24 MOTION OF THE 



CHAPTER III. 



OF THE MOTIONS OP 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 contracts 

 and propels its charge of blood, the arterial vein [the pul- 

 monary 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 percep- 

 tible. In like manner, the pulse in the right ventricle failing, 

 the pulse in the vena arteriosa [pulmonary artery] ceases also. 



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

 blood is seen to be forcibly propelled from the wound at the 

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

 monary artery is wounded, the blood will be seen spouting 

 forth with violence at the instant when the right ventricle 

 contracts. 



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

 the gills be divided, at the moment when the heart becomes 

 tense and contracted, at the same moment does the blood flow 

 with force from the divided vessel. 



In the same way, finally, when we see the blood in arte- 

 riotomy 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 ex- 

 pelled by the same movement. 



From these facts it is manifest, in opposition to commonly 

 received opinions, that the diastole of the arteries corresponds 

 with the time of the heart's systole; and that the arteries are 



