study to beat it. In the spring attack of 1918, the Germans introduced their “mustard gas.” Unlike its forerunners, it was poisonous to the skin as well as to the lungs. Breathed, it was deadly; where it touched the skin, it produced terrible burns which resisted all ordinary treatment. These wounds were not fatal unless they covered great areas of the body. In that, mustard gas was unsatisfactory.
Now in all the experiments following Second Ypres, the chemists had in mind three qualities of the ideal killing gas. First, it should be invisible, thus introducing the element of surprise. The early, crude gases, even in small quantities, betrayed their presence by the tinge they gave the atmosphere. Second, it should be a little heavier than the atmosphere; it should tend to sink, so as to penetrate dugouts and cellars. Third, it should poison—not merely burn—all exposed areas of the body. American ingenuity solved the problem. At the time of the Armistice, we were manufacturing for the campaign of 1919 our Lewisite gas. It was invisible; it was a sinking gas, which would search out the refugees of dugouts and cellars; if breathed, it killed at once—and it killed not only through the lungs. Wherever it settled on the skin, it produced a poison which penetrated the system and brought almost certain death. It was inimical to all cell-life, animal or vegetable. Masks alone were of no use against it. Further, it had fifty-five times the “spread” of any poison gas hitherto used in the war.
