Charles Herbert Best was most renowned as co-discoverer of insulin with Frederick G. Banting. Insulin, which is a hormone secreted by the pancreas, regulates the level of sugar in the blood. Its discovery in 1921 led to its use as a treatment for diabetes, which until that time had led swiftly to emaciation, coma, and death. Later in his career, Best assisted in the establishment of associations of diabetics to promote support groups and educational programs for their members. He also did important research on the nutrient choline and the blood anticoagulant heparin.
Best was born on February 27, 1899, in West Pembroke, Maine, a town near the border of the Canadian province of New Brunswick. His parents were Canadian citizens, both originally from Nova Scotia. Best was a direct descendant of Major William Best, who in 1749 was one of the founders of Halifax, Nova Scotia. Best's father, Herbert Huestes Best, was a country doctor whose practice straddled the U.S.-Canadian border. As a teenager, Best often accompanied his father on his rounds in a horse-drawn buggy. Best's mother was Luella Fisher Best.
After finishing high school, Best entered the University of Toronto in a liberal arts program. When World War I interrupted his education, he served as a sergeant in a regiment of the Canadian Tank Corps. He returned to Toronto in 1919 after the war to complete his education, but switched his course of study to physiology and biochemistry in preparation for a medical degree. Best played professional baseball in order to finance his education. He received his B.A. in 1921. In May of 1921, Best's physiology professor, John James Rickard Macleod, introduced him to Frederick Grant Banting, a 29-year-old orthopedic surgeon from London, Ontario. Best had worked as a research assistant for Macleod and planned to begin studying for [a] master's degree under him in the fall. Banting would be using Macleod's lab during the intervening summer to do experiments to find out the function of the pancreas in preventing diabetes, and he needed an assistant to help with analyses of blood chemistry. Another of Macleod's students was also interested in the job, so he and Best flipped a coin. Best won. On May 17, 1921, the day after he completed his examinations for his undergraduate degree, Best began working with Banting. It was a collaboration that would set the course of his career.
Discovers Treatment for Diabetes
Experiments done 30 years earlier had shown that when a dog's pancreas was removed by surgery the animal developed the symptoms of diabetes: it would grow insatiably thirsty, begin excreting large amounts of sugar in its urine, and then become listless, go into a coma, and die. Banting's idea was that the pancreas must secrete something in addition to its digestive enzymes in order to prevent this process. He was convinced that the crucial substance would be found in groups of cells on the pancreas called the islets of Langerhans. These cells could be isolated by tying off a dog's pancreatic ducts; the rest of the pancreas would atrophy after several weeks, but the islets of Langerhans would remain intact. An extract could then be made from the cells and injected into a diabetic dog. If Banting's idea was right, such an extract would relieve the symptoms of diabetes.
The way he originally planned the work, Banting would do the surgery, removing the pancreas from some dogs to make them diabetic and tying off the pancreatic ducts in others to isolate the islet cells. Best would do blood and urine tests on the dogs. As the research progressed, however, Best learned to do some surgery too. Best, for his part, had a personal interest in diabetes. His father's sister, who had lived with the Best family in West Pembroke, had died in a diabetic coma in 1918.
Banting and Best had expected to spend only eight weeks on their study. But it was July 30 before they were ready to prepare the extract. On that day, Banting removed the shriveled pancreas from a dog whose ducts had been tied. He and Best prepared an extract from it by chopping the pancreas into small pieces, grinding it in a chilled mortar with salt water, and filtering the mixture through cheesecloth. A blood sample from the diabetic dog showed its blood sugar level to be 0.2. Banting and Best injected some of their extract into the dog. An hour later its blood sugar level had dropped to 0.12. After another injection it registered 0.11. This dog died the next day, presumably from an infection. But Banting and Best were encouraged by the result and tested their extract on more diabetic dogs. They called the extract "isletin."
During the following months Banting and Best performed additional experiments to confirm and explain their results. With an injection of their extract they could revive a diabetic dog from its coma and prevent its imminent death. They found ways of obtaining the extract more easily and in larger quantities from the pancreases of fetal calves obtained from a local slaughterhouse. Macleod, who had been vacationing at his home in Scotland during the summer, returned in September and made suggestions for further studies. He also hired James Bertram Collip, a Ph.D. biochemist, to help purify the active component of the extract. Best continued with the work, but also began his M.A. program at the University of Toronto. That fall Banting and Best wrote their first paper describing the experiments with dogs, titled "The Internal Secretion of the Pancreas." It was accepted for publication in the February 1922 issue of the JOURNAL OF LABORATORY AND CLINICAL MEDICINE.
Photo: Courtesy of the National Library of Medicine.