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Francesco Redi
Francesco Redi performs experiments to challenge spontaneous generation. He placed meat in two containers, one covered and one uncovered, and observed that the uncovered meat putrefied while the covered meat did not. This experiment challenged the belief at the time that living organisms could arise spontaneously from non-living matter. -
John Needham
John Needham conducts experiments that appear to support spontaneous generation. He boiled broth and sealed it in a flask, but microorganisms still appeared in the broth. Needham concluded that spontaneous generation had occurred, but later experiments suggested that he had not heated the broth enough to kill all the microorganisms already present. -
Lazzaro Spallanzani
Lazzaro Spallanzani conducts experiments that challenge spontaneous generation. He boiled broth and sealed it in a flask, and observed that the broth remained sterile even when left for long periods of time. Spallanzani's experiments challenged the idea of spontaneous generation and suggested that microorganisms were not generated spontaneously but rather came from other living organisms. -
Louis Pasteur
Louis Pasteur definitively disproves spontaneous generation with his experiments. He used a swan-necked flask, which allowed air to enter but prevented microorganisms from entering. Pasteur boiled broth in the flask, and observed that the broth remained sterile until the neck of the flask was broken. This experiment demonstrated that microorganisms did not arise spontaneously but rather came from other living organisms.