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 Territories), Georgian Bay, French River and the Sudbury District. Banting married twice. His first marriage was to Marion Robertson in 1924; they had one child, William (born 1929-, died 1998). They divorced in 1932 and Banting married Henrietta Ball in 1937. In February 1941, Banting died of wounds and exposure following the crash of a Lockheed L-14 Super Electra/Hudson in which he was a passenger, in Musgrave Harbour, Newfoundland. After departing from Gander, Newfoundland, both of the plane's engines failed. The navigator and co-pilot died instantly, but Banting and the pilot, Captain Joseph Mackey, survived the initial impact. According to