Edward Jenner (1749–1823) is famous for saving mankind from smallpox. His first love was natural history, and he devoted himself to the study of birds. On learning about the centuries-old scourge of smallpox, he formed a great desire to end the suffering caused by the dread disease.

Jenner became fascinated by anecdotal evidence that men and women who contracted cowpox from milking dairy cows never came down with smallpox. He carefully gathered a large body of such evidence and then went to London, where he became a pupil of John Hunter and sought his advice. Encouraged by the great doctor to pursue his dream, he performed many experiments and observed the results with the greatest of care. His confidence grew.

His breakthrough came on May 14, 1796, when he took pus from the hands of Sarah Nelmes, a milkmaid infected with cowpox, and deposited it in scratches on the arms of an eight-year-old boy named James Phipps. This was the first-ever case of what we now call vaccination.

Once Jenner had assembled rock-hard evidence of the efficacy of the treatment, he published his findings—and stirred up a storm of criticism. Some of his opponents claimed that people inoculated with cowpox would grow horns. Jenner responded calmly and patiently to all protests, sparing no effort to improve the welfare of society and mankind. In the nineteenth century alone, tens of millions of lives were saved. Finally, in 1979, the World Health Organization declared smallpox officially eradicated from the planet.

Benefactors of mankind whose great deeds earn them a place in history are inevitably motivated by an intense desire to see their vision come true, and they make ceaseless efforts toward that end, come what may.