First Blood Transfusion

June 15, 1667 - The first "successful" blood transfusion was performed on this day. A French physician named Jean-Baptiste Denys gave a 15-year-old boy about 12 ounces of sheep blood. Despite being bled by leeches 20 times and having sheep blood injected into his system, the boy survived!

It seems that the amount of blood that actually got into the kid's bloodstream was too little to harm him, and his body was able to withstand the allergic reaction.

The "successful" procedure led to another transfusion on a different patient who also survived, but three times was not the charm. After Denys' third transfusion attempt, a Swedish Baron named Gustaf Bonde died.

It was a calf blood transfusion on a man named Antoine Mauroy that brought the whole bloody affair to an end. When Mauroy died his widow sued Denys for malpractice, but Denys was acquitted.

The controversy surrounding Denys' unorthodox procedure reached the boiling point and France outlawed transfusions in 1670.  It would take another 232 years before Karl Landsteiner discovered the 4 different blood types and opened the door to safe blood transfusions.