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Francesco Redi
Francesco Redi was born on February 18, 1626 in the city of Arezzo in Tuscany, Italy. He was an innovative scientist, physician, and poet. Redi was also a member of the Accademia del Cimento, which flourished from 1657–1667. It was during this decade that Redi produced his most important works. -
Redi’s experiment
Redi believed that maggots came from the eggs that were laid by flies so he put meat in various jars and sealed a few and left a few open. As he expected, only the jars that were open to air had maggots in it. This proved his theory because when the jars are sealed, flies were unable to lay eggs on the meat so there were no maggots. -
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John Needham
John Needham was an English naturalist and Roman Catholic cleric. He was the first clergyman to be elected to the Royal Society of London. He is also noted for his theory of spontaneous generation and the scientific evidence he had presented to support it. -
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Lazzaro Spallanzani
Lazzaro Spallanzani was born in Scandiano on Jan. 12, 1729. He entered a Jesuit college at the age of 15 and later studied law at Bologna, but very early he became interested in physics and developed an overall knowledge of nature. Spallanzani is well known for one of his major works on microscopical observation that concerned the systems of spontaneous generation, and was an attempt to disprove J.T. Needham's. -
Needham’s rebuttal
John Needham wanted to use the knowledge that boiling kills organisms to prove that spontaneous generation worked. He conducted an experiment to boil chicken broth to prove spontaneous generation. When he boiled chicken broth and put it in a sealed jar and microorganisms grew, people were more certain about the theory of spontaneous generation. -
Criticism from Spallanzani
In the same year John Needham conducted the chicken broth experiment, an Italian clergyman was not convinced. He modified Needham’s experiment and vacuumed the air out before sealing the chicken broth and boiling it. During that experiment, no microorganisms grew. However, some believers disagreed with Spallanzani and said he simply just proved that the theory needs air to work -
Pasteur puts spontaneous generation to rest
He performed a combined experiment of Needham’s and Spallazani’s. He boiled meat in a flask and heated the neck of the flask and bent it to an S shape. This allowed air to go into the flask but does not allow air borne microorganisms because they will settle on the S. Since no microorganisms grew, Pasteur proved the spontaneous generation theory wrong and also demonstrated microorganisms are everywhere. -
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Louis Pasteur
Louis Pasteur was a French chemist and microbiologist renowned for his discoveries of the principles of vaccination, microbial fermentation, and pasteurization. He discovered that microbes were responsible for souring alcohol and came up with the process of pasteurization, where bacteria are destroyed by heating beverages and then allowing them to cool. His work in germ theory also led him and his team to create vaccinations for anthrax and rabies.