On this day June 15, 1667
French physician Jean-Baptiste Denys, eminent physician to King Louis XIV of France, administered the first fully-documented human blood transfusion, giving the blood of a sheep to a 15-year old boy he partially recovered, but then he died.
There have not been since, it appears, any subsequent successful blood transfusion operations between species of such widely divergent taxonomic rank..
Denys performed another transfusion into a labourer, who also survived. Both instances were likely due to the small amount of blood that was actually transfused into these people. This allowed them to withstand the allergic reaction.
In the winter of 1667, Denys performed several transfusions on Antoine Mauroy with calf’s blood, who on the third account had died. Much controversy surrounded his death and his wife was accused for causing his death. Though it was later determined that Mauroy actually died from arsenic poisoning, Denys’ experiments with animal blood provoked a heated controversy in France. Finally, in 1670 the procedure was banned. In time, the British Parliament and even the pope followed suit. Blood transfusions fell into obscurity for the next 150 years.