On Vaccination Against Smallpox is Edward Jenner's publication of his research into creating the smallpox vaccine. When in 1788 a smallpox outbreak hit Gloucestershire, Jenner noticed that people who worked with cattle and had caught the mild disease cowpox, which was not fatal, then never came down with smallpox. He found ways to test his observation, and in 1796 his experiments showed that giving a small dose of cowpox to a person gave that person immunity to smallpox. Despite much initial disbelief by his peers, the smallpox vaccine became one of the most significant scientific breakthroughs. In this chapter, the author describes the causes for the vaccine and symptoms of smallpox.