"Magic to Medicine" takes viewers from a time of ignorance -- when blood was viewed primarily as a key element of religious rituals and the stuff of myths -- to the end of the 19th century, when blood transfusions finally became safe and routine. Adding context to this portion of the story are segments on William Harvey, who discovered that blood circulates through the body, a startlingly revolutionary idea at the time; Dr. Karl Landsteiner, who discovered blood types; and haunting accounts and re-enactments of George Washington's death, which was accelerated by overzealous bloodletting.