The Germans lost no time. Their attack against Wytscheate and Messines was made concurrently before daybreak. They had taken advantage of the darkness to carry out mass movements which could not be sighted from aeroplanes. The onset was both heavy and sudden, and it formed probably the greatest night operation on record. Darkness, it was now held, afforded the best protection against British rifle power. As this was an attack which had to succeed at all costs, the enemy took the heavy punishment inflicted by a furious resistance. A proportion of these German troops were lads of 17 and even younger. They had been used to fill up the gaps left by casualties, and mingled with the older men drove forward on the order of their officers and faced death at the muzzles of British rifles and the massed guns of the British Horse Artillery by hundreds. Both Wytscheate and Messines fell into the enemy's hands. At the same time with the evident object of arresting the movement of reserves assaults were made along the British line to the south of Messines past Armentières and along the valley of the Lys. This part of the attack was, of course, no more than strategical. For the purpose it was useless. Round both Wytscheate and Messines the enemy found himself confronted by quite unexpected forces. He could make no further advance from either. So costly indeed had been his attack upon Wytscheate, that the French infantry, launched upon a counter-attack with the aid of a British cavalry force, cleared him out of the place at the point of the bayonet.