Page:The Harveian oration, 1875 (IA b22314611).pdf/38

he first consisted in imagining a passage for the blood from the right to the left ventricle of the heart through the septum; the second in assuming an equally unreal anastomosis somewhere between the large arteries and veins; the third that the arteries dilate after the manner of bellows, and so occasion the pulse; and the fourth that the arteries do not contain and carry blood, but air.

Harvey meets the first of these errors by denying the state of things which they allege, as well as by statements which prove the extent and precision of his anatomical knowledge. As to communications between the two sides of the heart, he does not see them; and as to these anastomoses, he searches for them in vain in all the principal viscera, even when he resorts to the artifice of rendering them so friable by boiling, that he could shake their tissue like dust from even the capillary filaments.

The third fallacy, which attributed the pulse to “a power communicated from the heart through the coats of the arteries, and not to the shock of the blood contained within them,-” thus making “the coats of the vessel the cause of the pulse,”rested on the experiment of tying the artery upon a tube inserted within it—an experiment which