He was a public ward patient in the diabetic clinic Dr. Walter Campbell had founded a few years earlier at Toronto General Hospital.
Leonard’s diabetes had been diagnosed in 1919. By December 1921 the boy was reduced to skin and bones. On January II, 1922, Frederick Banting and Charles Best injected him with insulin. The results were not encouraging: the fall in blood glucose was not very marked, and ketones were still present in urine.
Twelve days after his frost injection, Leonard Thompson received an injection of Collip’s new extract. His blood sugar level became normal and his ketonuria was eliminated. He was able to eat and gained weight quickly.
At that time insulin still so impure that as a result of the first insulin injection Leonard had a 7.5 cm callus at the injection site on his left buttock.
First human to try insulin