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Francesco Redi
Francesco Redi was a Tuscan naturalist, physician and poet, best known for his experiments in Florence, which were considered very important in refuting the theory of spontaneous generation. -
Redi’s experiment
At that time, it was widely believed that worms arose spontaneously in rotten flesh. To achieve his goal of proving that spontaneous generation was wrong, he proposed an experiment.
The experiment is to see what happens to the meat depending on how the tapestry, with this experiment showed that worms appeared because microorganisms came in contact with the meat, so the covered meat did not appear worms and uncovered if . -
John Turberville Needham
English scientist and Catholic priest, defender of the theory of spontaneous generation. Needham will carry out many experiments in which they prepare a meat and vegetable broth. ... Needham will come to the conclusion that the microorganisms had to have developed the broths. -
Needham’s rebuttal
Needham, an English clergyman, claimed that spontaneous generation could occur and performed an experiment.
Needham briefly heated broth to its boiling point, to kill microorganisms, and poured it into flasks. Soon after the broth cooled, he sealed them.
Later, he observed living microorganisms in the broth, concluding that spontaneous generation was a fact.
Years later, this experiment was considered incorrect because there were some flaws that altered the result. -
Criticism from Spallanzani
Lazzaro Spallanzani did an experiment hat proved Needham's conclusions wrong.
Spallanzani sealed flasks filled with broth. Next, he boiled them for a long time. Later, the broth did not have any life. However, once he unsealed the flask, microorganisms rapidly grew in the broth.
Spallanzani concluded that spontaneous generation was false and microbes came from contaminated air.
The differences were that he boiled the broth for longer and the flask was healed during the whole process. -
Pasteur puts spontaneous generation to rest
He placed broth in a swan-beck bottle oriented downwards, and observed no life for one year. He then broke off the top of the bottle, exposing it more directly to the air and trapped particles, and after a few days he observed life.He concluded that the contamination came from life forms in the air, not a supposed “life force”.The pollution was more dense, so it remained in the S shaped neck, it didn't get to the broth. -
spontaneous production of scorpions
The hypothesis that the life of scorpions is based on, if you put it in a basil brick and expose it to the sun after a few days a scorpion would appear.