[5] During World War I he served in the Canadian Army Medical Corps.
After studying posttraumatic stress disorder and gas poisoning during the World War I, he became Deputy Director of Medical Services with the rank of brigadier during the World War II, and was created a Commander of the Order of the British Empire for his services.
[3] While at the University of Edinburgh, he was one of the first medical researchers to administer and study the effects of insulin.
In 1924, he moved back to Canada as Professor of Medicine at McGill University where he remained until his retirement in 1947.
Meakins married twice, first to Dorothy Brown (died 1926) and then to Sara Caldwell Young.