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 a series of tests. The exact definition of highest and best use varies, but generally the use must be the following: Only those uses that are, or may be, legally permitted are potential highest and best uses. This may exclude uses that are not, and unlikely to become, permitted by zoning, land use planning, uses forbidden by government regulations, and uses prohibited by deed restrictions or covenants. Properties with a use that predates existing zoning or other property regulations may be "legally nonconforming". Such "grandfathered uses" are generally legal even though they do not meet current zoning or other regulations.