Frederick Banting realized that this procedure would destroy the trypsin-secreting cells but not the insulin. Once the trypsin-secreting cells had died, insulin could be extracted from the islets of Langerhans. Banting discussed this approach with J. J. R. Macleod, Professor of Physiology at the University of Toronto. Macleod provided experimental facilities and the assistance of one of his students, Charles Best. Banting and Best, with the assistance of biochemist James Collip, began the production of insulin by this means. As the experiments proceeded, the required quantities could no longer be obtained by performing surgery on living dogs. In November 1921, Banting hit
William Banting James’s Street, London, was among the most eminent companies of funeral directors in Britain. As funeral directors to the Royal Household itself, the Banting family conducted the funerals of King George III in 1820, King George IV in 1830, the Duke of Gloucester in 1834, the Duke of Wellington in 1852, Prince Albert in 1861, Prince Leopold in 1884, Queen Victoria in 1901, and King Edward VII in 1910. The royal undertaking warrant for the Banting family eventually ended in 1928 with the retirement of William Westport Banting. In 1863, Banting wrote a booklet called "Letter on Corpulence, Addressed to