The train that departed Cassis for La Ciotat on the 22nd of July, 1876, carried two passengers in a single second-class compartment: young Rozès-Salles, who had just sat for his examinations at Saint-Cyr, and Édouard de Bouyn, a thirty-one-year-old mechanician whose existence was already consumed by dubious inventions and enterprises that the Gazette des Tribunaux would soon deem dangerous. When the convoy rolled into the station, one of them lay lifeless upon the carriage floor; the other, seated beside his travelling bag, appeared unable to answer the calls directed at him.
Shouts had alerted the passengers. At La Ciotat, stationmaster Malière entered the compartment to find the body of Rozès-Salles, Bouyn, and an open bag. Inside it he discerned a curved tube, fragments of glass or earthenware, a pocket watch with a broken chain, and a purse. These latter two articles belonged to the deceased. One Bubaton, who had quit his first-class compartment and reached the carriage along the footboard while the train was still in motion, had perceived Bouyn near the carriage door, his hand resting upon the bag; he seized him by the collar and held him fast until the train stopped.
At La Ciotat, the youth’s kin were waiting. Boubée, a naval lieutenant and brother-in-law to Rozès-Salles, testified before the court that the family had rejoiced at the thought of welcoming him home after his examinations. Seeing no sign of him, he had made his way toward the platform and sought information, only to learn at last that the young man had been discovered dead in a carriage. He and his wife were cast into consternation. Behind the legal exhibits seized by justice, the testimony restored to view those loved ones to whom this brief journey was meant to return a son and brother.
The prosecution disputed at the outset that any third man had travelled in the compartment. Between Cassis and La Ciotat, the train had made no intermediate stop; the doors were shut when opened at the station, and no witness had seen a passenger escape. Bouyn had initially spoken of a commercial traveller who, he claimed, had compelled both himself and Rozès-Salles to drink a liquid before vanishing. Then, during the preliminary investigation, he admitted that they had been entirely alone. He conceded that death could have come from none other than himself, whilst persistently repeating that he knew neither the cause nor the manner of it.
This memory, so remarkably minute upon so many subjects yet so utterly blank at the decisive hour, became one of the central threads of the proceedings. Bouyn spoke readily of his experiments, his machines, and his chemical attempts to manufacture diamonds; he answered the presiding judge’s inquiries with composure, only to declare himself incapable of recollecting the journey itself. As for the watch and the purse found in his bag, he claimed to have gathered them up mechanically. Justice perceived in their presence the clear proof of theft; the defence was to plead a wandering of the mind.
The investigators had discovered rubber bulbs, glass tubes, phials, and stitched compresses in the bag and along the permanent way. A pungent odour had struck the first travellers who stepped into the wagon. Several items corresponded to instruments sold to Bouyn by an instrument-maker dealing in electrical apparatus, who notably recognized a rubber bulb from his shop. The accused maintained that the device answered the needs of a secret infirmity; the physicians, upon examining him, found no trace of the alleged disease.
The inquiry likewise traced Bouyn’s researches into chemical agents. In a grotto near Marseilles, the authorities unearthed phials, acids, and laboratory instruments. According to the prosecution, he had prepared prussic acid and fitted a phial with tubes and a rubber bulb suited to ejecting its contents as a spray. He was alleged to have carried this apparatus aboard the train and directed the jet full at his companion. The press recounted this modus operandi with all the certitude of the bill of indictment; yet it recorded at the same time that the physicians discovered neither prussic acid nor chloroform in the stomach of the deceased. This absence was explained by the medical experts through the extreme volatility of the substances in question. Their reasoning thus preserved the hypothesis of poison, without ever turning their negative findings into positive discovery of its presence.
At the hearing of the 23rd of February, 1877, in Aix, the interrogation shifted the matter from the laboratory back to the railway carriage. Bouyn recounted the stages of his studies, his life in Marseilles, and the inventive schemes that, he declared, wholly absorbed his mind. He did not dispute that he and Rozès-Salles were the sole occupants. He acknowledged that he alone could have caused the youth’s death, yet protested that he remembered nothing of it. On the morrow, his mistress, the widow Thiriot, gave evidence regarding his fixed ideas and nocturnal hallucinations; she recounted that he had once stripped her of her bedsheets to construct a flying machine. Sister Saint-Thérèse reported words he had spoken at the hospital: when asked why he had not perished as well, he had reportedly answered, “I did what I could.” The keeper of the house of detention, on the contrary, described a calm prisoner capable of behaving with perfect reason, and suspected him of feigning.
The medical men summoned to the bar offered no uniform picture. Rousset described the objects and experiments discovered in the cavern; Rampal recalled Bouyn’s evasive answers touching the crime and the absence of any volatile residue in the stomach. Caillaux, who had examined the prisoner for several months alongside Rampal, deemed him criminally responsible, though family predispositions and his personal state ought, in his view, to diminish that responsibility. The physicians were apprised of a prior examination conducted in 1872 during a distinct prosecution for the theft of copper and lead. That earlier matter had ended in an acquittal. It was revived in the debates merely as a medical precedent; it resolved nothing concerning the traveller who had died upon the rails.
The presiding judge announced his intention to summon Dr. Castellan, who had taken part in that previous examination. The defence likewise requested Dr. Silbert, while the public prosecutor sought to hear Dr. Pontier, director of the Aix asylum. Their actual examination at the bar is not recorded in the proceedings. Maître de Séranon pressed above all that Bouyn’s father and brother be heard: the latter, he argued, might recount a nocturnal assault committed against him by the accused. The Advocate General demanded communication of the documents relied upon. The court declared it saw no utility in hearing the kin. The recorded refusal applied strictly to those two men; it does not warrant the conclusion that the requests concerning all the physicians were likewise rejected.
The depositions had clearly established the journey, the cries, the body, the bag, and the effects found therein. The prosecution set these facts alongside the seized apparatus, Bouyn’s successive statements, and his partial confessions. The defence counsel urged the jurors to discern irresponsibility in his hallucinations. Marlier, the Advocate General, maintained that extravagant schemes and disordered conduct could not suffice to obliterate the responsibility of a premeditated act. Maître de Séranon pleaded for an outright acquittal.
Following the closing arguments and the judge’s summing-up, the jury found Bouyn guilty of poisoning, while granting him the benefit of extenuating circumstances. The Court pronounced a sentence of twenty years’ hard labour, adding that upon the expiration of this term, he would remain under the surveillance of the high police. The published report recorded this sentence without specifying the ultimate disposition of the charge of theft.
At the bar, Boubée had spoken of a gentle and pious lad, awaited by his kin after the trials of his examination. Bouyn had spoken of machines, of chemistry, and of a journey of which he claimed to retain no trace. The sentence consigned the latter to twenty years in irons. The former would never return to his hearth: for his family, the arrival of that train had begun with an empty doorway, and ended with the grim answer delivered upon the platform.