French microbiologist and chemist Louis Pasteur (1822- 1895) is the founder of modern microbiology. Like Newton's classical mechanics, Pasteur pioneered the field of microorganisms.

Pasteur was one of the most accomplished scientists in19th century. He conducted many exploratory studies in his life and proved three important scientific problems:

(1) Every fermentation is due to the development of microorganisms. He found that heating can kill those nasty microorganisms that make beer bitter. Soon, "pasteurization" was applied to various foods and drinks.

(2) Every infectious disease is the development of a microorganism in an organism: Pasteur saved the French silk industry by discovering and eradicating a bacterium that invaded silkworm eggs.

(3) Microorganisms infected with diseases can reduce their virulence under special culture and become drug vaccines to prevent diseases. He realized that many diseases were caused by microorganisms, so he established the theory of bacteria.

1889, Pasteur invented the rabies vaccine, which can make people resist the terrible rabies. Other scientists applied Pasteur's basic ideas to develop vaccines against many serious diseases, such as typhus and polio. Although Chen Na, a British doctor, invented the method of vaccination before him, Pasteur was the first person who consciously cultivated and manufactured immune vaccines and widely used them to prevent many diseases.