It lasted one day. The judges had before them the depositions taken by the examining magistrate. Both Derues and his wife were interrogated. He maintained that he had not poisoned either Mme. de Lamotte or her son; his only crime, he said, lay in having concealed their deaths. Mme; Derues said: "It is Buisson-Souef that has ruined us! I always told my husband that he was mad to buy these properties—I am sure my husband is not a poisoner—I trusted my husband and believed every word he said." The court condemned Derues to death, but deferred judgment in his wife's case on the ground of her pregnancy.

And now the frail, cat-like little man had to brace himself to meet a cruel and protracted execution. But sanguine to the last, he still hoped. An appeal lay from the Chatelet to the Parliament of Paris. It was heard on March 5. Derues was brought to the Palais de Justice. The room in which he waited was filled with curious spectators, who marvelled at his coolness and impudence. He recognised among them a Benedictine monk of his acquaintance. "My case," he called out to him, "will soon be over; we'll meet again yet and have a good time together." One visitor, wishing not to appear too curious, pretended to be looking at a picture. "Come, sir," said Derues, "you haven't come here to see the pictures, but to see me. Have a good look at me. Why study copies of nature when you can look at such a remarkable original as I?" But there were to be no more days of mirth and gaiety for the jesting grocer. His appeal was rejected, and he was ordered for execution on the morrow.

At six o'clock on the morning of May 6 Derues returned to the Palais de Justice, there to submit to the superfluous torments of the question ordinary and extraordinary. Though condemned to death, torture was to be applied in the hope of wringing from the prisoner some sort of confession. The doctors declared him too delicate to undergo the torture of pouring cold water into him, which his illustrious predecessor, Mme. de Brinvilliers, had suffered; he was to endure the less severe torture of the "boot."

His legs were tightly encased in wood, and wedges were then hammered in until the flesh was crushed and the bones broken. But never a word of confession was wrung from the suffering creature. Four wedges constituting the ordinary torture he endured; at the third of the extraordinary he fainted away. Put in the front of a fire the warmth restored him. Again he was questioned, again he asserted his wife's innocence and his own.

At two o'clock in the afternoon Derues was recovered sufficiently to be taken to Notre Dame. There, in front of the Cathedral, candle in hand and rope round his neck, he made the amende honorable. But as the sentence was read aloud to the people Derues reiterated the assertion of his innocence. From Notre Dame he was taken to the Hotel de Ville. A condemned man had the right to stop there on his way to execution, to make his will and last dying declarations. Derues availed himself of this opportunity to protest solemnly and emphatically his wife's absolute innocence of any complicity in whatever he had done. "I want above all," he said, "to state that my wife is entirely innocent. She knew nothing. I used fifty cunning devices to hide everything from her. I am speaking nothing but the truth, she is wholly innocent—as for me, I am about to die." His wife was allowed to see him; he enjoined her to bring up their children in the fear of God and love of duty, and to let them know how he had died. Once again, as he took up the pen to sign the record of his last words, he re-asserted her innocence.

Of the last dreadful punishment the offending grocer was to be spared nothing. For an aristocrat like Mme. de Brinvilliers beheading was considered indignity enough. But Derues must go through with it all; he must be broken on the wheel and burnt alive and his ashes scattered to the four winds of heaven; there was to be no retentum for him, a clause sometimes inserted in the sentence permitting the executioner to strangle the broken victim before casting him on to the fire. He must endure all to the utmost agony the law could inflict. It was six o'clock when Derues arrived at the Place de Greve, crowded to its capacity, the square itself, the windows of the houses; places had been bought at high prices, stools, ladders, anything that would give a good view of the end of the now famous poisoner.

Pale but calm, Derues faced his audience. He was stripped of all but his shirt; lying flat on the scaffold, his face looking up to the sky, his head resting on a stone, his limbs were fastened to the wheel. Then with a heavy bar of iron the executioner broke them one after another, and each time he struck a fearful cry came from the culprit. The customary three final blows on the stomach were inflicted, but still the little man lived. Alive and broken, he was thrown on to the fire. His burnt ashes, scattered to the winds, were picked up eagerly by the mob, reputed, as in England the pieces of the hangman's rope, talismans.

Some two months after the execution of her husband Mme. Derues was delivered in the Conciergerie of a male child; it is hardly surprising, in face of her experiences during her pregnancy, that it was born an idiot. In January, 1778, the judges of the Parliament, by a majority of one, decided that she should remain a prisoner in the Conciergerie for another year, while judgment in her case was reserved. In the following August she was charged with having forged the signature of Mme. de Lamotte on the deeds of sale. In February, 1779, the two experts in handwriting to whom the question had been submitted decided in her favour, and the charge was abandoned.

But Mme. Derues had a far sterner, more implacable and, be it added, more unscrupulous adversary than the law in M. de Lamotte.

Not content with her husband's death, M. de Lamotte believed the wife to have been his partner in guilt, and thirsted for revenge.