DURING the last months of the War of 1914–18, a period which—from many points of view–may be compared with the present, the plant scientists and zoologists of the world were less involved in the war effort than they are to-day. Nevertheless, as such addresses and papers as Lyman's "Contributions of American Botanists for More Active Prosecution of War Work" (1918) and Stevens's "American Botanists and the War" (1918) show, some of the foremost plant scientists of the United States were prevailing upon their colleagues to engage in activities which might help the war effort. At the same time much consideration was given to the War from a biological point of view, as such publications as Nicolai's "Biology of War"(1919) and Pearl's "Biology and War"(1918) testify. Just before the end of the War many interesting papers on the role of botany and biology in the post-war world were published. These included "Botany as a National Asset" (Coulter, 1917) and "Botany after the War" (Davis, 1918), and were followed by an unusual number of inspired discussions by men like Lyman, Peirce and Gager. Though during those years a number of biologists did accomplish useful things in such fields as pioneering in dehydration, raising the agricultural output and discovering substitutes of vegetable origin, the foremost trend of thought, especially in the Allied countries, was concerned with biology in the post-war world, in human relations as well as in agriculture, etc. The Germans of that time were, comparatively, much more concerned with problems directly relating to the war effort than were their colleagues in the Allied countries. Diels wrote an entire volume on botanical substitutes; Haber and other chemists revolutionized the fertilizer situation.