After graduation, Foster joined the Army Medical Reserve and served as a first lieutenant in U.S. General Hospital Number 14 at Fort Oglethorpe, Georgia until his discharge in 1919. At the same time, he served as a house officer at Peter Bent Brigham Hospital (Boston) during 1917 – 1918.
After that, he decided to follow in his parents’ footsteps and go to China as a missionary.
Source from: Colby Special Collection