Jenner's Smallpox Vaccination

May 14, 1796

A Gloucestershire country doctor inoculated an eight-year-old boy with pus from a cowmaid's cowpox lesion, then challenged him with smallpox. The boy did not sicken. Edward Jenner had proved that a mild animal disease could protect against a deadly human one. Vaccination began on a village child's bare arm. Within a decade the technique had spread worldwide, and nearly two centuries later smallpox would become the first disease eradicated by human effort.