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Aristotle
In his book, "The History of Animals," Aristotle supported the idea of spontaneous generations, living things coming forth from nonliving things. He believed that nonliving materials contained pneuma, vital heat, which acted as a source of life. At the time, it was a "common knowledge" that simple, small organisms like worms, frogs, and beetles could appear from dust, mud, etc. -
Jan Swammerdam
A dutch biologist, Jan Swammerdam, desired to disprove the concept of spontaneous generations, to prove the unity of God's creation and how everyone was made with equal care. -
Francesco Redi
Back in 1668, many believed that maggots appeared spontaneously from rotting meat. An Italian physician and poet, Francesco Redi, believed that maggots developed from eggs laid by flies and thus conducted an experiment to prove his thought, putting meat in different flasks of different conditions. His theory turned out to be correct, however, even after this successful experiment, the belief in spontaneous generation still remained and even Redi believed it could still occur. -
Jean Baptiste Lamarck
Jean Baptiste proposed his theory of evolution to reconcile his own ideas with Aristotle's. He stated that as creatures strive for greater perfection, new organisms are created by spontaneous generation to fill the empty places on the lower rungs. He believed that life simply began through spontaneous generation. -
John Needham
In 1745, a Scottish clergyman and naturalist, John Needham set out a test to see if microorganisms appeared spontaneously after boiling. He boiled chicken broth, put it into a flask, sealed it and waited, eventually discovering that microorganisms did grow. This successful result convinced the population once again. -
Lazzaro Spallanzani
Lazzaro Spallanzani, not convinced of Needham's experiment, argued that the microorganisms could have entered the broth before it was sealed. To test this, he readjusted Neeham's experiment, drawing off the air to create a partial vacuum before boiling the broth. as a result, no microorganisms grew and he was proved to be right--except some argued that he only proved how spontaneous generation cannot occur without air. -
Louis Pasteur
In 1859, The French Academy of Sciences held a contest for proving or disproving spontaneous generation. Louis Pasteur modified Neeham and Spallanzani's method and bent the flask into a shape of an S so air could enter the flask but airborne microorganisms could not. As predicted, no organisms grew, and Pasteur successfully refuted the theory of spontaneous generation, showing that microorganisms are everywhere--even in air.
