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Francesco Redi
Francesco Redi was an Italian physician that questioned the spontaneous generation theory. Redi's most famous experiment was denying the idea that maggots could originate from rotting meat. He set up three groups of jars, each containing discomposed meat. The first jar was left open, the second was covered with a fine gauze and the third was covered completely. Redi observed that only the open jars got maggots while the covered remained free. Concluding maggots can't be born spontaneously. -
John Needham
John Needham was an English naturalist who did experiments that were interpreted as supporting the idea of spontaneous generation.
Needham did experiments in which he boiled nutrient solutions and then closed them in containers. He observed the microorganisms appeared in the containers. Needham concluded these results as evidence for the spontaneous generation of microorganisms. -
Lazzaro Spallanzani
Lazzaro Spallanzani was an Italian biologist who made contributions to refuse of the idea of spontaneous generation. Spallanzani's experiment was boiling nutrient solutions in covered containers. He controlled experimental conditions and used the covered containers that blocked the entry of microorganisms. He concluded that boiled solutions remained free of microorganisms. This said that microorganisms did not spontaneously generate but instead entered the solutions from the surrounding air. -
Louis Pasteur
Louis Pasteur was a microbiologist known for his contributions to microbiology and immunology.
Pasteur's experiment was filling a flask with a nutrient puree that helped the growth of microorganisms.Then, he heated the puree until it boiled, killing any microorganisms.
The flask had a long S-shaped neck. This design allowed air to enter the flask but stopped dust and microorganisms from touching the puree.
This concluded that altought the opening, microorganisms didn't grow inside the flask.