Joshua Gabriel Baker Campbell enlisted with the transportation units at the American Ambulance Hospital in 1914, with a group that would later be renamed Section Sanitaire Etats-Unis (SSU) 1 of the American Field Service. He left for Dunkirk on January 20, 1915 to provide aid during the long-range bombardments and air raids.
In early 1915 Campbell discovered a stray dog on the roadside in Belgium, whom he named “Khaki,” due to his color. According to a booklet entitled Khaki: The true story of how a brave dog cheered and helped his master in his work for the wounded in France, Khaki accompanied Campbell on trips to pick up wounded soldiers, helping by barking to clear the road ahead. Although Khaki was terrified of the bombshells, he would never let the AFS drivers go about their work alone. During the bombardment of Dunkirk, Khaki fought against his fear and helped the drivers search for survivors among the crumpling houses.
To read more about Khaki and his short time with AFS in 1915, you can download the full booklet here. The booklet was printed by British friends of Campbell without his knowledge. It contains handwritten commentary by Campbell, written forty years after the booklet was originally published.