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Experiments
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Redi’s experiment
In 1668, Francesco Redi, an Italian scientist, designed a scientific experiment to test the spontaneous creation of maggots by placing fresh meat in each of two different jars. ... Redi successfully demonstrated that the maggots came from fly eggs and thereby helped to disprove spontaneous generation. -
Needham’s rebuttal
In England, John Needham challenged Redi's findings by conducting an experiment in which he placed a broth, or gravy, into a bottle, heated the bottle to kill anything inside, then sealed it. Days later, he reported the presence of life in the broth and announced that life had been created from nonlife. -
Criticism from Spallanzani
Spallanzani poured broth into flasks and sealed them. Then, he boiled the flasks for a long time, to kill present microorganisms.
After some time, the broth did not have any trace of life. However, once he unsealed the flask, microorganisms rapidly grew in the broth. Spallanzani concluded that spontaneous generation was false and microbes came from contaminated air. -
Pasteur puts spontaneous generation to rest
Louis Pasteur's 1859 experiment is widely seen as having settled the question of spontaneous generation. He boiled a meat broth in a swan neck flask; the bend in the neck of the flask prevented falling particles from reaching the broth, while still allowing the free flow of air. He concluded that the contamination came from life forms in the air, not a “force”.