The geratest scientififc discovery

Scient is very magical,interesting.Many people to find discovery to solve problems.So the greatest scientific discovery is very important to people life and health. In my opinion.I thinks the greatest scientific discovery is Blood Groups.This discover is very important for save somebody's life.
Discover Blood Group is good for medicine.In 1628,the doctors know blood transfasion can save people's life.But sometime somebody trans blood can't save,they are died very fast.Somebody can save,more and more healthy.So the famous doctor Karl Landsteniner and his group in Austrian started research the blood.
First,they mixing blood from two individuals can lead to blood dumping or agglutination.The dumped red cells can crack and cause toxic reactions.So they discovered different blood groups.They areA,B,O,AB.The blood group is the greatest discovery in 17th century.
A persons blood type become a crucial matter when a blood transfusion is necessary.I think this scientific discovery is improant because this can save so many people's life.