Pasteur's Experiment

Pasteur's experiment demonstrated that microbes in the air cause spontaneous fermentation. He used swan-neck flasks with nutrient broth, allowing air in but preventing microbes from reaching the broth. When the broth remained sterile after boiling, no microbes grew. However, if the neck or broth was broken or contaminated, microbes appeared. This showed microbes come from the environment, not spontaneously generating. The experiment provided strong evidence that microorganisms are introduced from outside sources, supporting the germ theory of disease and the idea that sterilization prevents microbial contamination.