Benchmark 10I
Historical Perspectives: Discovering Germs
Grades 6-8, page 257

Pasteur found that infection by disease organisms--germs--caused the body to build up an immunity against subsequent infection by the same organisms. He then demonstrated that it was possible to produce vaccines that would induce the body to build immunity to a disease without actually causing the disease itself.

See Content Standard G History and Nature of Science (grades 9-12): Historical Perspectives