JCM writes to JJM advising segregation of blood in blood banks.
James C. Magee to Assistant Secretary McCloy, memo, September 3, 1941, box 35, entry 183, Records of the Office of the Secretary of War, in Thomas Guglielmo, "'White Cross, Double Cross': Race and America's World War II-Era Blood Donor Service," Journal of American History (June 2010): 70
For reasons not biologically convincing but which are commonly recognized as psychologically important in America, it is not deemed advisable to collect and mix caucasian and negro blood indiscriminately.