He practiced orthopaedic surgery following the war, but was not too successful because of his disinterest. He asked the professor of physiology at the university of Toronto if he could work on a problem he was interested in, and when he explained his idea relative to the pancreas, the professor poopooed his experiment.
Regardless, he was given a dirty little lab in which to work. Banting was 30, and he was assisted by a 23-year-old second-year medical student, Charles H. Best. After eight months, in 1922, these two isolated insulin and published their discovery, which revolutionised the treatment for diabetes mellitus.
Unfortunately, he was killed in an airplane accident in 1944.