84 WILLIAM HARVEY 



CHAPTER III 



OF THE MOTIONS OF THE ARTERIES, AS SEEN IN THE 

 DISSECTION OF LIVING ANIMALS 



IN connexion with the motions of the heart these things 

 are further to be observed having reference to the motions 

 and pulses of the arteries. 



1. At the moment the heart contracts, and when the breast 

 is struck, when in short the organ is in its state of systole, 

 the arteries are dilated, yield a pulse, and are in the state 

 of diastole. In like manner, when the right ventricle con- 

 tracts and propels its charge of blood, the pulmonary artery, 

 is distended at the same time with the other arteries of the 

 body. 



2. When the left ventricle ceases to act, to contract, to 

 pulsate, the pulse in the arteries also ceases; further, when 

 this ventricle contracts languidly, the pulse in the arteries 

 is scarcely perceptible. In like manner, the pulse in the 

 right ventricle failing, the pulse in the pulmonary artery 

 ceases also. 



3. Further, when an artery is divided or punctured, the 

 blood is seen to be forcibly propelled from the wound the 

 moment the left ventricle contracts; and, again, when the 

 pulmonary artery is wounded, the blood will be seen spout- 

 ing forth with violence at the instant when the right ventri- 

 cle contracts. 



So also in fishes, if the vessel which leads from the heart 

 to the gills be divided, at the moment when the heart be- 

 comes tense and contracted, at the same moment does the 

 blood flow with force from the divided vessel. 



In the same way, when we see the blood in arteriotomy 

 projected now to a greater, now to a less distance, and that 

 the greater jet corresponds to the diastole of the artery and 

 to the time when the heart contracts and strikes the ribs, 

 and is in its state of systole, we understand that the blood is 

 expelled by the same movement. 



From these facts it is manifest, in opposition to commonly 

 received opinions, that the diastole of the arteries corre- 

 sponds with the time of the heart's systole; and that the 



I 



