Early in February, the 1st Cavalry Division staff was blessed with the arrival of Major Desmond Fitzgerald (11th Hussars), who took Major Hambro's place as G.S.O. 2. The total tally of British casualties was announced during the first week in the month as 104,000, having exceeded, in less than six months of warfare, the numerical strength of the original British Expeditionary Force. A day "in front," with the engineers, mapping out new trenches and reserve positions, showed to how great an extent modern gun-fire had changed military theory. Before the War, a trench line was sought in a position that commanded a good "field of fire," _i.e._, that had in front of it as much open ground as possible. This war had taught that the most important item in the selection of a trench position was the extent to which the line could be hidden from the enemy gunners. The space commanded by the occupants of the trench and the nature of the terrain were secondary to the cardinal point of keeping the trenches well out of sight of enemy observers. Thus engineers might, years ago, select a hilltop as a trench position, the line commanding the receding slope to the valley below. After the experience of the greatest of all wars, they would preferably place it fifty yards behind the summit. More than fifty yards of "field of fire" was desirable, but not absolutely necessary. A fifty-yard space could be so covered with wire entanglements as sufficiently to delay an attacking enemy. Deep, narrow trenches with traverses to restrict the area of damage from shells bursting in the actual trench, and to protect from enfilade fire, were demanded by the newer conditions, but great care had to be taken that they should not be constructed in ground of so soft a nature that howitzer fire could too easily cave in the trench sides. We found it possible to select a trench line that could be well concealed, which, if taken by the enemy, would be under perfect observation from our own gunners and by them easily rendered untenable for the Huns. That the British were clever in this work of placing trenches in invisible positions was proven by the following report of an interview in Courtrai with a wounded German officer, whose regiment had been badly handled when attacking an English position in the Ypres Salient:--