Born at Westcombe Park, Blackheath on 9 June 1883, the only son of A G Mackenzie, FIA, and Beatrice E Dell, his wife. He was educated at Eastbourne College, at Emmanuel College, Cambridge, where he graduated after obtaining a third class in the Natural Sciences Tripos, Part I, and at the Middlesex H

Born in 1884 at Boston, Lincolnshire son of William Gilliatt, he received his medical training at the Middlesex hospital, where he was an outstanding student. He won the Hetley clinical scholarship, the junior Broderip scholarship, the Leopold Hudson scholarship and the Lyell gold medal and scholars