Source: Service record of Pte. James Aitken in a report on his death. Report indicates this soldier was injured during the collapse of a cook house (accident).
Family Search: When Private William Mark Mercer was born on 14 June 1880, in Port Hope, Durham, Ontario, Canada, his father, Horatio Nelson Mercer, was 23 and his mother, Mary Ann Nelson, was 14. He married Mable Dewell on 5 September 1908, in Port Hope, Durham, Ontario, Canada. They were the parents of at least 1 daughter. He lived in Durham, Ontario, Canada in 1911. He registered for military service in 1915. In 1915, at the age of 35, his occupation is listed as enamaler in Port Hope, Durham, Ontario, Canada. He died on 11 April 1940, at the age of 59, and was buried in Port Hope, Durham, Ontario, Canada.
History of the 18th Battalion CEF, "The Fighting Eighteenth" 