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Redi’s experiment
In 1668, Francesco Redi, an Italian physician, launched the initial significant challenge against the concept of spontaneous generation. Subsequently, Redi conducted an experiment where he placed dead maggots or flies in a sealed jar with decaying meat and observed that no new flies were generated. On the other hand, when live maggots or flies were placed in the same environment, they were able to generate new flies. -
Needham’s rebuttal
John Needham, an English clergyman, asserted in 1745 that spontaneous generation was possible and carried out what he deemed the definitive experiment. This experiment involved boiling a broth mixture briefly, cooling it to room temperature in an open container, sealing it in flasks, and then observing the growth of microbes a few days later. -
Criticism from Spallanzani
Despite John Needham's findings, Lazzaro Spallanzani disagreed with his conclusions and conducted several meticulously executed experiments using heated broth. Spallanzani discovered that boiling the broth for one hour was sufficient to sterilize it, but a few minutes of boiling was insufficient to kill any bacteria present initially. Furthermore, Spallanzani concluded that the microorganisms found in the flasks of spoiled soup had entered from the air. -
Pasteur puts spontaneous generation to rest
Louis Pasteur put the theory of spontaneous generation to rest with a straightforward yet ingenious experiment. He boiled nutrient broth in a flask with a long, curved neck and allowed it to remain open to the air. However, the design of the flask prevented any microbes from entering the sterile broth area.
