Further, the idea was to employ a fresh body of troops for each bound. Thus, when the troops detailed for a particular bound had reached their objective, they remained on it, and disposed themselves in the most suitable manner to hold the ground they had gained against counter-attacks. A fresh body of troops then passed through them and made good the next bound, consolidating in their turn the ground gained. This form of attack became the sealed pattern for all attacks carried out by the Highland Division, and was largely responsible for the many outstanding successes of the Division. Gradually as the war progressed and the Division achieved one success after another, its value became apparent, and it eventually became the stereotyped form of attack in the majority of the Divisions in France. During this period, apart from the training of units under their own commanders, Divisional schools of instruction were formed to give individual training to officers and N.C.O.'s. A Divisional grenade school was formed, at which 13 officers and 260 other ranks were put through a course every week. At this course instruction was given in the Mills bomb, which had now replaced the former types of improvised bomb. A Divisional school for infantry was also opened at Villers-Bocage under Lieut.-Colonel D. Baird, commanding the 8th Argyll and Sutherland Highlanders. At this school 20 officers and 40 N.C.O.'s attended a series of fourteen-day courses. The object of this school was to increase the powers of command of the senior officers and N.C.O.'s, and to improve their knowledge of tactics. A show-ground was also laid out, where the best methods to be adopted in trench warfare could be demonstrated. Here also types of trenches suitable to the varying natures and conditions of ground were constructed for purposes of instruction. On 8th February the course of training was interrupted by the move of the Division to the Daours area, with a view to taking over from the 30th Division, on the sector on the north bank of the Somme. The orders for this relief were, however, cancelled on the 18th February, and the Division moved back to the Flesselles area. During this period the composition of the Division underwent considerable alteration. The three Lancashire battalions left the Division on 3rd January 1916 to join the 55th (West Lancashire) Division. The 6th Scottish Rifles joined the 33rd Division. They were met again later by many of their former comrades of the Highland Division in High Wood in July and August 1916. These four battalions were replaced by the 4th and 5th Black Watch, the 4th Seaforths and 4th Camerons. Brigadier-General C. E. Stewart, Black Watch, was placed in command of this brigade, and it retained the title 154th Infantry Brigade.