Louis Pasteur (1822??895) was a French chemist and microbiologist renowned for his discoveries of the principles of vaccination, microbial fermentation and pasteurization. He reduced mortality from puerperal fever, and created the first vaccines for rabies and anthrax.

Pasteur's medical discoveries provided direct support for the germ theory of disease and its application in clinical medicine. Together with Ferdinand Cohn and Robert Koch, he is regarded as one of the three main founders of bacteriology.