A menacing yellow-green cloud hovered over several kilometres of ground, moving directly towards the Allied lines. The Germans had just launched a poison gas attack against the French 45th Divsion, whose men suffocated, eyes and throats burned, or fled if they could. In the upheaval, the left flank of the zone held by the Canadians was exposed, resulting in the loss of 6000 men – either killed or wounded – even though they had not been badly affected by the gas.
