A single 30-day span begat much of modern biology
The year 1859 ended with two big scientific bangs. On Thursday, November 24th, the first edition of On the Origin of Species by Means of Natural Selection was published by John Murray in London. Fifteen days later and across the English Channel, on the evening of Monday, December 9th, Louis Pasteur presented to the Chemical Society of Paris his first experimental results attacking the doctrines of spontaneous generation. Two such monumental discoveries would have made it a good month in any branch of science. Although it was not obvious at the time, Darwin and Pasteur were laying out the foundations of contemporary biology.
The story we often hear about Pasteur falls into the “we once were blind, but now we see” narrative. In this version, superstition and ignorance reigned before Pasteur; light and reason ruled thereafter. Until Pasteur, we are taught, we did not understand that only life begets life. After his observations and experiments (so the story goes), we did. The real events, however, are far more interesting—and complex. Pasteur waded into a controversy that had been ongoing since the time of the ancient Greeks, and had become an enormously active area of investigation and speculation from the 18th century onward. Natural scientists and philosophers sought to understand the relationships between chemistry and biology. The emergence of microscopy—and with it the realization that living beings were everywhere, even beyond the reach of the human eye—made the question more urgent: Where was all of this life springing from?