The First Victory That Promised the Last

In May 1796, Edward Jenner made a daring wager against humanity's deadliest scourge. In a cottage garden in Berkeley, Gloucestershire, he took fluid from a cowpox lesion on the hand of dairymaid Sarah Nelmes and scratched it into the arm of eight-year-old James Phipps. Weeks later, Jenner exposed the boy to smallpox itself. James never fell ill. That single moment of immunity was a firstfruit.…