Skene St, Aberdeen AB10 1HT, United Kingdom
Macleod received his early education at the Aberdeen Grammar School.
King's College, Aberdeen AB24 3FX, United Kingdom
Macleod studied medicine at Aberdeen University, and graduated with distinction as Bachelor of Medicine and Bachelor of Surgery in 1898, winning the Matthews Duncan and Fife Jamieson medals.
(Co-authored with Leonard E. Hill)
Co-authored with Leonard E. Hill
Macleod received his education at the Aberdeen Grammar School and Aberdeen University. He studied medicine at Marischal College, and graduated with distinction as a Bachelor of Medicine and a Bachelor of Surgery in 1898, winning the Matthews Duncan and Fife Jamieson medals; he was also awarded the Anderson traveling scholarship and spent a year in the Physiology Institute at Leipzig, where he studied biochemistry under Siegfried and Burian.
In 1900 Macleod joined the London Hospital Medical College as a demonstrator in physiology under Sir Leonard Hill. He became a lecturer in biochemistry at the school in 1902 and was also selected as Mackinnon research scholar of the Royal Society.
During his short stay in London, Macleod published an account of experiments on intracranial circulation and on caisson disease, carried out in conjunction with Hill; he retained his interest in the problems of respiration throughout his life, publishing many papers on the control of respiration between 1902 and 1922. In 1903 he published a text entitled Practical Physiology, and in the same year, he was appointed professor of physiology at Western Reserve University, Cleveland (now Case Western Reserve University). Here he remained as a teacher and researcher for fifteen years, In 1918 he became professor of physiology at the University of Toronto and not long afterward published, with collaborators, a textbook of nearly 1,000 pages, Physiology, and Biochemistry in Modern Medicine. This text, which reached its seventh edition the year before Maclcod’s death, was widely read and consulted. Its title reveals it as one of the last of such broad scope and, at the same time, as the precursor of other, more recent wide-ranging treatises appealing both to the special student and to the clinician.
In his first years at Western Reserve Macleod published a series of papers on the carbamates and one on purine metabolism. In 1907 there appeared the first of a long series of "Studies in Experimental Glycosuria" in the American Journal of Physiology, studies on the breakdown of liver glycogen, whether produced by piqftre, stimulation of the splanchnics, reflexly by asphyxia, or by injection of adrenaline. He conceived of the problem as one fundamentally involving the access of the diastatic enzyme to the stored glycogen. In 1913, nearly ten years before the discovery of insulin, Macleod wrote a book on diabetes and its pathological physiology, an expansion of lectures which he had delivered during the summer of 1912 at the University of London. Although he published on surgical shock and other subjects, his first years in Toronto were devoted chiefly to studying the peculiarities of respiration in decerebrate animals and of the effects of anoxemia and of excess oxygen. Later, in 1921, he made a thorough examination of the control of the blood-sugar level in the normal and in the depancreatized animal and of the roles played by the liver, the muscles, and the pancreas in the metabolism of sugar.
His return to work on carbohydrate metabolism had been stimulated by the initial successes of Banting and Best. As J. B. Collip subsequently observed, Macleod had already attained, by the time of his arrival in Toronto, "an outstanding position in the field of carbohydrate metabolism, and it was both appropriate and fortunate that the discovery of insulin should have been made in his laboratory." It was early in 1921 that Macleod agreed to receive Frederick G. Banting, a young surgeon, into his department to carry out investigations aimed at determining the true function of the pancreatic islets; C. H. Best, a member of the professor’s senior class in physiology, was assigned to be Banting’s assistant. Banting and Best began their research on May 16. The general pattern of their work, following Banting’s conception of how the islets might be freed from the acinar tissue of the gland and then extracted, was worked out with Macleod; but its first results were obtained in midsummer when Macleod had gone to Scotland. On his return, he discontinued his work on anoxemia and turned all the resources of his laboratory to the new work. J. B. Collip joined the team; and usable preparations of insulin were ready, and were used with success, early in 1922.
Macleod was president of the American Physiological Society at the time of the discovery of insulin and had received many honors; now they multiplied. In 1923 Banting and Macleod shared the Nobel Prize; Banting divided his share with Best, and Macleod divided with Collip. Macleod became a fellow of the Royal Society in 1923 and was awarded honorary degrees by Toronto, Western Reserve, Aberdeen, and other universities. In 1928 he returned to Scotland as a regius professor of physiology at Aberdeen. Productive work there, and at the Rowett Institute, continued to add to the knowledge of carbohydrate metabolism. The metabolism of the decerebrate eviscerated animal, with special reference to the respiratory quotient, occupied much of his time until crippling arthritis put an end to his laboratory work; even then he continued to direct the activities of his department. Macleod’s last important publication marked his return to an earlier problem, the nervous control of the glycogenic function of the liver.
(Co-authored with Leonard E. Hill)1905
As a man, Macleod was described as loyal, engaging, affectionate, and serene.
Macleod married Mary Watson McWalter in 1903; they had no children.