What Canadian invention has global impact?

The Canadian discovery of insulin in 1921 and 1922 at the University of Toronto transformed type 1 diabetes from a fatal disease into a manageable condition and is regarded as one of the most important medical advances of the twentieth century. Surgeon Frederick Banting and medical student Charles Best ran the key experiments in the laboratory of Professor John Macleod, working on dogs in the summer of 1921, and biochemist James Collip purified the extract in time for human trials.

On January 11, 1922, fourteen-year-old Leonard Thompson became the first person to receive an insulin injection at Toronto General Hospital. The first dose, prepared from Banting and Best's extract, caused an allergic reaction; Collip's purified version, administered twelve days later, brought Thompson's blood sugar down dramatically. He lived another thirteen years.

Banting and Macleod shared the 1923 Nobel Prize in Physiology or Medicine. Banting split his half of the prize money with Best, and Macleod split his with Collip, publicly recognising the team. The University of Toronto sold the patent to the university's Connaught Laboratories for one Canadian dollar so that insulin would remain affordable for diabetic patients worldwide. Connaught and the U.S. company Eli Lilly began commercial production within months.

The discovery is remembered through the Banting House National Historic Site in London, Ontario, the Banting and Best Diabetes Centre at the University of Toronto, and the designation of November 14, Banting's birthday, as World Diabetes Day. The original 1921 laboratory notebooks are held by the Thomas Fisher Rare Book Library in Toronto, and the discovery is taught in Canadian schools as evidence that Canadian scientific research can change the world.