Forrest was a qualified doctor of the Medical Officer Reserve Corps, U.S.A., who volunteered to serve with the British Army during the Great War. He travelled from the U.S.A. on board the SS "New York", which sailed from New York arriving in Liverpool on 28th January 1917. He was working in the 3rd London General Hospital in Wandsworth when he married Muriel Tessa Clare McPhail (seemingly known as Tessa) in St.James Norlands, Kensington, London on 26th January 1918.
He entered the war on 8th April 1918, then on the 13th August reported his arrival for duty with the Assistant Director of Medical Services, 11th (Northern) Division, who posted him to serve with the 34th Field Ambulance. On 18th December 1918 he was transferred to the 58 Bde, R.F.A. as their new Medical Officer to replace Lt Gale R.A.M.C. On 12th March 1919, he left 58 Bde, R.F.A. and reported to the Director of Medical Services, 2nd Army for duty.
After the war he returned to the U.S.A. with Muriel and their new-born daughter Doris, and in 1920 started a career with the U.S. Public Health Service, for whom he worked for the rest of his career. During World War 2 he served with the US Medical Corps rising to the rank of Lieutenant Colonel, and acted as the deputy surgeon general of the Veterans’ Administration. During the 1950s he worked for eight years as the medical director of the Veterans' Administration Hospital in Fresno, California. He the son of doctor James Johnston Bell and Caroline Belle Bell (née Myers). [Information researched and kindly provided by David, whose website to the 58th Bde, R.F.A. can be found at this website address https://58fab.com/]