Frederick Banting in the blood which was then excreted in urine. Attempts to extract insulin from ground-up pancreas cells were unsuccessful, likely because of the destruction of the insulin by the proteolysis enzyme of the pancreas. The challenge was to find a way to extract insulin from the pancreas prior to its being destroyed. Moses Barron published an article in 1920 which described experimental closure of the pancreatic duct by ligature; this further influenced Banting's thinking. The procedure caused deterioration of the cells of the pancreas that secrete trypsin which breaks down insulin, but it left the islets of Langerhans intact. Banting
Highest and best use Since their use predates these regulations, they are "grandfathered in". However, some such uses may not be reproduced if the legally nonconforming improvement is destroyed or damaged beyond a certain point. "Legally permissible" can be a tricky conceptual test, because even uses that are currently not permitted may be considered. This happens when there is a reasonable prospect (at least 50%) that the regulation, zoning, deed restriction, etc. can be changed to permit the proposed use. Any potential use must be physically possible given the size, shape, topography, and other characteristics of the site. For example, a single story warehouse