When the big 19e chemist and microbiologist of the century Louis Pasteur died in 1895, his will specifying that his treasure of 102 laboratory notebooks be kept private forever. About 75 years later, however, one of his heirs donated them all to the Bibliotheque Nationale in Paris. What scholars have found in these notebooks shows that Pasteur was a brilliant scientist but also fundamentally dishonest.
1. Pasteur started out as a chemist. During those early years, he discovered that many molecules and chemical compounds are “chiral”. It’s a word that comes from cheir, the Greek word for “handed over”. In the same way that the left and right hands are asymmetrical while being mirror images of each other, many molecules are “handed”. The properties of “left-handers” are generally different from those of their mirrored “right-handers”.
2. For example, tagatose is a natural sweetener. Chemically, it is an asymmetric mirror image of milk sugar (lactose). Both are sweet. Even so, human digestive systems cannot easily absorb tagatose. This is why, for us, it is “no cal. Spearmint and caraway oils are mutually chiral. They have different smells. Many pharmaceutical compounds are enantiomers (which is the word for mutually chiral pairs).
3. Some time after Pasteur discovered chirality, he became a microbiologist. He was the scientist who gave the world strong evidence that germs, not evil spirits or miasmas, cause disease.
4. Perhaps most famous, Pasteur created the process now known as pasteurization. Heat (in the right amount and at the right time) applied to each molecule of milk or juice (for example) kills many germs without affecting the taste.
5. Pasteur also developed three first vaccines. One avoided chicken cholera, the other protected anthrax, and the other overcame rabies infections. In general, Pasteur and Edward Jenner have demonstrated the compelling benefits of vaccines in saving lives. Unfortunately, the general acceptance of Pasteur’s last two vaccines depended on gargantuan disappointments.
6. Anthrax is a naturally occurring bacteria that can be fatal to humans and other animals. It is found in the soil, which is why grazing cattle are particularly vulnerable. In 1881 there was an epidemic among the sheep. Pasteur created a weakened anthrax sample and injected 25 sheep with two hits each. Then he injected full strength anthrax into those sheep and into 25 unvaccinated sheep as well. All 25 vaccinated animals survived. All unvaccinated animals died.
7. Hallelujah, the vaccine worked! So what is the problem? Ethical scientists share facts and methods so that other scientists can build on their findings and science in general can advance. Pasteur, however, lied about how he developed the vaccine. He said he weakened the anthrax by exposing it to oxygen. (This was essentially how, in the 1870s, he had weakened the cholera bacteria that killed chickens.) In fact, he weakened his anthrax samples with a technique that veterinarian Jean-Joseph Toussaint had put in place. on point. Toussaint’s method was based on the chemical potassium bichoromate. If Pasteur had taken the time to attenuate his anthrax samples with oxygen, he would have created a safe and effective vaccine, but too late to have won the monopoly on vaccine production.
8. Pasteur’s oxygen method ultimately produced a safe and effective vaccine. But, come on. Cheating is cheating.
9. Pasteur’s rabies vaccine has also worked wonderfully. Once again, however, he cheated with the “twist” he put on things.
10. Rabies is a viral disease usually transmitted by bites from animals. Affecting the brain, it is almost always fatal, and death is particularly excruciating.
11. In 1885, Pasteur took brain tissue from infected rabbits and attenuated the virus. He tested the vaccine on dogs. Perfect! Then he made people talk about his success. During this time, he developed another method to weaken the rabies virus in rabbit brain tissue.
12. Due to the much publicized success of Pasteur’s first method, a young boy named Joseph Meister who had been bitten 14 times by a rabid dog was brought to him. Pasteur assured the mother of the child with news of her safe and effective vaccine.
13. If Pasteur had been honest, however, he would have explained to the mother that he was about to inoculate her son with the weakened rabies virus by his new method. He had never tested it on anyone, not even on dogs.
14. Pasteur administered Joseph Meister 13 inoculations of untested vaccine over 10 days.
15. Fortunately, the new method was as safe and effective as the one already tested. The child has lived.
Pasteur once quoted the poet Virgil: “Audentes fortuna juvat.” Luck comes to the daring.
Well yes. But sometimes not. What if little Joseph Meister had died when the already tested formulation of the rabies vaccine might have saved him? With the child dead and Pasteur in disgrace, how long would it have taken another scientist to develop a brand new rabies vaccine? How many people have died of rabies in the meantime?
Vaccines work wonders. It is not in question. In my mind, Louis Pasteur’s reputation should be.
Other articles in the Vaccine arch series:
—The Villains and Heroes of the Yellow Fever Vaccine, in 30 facts and with a line of lyrics by Johnny Cash
—25 facts about coronavirus and diphtheria vaccines: stories from the vaccine vault
—Vaccines against smallpox and coronavirus: 30 facts from “The Vaccine Vault”