Childhood & Early Life
John James Rickard Macleod was born on September 6, 1876 in Clunie, Central Scotland to Robert Macleod and Jane McWalter Macleod. His father was a clergyman. Immediately following his birth, the Macleod family shifted base to Aberdeen, following his father’s transfer.
At Aberdeen, Macleod studied at Aberdeen Grammar School. Following his early education, he enrolled at the Marishchal College at the University of Aberdeen to study medicine. Brilliant in academics, he topped his class in first year.
In 1898, Macleod received his doctorate in medicine. Following his honorary doctorate degree, he received a travelling scholarship which led him to study physiological chemistry at the University of Leipzig, Germany, in 1899. Macleod published his first ever scientific paper in Germany.
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Upon returning to Britain in 1900, Macleod started working as a demonstrator in physiology under Sir Leonard Hill at the London Hospital Medical School.
For a year, Macleod and Hill collaboratively studied caisson sickness, a kind of illness that mostly affected people working under high atmospheric pressure of the submerged caissons. The sickness was commonly found in deep-sea divers and underwater tunnel builders. Together the two studied different case history of the disease to determine its cause. They concluded that rapidly coming out from the water caused bubbling of nitrogen in blood and tissues which led to caisson sickness. In 1903, they published a series of articles on the same.
In 1902, Macleod was appointed as a lecturer in biochemistry at the London Hospital Medical School. The same year, he received his doctorate in public health from Cambridge University. He also received the McKinnon research studentship of the Royal Society of Medicine.
In 1903, Macleod moved to the United States. He took up the post of a lecturer in physiology at the Western Reserve University, in Cleveland Ohio. While at Western Reserve University, Macleod pursued his research in caisson sickness. However, he developed an interest in carbohydrate metabolism in relation to diabetes.
In 1903, he was elected as a member of the American Physiological Society. His role play in the organization steadily augmented making him an important member of the organization. By 1921, he was appointed to the chair of the President of the APS.
From 1907 to 1910, his interest in diabetes led to intensive research on the topic. He published several works during this time such as ‘Diabetes; Its Physiological Pathology’ and also actively contributed to various journals. His works made him a popular name in any discussion on carbohydrate metabolism.
During World War I, Macleod committed himself to war-time duties. He served as a physiology lecturer for part of the 1916 winter semester at the McGill University in Montreal, Canada. He served as the Director of the Physiology Laboratory and an Associate Dean of the Faculty.
In 1916, he published the work, ‘Physiology and Biochemistry in Modern Medicine’. Five years later, he cemented his position by delivering an important paper, ‘Methods of Study of Early Diabetes’ to a diabetes symposium at Ontario Medical Association .
In 1920, he first met Frederic Banting, a Canadian physician who had an idea of curing diabetes from a secretion in the pancreas. Though Macleod wasn’t impressed by Banting’s idea, he nevertheless lent space to the latter at his laboratory during the summer vacation and even gave him experimental animals. Banting was assisted by Macleod’s student, Charles Herbert Best as a demonstrator.
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Together with Best, Banting achieved a breakthrough in his research. The duo successfully isolated an internal secretion of the pancreas and succeeded in lowering the blood sugar level of another dog whose pancreas had been removed.
To be double sure of their findings, Macleod, Banting and Best did further research and experiments on the isolation of the secretion of pancreas. The success in their work led him to publish their reports in various journals. In 1921, the trio was joined by biochemist James Collip who helped in purifying the extract.
The first ever human clinical trial involving insulin at the Toronto General Hospital was a failure. In January 1922 the first successful clinical trial was performed. It was tagged as a miraculous achievement given that until then, there was no possible cure for diabetes. Insulin proved to be crucial in the treatment of diabetes, for it prevented augmentation of the disease and further transformed severe cases into milder ones. It also prevented diabetic coma and death.
In May 1922, the pharmaceutical company Eli Lilly & Co. took over mass production, but without an exclusive license, as the patent was transferred to the British Medical Research Council to prevent exploitation.
From August 1922 to May 1923, Macleod served as official secretary of the insulin committee created by the board of governors of the University of Toronto to deal with patenting and licensing issues. He was also responsible for coordinating the patenting of insulin in Great Britain and the United States, and was the main contact for Eli Lilly. It was only in 1926 that insulin was isolated in pure form by John Jacob Abel, and eventually became available as a manufactured product.
In 1926 Macleod published a book on diabetes and insulin titled ‘Carbohydrate Metabolism and Insulin’. In 1928 Macleod returned to Scotland. Therein, he replaced his former teacher Professor John Alexander MacWilliam to become Professor of Physiology at his alma mater. He was later appointed as the Dean of the University of Aberdeen Medical Faculty. Between 1929 and 1933 he was also a member of the Medical Research Council.
At Aberdeen, he actively continued his research and experiments. His subsequent work and publications involved a variety of physiological and biochemical topics, including diabetes, carbamates, purine metabolism, the breakdown of liver glycogen, intracranial circulation, ventilation, and surgical shock. He returned to conducting experiments on the role of the central nervous system in the causation of hyperglycemia, which he first researched on in 1908.
During the later phase of his scientific career, he came up with the work, ‘The Fuel of Life: Experimental Studies in Normal and Diabetic Animals’. In 1933, he made a lecture tour of the US and the following year came up with the 7th edition of his book, ‘Physiology and Biochemistry in Modern Medicine’.
Awards & Achievements
In 1919, Macleod was elected as a member of the Royal Society of Canada. Furthermore, he gained membership of the Royal Society of Edinburgh and London and London’s Royal College of Physicians. He was made an honorary fellow of the Academia Medica, Rome, a corresponding member of the Medical and Surgical Society, Bologna, the SocietéMedicaChirurgica, Rome, and the Deutsche Akademie der NaturforscherLeopoldina, as well as foreign associate fellow of the College of Physicians, Philadelphia.
In 1921, he became president of American Physiological Society which he served until 1923. For a year, from 1925 until 1926 he presided over the Royal Canadian Institute.
In 1923, Macleod received the prestigious Nobel Prize in Physiology or Medicine for the discovery of insulin together with Banting. He shared his half of the prize money with Collip, while Banting shared his half with Best.
He received honorary doctorates from the universities of Toronto, Cambridge, Aberdeen, and Pennsylvania, as well as from Western Reserve University and the Jefferson Medical College.
Personal Life & Legacy
Macleod was married Mary W. McWalter. The couple had no children.
During the 1930s, he suffered from acute arthritis that resulted into severe pain and limited movements. With passing time, his health declined further to a point in 1935 when he was admitted to a nursing home.
He breathed his last at his home in Aberdeen on March 16, 1935.
The argument behind Macleod’s involvement in the discovery of insulin made him a controversial figure in Canada due to Canadian physicist, Frederick Banting’s story. However, his reputation enhanced with the passage of time and his contribution to science was recognized in the country. The auditorium at Toronto University Medical Research Center was named in his honor. He was also inducted in the Canadian Medical Hall of Fame in 2012.