A Brief History
Long ago people tried to transfuse blood from one person to another,
often with fatal results. Death was caused by the red blood cells of the donor clumping together in the recipient's body. This is called agglutination. The clumps block up blood vessels and stop blood flow.
In some ways, every person's blood is the same. However, when analysed under a microscope, distinct differences are visible. In the early 20th century, an Austrian scientist named Karl Landsteiner classified blood according to those differences.
In 1898, it was discovered that inherited differences in people's red cells were the cause of many of the incompatibilities seen with transfusions. Four blood types were identified. During World War I, when human blood was needed for transfusions for wounded soldiers, studies of how to preserve and transport blood began.
Not until World War II, however, did the development of effective reservative solutions make blood transfusions widely and safely available. There have been many advances since then, including the discovery of additional types of blood such as the Rh positive and Rh negative classifications.
ęCopyright TQ Team 25896, 1999. The Circulatory System- Online Learning.