Page:The Harveian oration 1911.djvu/15

10 OLD AND NEW VIEWS ON attained to the truth that I should extricate myself and escape from this labyrinth and that I had discovered what I had so much desired, both the motion and the use of the heart and arteries. Since which time I have not hesitated to expose my views upon these subjects, not only in private to my friends, but also in public in my anatomical lectures, after the manner of the Academy of old."

Then after many years of demonstrations, in his Lumleian lectures, he published his well-known "Exercitatio de Motu Cordis et Sanguinis," a work of 67 pages, marvellous for its conciseness, in which he proves for all time-

"(1) That it is the contraction, not the dilata- tion of the heart which coincides with the pulse, and that the ventricles, as true muscular sacs, squeeze the blood which they contain into the aorta and pulmonary artery; (2) that the pulse is not produced by the arteries enlarging and so filling, but by the arteries being filled with blood and so enlarging; (3) that there are no pores in the septum of the heart, so that the whole blood in the right ventricle is sent to the lungs and round by the pulmonary veins to the left ventricle, and also that the whole blood in the left ventricle is again sent into the arteries round by the smaller veins into the venæ cavæ, and by them to the right ventricle again, thus making a complete double 'circulation'; (4) that the blood in the arteries and that in the veins is the same blood; (5) that