Such, in a manner of speaking, has been my acquaintance with poison-gas, or toxic-gas, as the chemists call it. I was in the Ypres salient, on the British front, when the first gas attack in the history of warfare was launched against the Africans and Canadians on April 22, 1915, and that night, in the hospitals, I saw the earliest victims of gas warfare, gasping on their cots like fish thrown on the bank to die. On several occasions during the months which followed I again encountered the malign creature—on the Yser, in the Champagne, in Alsace, and on the Isonzo—and on each succeeding occasion it was more threatening and was causing greater concern. So that when, after the United States had been at war a year or more, I visited the great arsenal at Edgewood, on the shores of Chesapeake Bay, and was shown the vast plants devoted to the production of chlorine, chlorpicrin, phosgene, mustard, and other deadly gases, and caught the familiar nauseous odor, I felt as though I were renewing an old and undesirable acquaintance. I doubt if the Germans started the war with the intention of utilizing poison-gas, for they did not introduce it until nine months after the beginning of hostilities, and even then they apparently failed to realize the terrible potency of their new weapon, for they waited twenty-four hours before following it up with a bayonet attack, evidently fearful that the gas had not dissipated. As a matter of fact, the gas dissipated within thirty-five or forty minutes after its release, though in that time it annihilated 80 per cent of the French, Canadians, and Senegalese opposing it. Had the Germans taken instant and vigorous advantage of the confusion and dismay created by their unexpected use of chlorine, they could unquestionably have broken the Allied front, pushed through to the Channel ports, and changed the entire course of the war. (I might mention, parenthetically, that the British had been warned by a deserter, a week before, that the Germans were making preparations for a gas attack, but they did not believe him.) But the men in the spiked helmets failed to take advantage of the Allies’ temporary panic; the latter had time to improvise a means of defense, and the opportunity of the Germans to win the war by the use of gas was gone. So effectively, indeed, did the Allies turn the new weapon to their own uses that, before the close of 1916, the Germans were putting out feelers for the purpose of bringing about a cessation of this form of warfare. Then the United States entered the war, whereupon all the resources of American laboratories and chemical manufactories were directed toward the production of gas in quantities of which the Germans had never dreamed.