Who was Louis Pasteur and what did he do?

Louis Pasteur was a 19th-century biochemist whose work with germs and microorganisms opened up whole new fields of scientific inquiry, aided industries ranging from wine to silk, and made him one of the world's most celebrated scientists.

Louis Pasteur was born on 27 December 1822 in Dole, Jura, France. He was to become known as the founder of microbiology. Pasteur was the one who discovered the role of bacteria in fermentation. In 1857, through experimentation and research with bacteria, he determined that certain microorganisms contaminated fermenting beverages. He used this knowledge to develop a process whereby liquids such as milk were heated to kill all bacteria and moulds which were already contained within them. This process became known as pasteurisation.

The first test of pasteurisation was completed by Pasteur with the assistance of Claude Bernard, on 20 April 1862. Pasteur then recognised that infectious diseases are caused by microorganisms, and his research soon led others to investigate sterilisation, disinfection, vaccines, and eventually antibiotics. Pasteur created and tested vaccines for diphtheria, cholera, yellow fever, plague, rabies, anthrax, and tuberculosis. The rabies vaccine was first tested on a nine-year-old boy named Joseph Meister, on 6 July 1885. Meister was bitten by a rabid dog, and was subsequently treated by Pasteur with a rabies virus he had grown in rabbits but weakened by drying, a treatment he had earlier tried on dogs. The treatment was successful and the boy survived without ever developing rabies. Joseph Meister later went on to become a caretaker at the Pasteur Institute.

Pasteur was subject to strokes from the early age of 46, and eventually died in 1895 from complications resulting from these strokes.