David joined the 141st Field Ambulance on 31st August 1916 as a reinforcement. On 26th February 1919 he proceeded to No 5 General H.Q. School of Chemistry for a course in pharmacy. He rejoined the unit from the course on 4th April 1919. On 2nd September 1919 he proceeded from Kinmel Park for dispersal and was struck off the strength of the unit.