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
secretions of the diseased dying, then flying away they deposit their
excretions on the food in neighboring dwellings, and persons who eat
it are thus infected." It is interesting to find that the Professor of
the Practice of Medicine in the Papal University at Rome when this
book was published, far from resenting, as many professors of medicine
might, the excursion of an outsider into his science, said Fathe