Banting and contributed to the discovery of the pancreatic hormone insulin, which led to an effective treatment for diabetes. In the spring of 1921, Banting travelled to Toronto to visit J.J.R. Macleod, professor of physiology at the University of Toronto, and asked Macleod if he could use his laboratory to isolate pancreatic extracts from dogs. Macleod was initially sceptical, but eventually agreed before leaving on holiday for the summer. Before leaving for Scotland he supplied Banting with ten dogs for experiment and two medical students, Charles Best and Edward Clark Noble, as lab assistants. It was reported that Best and Noble flipped a coin to see who would assist Banting during the first period of four weeks. According to Best, however, this was the product of a journalist’s imagination, or "newspaper fiction". MacLeod was overseeing the work of Banting, who had no experience of physiology, and his assistant Best. In December 1921, when Banting and Best were having difficulties in refining the pancreatic extract and monitoring glucose levels, MacLeod assigned the biochemist James Collip to the team. In January 1922, while Collip was working on insulin purification, Best and Banting administered prematurely their pancreatic extracts to 14-year-old Leonard Thompson, who suffered a severe allergic reaction. Eventually, Collip succeeded in preparing insulin in a more pure, usable form. Banting, Best and Collip shared the patent for insulin, which they sold to the University of Toronto for one dollar. In 1923, the Nobel Prize Committee honoured Banting and J. J. R. Macleod with the Nobel Prize in Medicine for the discovery of insulin, ignoring Best and Collip. Banting chose to share half of the prize money with Best. The key contribution by Collip was recognised in the Nobel speech of MacLeod, who also gave one-half of his prize money to Collip. In 1972 the Nobel Foundation officially conceded that omitting Best was a mistake. In fact, Best was not considered because he was never nominated. Nomination for a Nobel Prize can only be made by certain individuals, including former recipients of the Prize, and his central role along with Banting was simply not known to those who had the ability to make nominations. Best was subsequently nominated for the 1950 Nobel Prize in physiology based on his work on choline and heparin. Professor of physiology Best succeeded Macleod as professor of physiology at University of Toronto in 1929. During World War II