In 1796, English doctor Edward Jenner tried a very risky experiment.
He exposed James Phipps, age 8, to a mild disease called cowpox. Then, about six weeks later, he infected James with a deadly, contagious disease called smallpox. Jenner thought people like James, who caught cowpox, would be protected against smallpox. He was right. Within five years, people all over the world were using Jenner’s smallpox vaccination. Suddenly, a disease that had killed millions began dying out. In 1980, smallpox became extinct.
Today, Americans on average live almost twice as long as they did in Jenner’s time. That’s mostly because of advances in medicine and science. They weren’t caused by the Industrial Revolution, but they happened at about the same time.