Puzzle No. 67: Chain

The germ theory of disease holds that specific microorganisms such as bacteria invade the body and cause specific infectious illnesses, overturning the long-dominant miasma theory that attributed disease to bad air. Louis Pasteur laid the groundwork in the 1860s and 1870s by disproving spontaneous generation, demonstrating that microbes cause fermentation and decay, and linking germs to disease in silkworms, work that culminated in his anthrax vaccine of 1881. The decisive proof came from Robert Koch, who isolated the anthrax bacillus in 1876 and, on 24 March 1882, announced before the Berlin Physiological Society that Mycobacterium tuberculosis was the cause of tuberculosis, then the leading cause of death in Europe. Koch followed with the cholera bacterium in 1883 and codified Koch's postulates, the rigorous criteria for proving that a particular microbe causes a particular disease. The establishment of germ theory revolutionised medicine, surgery, and public health, providing the scientific foundation for antiseptic practice, vaccination, sanitation, and the entire discipline of bacteriology.

Read the full story · See the world in 1882 CE

Before Germ Theory of Disease Established by Pasteur and Koch

Before Germ Theory of Disease Established by Pasteur and Koch

Before Germ Theory of Disease Established by Pasteur and Koch

Before Germ Theory of Disease Established by Pasteur and Koch

Before Germ Theory of Disease Established by Pasteur and Koch

Before Germ Theory of Disease Established by Pasteur and Koch

Before Germ Theory of Disease Established by Pasteur and Koch

Before Germ Theory of Disease Established by Pasteur and Koch

Before Germ Theory of Disease Established by Pasteur and Koch

Before Germ Theory of Disease Established by Pasteur and Koch