Page:The Harveian oration - delivered at the Royal College of Physicians June 24, 1882 - by George Johnson (IA b21517046).pdf/44

 why, when a ligature is applied, the veins swell beyond and not on this side of the obstruction, which those who practise venesection know by experience; but the opposite ought to occur if the motion of the blood and spirit is from the viscera over the entire body; for the passage outward being blocked, a swelling of the veins should occur on this side of the ligature.' Then, after quoting Aristotle's explanation, which is quite unintelligible, he gives his own: 'In explanation of this it is to be observed that the orifices of the heart are so arranged by nature that there is an entrance from the vena cava into the right ven- tricle, whence there is an open passage into the lungs, and from the lungs there is an entrance into the left ventricle, and thence into the aorta, valves being placed at the orifice of the vessels to prevent reflux. There is thus a perpetual move- ment from the vena cava through the heart and lungs to the aorta, as we have explained in our peripatetic questions.' Up to this point Cesal- pino's description is clear and correct; but it goes not beyond the knowledge of his contempo- raries. After this, confusion begins to be appa-