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384 BCE
Aristotle
Aristotle was a Greek philosopher who proposed the theory of spontaneous generation. He believed that living organisms such as mice, maggots, and eels could arise spontaneously from decaying matter. -
Francesco Redi
Redi was an Italian physician and naturalist who conducted experiments in the 1660s to disprove the theory of spontaneous generation. He demonstrated that maggots do not arise spontaneously from decaying meat but are instead the offspring of flies that lay their eggs on the meat. He did this by covering some jars of meat with gauze to prevent flies from laying their eggs on it, while leaving other jars uncovered. The uncovered jars produced maggots while the covered jars did not. -
John Needham
Needham was an English naturalist who conducted experiments in the mid-18th century to support the theory of spontaneous generation. He boiled nutrient broth in sealed flasks, which he believed would sterilize the broth and prevent the growth of microorganisms. However, he later observed the growth of microorganisms in the flasks and concluded that they must have arisen spontaneously from the broth. -
Lazzaro Spallanzani
Spallanzani was an Italian Catholic priest and biologist who repeated Needham's experiments with some modifications. He boiled nutrient broth in flasks and then sealed them with cork after the broth had cooled down. He observed no growth of microorganisms in the flasks and concluded that microorganisms do not arise spontaneously but are instead introduced from the air. -
Louis Pasteur
Pasteur was a French microbiologist who conducted experiments in the mid-19th century that finally disproved the theory of spontaneous generation. He used a specially designed flask, which allowed air to enter but prevented microorganisms from entering. He boiled nutrient broth in the flask and observed no growth of microorganisms, even after long periods of time. This experiment demonstrated that microorganisms do not arise spontaneously but are instead introduced from the air.