Edward Jenner, Born in 1749, was a typical British physician and rural practitioner, educated under John Hunter. His most well-known contribution to human knowledge is the important discovery of the principles of inoculation.
He first begant to study the principles of inoculation when he realized that milkmaids who had had minor cowpox boils on their hands from milking cows were, afterward, immune from the smallpox disease.
He tested his theories in July of 1796 during which time introduced a benign dosage of cowpox matter (thanks liveforever) into a young boy, James Phipps, from a donor, Sarah Nelmes. Forty-Five days after the inoculation took place Jenner exposed the boy to an arguably larger dosage of the smallpox virus, and to his delight the boy did not become infected.
Jenner published his finding of 123 total cases in 1796, and his discovery was rapidly accepted and popularized. By 1800, more than 6,000 individuals had undergone innoculation in the same manner. Even Catherine the Great received an inoculation, a privilege for which she paid 12,000 pounds sterling.
Jenner died a national hero in 1823.