He was born in
Leith on 22 March 1888, the son of George Hunter Cruickshank. He had a twin brother,
Martin Melvin Cruickshank. He was educated at
Robert Gordon's College and studied medicine at
Aberdeen University graduating MB ChB in 1910. He then attended
University College, London as a research fellow 1912-14. In the
First World War he joined the
Royal Army Medical Corps with his twin brother, but quickly they were separated by events. He was commissioned as a lieutenant in February 1916 rose to the rank of captain, serving in both France and Italy. In 1919 he was based in
Cologne as part of the Prisoners of War Repatriation Command for the 3rd Bavarian Army Corps. After the war he became an associate at the
University of Washington School of Medicine. Aberdeen University granted him an honorary MD in 1920. He then spent until 1935 as a travelling professor, lecturing in US, Canada, China and India regarding physiology and nutrition. During this period he became the first appointee in physiology at the
Peking Union Medical College. From 1935 until 1958 he remained in
Scotland as professor of physiology at
Aberdeen University. In 1929 he was elected a fellow of the
Royal Society of Edinburgh. His proposers were
Diarmid Noel Paton, Sir
Edward Albert Sharpey-Schafer, Sir
Edmund Taylor Whittaker, and
Ralph Allan Sampson. Aberdeen University awarded him an honorary Doctor of Letters (LLD) in 1959. He died on 29 December 1964 in
Aberdeen. ==Family==