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Francesco Redi
Francesco Redi was an Italian physician. He made an experiment to disprove the theory of spontaneous generation. -
Redi's experiment
Francesco Redi is the first to disprove spontaneous generation (but not completely) using an experiment that consisted of 3 jars of meat: One was sealed completely, one was covered with cloth, and the last was left out in the open. In his conclusions, he saw that the maggots could only be born in the meat when the flies had access to it or on top of the cloth. -
John Needham
John Needham was an English biologist. He tried to prove that spontaneous generation was a true theory, and for a while, he succeeded. -
Lazzaro Spallanzani
Lazzaro Spallanzani was an Italian priest who did a lot of experiments (including the first in vitro fertilization), one of which was an experiment to disprove Needham's theory. -
Needham’s rebuttal
John Needham creates a rebuttal towards Redi’s results.
Needham created a test in which the broth was boiled in order for it to be sterilized. After this, the flasks containing gravy were sealed and a couple of days later, microbes such as mould could be seen growing on the gravy, proving that life came from non-living matter such as gravy. -
Criticism from Spallanzani
Spallanzani thought that Needham's experiment was incorrect so he decided to recreate it. His experiment included one flask with a seal and one without. His results showed that the flask that was not sealed had no life. Although his theory was right, scientists such as Needham said that spontaneous generation could not occur without air. -
Louis Pasteur
Louis Pasteur was a French chemist, renowned for his discoveries of the principles of vaccination, microbial fermentation, and pasteurization. -
Pasteur puts spontaneous generation to rest
To put an end to spontaneous generation, Pasteur recreated the experiment but left room for air to enter the broth. The idea was that the special swan-neck's flasksbend in the neck prevented falling particles from reaching the broth, while still allowing the free flow of air.