Germ Theory

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The germ theory, which emerged in the late 19th century, demonstrated that microscopic germs caused most human infectious diseases. The germs involved included bacteria, viruses, fungi, protozoa, and prions. Louis Pasteur (1822-1895), a French chemist and microbiologist, and Robert Koch (1843-1910), a German physician and microbiologist, are credited with the discovery of the germ theory in the 1860s-1880s.

More about: Germ Theory


  • 1859
    Louis Pasteur disproves spontaneous generation of life.
  • 19 Feb 1878
    Louis Pasteur presents germ theory for the first time.