The mobility of an army is essential; there fore the Sanitary Service must operate effi ciently, in such a manner as not to obstruct military operations, and with a minimum amount of transportation and personnel. In the Zone of the Advance the medical administra tion provides only emergency treatment and prompt transportation of the wounded to the rear, always with such disposition that men fit for duty are retained at the front and the fight ing force relieved of the impediment incident to the presence of men incapacitated for duty. When battle impends, the resources of the San itary Service behind the Zone of the Advance are placed in readiness to meet the demands for the care and transportation of the wounded which may reasonably be expected, and per sonnel and supplies are advanced as near the seat of operations as practicable, reaching for ward into the Zone of the Advance if condi tions warrant it. The Sanitary Service of the Line of Communication (1) provides such facilities that the wounded may return to the front without delay; (2) furnishes prompt evacuation service so that the fighting forces will be promptly relieved of wounded and the Sanitary Service of the Zone of the Advance can keep in touch with their combatant organiza tions; (3) furnishes a system of supply to enable the sanitary troops in the Theatre of Operations to replenish equipment and supplies by direct method and without delay; and (4) maintains satisfactory sanitary conditions among the troops on the Line of Communica tion and, if necessary, takes charge of sanitation among the inhabitants of occupied territory.
The Ambulance Service supervises trans portation of wounded from the first-aid sta tions to the base hospitals. On the march not in the immediate presence of the enemy an entire ambulance company may be placed with the advance guard. Ambulances of one or more companies may be distributed through the main body, an ambulance following each regiment or independent battalion ; later, these join their companies. An ambulance company operates in two parts, with personnel at war strength as follows : (a) With the dressing station, includ ing the litter bearers, with equipment on pack mules; four officers, one sergeant first-class, six sergeants, one acting cook, 40 privates first-class and privates — all of the Medical De partment — and (b) with the wheeled trans portation ; one officer, one sergeant first-class, one sergeant, one acting cook, XI privates first class and privates (one as farrier, one as saddler, 20 musicians, 12 as ambulance drivers and 12 as ambulance orderlies)— all of the Medical Department; also, one sergeant (black smith) and three privates (drivers) of the Quartermaster Corps. Regulations provide that all ambulances, wagons, animals, hospital trains, ships and boats, with their personnel assigned to the Medical Department, shall not be diverted from the medical service. Supplies for the sick and wounded are transported so far as possible by the medical superintendents of the Trans port Service. For evacuation of the wounded to the rear, all transport available is pressed into service, including combat wagons, field train wagons, automobiles and other civilian transportation of all kinds.
While the organization of the Medical De partment may logically be treated first with a general consideration of the various branches of the service and divisions of the surgeon general's office, and with the successive steps taken in building the service from the interior to the battlefield, in considering the Theatre of Operations one must visualize the entire cone above the base, through the Line of Communica tion and Zone of the Advance to the very fore front of battle. And as casualties regularly pur sue a course backward from the active front, consideration of medical activities in the Theatre of Operations may well be in this order.
The wounded man applies a dressing from his own first-aid or converts his belt or shoe lace into a tourniquet if able— or a comrade does it for him if he, is incapacitated — when medical aid by a regimental medical orderly is not available. As the engagement develops, an Aid Station is established for each regiment as the number of wounded brought in by the field ambulance bearers warrant. (In many cases bandsmen are assigned to duty as stretcher bearers for first aid). The time and place for opening an aid statism are determined by the organization commander, unless he has author ized the surgeon to use his discretion in the matter. In this case, the surgeon of each regi ment, with the necessary equipment carried on a pack mule, establishes the station. The Aid Station is always in immediate touch with the combatant unit. The requirement that the sani tary personnel with combatant organizations keep in touch with those organizations may make it necessary for them to leave the wounded where they fall, pausing only to administer such aid as may be absolutely essential. In the case of mounted troops, the sanitary detachment accompanies troops during the whole course of the engagement, pausing only long enough to render first aid and to collect the wounded at a place where they can be turned over to an inhabitant to be cared for. Cases left behind will be collected and cared for by the dressing station party as it advances. In some cases dressing station and aid station are located to gether. Treatment at the Aid Station at which the wounded are originally assembled by the Sanitary Service is usually limited to first-aid and to readjustment of dressings, with some times an emergency operation. During and after an engagement diagnosis tags are attached to all wounded (and also the dead) as soon as practicable; they are made out in duplicate. At these stations the Sanitary Service with the troops connects with the service of the sani tary train. Men with trivial wounds are sent back to their commands when the wounds are dressed. Those slightly wounded hut able to walk are directed to the station for slightly wounded, several miles in the rear, so that dressing stations and field hospitals may not be congested unnecessarily. If time has permitted the installation of a more elaborate system, the wounded may be taken by trolley from tho trench first-aid station through a communicating trench to the Advance Dressing Station ; other wise they are taken on hand-stretcher or perambulator.