Vannevar Bush, the American engineer who dominated government scientific research in the 1940s, once mused that there was something in man that made him hesitate about poisoning or spreading diseases in humans, cattle, or crops. Even Hitler had refrained from it, Bush said in his 1949 book Modern Arms and Free Men. Whatever the reason, he wrote, “somewhere deep in the race there is an ancient motivation that makes men draw back when a means of warfare of this sort is proposed.” The chapter in which he wrote this dealt in particular with two strange methods of warfare, biological and radiological. Both of these promised to harm one's enemies indirectly through contaminated land, water, or entire ecosystems, and both have since fallen under various rubrics, including weapons of mass destruction and environmental warfare. Bush was intimately familiar with the latest developments on them; he wrote the book while serving as chair of the National Military Establishment's Research and Development Board, which liaised with the Joint Chiefs of Staff (JCS) on military matters related to science and technology. He suggested in his book that few military men took biological weapons seriously, that relatively little money was spent on them, and that scientists shied from involvement in developing such weapons, all because of this innate human reaction against them. Since that time, the general public's antipathy toward biological weapons in particular and toward any kind of modification of the environment for purposes of war has been borne out by international conventions such as the Biological and Toxin Weapons Convention of 1972 and the Environmental Modification Convention of 1977.