Liotot was a surgeon with the La Salle expedition. Most of what has been written of him is based on the assumption that he was the only member of the company to serve in that capacity. Both Henri Joutel and Pierre Talon, however, suggest otherwise. Since accounts of the expedition frequently mention "the surgeon" without naming him, it is difficult to distinguish Liotot's deeds. It is not known with certainty, for example, that Liotot delivered the Barbier infant, the first White child of record to be born in Texas; or whether he treated Crevel de Moranget (whom he later murdered) when Moranget was seriously wounded by a Karankawa arrow. It probably was Liotot who amputated the gangrenous leg of Sieur le Gros, victim of a rattlesnake bite. This first known surgical amputation of a limb in Texas did not rescue the patient, who later died, and the surgeon's name does not appear.
Liotot's medical-surgical services, in any case, are overshadowed by other deeds attributed to him by Joutel: he was the axe murderer of three of La Salle's men and a participant in the plot by which the leader himself was assassinated. He waited in ambush with La Salle's slayer, Pierre Duhaut, then mocked the leader as he lay lifeless on the ground, derisively calling him grand basha. Some weeks later, while the Frenchmen were still among the Hasinai, Liotot himself was slain. This second round of bloodletting began with a falling-out between Duhaut and Hiems, or James, whom Joutel describes at one point as La Salle's surgeon. While Hiems fatally shot Duhaut, his companion, Rutre (or Ruter), shot Liotot, apparently to prevent him from interfering. Pierre Talon, who was eleven years old at the time, attributes to "an Englishman named James [Hiems]" the part in La Salle's murder that Joutel assigns to Liotot. His confusion of identities probably resulted from both Hiems and Liotot serving as surgeons. Although agreeing that James killed Duhaut, Talon further confuses events by stating that James was killed a few days later by Rutre, and that Rutre was subsequently slain by "a surgeon." The surgeon, fearing the same fate, went to live among the Toho tribe, taking Pierre Talon with him. Talon claims to have witnessed this surgeon's death during the Tohos' battle with an enemy tribe. This account notwithstanding, it appears certain that Liotot died by Rutre's gun, as Joutel says he did.