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,
Highest and best use net economics. An example might be an industrially-used site that can now be used legally for high-rise residential buildings, but would cost so much to clean up (remediate) that the value as currently used is higher. In that case, if it can be continued, the existing industrial use could be the highest and best use. In some cases appraisers are given specific instructions as to an assumed highest and best use. This use might not pass the tests discussed below as a legitimate highest and best use, and may very well produce a different value. One example of this might