[3] During World War II, Fisher served as a surgical lieutenant in the Royal Canadian Navy, and was aboard HMS Voltaire when it was sunk by German gunfire in 1941 off the coast of Cape Verde.
[4] Following his return to Canada, Fisher began his residency at McGill University at the Royal Victoria Hospital.
[1] Fisher proved, by a series of pathological studies, the relationship between stroke and the formation of blood clots in the heart in patients with atrial fibrillation.
[5] He contributed greatly to the understanding of stroke, more specifically carotid artery disease[1][5] and lacunar infarcts and their syndromes.
[2] In 1952 he was the recipient of the Royal College of Physicians of Canada's Prize in Medicine, and in 1998 he entered the Canadian Medical Hall of Fame.