In the year 1990 when Dr. Karl Landsteiner at the University of Vienna, when some of the blood transfusions were successful while another were Not and people died!
Human blood groups are very old genetic indicators which have evolved over several million years. Karl Landsteiner was born on 14th June 1868, in Vienna, Austria; he died on 26thJune 1943 AD, at 75 years old, in the United States.
The emergence and evolution of blood groups in humans are still not clear. Based on the primary races hypothesis, it was thought that in the three major races of man, blood groups A in Europe, B in Asian, and finally O in South America have been emerged and gradually due to the migration and mixing of the races, became the present situation.
By mixing the red cells and serum of each of his staff Landsteiner discovered the ABO blood group system. By Series of experiments and blood grouping, he found other Blood Groups like A, B, C ( C was Replaced my O blood group later).
The fourth less frequent blood group AB was discovered a year later. In 1930, Landsteiner received the Nobel Prize in physiology and medicine for his work