Among the proofs against her, that which alarmed her the most was a written confession containing a narrative of her life, kept by her in the casket which she made such desperate efforts to recover. No wonder she was now horrified at what she had thus committed to paper. In the first article she declared herself an incendiary, confessing that she had set fire to a house. Madame Sevigné, speaking of this paper, says, "Madame de Brinvillier tells us, in her confession, that she was debauched at seven years old, and has led an abandoned life ever since; that she poisoned her father, her brothers, and one of her children; nay, that she poisoned herself, to try the effect of an antidote. Medea herself did not do so much. She has acknowledged this confession to be of her writing,--a great blunder; but she says she was in a high fever when she wrote it,--that it is mere frenzy,--a piece of extravagance which no one can read seriously." In a subsequent letter, Madame de Sevigné adds, "Nothing is talked of but the sayings and doings of Madame de Brinvillier. She says in her confession that she has murdered her father;--she was afraid, no doubt, that she might forget to accuse herself of it. The peccadilloes which she is afraid of forgetting are admirable!" The proceedings of her trial are fully reported in the _Causes Célèbres_. She found an able advocate in the person of M. Nivelle, whose pleading in her behalf is exceedingly learned and ingenious. He laboured hard to get rid of the confession; maintaining that this paper was of the same nature as a confession made under the seal of secrecy to a priest; and cited a number of precedents to show that circumstances thus brought to light cannot be used in a criminal prosecution. Her confused, evasive, and contradictory answers to the questions put to her on her interrogatory by the court,--a very objectionable step, by the way, of French criminal procedure,--were considered as filling up the measure of evidence against her; though, in this case, it was sufficiently ample without the aid either of her confession or examinations before the judges. The _corpus delicti_ (in the language of the law) was certain. The deaths of her two brothers by poison were proved by the evidence of several medical persons; and the testimony of other witnesses established the commission of these crimes by St. Croix and her, through the instrumentality of La Chaussée.