By 1941, the Great Depression was over. The Texas A&M campus had more buildings, but lower salaries, more students, and fewer courses. That same year, the Brazos Plantation Farm was purchased for use under the direction of the School of Agriculture.
In 1937, President Franklin Roosevelt toured the A&M campus. By 1939, the A&M Board of Directors had authorized the use of the College by the federal government in any capacity. In 1940, Congress passed the Selective Training and Service Act. The United States entered World War II after the Japanese bombed Pearl Harbor on December 7, 1941, and the Texas A&M campus became a training post for Army, Air Corps, Navy, and Marine personnel. Throughout the early months of the war, confusion reigned as students were urged to stay in school, while military divisions and local draft boards appealed for enlistment. By 1943, however, almost everyone available was going to war. In 1941, enrollment at A&M reached a high of 6,679 students. By 1944, only 1,893 students remained.
Texas A&M furnished more officers to the war effort than the United States Military Academy at West Point. Some 20,229 current and former Texas A&M students and faculty served in the armed forces during World War II; 14,123 were officers, 29 in the rank of General. Faculty from the School of Agriculture also entered military service, among them Dr. Raymond Reiser, a charter member of the Department of Biochemistry and Nutrition; James Russell Couch, who would later discover the growth effects of antibiotics in poultry; entomology instructors Manning A. Price and Dial F. Martin; and former entomology department head J. C. Gaines. Many who served returned immediately to teaching after being discharged, while others sought employment in industry.
Texas A&M was an all-male college, and its original mission was to teach agriculture, the mechanical arts, and military techniques, as well as science and classical studies. The loss of faculty and students to the war effort, the attraction of soaring salaries in industry, and a focus on military-science programs delayed research projects and coursework. However, important research programs continued on campus and across the state. In College Station, the agriculture faculty and students provided vital support for the war effort. Between 1943 and 1945, the Texas A&M meats lab was the only approved slaughter facility in Brazos County. Meat processed through the lab helped to provide about 9,000 meals per day at A&M. Across the state, agricultural research aided the war effort: families learned to grow their own vegetables in “victory” gardens and preserve them at home, and research stimulated production of grain sorghum, cotton, and poultry and increased the nutritional value of foods. One important development, led by Professor Robert E. Karper, was the production of starch from grain sorghum. Japan had cut off the United States’ main supply of starch, from cassava root (tapioca), and sorghum starch became a valuable replacement that could be used in food products, adhesives, and sizing for paper and fabrics. Many of the technological innovations in agriculture during World War II helped set the stage for what would be the golden age of science and agricultural research in the years that followed.
After the war, returning students and other veterans interested in taking advantage of the educational benefits offered by the G.I. Bill flooded the Texas A&M campus, and enrollment boomed.