J.J.R. Macleod: His Life and Works Before and After the Toronto Insulin Years.

This article focuses on the life and career of John James Rickard Macleod, a prominent early 20th-century academic physiologist best known for his role in the discovery of insulin. Trained in medicine at the University of Aberdeen, Macleod advanced through research and teaching positions in Europe and North America, gaining international recognition for his work on carbohydrate metabolism and diabetes. In Toronto, he led the team that developed the first clinically effective insulin treatment, a breakthrough that earned him a shared Nobel Prize but also sparked enduring controversy over credit and contributions. After returning to Aberdeen in 1928 as Regius Professor of Physiology, Macleod continued a distinguished career in research, mentorship, and academic leadership until his death in 1935. The article emphasizes Macleod’s broad scientific achievements beyond the insulin years and his lasting impact on physiology and medical education.