he tried to detect arsenic using the old methods. While he was successful, the sample had decomposed and did not convince the jury of the defendant's guilt. Frustrated at this turn of events, Marsh developed a glass apparatus that detected minute traces of arsenic and measured its quantity. The sample is mixed with arsenic-free zinc and sulphuric acid, any arsenic present causing the production of arsine gas and hydrogen. The gas then is led through a tube where it is heated, decomposing into hydrogen and arsenic vapor. When the arsenic vapor impinges on a cold surface, a mirror-like deposit of arsenic forms. Arrest and trial 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