Vaccination

Material from cowpox blisters was used to stimulate immunity against smallpox. This early form of vaccination demonstrated that exposing a person to a less dangerous cowpox infection could provide protection against the more lethal smallpox disease.
 Edward Jenner England 1796 Vaccination

Material from cowpox blisters was used to stimulate immunity against smallpox. This early form of vaccination demonstrated that exposing a person to a less dangerous cowpox infection could provide protection against the more lethal smallpox disease.