French biologist and chemist Louis Pasteur (1822–1895) is considered the founder of modern microbiology. His discoveries provided the conclusive evidence necessary to firmly establish the theory of germs, i.e. the fact that microbes are the primary cause of several diseases.
His research disproved the theory of spontaneous generation and paved the way to a new concept of hygiene across the world. He invented the pasteurization process to remove pathogens from food and developed the first vaccine against rabies in 1885.
Thanks to the impact of his studies, many diseases were eradicated in the following decades, relieving humanity from several epidemics that had erupted throughout human history. Joseph Lister, shortly after, revolutionized surgery by introducing antiseptic methods, with surgeons that now started to wash their hands before seeing a patient.
After Pasteur’s death, his assistant Émile Duclaux became the director of the Institute Pasteur, founded in 1887 in Paris and wrote The History of a Mind dedicated to the memory of his mentor.