Modern gas warfare dates from April, 1915, when the Germans first liberated the abominable cloud of gaseous chlorin on unsuspecting allied forces at the western front. Since then this heinous mode of attack has experienced numerous variations, which have been discussed in The Journal.1 Meanwhile, methods of defense and protection have also been devised, one succeeding another as rapidly as inefficacy or inferiority was discovered. The respirator has become part of the outfit of the modern soldier in the trenches.
"The use of a gas shell to force a man to put on his mask," says Major Auld, the gas expert of the British Military Mission, in speaking of tear gas shells, "is practically neutralization. If at the same time you can hurt him, so much the better. Hence the change in gas-shell tactics, which consists in replacing the purely lacrimatory substance by one that is also poisonous." Accordingly
THE PATHOLOGY OF "MUSTARD GAS". JAMA. 1918;70(25):1947-1948. doi:10.1001/jama.1918.02600250047013