Pierre Paul Emile Roux
From the Super Mario Wiki
Pierre Paul Émile Roux, stylized in-game as Pierre Paul Emile Roux, was a scientist who worked closely with Louis Pasteur as an assistant, helping him synthesize vaccines. After being recommended to work under Louis by Émile Duclaux, he and Louis worked on examining and treating various diseases, notably fowl cholera and anthrax, eventually creating a rabies vaccine in 1885 after several years. However, according to Mario's Time Machine, Bowser steals part of the vaccine in a Flask before it can be properly created, and in the process of returning it to its rightful owner, Mario ends up meeting Pierre.
Mario's Time Machine
In Mario's Time Machine, Pierre Paul Emile Roux was living in Paris at some point in 1885, working out of a university, when Mario meets him. Mario politely asks if he's not intruding, and Pierre invites him in, saying that he has some free time since he is no longer assisting Louis Pasteur with his current experiment. Mario asks why he is not helping Louis anymore, and he explains that one of them thought that they were ready to start testing their vaccines on human subjects, while the other thought it was too early. Mario then asks him what is a vaccine, and Pierre uses a vaccine for rabies as an example, describing it as "a preventative dose of the same microorganisms that cause rabies". He also elaborates that he thought that it was too early for human testing, but that Louis pushed on regardless. However, he then goes on to describe him as a caring man. Pierre is only worried because Louis is about to test it on a rabies-infected boy who is certainly going to die if the vaccine fails to work. While Pierre is not sure if it could work on humans, the vaccine has been effective on animals; to prove his point, he gives Mario a vaccinated and healthy Bunny. Mario is impressed by how exciting chemistry is, and Pierre agrees, but he goes to turn on a furnace because he suddenly feels cold. Mario then gives him a Scarf, and Pierre gladly accepts it. He then mentions how he wishes he was still working with Louis, as a stroke left his left arm paralyzed and he now has to rely on assistants, including his wife, Marie Pasteur. Mario then pulls out the Flask in his possession and he wonder if it could help Louis. Pierre quickly recognizes it and demands Mario to bring it to Louis immediately.