The casualty clearing station is, to medical activities, the" great divide." On the side toward the front, professional interests are subordinated to the urgent necessity of keeping the lines clear of sick and wounded.

 

This means the retention only of those who can quickly return to the fire trench or other duty, and the  expeditious, though careful, evacuation of those whose man-power value is partly or wholly erased. On the side toward the base technical considerations are predominant, with the result that the special care and treatment of several types of injury and disease are begun.

From a practical point of view, that of the patient, this arrangement is agreeable, for the quicker he gets out of shell fire, over the hump of the casualty clearing station and down the more peaceful lines of communication, the better is he pleased.

This position between frontline and hospital conditions continually recurs to the mind when studying the administration and work of a casualty clearing station. At first called a "clearing hospital," its functions of rapidly sorting and evacuating casualties soon altered it to "clearing station," The pendulum of its work now swings between the two; during quiet times, when only the sick and wounded incident to ordinary trench warfare arrive, it is much a hospital, its work resembling that done in stationary or general establishments; while during an offensive, with the inflow of battle casualties, it is very much a station, for like a field ambulance, but on a larger scale, it only holds for treatment certain selected cases (about 10 per cent.) and evacuates the remainder as quickly as possible. With these varying conditions its old limit of 200 beds is long since gone, and its capacity is now anything from a thousand upward. Formally a medical unit on the lines of communication, its increasing importance, together with the growth of army areas, in which in time it was always found, caused its change to an army establishment under the administration of the director of medical services concerned. The medical units of an army are usually arranged in groups, each group being responsible for a definite sector of the front. Such a group is composed of 2,3 or more casualty clearing stations; a motor ambulance convoy; an advanced depot of medical stores; a mobile laboratory and frequently a mobile x-ray.

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The director of medical services is responsible for this grouping and for certain details of its work. In addition to the units thus focused the director may have one or more stationary hospitals under his authority. These establishments are useful for the reception of such special cases as "Not yet diagnosed nerve," often known as " shell-shock sick" in contradistinction to true shell shock;

"Pyrexia of unknown origin;" infectious diseases and self-inflicted wounds. As already indicated in Fig. 16, certain special cases go direct from the field ambulances to designated stationary hospitals, but the greater number are sent from the casualty clearing station. The director issues instructions in regard to them and arranges for their transportation by the motor ambulance convoy or occasionally by civilian trains, "Chemin de fer economique." . In order to coordinate the medical work of corps and army the director, from time to time, issues in his routine orders to deputy directors instructions and details of the arrangements made in regard to casualty clearing stations.

In examining the internal arrangements of a casualty clearing station it will again be helpful to emphasize by considering separately the methods followed during inactive warfare and the changes that take place to meet active conditions.

DURING PEACE WARFARE.

The staff required to meet the demands of quiet times is not large. It is generally made up of the officer commanding; 1 quartermaster; 1 surgical specialist; 1 anesthetist; 4 other medical officers; 1 dentist; 1 matron; 6 nursing sisters, and 80 non-commissioned officers and men.

The station is, as a rule, at least six miles from the front line and occupies a place in an army group which is frequently accommodated in hutments or partly housed in huts and partly under canvas.

The arrangement of a well-planned casualty clearing station is illustrated in the frontispiece. It will be seen that in addition to ambulance transport there is a tramway system by which the wounded can come from the field ambulance when casualties are heavy. It is also in immediate contact with a railway siding, so that the movement of patients from the evacuation huts into the hospital train is easily made. Several dugouts are in evidence, this establishment having received some attention from the enemy. The left side of the plan, with its wards, dispensary, etc., suggests the hospital and its attention to patients; while the right, with its evacuation area, suggests the clearing station and rapid movement of casualties toward the base. The internal economy by which all admissions are expeditiously, yet methodically, sorted and disposed of toward left or right is better described under battle conditions. 

In addition to the sources of supply mentioned under field ambulance arrangements, patients arrive from both corps and army units, so that sick and wounded are received as follows:

1. From advance dressing stations

2. From main dressing stations.
 

3. From rest stations.
 

4. From medical officers of corps or army units.

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The wounded who require further surgical attention are operated upon and held until considered fit for evacuation. The exact meaning of the phrase "considered fit for evacuation" varies from time to time, depending largely upon the number of casualties being received. All wounded who do not require surgical interference and all sick who are fit to travel, but who will not be fit for duty within three weeks, are evacuated to the base by the first hospital train. Sick who will be fit for duty within a period of three weeks may be treated at the clearing station. About 30 per cent. of the sick admitted are so held and discharged to duty.

The casualty clearing station periodically receives orders from the director of medical services to clear, in which case patients who would otherwise be retained at this station are sent to the base. 

 

The director is notified each morning as to the number of lying and sitting cases that await disposal, and, acting on this. information, arranges the necessary transportation for evacuation to one or more of the following destinations:

1. Base hospital by hospital train.
 

2. Stationary hospital, lines of communication, by hospital barge or train.

3. Stationary hospital, army area, by motor·ambulance convoy or civilian train.

Men belonging to units in the immediate neighborhood on being discharged to duty proceed on foot, while men belonging to units not in the immediate neighborhood obtain their transportation through the railway transport officer.

DURING BATTLE.
 

With the beginning of an offensive the arrangements and work of the clearing station change from the stodgy to the interesting. The flow of battle casualties to the group has been provided for by the arrival of more motor ambulance convoys, motor lorries, and char-a-bancs, to which is added the active operation of the tramway system, should this be available. The personnel increases to a number limited only by what the commanding officer demands or by what the director is able to supply.

 

They are mostly drawn from hospitals at the base or possibly on the lines of communication, but field ambulances may also be obliged to contribute, while additional stretcher-bearers are obtained from labor battalions and prisoners' camps. An outstanding feature is the "surgical team," made up of a surgeon, an anesthetist, a nursing sister and two orderlies, all specially qualified for their work. Usually several of these teams are sent to each clearing station behind a battle front. All casualties, lying, sitting or walking, are brought to the reception hut (see frontispiece). Here clerks quickly obtain the names and necessary particulars for the records. The patients are then immediately taken by the stretcher-bearers to the dressing hut. This has 4 or more  dressing tables at one end while the remaining floor space will accommodate at least 50 stretchers. On one side, and connected with this hut by a short passage, is an operating annexe with x-ray apparatus at one end and 2 or more operating tables at the other.

Off the dressing hut, on the opposite side, is the pre-operation or preparation hut, with 4 tables at one end and again space for stretchers.

So important is the work of the dressing hut that either the chief surgeon or the second surgeon, properly assisted, are on duty here .. As patients are brought in from the reception room their bandages are cut down and their wounds exposed by the orderlies in attendance. They are then examined by one of the surgical experts and classified and distributed . under the following headings:

1. Those fit for immediate evacuation. If dressings are clean, they are often replaced, bandages applied and patients sent to the evacuation section. (" Area" in illustration.)

2. Those fit for immediate evacuation, but dressings soiled. Wounds are redressed and patients sent to evacuation section.

3. Those requiring minor operations, such as enlargement of wounds. Dressings replaced and patients sent to operating annexe. 

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4. Those requiring, and fit for, immediate operation. Dressings are replaced and patients sent to preparation hut.

5. Those suffering from severe shock, whether requiring operation or not. These are sent to the resuscitation ward.

6. Those not to be operated upon, but who must be kept under observation until evacuation by the hospital train, such as head cases, certain fractures, etc. They are dressed and sent to wards kept for this purpose in the postoperative'  section.

It will be remembered that in order to assist the clearing stations in times of stress, certain selected cases were marked by the field ambulances" Need not be dressed for 24 hours." Notwithstanding this hint, an endeavor is always made by the surgeon to see the wounds of every casualty that passes through the reception hut to him; for it may happen that the slighter injuries, from their very insignificance, are neglected, become infected, and so perhaps serious. It is therefore only in times of severe pressure that these cases, together with those of the walking wounded, whose bandages are clean, who have no pain, and no obvious signs of trouble, are sent to the evacuation section without their injuries being inspected. The patients in the preparation hut have their uniforms removed, are put into hospital clothing, and, so far as possible, made ready for the operating theatre. While they wait, a small dose of morphine is frequently given, and if the ears be stuffed with cotton-wool, a remarkable number will rest, sleep, and take the anesthetic easily.

The resuscitation ward is probably the most important of the huts reserved for special conditions. 

The medical officer in charge of this ward sees each patient as he is brought in and attaches a card, giving instructions as to the treatment he should receive and the number of the table in the operating room to which he will be sent as soon as he is resuscitated.

The operating room is a large hut, down one side of which extends a long table. On this; and facing each of the four to eight operating tables, there are small sterilizers for the instruments used at each particular table; while in an annexe are the large sterilizers for dressings. Here the surgical teams work in relays, there being usually from three to six busy at any given time. During every operation, a clerk, or more often the anesthetist, makes notes in regard to what is wrong, and the essential details of what is done. This information is entered on the man's" field medical card," which is then placed in its water-proof envelope and goes with the patient to the base.

After operation the patients may be sent direct to the evacuation section, but more frequently go to the postoperative wards. These consist of a row of huts, each accommodating some 40 cases. A nursing sister and two orderlies are on duty in each, and the medical officers detailed to the chest and resuscitation wards, are also available in case of emergency in any part of the section. 

The evacuation section contains ample accommodation for all lying, sitting, and walking cases, but there are no beds, as stretchers are used in readiness for en training. The commanding officer generally makes this section his particular charge, and his chief surgeon also pays repeated visits, in order to make sure that none of those waiting disposal have developed symptoms necessitating further surgical interference. At the casualty clearing station, as at the dressing station of the field ambulance, food is an important desideratum in the care of wounded men.

Arrangements are generally made whereby walking wounded can be fed while waiting admission, or else they parade later in the dining room. Nourishment is also taken to the lying and sitting patients in the evacuation section by means of food wagons, while each of the postoperative wards has its small diet kitchen.

During active warfare the clearing stations must notify the director of medical services every hour as to the number of lying and sitting cases awaiting evacuation at their respective establishments. The director then makes arrangements for the necessary hospital trains. There is supposed to be a casualty clearing station for every division in the field, so that a group of three such stations is expected to take ·care of all casualties arriving from a sector of front corresponding to a corps of three divisions. It is evident that it is practically impossible for any clearing station to continue work indefinitely under the strain put upon it, particularly by battle conditions.

Two arrangements to allow of some respite are in vogue among the members of various groups.

The first, usually adopted in peace warfare, is that one of the stations shall. receive all patients arriving during twenty-four hours, evacuate them on the following day, and on the third clean up, rest, and get ready to receive again on the' succeeding day. The second, generally adhered to during an offensive, is that each clearing station of the group, in turn, receives 150 lying cases, or the equivalent in lying and sitting, two sitting being considered as equal to one lying. 

This completes the description of a casualty clearing station and its activities in so far as they touch upon the present discussion; but, in conclusion, some mention must be made of the action taken by the unit concerned in the temporary  or permanent loss of the man who is a casualty. When the sick or wounded man passes through the regimental aid post into any of the various establishments conducted by the field ambulance, and later, in most cases, to the clearing station, he is shown on the records of his unit as in hospital, but still remains on its strength. If not returned to duty by this station, but passed instead to a stationary hospital or the base, he is then struck off the strength of .his battalion or other unit. It thus happen that when a casualty is evacuated for further treatment" from the' casualty clearing station he 'passes to that bourne  from whence he may return only as a reinforcement., 

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1 Such a unit is termed an "Evacuation Hospital" by the Americans

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