germ-theory

In 1859, Louis Pasteur designed a flask whose curved neck let air in but kept microbes out. The broth stayed sterile until the neck was broken. Here is the full experiment.

Ignaz Semmelweis proved in 1847 that doctor handwashing reduced puerperal fever deaths from 18% to under 2%. The medical establishment rejected him anyway. Learn why.

Robert Koch proved specific bacteria cause specific diseases, discovered TB and cholera pathogens, and won the 1905 Nobel Prize. His postulates still govern microbiology today.

Louis Pasteur founded germ theory, developed the rabies vaccine, and invented pasteurization. His biography, verified quirks, and the 1995 discovery about his lab notebooks.

The Black Death killed a third of Europe. The 1918 flu killed more people than World War I. Epidemics have redirected history more than any army.

Medicine has gone from bloodletting and prayer to gene editing in just a few centuries. Here's how we got there.