From the earliest times the vital importance of blood to the human system has been fully appreciated. It has been supposed to carry in it some of the virtues, such as the youth and health, of its possessor, and it has therefore been commonly regarded as a sacrifice acceptable to the gods. References to blood in the Old Testament, in classical authors, and, it is stated, in the writings of the ancient Egyptians, refer rather to these mystical attributes than to any definite transference of it from the veins of one animal to those of another. One of the earliest references to actual transfusion of blood that has been noticed is to be found in a work by Libavius of Halle, published in 1615. The passage has been translated as follows: "Let there be present a robust healthy youth full of lively blood. Let there come one exhausted in strength, weak, enervated, scarcely breathing. Let the master of the art have little tubes that can be adapted one to the other; then let him open an artery of the healthy one, insert the tube and secure it. Next let him incise the artery of the patient and put into it the feminine tube. Now let him adapt the two tubes to each other and the arterial blood of the healthy one, warm and full of spirit, will leap into the sick one, and immediately will bring him to the fountain of life, and will drive away all languor."It may be assumed, however, that this was only an idea, and had not yet been carried into practice. It was, indeed, unlikely that any attempt to perform blood transfusion[2] would be made until the conception of the circulation of the blood had been promulgated, and this in 1615 had not yet taken place.William Harvey had been appointed physician to St. Bartholomew's Hospital in 1609, and already in 1616 as Lumleian lecturer had stated his theory of the circulation, but not until its publication twelve years later could it be generally known. His treatise entitled Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus, which appeared in 1628, may therefore be regarded as the point from which blood transfusion first arose. It has often been stated in the literature of the subject that the first transfusion was performed in 1492, when the blood of three boys is supposed to have been transfused into the veins of the aged Pope Innocent VIII.[1] This, however, seems to have been a mis-statement of the facts. Actually a Jewish physician prepared a draught for the Pope from the blood of three boys, who were bled to death for the purpose.[2] The drinking of blood was not a new idea; this particular incident is of no special interest, and may now be allowed to sink into oblivion