A soldier wearing a gas hood, 1917 (c).

Fabric bags and hoods were treated with anti-gas chemicals. Although they gave some protection against the gases then in use they were eventually replaced by the canister gas mask or small box filter respirator. Gas first was used in the Middle Eastern theatre by the British in April 1917 during the Second Battle of Gaza. Photograph, World War One, Egypt and Palestine (1914-1918), 1917 (c).