About Jean-Baptiste Denis (-1704), the 17th Century doctor who made blood transfusion history...In 1667 Parisian doctor Jean--Baptiste Denis performed an operation that had never previously been attempted -- he transfused blood into another human being. This was the first attempt at a procedure that over subsequent centuries was to save the lives of thousands of people. But at the time Denis was nearly convicted of murder. The victim of Denis's experiment was a middle--aged man suffering from mad rages. Denis believed that by transfusing the blood of a calf into the man the man would assume the placid nature of the calf. The experiment appeared to work. The highly toxic blood made the man in question very ill and therefore very placid. It is now believed that the man was in fact suffering from syphilis, which induced his violent behaviour. The symptoms of the syphilis would also have been relieved by the high fever that the toxic blood would have induced. Encouraged by this apparent success, though unaware of the reasons for it, many other people attempted similar experiments. Eventually the man died and Denis was arrested for his murder. Further investigations revealed however that the man had not in fact died from the blood transfusion (although he certainly would have done so very shortly) but from cyanide placed in his food by his wife. Giving an insight into the first attempts at a procedure that has gone on to be developed for the benefit of humanity, and into the symbolism of blood throughout the history of medicine, Blood and Justice raises ethical issues that are as relevant today as they were at the time.