In the succeeding number of the _Philosophical Transactions_, October 21, 1667, the remarks of another French experimenter, Gaspar de Gurye, are quoted. These are of considerable interest, as they contain the first warning of the dangers attending the administration of incompatible blood. De Gurye affirms “that an expert Acquaintance of his, transfusing a great quantity of blood into several Doggs, observed alwayes, that the Receiving Doggs pissed Blood.” Other cases were subsequently recorded by Denys. In one he claims to have cured a patient suffering from “an inveterate Phrenzy.” His account of it is too long to be quoted here in full, but it is of special interest in that it contains the first account of hæmolysis and the attendant symptoms in man which follow the transfusion of incompatible blood. The blood of a calf was used in this instance and on two occasions; at the first transfusion only a small amount was given, but at the second, “the Patient must have received more than one whole pound. As this second Transfusion was larger, so were the effects of it quicker and more considerable. As soon as the blood began to enter into his veins, he felt the like heat along his Arm and under his Arm-pits which he had felt before. His pulse rose presently, and soon after we observed a plentiful sweat all over his face. His pulse varied extremely at this instant, and he complained of great pain in his Kidneys, and that he was not well in his stomack, and that he was ready to choak unless they gave him his liberty. “Presently the Pipe was taken out that conveyed the blood into his veins, and whilst we were closing the wound, he vomited store of Bacon and Fat he had eaten half an hour before. He found himself urged to Urine, and asked to go to stooll. He was soon made to lie down, and after two good hours strainings to void divers liquors, which disturbed his stomack, he fell asleep about 10 a Clock, and slept all that night without awakening till next morning, was Thursday, about 8 a Clock. When he awakened, he shewed a surprising calmness, and a great presence of mind, in expressing all the pains and a general lassitude he felt in all his limbs. He made a great glass full of Urine, of a colour as black, as if it had been mixed with the soot of Chimneys.” The hæmoglobinuria, which was not at that time attributed to its true cause, cleared up in the course of a few days, and the patient appeared to be greatly benefited. Although the first transfusion performed upon a human being was done in France, similar experiments were shortly afterwards carried out in England. The passage already quoted concerning the “sundry instances” mentioned in Sprat’s _History of the Royal Society_ is amplified by the diarist, Samuel Pepys, who witnessed the experiments on at least one occasion. His first reference to the subject is under the date November 14, 1666: