He conducted a series of experiments in the mid-1800s using swan-necked flasks. These flasks allowed air to enter but prevented dust and other particles from reaching the broth inside.
Here's how his experiments worked:
1. Sterilize the broth: Pasteur boiled broth in swan-necked flasks, killing any existing microorganisms.
2. Leave the flasks open: He left the flasks open to the air, allowing air to flow in but preventing dust and particles from reaching the broth.
3. Observe the results: The broth in the swan-necked flasks remained clear and sterile, even after long periods.
4. Break the neck: Pasteur then broke the neck of some of the flasks, exposing the broth to the dust and particles in the air.
5. Observation: The broth in the broken-neck flasks quickly became cloudy with microbial growth, showing that the microorganisms came from the air, not from the broth itself.
These experiments disproved the long-held theory of spontaneous generation, which claimed that living organisms could arise from non-living matter. Pasteur's work helped establish the foundation for the germ theory of disease and revolutionized our understanding of biology.
