The results of 9 April 1917 were to be overshadowed by the attritional nature of the rest of the battle, as the offensive continued due to the demands of coalition warfare. As with most logistical or combat support elements, the work of the RAMC continued. Whether the “routine” casualties of trench holding or the peaks following attacks [or counter-attacks], the main burden continued to fall on the bearer companies. Whilst within a division it was sometimes possible to rotate brigades out of the line, with the bearer divisions of the three field ambulances effectively merged an equivalent relief was impossible. The process of evacuation was only able to continue as the structure of a field ambulance allowed an internal rotation of suitable men within units without any disruption of command and control.
As the fighting continued the various units of the BEF rotated in and out of the line. As their divisions heading to the rear areas, for many a period of rest beckoned, but a field ambulance had to continue providing medical support to its division. In the operation orders relating to moves out of the line, we see the field ambulances being temporarily affiliated back to brigades for administrative purposes, but also being ordered to set up Divisional Rest Stations. Through this facility, men could recover from minor wounds or illness, but stay within the division, desirable both for elements of esprit de corps but also for maintaining the strength of the division.
The larger distances between the frontline and Arras gave more tactical freedom in the placement of medical posts, more of the general principles expressed in RAMC 1911 could be followed; posts appear in hollows, adjacent to roads, but the slow extension of the chain of evacuation required more collecting and relay posts, eventually supplemented with vehicle loading posts.As the offensive stalled these posts took on an air of permanence, the location of many now being marked with Commonwealth War Graves Commission [CWGC] cemeteries. In these the periods of occupancy can be clearly identified by the burials, the association of cemeteries with medical facilities is an unfortunately obvious one, but this is more commonly associated with dressing stations and CCSs. At these forward posts staff applied a triage sieve preventing casualties unlikely to survive passing further down the chain. This was made easier as the various collecting and relay posts sat outside the regimental family and could make a less emotional, more realistic appreciation of the casualty’s chances.
Whilst not always completed immediately an admission and discharge book [A&D book] was kept for each field ambulance, showing the nature [and numbers] of casualties passing though the unit. The A&D book of the 51st Field Ambulance still exists, it shows a surprising amount of men attending the ADS sick, with most being evacuated. Concern to keep the ADS clear dictated the swift evacuation of the sick, but was reliant on a vigorous filtration at unit level by the RMO. The A&D book covering 24-25 April 1917 has 90 admissions. Of these 12 were sick, all of whom are evacuated. A further two had suffered soft tissue injuries and were also evacuated, in this case to the Corps Rest Station. Of the 76 injured most  were gunshot wounds, the majority  being to the limbs.In this period there were four deaths in the ADS; two from abdominal injuries, a situation the field ambulance was not adequately equipped for; one a double traumatic amputation; the last being shrapnel wounds to the thigh. The field ambulance's pragmatic approach to triage and casualty assessment at forward posts coupled with the careful work to counter shock had resulted in a low mortality rate at medical facilities.
A record of operations carried out at No 19 CCS allows for an examination of the type of casualty making it through the whole chain of evacuation to surgery. On 11 April 1917 Captain Donaldson performed 18 operations, all gunshot wounds; 15 leg, 1 shoulder and 1 buttock injury.All of these were evacuated before the end of the day. Faced with the high number of casualties of an offensive the finite resources of the AMS had to be directed towards those with most chance of success. This principle was applied from the first field ambulance post through to the CCS.
For example, men of the 2/2 London Field Ambulance tent divisions were sent forward as reinforcements and replacements of the bearer company, TNA: WO 95/2944 entry for 14 April 1917
In the post war Babtie Committee this was deemed to be one of the great successes of the field ambulance, TNA: WO 32/11395.
Vehicle loading posts were originally staffed by a RAMC NCO purely responsible for the loading of the ambulance cars and accounting for the equipment. By 28 April 1917 both the 14th and 56th Divisions have more substantial posts.
The Great War Digital product “Linesman” provides translation from contemporary trench maps to modern day IGN maps. Allowing for the inherent inaccuracy of mapping it is possible to identify the approximate position of wartime locations.
Within the area of this study,
A number of cemeteries are named after dressing stations. St Mary’s ADS near Loos is but one example, with cemetery registers often identify nearby medical facilities.
 An order is issued in October 1917 that “Moribund Cases are not to be moved from Field Ambulance.” The definition of these cases seems to have been left to the reader. Standing Orders of ADMS 56th Division in TNA: WO 95/2038.
Most of these have been destroyed, the following is taken from examination of part of a small sample kept within TNA: MH106.
This incidence of injury to the limbs is slightly higher than the 40% suggested in Major T. Mitchell, Medical Services, Casualties and Medical Services of the Great War (London: Imperial War Museum, 1997) p. 279
TNA: WO 95/414 No 19 CCS.