Frederick Banting upon the idea of obtaining insulin from the fetal pancreas. He removed the pancreases from fetal calves at a William Davies slaughterhouse and found the extracts to be just as potent as those extracted from the dog pancreases. By December 1921, he had also succeeded in extracting insulin from the adult pancreas. Pork and beef would remain the primary commercial sources of insulin until they were replaced by genetically-engineered bacteria in the late 20th century. In spring of 1922, Banting established a private practice in Toronto and began to treat diabetic patients. His first American patient was Elizabeth Hughes Gossett,
Frederick Banting George V. Frederick Banting was born on November 14, 1891, in a farm house near Alliston, Ontario. The youngest of five children of William Thompson Banting and Margaret Grant, he attended public high schools in Alliston. In 1910, he started at Victoria College, part of the University of Toronto, in the General Arts program. After failing his first year, he petitioned to join the medical program in 1912 and was accepted. He began medical school in September 1912. In 1914, he attempted to enter the army on August 16, and then again in October, but was refused due to poor