Twenty-five years ago a German youth (one of the favourite pupils of the great chemist, Professor Keukle) graduated at Bonn. He came of an illustrious family; his grandfather, the Swedish professor, Scheele, discovered chlorine gas. His father, born in Germany, died in the discovery of “prussic acid,” the most quickly fatal drug known. The youth, with sixteen deep scars on his head and face from duelling under the vicious German code, was a man of proved valour. Who was better to send to the great developing home of liberty and freedom and study its industry, and prepare for a day which was already dazzling the newly enthroned Kaiser? Dr. Hugo Schweitzer was chosen to go with him and collaborate. He, as the head of the Bayer Chemical Company--a German concern that practically monopolized the trade in synthetic drugs in the United States--was to report on, to model, or undermine our development of industrial chemistry. Dr. Scheele was to report on and develop the plan and chemistry of warfare, explosives, incendiaries, poison gas, and the products Germany should import and accumulate to make her sure and independent on the day she should strike the world. Did these young men faithfully accomplish their tasks? Dye making was almost an unknown art in America when the war broke out; chlorine gas was a laboratory curiosity; potash was a German salt--we had been led to believe our millions of tons of the mineral were insoluble. Where necessary, those of our chemists who had learned the secrets were retained and paid. The list of our chemical houses reads like the telephone directory of Unter den Linden, and the Alien Property Custodian has since spent many nights over their affairs. While the German plenipotentiaries were busy at The Hague agreeing to the elimination of poison gas and incendiaries from warfare, their chemists in the United States, paid regularly but meagerly through the Embassy at Washington, exchanged views in writing and by cable with the chemists of the Fatherland over the most fatal methods for the use of the gas which had just been developed for the purpose. Mustard gas was used against the Allies in 1917, a new and atrocious device, “only discovered and recently used by the Germans because of the brutality of their enemies.” A few formulæ for this product were in Dr. Scheele’s laboratory in New York about five years before the war, and tactics of the uses discussed in the trips which he made home every two years “to keep up to date.”