Microorganisms
In Lazzaro Spallanzani's Experiment he proved microorganisms could be killed by boiling. He believed microbes move through the air and could be killed by boiling. Spallanzani filled 4 flasks with a broth. One flask was left opened, one flask was sealed, one flask was boiled and left open, and one flask was boiled and sealed. The first flask was left open and turned cloudy, and microbes were found. flask two remained sealed and again microbes were found and the broth was cloudy. Flask three again the same thing happened. However in flask four the broth was not cloudy and no microbes were found. This proved to Lazzaro that microbes do not form out of nowhere. If microbes formed out of nowhere then all flasks would have microbes. Critics of Spallanzi said he killed the life force that was required for spontaneous generation. This experiment paved the way for research later done by Louis Pasteur.