In 1921, Frederick Banting was a young doctor with an idea: could the mysterious secretions of the pancreas be used to treat diabetes? We now call this substance insulin, and its life-saving discovery was an impactful milestone in medical science. Banting and his assistant, Charles Best, worked together in a small lab to test the theory with street dogs. Banting formed a special bond with one of his test dogs and gave her a name: Marjorie. After Marjorie...