Professor Foster admits that Caesalpinus had a wonderful power of synthetising knowledge already in hand and anticipating conclusions in science that were to be confirmed subsequently. In his Medical Questions, though the work is written in rambling, discursive vein, he enunciated views which, however he arrived at them, certainly foreshadowed or even anticipated those which {238} were later to be established on a sound basis. Foster quotes a passage in which Caesalpinus made it very clear that he thoroughly understood the mechanism of the circulation and grasped every detail essential to it. After quoting this passage, which it must be confessed is rambling, Foster thus sums up what Caesalpinus has to say with regard to the circulation:-- "He thus appears to have grasped the important truth, hidden, it would seem, from all before him, that the heart, at its systole, discharges its contents into the aorta (and pulmonary artery), and at its diastole receives blood from the vena cava (and pulmonary vein)." "Again, in his Medical Questions he seems to have grasped the facts of the flow from the arteries to the veins, and of the flow along the veins to the heart." That there was no change of Papal policy in the next century can be gathered from an interesting phase of Papal interest in science which, though not directly concerned with medicine, eventually resulted in important theoretic advances in medical science. This was the encouragement of Father Kircher's work at Rome. Father Kircher was the Jesuit who made the first scientific museum. As the result of his general interest in things scientific he wrote a little book on the pest. In this book he stated in very clear terms the modern doctrine of the origin of disease from little living things, which he called corpuscles. Because of this Tyndall attributes to Father Kircher the first realization of the role that bacteria play in disease. Even more wonderful than this, however, was Father Kircher's anticipation of modern ideas with regard to the conveyance of disease. He insisted that contagious diseases, as a rule, were not carried, as had been thought, by the air, but {239} were conveyed from one person to another, either directly, or by the intermediation of some living thing. He considered that cats and dogs were surely active in conveying diseases, and he even reached the conclusion that insects were also important in this matter. His expressions with regard to this are not of the indefinite character which one often encounters in the supposed anticipation of important principles in medicine, but are very precise and definite. Father Kircher is quoted by Dr. Howard Kelly, of Baltimore, in his life of Major Walter Reed, whose work in showing that yellow fever is transmitted by mosquitoes is well known, as saying in one place, "Flies carry the plague," and in another place, "There can be no doubt that flies feed on the internal