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Francesco Redi
Francesco Redi, an Italian physician, did an experiment in 1668 which consisted of putting meat in jars to disprove spontaneous generation. He showed that maggots only appeared in meat when flies could lay eggs, proving that life arises from other life, not spontaneously. -
John Needham
John Needham was an English biologist, and he attempted to support spontaneous generation by boiling broth briefly, sealed the container, and observed microbial growth. This concluded that life arose spontaneously, though his method was later criticized for contamination. -
Lazzaro Spallanzani
Lazzaro Spallanzani, an Italian scientist, improved on Needham’s experiment by boiling broth for longer and sealing the flasks. No microbial growth occurred unless the flasks were opened, and that lead him to conclude that microorganisms come from the air, not spontaneous generation. -
Louis Pasteur
Louis Pasteur's flask experiment definitively disproved spontaneous generation. He boiled broth in flasks with curved necks, allowing air in but trapping microbes. The broth remained sterile until the flask was tilted or the neck broken, proving life does not arise spontaneously.