His famous experiment, conducted in the 1860s, involved using swan-necked flasks. These flasks allowed air to enter but prevented dust particles (and therefore any airborne bacteria) from reaching the broth inside.
Here's how the experiment worked:
1. Sterile broth: Pasteur boiled broth in swan-necked flasks, killing any existing bacteria.
2. Exposure to air: The broth was then left exposed to the air, but the swan-neck prevented dust particles from entering.
3. No growth: The broth in these flasks remained clear, indicating no bacterial growth.
4. Breaking the neck: Pasteur then broke the necks of some flasks, allowing dust particles to enter the broth.
5. Growth: This broth quickly became cloudy, showing bacterial growth.
This experiment convincingly demonstrated that bacteria only arise from existing bacteria, disproving the theory of spontaneous generation which proposed that life could arise from non-living matter. This was a landmark discovery in the field of microbiology and contributed significantly to the development of germ theory.
