Louis Pasteur: Biography of a Great Thinker || History of Science

Louis Pasteur's early academic efforts were not stellar, but he was persistent and enthusiastic about his widely varied interests. After a few failed starts at a few different institutions, he eventually succeeded in his studies in chemistry and physics, obtained his medical license, and most fortunately found a good mentor in Antoine Ballard, the chemist who discovered bromine. Although Pasteur had earned a position as a physics professor at another institution, Ballard wanted Pasteur to stay in his lab at the Ecole Normale Supérieure as a graduate student in chemistry. Never underestimate the importance of a fertile working environment. While in Ballard's lab, Pasteur did groundbreaking work in crystallography. Louis Pasteur's thesis work, an analysis of crystallized tartaric acid, showed there were two different versions of the molecule formed. Depending on whether the molecule was isolated from living material, the yeast used in making wine, or synthesized in the lab. Pasteur carefully examined the crystals by shining light through them, and found that the yeast-derived crystal bent light one way, but the synthesized crystal bent light in the opposite direction. And if he mixed the two kinds of crystals together in equal amounts, they canceled each other out and the light wasn't bent at all. This was the first time anyone had demonstrated two chiroforms, or handedness, of the same molecule. After making a name for himself in crystallography, Pasteur was offered multiple academic positions, and soon became the dean and professor of chemistry at the new Faculty of Sciences in Lille. Lille is not known as a cultural capital like Paris. Rather, it's more of an industrial town, known for its wineries and distilleries. The Ministry of Public Instruction encouraged the faculty of Pasteur's new school to make themselves useful to the public, and not hide away in their ivory towers. The people of Lille needed help with their food going bad. The wineries often had problems with their wine turning to vinegar. The dairies had problems with milk spoiling. Beer would go off, but no one could understand why. Pasteur tackled all these problems, and at the same time took on the common misconception of spontaneous generation. That is, people still commonly thought life sprang out of non-living material, like spoiling meat giving rise to nuggets. Pasteur was able to show that the beverage's spoiling was due to biogenesis, that is, the presence of microorganisms multiplying and spoiling the food. He put a clean sample of boiled broth in a swan-necked flask. If left undisturbed, it would not spoil. But if he broke the neck off the flask, the broth went bad. Pasteur was able to show that it was the presence of microorganisms that were settling in the neck of the swan-necked flask that were getting into the broth, not due to spontaneous generation from the broth itself. Pasteur concluded that it was microorganisms that were responsible for spoiling other beverages, such as wine, beer, and milk, and developed a heating process to reduce the number of microorganisms and keep food from spoiling for an extended period of time. We call this process pasteurization and use it to this day. Pasteur also made invaluable contributions to the silkworm industry, which was flagging due to the loss of many silkworms to disease. Pasteur was able to identify the microbe attacking silkworm eggs, thereby rescuing an important sector of French commerce. Pasteur's experience with microbes causing spoilage of food and infections in animals led him to encourage doctors to sanitize their equipment and to wash their hands before surgery. After the tragic loss of three of his children to typhoid fever, Pasteur focused all of his attentions on combating infectious disease. Pasteur continued to make groundbreaking discoveries in the most unlikely of conditions. For example, he was studying cholera in chickens. Through a series of lucky coincidences, Pasteur and his assistant unknowingly inoculated their chickens with the weakened batch of cholera bacteria. The chickens recovered quickly rather than dying, and afterwards could not be infected with a good batch of the bacteria. Pasteur concluded the animals were now immune to the disease, and he saw a new way to make vaccines, a less virulent form serving as protection against a deadly form of a disease. As Pasteur said in a lecture to his students at Lille, chance favors the prepared mind. A less intuitive scientist might have scrapped the entire experiment, but Pasteur understood the implications of the results. He went on to create vaccines for anthrax and rabies. The story of Pasteur testing his rabies vaccine is right out of a Hollywood movie. Pasteur and his colleague Emile Roux had successfully tested the vaccine on dogs, but the first human trial was an unplanned and desperate act. On July 6, 1885, Pasteur administered the vaccine to nine-year-old Joseph Meister, who had been viciously mauled by a rabid dog. Pasteur was not a licensed medical doctor at the time and could have gone to prison, but thankfully the boy lived and Pasteur was hailed as a hero. So great was the resulting acclaim that Pasteur was able to found the Pasteur Institute in Paris, dedicated to fighting infectious disease. It still stands and is world-renowned for the many discoveries made there. It is now also a mausoleum and houses the tomb of its namesake, the father of germ theory, the father of microbiology, Louis Pasteur.