W. H. Freeman's "Pasteur's Experiment"
Read this review of Pasteur's experimental design for testing spontaneous generation. Pasteur's steps of observing, asking a question, making a hypothesis, conducting an experiment, and then accepting (or rejecting) his hypothesis later became codified as the scientific method.
Click http://bcs.whfreeman.com/webpub/biology/sadavalife9e/animated%20tutorials/life9e_0401_script.html link to open resource.