Despite this discovery, word on the
Marsh test had not reached Brive. The doctors doing the autopsy on Lafarge only took the stomach before burial, and they subjected this body part to the old methods, which, unknown to them, proved to be unreliable; but they finally asserted that arsenic was found in quantity in the body of Charles Lafarge. More surprising was the analysis of the rat-poison paste; it turned out to be nothing more than a mixture of flour, water and soda. This led to the possibility that Marie used the real arsenic to murder her husband. Any remaining doubts that may have lingered vanished when Emma Pontier turned over the small malachite box, and Dr. Lespinasse found that it contained arsenic. Marie was arrested and held in jail in Brive. A young French lawyer,
Charles Lachaud, was appointed to her defense and was assisted by three others, Maîtres Théodore Bac (who later became mayor of
Limoges during the
1848 Revolution), Paillet, and Desmont. Before they began their work, there was another surprise. The newspaper stories regarding Marie Lafarge turned up something from her past.
Theft Before she met Charles Lafarge, Marie had gone to the châteauone of the viscountess de Léautaud, one of her schoolmates. While there, her friend's jewels disappeared, and the sûreté was called to investigate the matter. When it was suspected that Marie was the culprit, the viscount thought that too improbable, and the matter was not pursued. In the wake of the newspaper stories regarding the murder, the viscount was reminded of the theft and demanded a search for the jewels in Marie's room in Le Glandier. When the jewels turned up during the search, some newspapers believed her and put all the blame on the viscountess. Nonetheless, when she was put on trial for theft, the court was not so persuaded. Marie was found guilty and sentenced to two years' imprisonment in the nearby town of Tulle.
Trial By this time, the Lafarge affair had generated so much interest that the curious arrived from all over Europe to watch her murder trial, elevating it to a cause célèbre. Thus, when Marie entered the
assize court of Tulle for the first time on 3 September 1840, dressed in mourning and carrying a bottle of
smelling salts in her hand, projecting the image of a woman unjustly accused, the spectators immediately were divided into pro- and anti-Marie factions. Coincidentally, Maître Paillet, one of Marie's defense lawyers, was also the lawyer of the renowned toxicologist
Mathieu Orfila, who was the acknowledged expert on the Marsh test in France. He realized that as the case hinged largely on the tests made by the Brive doctors, Paillet wrote to Orfila and showed him the test results. Orfila then submitted an
affidavit stating that the tests were conducted so ignorantly that they meant nothing. As soon as the Brive doctors testified that arsenic was present in Lafarge's body, Paillet read the affidavit aloud, told the court about the Marsh test, and demanded that Orfila be called. The prosecutor replied that he would consent to the test because he was confident of Marie's guilt, but he felt there was no need to call on Orfila to do it. The president of the court ruled in favor of the prosecutor's suggestion. Therefore, in lieu of Orfila, two well-known apothecaries from Tulle, M. Dubois and his son, and a chemist from Limoges named Dupuytren, were assigned to conduct the tests. While they were performed, the trial proceeded at a snail's pace. When they finally entered the courtroom, everyone waited to see what they would say. The elder Dubois testified that despite using the Marsh test carefully, they failed to find any arsenic. Almost immediately, the courtroom was in an uproar as Marie felt vindicated. By then, the prosecutor had read Orfila's book and knew that in some cases, the arsenic left the stomach but had spread to other parts of the body. He arranged for the body of Lafarge to be exhumed. Again, the three chemists performed the test on the samples taken—and again, no arsenic was found. The prosecutor had one card left to play. He had not forgotten the food items that Marie gave to Charles and were set aside. He requested that the test be performed on those as well. The defence, by then in a magnanimous mood, agreed. This time, when the chemists arrived, they declared that they tested positive for arsenic, with the eggnog containing enough "to poison ten persons". The prosecutor took this fact as a chance to recoup his earlier setbacks. He declared that in view of the contradictory results, it was apparent that the court should call upon Orfila to settle the issue once and for all. Because it was the defence who originally asked for Orfila, they could not object to this request. The defence agreed, confident of Marie's acquittal.
Mathieu Orfila When Orfila arrived, he insisted that the local chemists witness his experiments that night. He used the same test materials and chemical reagents that they used in the earliest tests and performed the Marsh test in an anteroom of the courthouse, behind locked and guarded doors. At last, on the afternoon of the next day, Orfila entered the courtroom, followed by the three chemists with bowed heads. He declared that he had found arsenic on the samples taken from the body of Lafarge, excluding all other extraneous sources, such as arsenic naturally occurring in the body, from the reagents, or from arsenic from the earth surrounding the coffin. The courtroom was stunned, especially Maître Paillet, as he listened to Orfila, his client and defense witness, explain the misleading results obtained by the local experts with the Marsh test. It was not the test that gave the erroneous results, but rather, the test was performed incorrectly. Knowing that Orfila's testimony had tipped the balance against them, the defense team sought to call a known opponent of Orfila,
François Vincent Raspail, to refute his testimony. While Raspail had agreed, as he had done in previous courtroom clashes with Orfila, he arrived four hours too late. The jury had decided on Marie's case: guilty. ==Conviction and controversy==