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100
Birth of Spontaneous Generation BC 600
Anaximander, a Milesian philopher was probably the first to suggest hat life arose spontaneously. He believed that everything arose out of the elemental nature of the universe. -
400
Aristotle's Argument BC 400
Aristotle argues that spontaneous generation is real in 400 BC with The History of Animals. He argued that living organisms could spawn from non-living organisms that contained "vital heat". -
Rejection of Spontaneous Generation
Francesco Redi, an Italian physician conducted an experiment to test spontaneous generation. He proved that maggots did not, arise spontaneously, but from eggs laid by adult flies. He believed he disproved spontaneous generation; however, the general public still believed in the theory. -
Supporting the theory
In 1745, John Needham, an English naturalist along with a French naturalist, Comte de Buffom, attempted to prove once an for all the validity of spontaneous generation. Everyone knew that boiling killed microorganisms, so he proposed to test whether or not microorganisms appeared spontaneously after boiling. He boiled chicken broth, put it into a flask, sealed it, and waited. Microorganisms grew and he thought he had won the battle in support of spontaneous generation. -
Disproving Needham's Experiment
Italian physiologist Lazzaro Spallanzani showed that when broth was heated after being sealed in a flask, it did not generate life forms. He suggested that Needham's broths had probably supported growth after being heated because they had been contaminated before being sealed in their containers. Needham counterclaimed that heat destroyed the "vital force" needed for spontaneous generation, and that, by sealing the flasks, Spallanzani had kept out this vital force. The argument continued... -
The end of Spontaneous Generation
The French Academy of Sciences sponsored a contest for the best experiment either proving or disproving spontaneous generation. Pasteur's winning experiment was a variation of the methods of Needham and Spallanzani. He boiled meat broth in a flask, heated the neck of the flask in a flame until it became pliable, and bent it into the shape of an S. Air could enter the flask, but airborne microorganisms could not - As Pasteur had expected, no microorganism grew and the rest is history.
