Fueled by this victory, Denys went on to perform the same transfusion to another patient, a laborer, who also survived the procedure without complications. Unfortunately, the transfusion’s success became short-lived as his third patient, a Swedish royal called Gustaf Bonde, died after the second transfusion.
You would expect Denys to rethink his methods, but in the winter of the same year, he went on to transfer calf’s blood to Antoine Mauroy, a mentally ill man. Mauroy, as with the previous patient, succumbed to death by the third transfusion. Mauroy’s wife sued Denys in court, saying that the physician was responsible for the death of her husband. Facing a murder charge, Denys was eventually acquitted, as it turned out that Mauroy’s death was caused by arsenic poisoning. It was, later on, discovered that his wife was responsible for the crime.