 In Cambridge, under Krebs’ mentorship Edson conducted an extensive investigation on the metabolism of ketone bodies, substances produced in excess by humans during starvation or undiagnosed diabetes.Some of these studies (Edson and Leloir, 1936) were a link in a chain of experiments leading to Krebs' 1937 proposal of the citric acid cycle.During the same period Edson identified the product of purine ring formation in pigeon liver as hypoxanthine, which was converted to uric acid in the liver (Edson, Krebs and model,1936; Edson,1946).