June 26: Blood Types

Karl Landsteiner, an Austrian-born scientist who identified the main human blood groups, A, B, and O, in 1901, died on this date in 1943. Landsteiner also discovered the polio virus (with Erwin Popper) in 1909, identified the Rhesus factor (with Alexander S. Wiener) in 1937 —which enabled safe blood transfusions — and received the 1930 Nobel Prize in Physiology or Medicine.

“The time is past when one man can know all of science. Karl Landsteiner was one of the last possessed of the tremendous intellect that could comprehend and, better still, use practically all of the scientific knowledge of his time.” -- Michael Heidelberger