The Other Side of Louis Pasteur’s Discoveries in Science and Medicine

Known for his achievements in the development of Germ Theory and the rabies vaccine, Louis Pasteur’s laboratory notebooks show us a story rarely told.

We received an email from a student who is researching the moral and ethical issues around human subject experimentation as it pertains to the decision by Louis Pasteur to use his experimental vaccine on Joseph Meister in 1885. The reader noted this entry in the History of Vaccines timeline:

That entry reads, in part: “Pasteur had never before successfully used the vaccine on a human. (Pasteur’s notebooks indicated that two previous attempts had been made. One involved a 60-year-old man who left the hospital after only one injection and did not return. The other was 10-year-old girl, treated with one injection, who died before the second could be given.)” The student could not find a source for that information. Lucky for them, we here at the History of Vaccines always have our sources handy. We like to be ready when someone asks for a citation.

The article we used is The Science of Louis Pasteur: A Reconsideration.1 The commentary paper is itself a response to a paper from 1993 by history professor Gerald L. Geison at Princeton. Louis Pasteur, like many scientists still do today, kept a detailed set of notes on his experiments. Those notebooks were not made available to the public until the 1970s. It was then that Professor Geison started looking into the life and times of Pasteur. His work culminated in a paper that found at least three instances of scientific misconduct by Louis Pasteur.

First, Louis Pasteur lied in saying that a successful vaccine against anthrax was made using his techniques. The technique used for the vaccine in that trial belonged to a colleague. Pasteur’s technique apparently didn’t produce a good vaccine, so he chose to use the other technique to save face. Second, he gave his rabies vaccine candidate to two people, a man and a little girl. The man left the hospital after just one injection and was lost to history. The little girl died a few days later. Both had been exposed to potentially rabid dogs, so Pasteur was “consulted” on what to do to save them, so he chose to use his experimental vaccine. Finally, the third instance of scientific misconduct is the story we have all heard about: young Joseph Meister is bitten by a rabid dog, and Pasteur administers his experimental vaccine, saving Joseph’s life. A second young boy went through the same procedure.

We’ll spare you the ethical/moral discussion over his experiments.

While Pasteur advocated for animal experiments before moving on to human trials, it seems that he did not conduct experiments in that order when it came to the rabies vaccine. According to Professor Geison, Pasteur famously said that his rabies vaccine had been tested on dozens of rabid dogs, with good results. But that was not the case. Because of his success with Joseph Meister and Jean Baptiste Jupille, Pasteur started administering his vaccine to people, with no evidence that he went through the dog trials he claimed to have done publicly.

Viewed through the lens of modern ethical standards (and laws) on experimentation with human subjects, what Pasteur did could be classified as misconduct. However, rabies was — and still is — one hundred percent deadly if the infection is allowed to progress to symptoms without a post-exposure vaccine. Certainly, that is something that allowed Louis Pasteur to do what he did. However, as Professor Geison also points out, the stunt with the anthrax vaccine cannot be justified even when looking at it with the sensibilities of the late 1800s.

Pasteur and the institute he founded made significant contributions to the advancement of science and technology. For well over a century, students have been learning of the greatness of Louis Pasteur and how his flask experiments led to the acceptance of Germ Theory as the best theory of how infectious disease works to go from person-to-person. However, very little is mentioned about the contents of his notebooks, which are quite the insight into the workings of a brilliant mind.


  1. Martinez-Palomo, A. (2001). The Science of Louis Pasteur: A Reconsideration. The Quarterly Review of Biology76(1), 37–45.

Author: René F. Najera, DrPH

I am the editor of the History of Vaccines site, an online project by the College of Physicians of Philadelphia. All opinions expressed on these blog posts are not necessarily those of the College or any of my employers. Check out my professional profile on LinkedIn: Feel free to follow me on Twitter: @EpiRen