Louis Pasteur published The Germ Theory and Its Applications to Medicine and Surgery in 1878. The book gathered and presented his argument that microscopic organisms could cause fermentation, decay, and infectious disease, helping move medicine away from vague ideas about “bad air” and spontaneous generation.
Pasteur’s work built on experiments with wine, beer, and other fermenting liquids. He showed that different microorganisms produced different chemical changes, and that heating could reduce unwanted microbial activity—a process later known as pasteurization. These findings supported the broader idea that disease could have specific biological causes.
The 1878 publication appeared during a period when Pasteur’s ideas were being tested and debated by physicians and scientists. It should not be confused with his later rabies research, which culminated in the first human treatment in 1885. Nor should the title be mistaken for a modern textbook: it was a historically important statement of Pasteur’s developing scientific program.