OF VITAL MOTION. 117 



when, judging from the state of the ventricle, there 

 is the freest innervation. In harmony with these con- 

 siderations, we may suppose that the filling of the 

 entire side of the heart is a single act, though it ap- 

 pears twofold. Owing indeed to the decided and rapid 

 diastole of the ventricle, we may suppose the blood to 

 be suddenly drawn away from the auricle, and not sent 

 away ; and so the apparent contraction of the auricle 

 at this time may be collapse of the thin walls of the 

 organ, instead of true and positive systole. 



We may consider, in short, that the movements 

 observable in the auricles are secondary and not pri- 

 mary. The systole we may consider as complementary 

 to the arterial pulse, each phenomenon being dependent 

 upon actions which take place in a remote seat namely, 

 in the ventricles. The diastole also we must regard as 

 mainly dependent upon the general current of the 

 blood, which, proceeding from the pulse and capillary 

 power, flows onwards from the veins. There is indeed 

 more confirmed activity in the auricles than in the 

 neighbouring veins, but when the activity is compared 

 with that of the ventricles, it becomes insignificant and 

 scarcely appreciable. 



