Peterswald (or 'Pete" to his closest friends) was educated at Edinburgh University, where he graduated M.B., Ch.B. in 1901. After qualifying he made several voyages as a ship surgeon, and residentships at Stirling and Chester before starting practice at Colinton. He took the diploma of D.P.H. in 1910, then became school medical officer in Fife, acting also as Assistant M.O.H. for the county. He resigned this position on receiving a temporary commission at the rank of lieutenant in the R.A.M.C. on 21st November 1914. He was promoted to temporary captain one year later. In France he was attached to the Kings Own Yorkshire Light Infantry but after struggling for weeks against illness, he was invalided home in July 1915. His illness was found to be incurable and he spent the last six months of his life in a nursing home. He was buried on the 25th February. Peterswald was the son of Gilchrist Gray Pattison.