From a medical standpoint, World War I was a miserable and bloody affair. In less than a year the American armed forces suffered more than 318,000 casualties. When the United States entered the war in 1917, the army did not have an established medical corps. During the war, the army medical corps copied parts of the French and English medical system that had been in use for the past three years. This system arranged military medical staff in a practical manner. Stretcher-bearers first came into contact with the wounded and moved them from trenches to waiting ambulances. The first aid treatment these medics gave often saved lives.* From there, the wounded would be taken to either mobile dressing stations or field hospitals, while the gravely injured would be driven to base hospitals behind the lines.

 

* Sourced from WWI: Medicine on the battlefield by John Campbell