continuously being spontaneously generated about us is very ancient in origin. It originated in the superficial observations and non-scientific explanations of our ancestors, and was perpetuated by the authority of great leaders, such as Aristotle and Augustine. Aristotle, whose ideas dominated the world for two thousand years, states explicitly that living beings are generated spontaneously from decomposing carcases. St. Augustine fulminates against the atheism of any who dare deny the doctrine, and cites what he considers irrefutable proofs of it. The alchemists gave recipes for the creation of various animals. Thus, Van Helmont gravely tells us, "You need only close up a dirty shirt with a measure of wheat in order to see mice engendered in it—the strange offspring of the smell of the wheat and the animal ferment attached to the shirt."
However, the more careful observation of a later period had cast discredit upon the traditional view. Thus, it had been shown irrefutably that the stock-proof of the spontaneous generationists—the appearance of maggots in decaying organic matter—was due to the hatching of flies' eggs. But the invention of the microscope, with its revelation of millions of minute forms hitherto unsuspected, revived the doctrine.
The lapse of a year after the letters cited above enabled Pasteur to announce, "Of gases, fluids, electricity, magnetism, ozone, things known or things occult—there is nothing, in the air, conditional to life except the germs it carries."
This dictum was at once fiercely attacked by the generationists who included in their party savants of European fame, the most notable being Bastian, of London. The discussion held the almost breathless attention of the newspaper-reading world, and ended some years later in Pasteur's triumphant demonstration of his thesis.
You can readily imagine that this research was not prosecuted by Pasteur because of its mere academic interest. He appended to his first paper, quoted above, this query—"What could be more desirable than to push these studies far enough to prepare the road for a series of researches into the origin of various diseases?"
In 1861 Pasteur discovered the ferment of butyric acid. In the following year he discovered the ferment of acetic acid, and showed that microbes could be distinguished into two grand classes—aerobes and anaerobes. The Academy of Sciences, which had rejected his name when offered for membership upon several previous occasions, could not longer refuse to honor a man whose fame was now world-wide. He was elected a member at the end of 1862.
The manufacturers and dealers in fermented liquors had always been subjected to annoyance and loss by their inability to make wines and beers of uniform standard and to keep them in the condition