ABO blood group system letter O for "ohne", meaning without or zero; Landsteiner chose the latter.) This classification was adopted by the National Research Council and became variously known as the National Research Council classification, the International classification, and most popularly the "new" Landsteiner classification. The new system was gradually accepted and by the early 1950s, it was universally followed. The first practical use of blood typing in transfusion was by an American physician Reuben Ottenberg in 1907. And the large-scale application started during the First World War (1914-1915) when citric acid was developed as blood clot prevention. Felix Bernstein demonstrated the correct blood
Blood type personality theory methodology of his conclusions was unclear. Because of this, he was heavily criticized by the Japanese psychological community, although his books remain popular. His son, Toshitaka Nomi, continued to promote the theory with a series of books and by running the Institute of Blood Type Humanics. He later established the Human Science ABO Center for further research and publication in 2004. Some researchers believe blood types are associated with personality traits. Many medical surveys have been conducted, such as those for hormone secretion traits (DBH, COMT, MAO etc.), or the blood-type antigens in neurons, or the antigens expressed on surfaces