong taste of vitriol. La Chaussée did not lose his head. ‘No doubt it is the glass Lacroix (the valet) used this morning,’ he said, ‘when he took medicine.’ And he hastily threw the contents of the glass into the fire.
The civil lieutenant went to his estate at Villequoy in Beauce, to spend Easter with his family. In 1670 Easter fell on April 6. His brother the councillor made one of the party, and took La Chaussée with him as his only attendant. While they stayed at Villequoy La Chaussée helped in the kitchen. One day a tart came to table, of which all who ate were very ill on the morrow, while the others remained quite well. On April 12 they returned to Paris, and the civil lieutenant had the appearance of a man who had suffered great pain.
The details of the poisoning are horrible. As D’Aubray did his best to restore his health, the poison did not take effect so quickly as usual; he was very difficult to kill. La Chaussée, assiduous in his attentions, gave his master poison at every possible opportunity. His body was so offensive during his illness that it was impossible to remain in the room with him; and he was so irritable that no one could approach him. Madame de Brinvilliers rarely showed herself, but sent her pious sister to take her place. Meanwhile La Chaussée was unremitting in his care; no one but him could change the bedclothes or the mattress. The unhappy man suffered unspeakable torture. La Chaussée could not help exclaiming: ‘This fellow holds out well! He’s giving us a good deal of trouble! I don’t know when he will give up the ghost!’
Madame de Brinvilliers was at Sains in Picardy. She told Briancourt, the tutor who had become her lover, that the poisoning of her brother the councillor was in progress. She explained to him that she wanted to set up ‘a good house'; that her eldest son, who was already nicknamed the President, would one day fill the post of civil lieutenant, and added that ‘there was still a good deal to be done.’ These sentiments were sincere. Madame de Brinvilliers endeavoured to bring up and establish her children—'who were her own flesh,’ as she said—in conformity with the brilliant dreams she nourished for the future of her ‘house.’ True, she began to poison her eldest daughter, but that was because she thought her a ninny. She was seized with regret, however, and made her drink milk as an antidote.
Such was one of her dominant preoccupations. To this must be added her longing to live with ‘honour,’ that is, with a brilliant household, with beautiful ornaments, keeping up a great style, and entertaining her lovers with magnificence. She longed for ‘the glory of the world,’ a phrase continually on her lips. It was for ‘honour’ that she poisoned so many people. Such was her own statement.
The martyrdom of her brother the civil lieutenant lasted three months. ‘He grew thin,’ declares his physician, ‘and emaciated; lost his appetite, often vomited, and had burning pains in the stomach.’ He died on June 17, 1670. The councillor died in the following September. In this case, Dr. Bachot, the civil lieutenant’s usual attendant, along with surgeons Duvaux and Dupré and the apothecary Gavart, declared after an autopsy that the deceased had been poisoned; but so little were the perpetrators of the crime suspected that La Chaussée drew a hundred crowns left him by his master as a reward for his faithful service.
We must follow the career of the marquise after the poisoning of her father and brothers, to understand to what depths her ill-regulated passion had thrown this woman, who belonged to the highest ranks of society by her name, her fortune, and the position of her family, and who was so charmingly endowed by Nature.
She was at the mercy of a lackey, who held her honour and her life in his miserable hands. ‘She used to receive him privately in her sitting-room, where she gave him money, saying, “He is a good fellow, and has done me great service”; and she caressed him.’ Visitors coming upon her unawares found the marquise ‘in great familiarity with La Chaussée,’ and ‘she made him hide behind her bed when the Sieur Cousté came to see her.’
Sainte-Croix was a more formidable accomplice. What must have been the agony of this proud and passionate woman when she understood little by little that this man, to whom she had sacrificed everything, had seen in her only an instrument of his own pleasure and fortune, and now profited by his mastery of her secrets to squeeze money out of her by the most vulgar methods of intimidation! Sainte-Croix had locked up in a small box, which was to become famous, the letters, thirty-four in number, sent him by the marchioness, the two promissory notes signed by her after the murder of her father and brothers, and several bottles of poison. ‘The said Lady Brinvilliers coaxed Sainte-Croix to give her his box, and wished him to give her her note for two or three thousand pistoles; otherwise she would have him poniarded.’ The woman speaks out in this last phrase. At other times, desperate, frantic with terror, she thought of poisoning herself. She implored Sainte-Croix to give her the box, and when she received no answer, sent him this touching note: ‘I have thought it best to put an end to my life, and I have therefore taken this evening what you gave me at so dear a price—the recipe of Glaser; by which you will see that I have willingly sacrificed my life to you; but I do not promise you, before I die, that I will not await you somewhere to bid you a last farewell.’ In the last line she becomes herself again; there you have the menace of the offended woman.
What scenes for a romancer to write! One day, by way of reply to these cries of blood, Sainte-Croix made her swallow poison. It was arsenic; but the pain she felt warned her immediately, and she absorbed great quantities of warm milk and so saved herself. She was ill from the effects for several months. She declared after the death of Sainte-Croix ‘that she had done what she could to get the box from him while he was alive, and if she had succeeded, she would afterwards have cut his throat.’