Pasteur's test of spontaneous generation.
By sterilizing a food source and keeping it isolated from the outside, Pasteur observed no putrefaction of the food source (top panel). Upon exposure to the outside environment, Pasteur observed the putrefaction of the food source (bottom panel). This strongly suggested that the components needed to create life do not spontaneously arise.
Source
Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:
"Experiment Pasteur English."
http://commons.wikimedia.org/wiki/File:Experiment_Pasteur_English.jpg
Wikimedia
Public domain.
