How did Louis Pasteur extend the work of Edward Jenner?

influenced by Edward jenner ,pasteur reasoned that if a vaccine could be found for smallpox , vaccines could be found for all diseases ... it was during this study pasteur changed the field of virology forever . in 1879, pasteur observed, by chance , that old bacterial cultures lost their virulence .                            hope this helps :)

the answer to number 5 is fort sumter