ABSTRACT
Three independent branches of research (contagion, vaccination, and basic research on germs) came together in the latter part of the 19th century to formulate the ‘‘germ theory of disease’’ and to herald in what is often termed ‘‘the golden age of microbiology’’ from around 1875 to 1900. These branches subsequently developed into the subdisciplines of bacteriology, mycology, virology, parasitology, and immunology.
