The first "blood bank" in the United States was established on this date in 1937 at the Cook County Hospital in Chicago. Scientists had struggled with the idea of blood transfusion since the 17th century. But only when blood types and the Rh factor were understood did sharing blood become possible. Refrigeration was the final step in the creation of a large, readily available supply of blood.
This date is the anniversary of the assassination, in 44 B.C., of Julius Caesar. In the Roman calendar, the 15th day of March was known as the "ides," and is remembered today by way of the famous warning by the soothsayer in William Shakespeare's play Julius Caesar: "Beware the ides of March."
