Suppose a soldier is hit by a piece of shell or sniper's bullet while he is in a trench which his battalion is holding. He is first attended by the stretcher bearer nearest to him at the time, who should use the man's own aseptic dressing which each soldier is compelled to carry in the lining of his coat or tunic. The injured man is then taken to the dugout of the M.O., if necessary on a stretcher, where the M.O. rearranges the dressing, gives a dose of morphine if pain is severe, and after seeing that all hemorrhage is stopped and the man is comfortable, he hands the case over to the field ambulance stretcher bearers who always serve him and live in an adjoining dugout. This squad carries the case back--through the trenches if there is no hurry, but overland if haste is important--to the advanced dressing station of the field ambulance. If this should be a particularly hard trip it may be done in relays. For there relay post dugouts are established with other bearer squads.
The A.D.S. is usually situated a mile or so in the rear of the trenches, preferably in a large cellar, but at any rate in a fairly well sheltered area where cots are ready to receive fifty or more patients. At the A.D.S. one or two of the medical officers of the field ambulance are stationed with a large staff of men. The patient is here made comfortable; given coffee or cocoa; name, number and battalion recorded; and finally he is inoculated with anti-tetanic serum. This has practically wiped out tetanus, or lock-jaw, which was very prevalent at the beginning of the war. He is kept here till a convenient time, which may be after dark, when he and any others who may have come in are put into ambulances and taken to the M.D.S.--main dressing station--of the field ambulance, another two or three miles behind. The M.D.S. may be in some old château, or in a group of huts, or, if the weather is mild, in tents. Here a light case, or slightly wounded man, may be kept for a few days and then sent back to the line or to a rest station to recover his stamina and quiet his nerves. But if the case should be a serious one, such as a shattered leg or arm or a large flesh wound that will take a considerable time to heal, he is again transferred by ambulance to the C.C.S.--Casualty Clearing Station--another two to four miles back.