and surgical stores, and for sanitary duties. Sick and wounded are collected in the first instance by a regimental medical service and passed from it to the field ambulances of the divisions. They are cleared from the divisions by motor ambulance convoys, which convey them to casualty clearing stations, whence they are passed down the lines of communication by rail, canal or road to the permanent hospital bases, and from there by sea- going hospital ships to the hospitals in the United Kingdom. The collecting zone may be regarded, therefore, as the area of work back to the casualty clearing stations; the evacuating zone as the lines of communication down to the sea bases or to the United Kingdom, and the distributing zone as the area of the hospital bases and the home territory.
The Regimental Medical Sennce. Each regiment of cavalry, battalion of infantry, brigade of artillery, ammunition column, squadron or bridging train of engineers and certain supply trains has an officer of the R.A.M.C. attached to it, together with a small detachment of R.A.M.C. other ranks for technical charge of water carts and water supplies. Sixteen men of the regiment are placed under him during battle as stretcher-bearers; and a non-com- missioned officer and eight men, trained in sanitary duties, also work under him. Wounded are collected to a regimental aid po'st, which is established by the medical officer in a shelter or protected spot near regimental headquarters.
Field Ambulances. There are two forms of ambulances, the cavalry field ambulance for cavalry divisions and the field ambulance for divisions. They differed considerably in organization and trans- port before the World War, but since then the chief difference is in their transport. A cavalry division has a cavalry field ambulance for each brigade of which it is composed. Thus a cavalry division of four cavalry brigades would have four cavalry field ambulances. Divisions have three field ambulances each. Both a cavalry field ambulance and a field ambulance are composed of a bearer division and a tent division, and are organized in two sections, each section being formed of half the bearer and half the tent division. In the bearer division there are 18 stretcher detachments. They bring wounded back from the regimental aid posts to an advanced dress- ing station formed by one of the tent sub-divisions at a point to which wheeled transport can come up. Wounded are conveyed from the advanced dressing station to a main dressing station formed some distance back by the remainder of the field ambulance or by other field ambulances where there is less exposure to enemy fire than at the advanced dressing station. Formerly both classes of ambulance had each 10 horse-drawn ambulance wagons, six of which in cavalry field ambulances were light wagons, the remaining four being heavy wagons of the same type as the 10 wagons of the field ambulance. Motor ambulance cars replaced a proportion of the horse-drawn wagons after the British Expeditionary Force moved from the Aisne to the Flanders front in 1914. The ambulance transport of the cavalry field ambulance now consists of four motor ambulance cars and six light horse-drawn ambulance wagons; that of the field ambulance is seven motor ambulance cars and two heavy horse- drawn ambulance wagons! They are employed in battle in carrying wounded from the advanced to the main dressing station, but may go forward in advance of the former where it is possible to do so. Their carrying capacity is two lying or eight sitting in the light wagon or light ambulance car, and four lying or 12 sitting in the heavy wagon or motor ambulance car. Field ambulances are divisional troops and come under the command of the assistant director of medical services of the division.
Motor Ambulance Convoys. The first motor ambulance convoy used by the British in war was organized at the end of Sept. 1914 dur- ing the battle of the Aisne. It was formed of ambulance cars sent to France by the War Office early in Sept. and was rapidly followed by similar convoys, some of which were provided by voluntary organiza- tions. Previously the system by which sick and wounded were brought from the field ambulances to railhead was to load them in the lorries of the supply columns returning empty to refill. But the system broke down early in the World War partly because this form of transport subjected the wounded to serious discomfort and jolting, and partly because the requirements of supply services and medical services were in conflict with one another. A motor ambulance con- voy consists of 50 motor ambulance cars; it is under the command of an officer R.A.M.C. with R.A.M.C. personnel for medical duties, and a R.A.S.C. personnel, under an officer R.A.S.C.,as drivers and mechanics. The number of these convoys allotted to an army is usually in the proportion of one for each army corps of which the army is composed, and one as an army reserve. They are normally army troops under the control of the director of medical services, who may, however, place them at the disposal of deputy-directors of army corps. Their function is to clear the field ambulance main dressing station of sick and wounded to casualty clearing stations at or near railheads, and to perform all other ambulance transport duties by road not carried out by the transport of field ambulances. In the event of railway transport breaking down or proving insuffi- cient to relieve congestion of sick and wounded in the front areas,
motor ambulance convoys may be employed for conveying sick and wounded to hospitals at the base.
Casualty Clearing Stations. These are medical units which form the link between the collecting and evacuating zones, or between the divisions of the field army and lines of communication. Their func- tion is to receive the sick and wounded from the divisional field ambulances. Sick and wounded likely to be fit for duty after a short period of treatment are retained, as are also those too seriously ill for further transport. The remaining sick and wounded, after receiving temporary medical and surgical treatment, are evacuated as rapidly as circumstances and railway transport permit to the hospitals at the base. Casualty clearing stations are consequently organized with a convalescent or lightly wounded section, a hospital section, and an evacuating section. The number of casualty clearing stations allotted to an army is in the proportion of one for each division, but they are essentially strategical units and are army troops, the director of medical services being responsible for placing them where they may best receive and evacuate the number of wounded anticipated in battle. They are mobilized with personnel and equipment for the care of 200 casualties at a time, but are capa- ble of expansion to any extent in the field from local resources or by bringing up additional equipment and stores from the base, whenever the nature of the operations admits of this being done. The organi- zation of casualty clearing stations, therefore, depends very much on the nature of the military operations. The general principle upon which it is based is the mobilization of a light mobile unit in the first instance capable of following up an advancing army with sufficient equipment and shelter for surgical work at an advanced operating centre, and adding to it more extensive accommodation and equipment whenever circumstances permit. In its original composition a casualty clearing station had no transport of its own. During the World War three 3-ton lorries were allotted to it. It was customary to group them in twos or threes in the same locality. The lorries of a group of three casualty clearing stations would thus be sufficient to carry forward the advanced operating section of one of the three, and then return for the others. The weight of the original equipment, including marquees for 200 patients, was 21 tons, so that the nine lorries were capable of carrying this load. The heavier equipment and more extensive accommodation added during stationary warfare required 50 to 60 lorries for moving a casualty clearing station by road, or a complete train by rail. Casualty clearing stations are allotted two 3-ton motor lorries each.
Ambulance Trains. The evacuation of wounded by railway is effected by specially constructed or by improvised ambulance trains. The former are composed of ambulance coaches with through com- munication and accommodation varying from 300 lying down to 600 sitting up. They are commanded by an officer of the R.A.M.C. and are administered by the director of medical services on the lines of communication, whose staff regulate their journeys in association with the railway transport staff and in accordance with the demands of the field army. They are mobilized as a rule in the proportion of one for each division in the field, but their number depends on the length of the journeys from front to base and the time taken to return. Improvised ambulance trains are made up of passenger coaches or goods vans specially fitted for carrying sick and wounded. The ambulance trains were of this kind at the beginning of the World War, and were organized to carry 396 lying down on stretchers placed on special frames constructed to carry three stretchers each. Four frames were placed in each of 33 goods vans. Improvised trains subsequently were used in emergency only and were usually in the form of passenger coaches for transport of patients sitting up. When these improvised trains are used rest and refreshment stations are opened at intermediate halting places for supplying food and com- forts and for removing patients unfit to continue the journey and transferring them to local hospitals. Rest stations for attending to patients pending their removal to hospital are also opened at stations where all classes of ambulance trains unload. They are formed by detachments from hospital units or by voluntary aid.
Ambulance Flotillas. Although ambulance flotillas of river steamers or barges are war establishment units of continental armies, they are not definitely organized units of the British Army.' They were formed, however, in 1914-8 for use on the canals in the north of France, and were composed of barges specially equipped as hospital wards and towed by steam tugs. Each barge had 30 beds, kitchen and stores, and accommodation for a staff of one medical officer, two nursing sisters and nine R.A.M.C. orderlies. Six barges formed a flotilla, and four flotillas were organized. They brought seriously wounded from casualty clearing stations to such hospitals on the lines of communication as were on or near a canal.
Hospital Ships. Passenger or other ocean-going ships are char- tered in time of war and fitted out as hospital ships for evacuating sick and wounded from the sea bases of a theatre of war to the United Kingdom. Their number and carrying capacity depend on the nature of the campaign, but the most suitable are those which are neither too large nor too small. A ship carrying 600 to 800 patients in cots was regarded as the best during the World War.
Hospitals are of two kinds, general and stationary. The former are fully equipped for all kinds of medical or surgical work. They are organized for 520 or 1 ,040 hospital beds, the smaller in the proportion of two and the larger in the proportion of one for every division in the
