The Germ Theory of Disease 1862 – Invisible Creatures

French chemist and microbiologist Louis Pasteur conducted pioneering research into the causes and prevention of disease and carried out experiments to support the idea that microorganisms cause many diseases, known as the "germ theory of disease" .

In a famous experiment in 1862, Pasteur showed that bacterial growth in sterilized nutrient solutions did not result from spontaneous generation (abiogenesis). The theory of spontaneous generation proposes that life frequently arises from nonliving matter. For example, no organisms developed in a flask with a long, thin, curved neck that made it unlikely for dust, spores, and other particles to enter the solution. Pasteur observed that organisms began to grow in the medium when the flasks were broken. 

During his career, Pasteur also studied

• wine fermentation, as well as diseases in sheep and silkworms. 
• Pasteur, who developed a vaccine against rabies, demonstrated that pasteurization (heating a drink at a specified temperature for a period of time) reduces microbial growth in food. 
• In his anthrax studies, he showed that even highly diluted solutions of bacteria from the blood of infected animals could kill animals if the bacteria were allowed to multiply in a culture medium before being injected into the animals.

Pasteur was not the first person to suggest that invisible creatures cause disease. Indeed, Roman scholar Marcus Terentius Varro had issued the warning "Beware of creatures that cannot be seen with the eye, move through the air, and enter the body through the mouth or nose, causing serious illnesses" in 36 BC. However, Pasteur's extensive scientific experiments on microbial causes of disease revolutionized medicine and public health.

Description of the Article Image: Louis Pasteur conducting an experiment

Historical Figures Mentioned in This Article: Marcus Terentius Varro (116 BC–27 BC), Louis Pasteur (1822–1895)

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