Today in History—June 15: The First Blood Transfusion
On this day in 1667, a French physician attempted something no one had ever done before: a blood transfusion. Specifically, he transfused blood—not from a human, but from a sheep—into a teenage boy suffering from a severe fever, fully documenting the procedure’s signs and symptoms.
The doctor, Jean-Baptiste Denis, the personal physician of King Louis XIV, thought animal blood might be safer—and maybe even calming. Sheep, after all, were gentle creatures. Perhaps their blood could soothe the human body.
The patient survived. That outcome alone made the procedure extraordinary.
At the time, the human body was still a mystery, and the idea that blood could be transferred between living beings was hugely radical. The science of circulation had only recently been described, and no one fully understood how blood functioned—they only knew that it mattered.
But early success can be misleading. Encouraged by his first result, Denis performed a second transfusion on a mentally ill patient, Antoine Mauroy, using calf’s blood. At first, the outcome seemed promising: The patient appeared calmer, even improved. But after a second (or, by some accounts, third) transfusion, Mauroy died. Denis was taken to court. Although he was cleared of wrongdoing in the death—it turned out that Mauroy’s wife had poisoned him with arsenic—the court also ruled to ban blood transfusions.
Early transfusion experiments used animals chosen for their temperament—lambs were considered ideal, being docile and “pure.”
The results really were too unpredictable.
It would take nearly two centuries for transfusions to become safe and reliable, with the crucial turning point being the discovery of blood types in about 1900.
But on this day in 1667, medicine took its first bold, strange step toward modern transfusion science. And it all started with a sheep…who is generally believed to have survived.
- 0: Understanding of blood types at the time
- 8: Blood types determined by the ABO group system and Rh factor
- 9 ounces: Amount of sheep’s blood injected into the boy
- 1844: Charles Goodyear patents rubber vulcanization
- 1864: Arlington National Cemetery is established on Robert E. Lee’s family estate
- 2007: Game show host Bob Barker’s last episode of The Price Is Right airs
