NCOs supervised training in the Massachusetts National Guard Ambulance Corps, the Army's first specialized medical unit. This corps was one of several created in the nineteenth century to execute technical missions. The Ambulance Corps relieved regiments of the responsibility for transporting casualties to the field hospitals during combat. This change freed the infantry to continue fighting and increased the patient's chances of recovery. Here a sergeant directs the unloading of a litter from an ambulance during a training encampment. By the end of the nineteenth century, most volunteer militiamen wore uniforms only slightly modified from the Regular Army's, generally relegating state-specific markings to buttons, belt plates, and cap devices. Because no federal counterpart organization existed for the Ambulance Corps portrayed in this picture, Massachusetts used insignia originally developed for personnel assigned to the hospital corps. The sergeant's rank is indicated by the chevrons of an acting hospital steward (green and white with the red Geneva cross) with matching stripes down his trousers by his 1840 model NCO sword. The private's branch identification is in the form of the Geneva cross on his brassards and by two special items of individual equipment: a hospital corps pouch to carry his first-aid supplies (a modification of an obsolete leather cartridge box), and the hospital corps knife (a tool, not a weapon). Around his neck, and secured by the waist belt in front, is a leather litter sling.