Macleod Before Banting

Abstract. John James Rickard Macleod provided the facilities and support that enabled Frederick Banting and Charles Best to perform the experimental work that resulted in the discovery of insulin. This review considers Macleod's intellectual contribution to the initial discovery in light of his previously expressed opinions on glucose metabolism. He acknowledged the likely existence of an internal secretion from the pancreas and was aware of previous work in the area; however, seeking it was not among his research priorities. His advice in the immediate aftermath of the discovery does not appear to have made any essential contribution to the project, although he made its ultimate success possible. Instead, he gave Banting the chance he needed, gave him full credit for what he achieved, and promoted insulin tirelessly as a gift to the world.