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
Rh blood group system factor is not identical to the rhesus monkey factor; but by then, "Rhesus Group" and like terms were already in widespread, worldwide use. Thus, notwithstanding it is a misnomer, the term survives (e.g. "rhesus blood group system", and the obsolete terms "rhesus factor", " rhesus positive", and "rhesus negative" - all three which actually refer specifically and "only" to the Rh D factor; and, thus, are misleading when unmodified). Contemporary practice is to use "Rh" as a term of art instead of "Rhesus"; viz. "Rh Group," "Rh factors," "Rh D," etc. The first rhesus blood type was discovered in 1937