The Butchering Art: Joseph Lister's Quest to Transform the Grisly World of Victorian Medicine

by Lindsey Fitzharris

In a series of experiments, Pasteur boiled fermentable substances to rid them of any existing microorganisms. He then placed these substances in two different kinds of flasks. The first was an ordinary flask with an open top. The second had a neck shaped like an S that prevented dust and other particles from entering the flask. This flask also remained open and exposed to the air. After a certain amount of time, the first flask began to teem with microbial life, while the swan-neck flask remained uncontaminated. From these experiments, Pasteur finally proved that microbes were not generated spontaneously; otherwise, the flask with the curved neck would have become reinfected. His experiments established what is now considered one of the cornerstones of biology: Only life begets life. In a speech on his findings delivered to the Sorbonne, Pasteur said, “Never will the doctrine of spontaneous generation recover from the mortal blow of this simple experiment.” It wasn’t long before the word “germ” was being used to describe these protean microbes.