148 Circulation of the Blood 



was lost from the farther orifice of a divided vein 

 because nature was disturbed, still that the incision 

 does not close the nearer orifice, from which nothing 

 either escapes or can be expressed, whether nature be 

 disturbed or not. Others argue in the same way, main- 

 taining that, although the blood immediately spurts out 

 in such profusion with every beat, when an artery is 

 divided near the heart, it does not therefore follow that 

 the blood is propelled by the pulse when the heart and 

 artery are entire. It is most probable, however, that 

 every stroke impels something ; and that there would 

 be no pulse of the container, without an impulse being 

 communicated to the thing contained, seems certain. 

 Yet some, that they may seize upon a farther means 

 of defence, and escape the necessity of admitting the 

 circulation, do not fear to affirm that the arteries in the 

 living body and in the natural state are already so full 

 of blood, that they are incapable of receiving another 

 drop ; and so also of the ventricles of the heart. But 

 it is indubitable that, whatever the degree of distension 

 and the extent of contraction of the heart and arteries, 

 they are still in a condition to receive an aditional 

 quantity of blood forced into them, and that this is 

 far more than is usually reckoned in grains or drops, 

 seems also certain. For if the ventricles become so 

 excessively distended that they will admit no more 

 blood, the heart ceases to beat, (and we have occasional 

 opportunities of observing the fact in our vivisections,) 

 and, continuing tense and resisting, death by asphyxia 

 ensues. 



In the work on the Motion of the Heart and Blood, 

 I have already sufficiently discussed the question as to 

 whether the blood in its motion was attracted, or im- 

 pelled, or moved by its own inherent nature. I have 

 there also spoken at length of the action and office, of 

 the dilatation and contraction of the heart, and have 

 shown what these truly are, and how the heart contracts 

 during the diastole of the arteries ; so that I must hold 



