The Germans were the first to use gas. On 22 April 1915 on the Ypres sector they attacked, using chlorine, which was released from cylinders and blown by the wind towards the French lines. The effect was dramatic and immediate: taken entirely by surprise, the French, with their Colonial Turco troops, ran, spluttering with pain, away from the green cloud. Strangely, the Germans seemed to have no reserves ready to exploit the gap which had opened in the Allied lines. Furious fighting followed, and the day was saved by Canadian troops who quickly moved up to fill the breach. Within a few days the Allies issued an elementary form of respirator which consisted of a cotton wool pad, dipped in a chemical solution that was tied with tapes over the nose and mouth to give protection against the fumes. Another German innovation was ‘stink gas’. A foul-smelling gas was mixed with the poison, which encouraged the soldiers to take off their helmets to clear the smell, only to fall prey to the poison. The soldier whose health had been destroyed by gas was one of the most pitiful sights after the War.