Ellis Harding was a contract surgeon of the "Harvard Unit" attached to the Royal Army Medical Corp. He graduated in 1911 and received his medical degree in 1916
He joined the the Harvard Surgical Unit on May 31, 1916. The unit manned General Hospital No. 22, BEF.
According to his Harvard bio, he was "commissioned temporary honorary captain, RAMC, in March 1917 and detailed to Casualty Clearing Station No 10 from September to December 1917 after which he was detailed tot he 1/1 Northumbrian Field Ambulance, 50th Division until December 1918 and thereafter served as battalion medical officer of the 4th King's Royal Rifle Corps.
He completed his duties in January 1919 and was credited with service during the Battle of Paschendaele Ridge (1917) and Somme Offensive (1918). He was awarded the Military Cross.
This photo was taken in France in August 1916.