54 MOTION OF THE 



is established, only that here everything takes place more slowly, 

 and is more distinct. This point in particular may be observed 

 more clearly than the noon-day sun : the vena cava enters the 

 heart at its lower part, the artery quits it at the superior part ; the 

 vein being now seized either with forceps or between the finger 

 and thumb, and the course of the blood for some space below 

 the heart interrupted, you will perceive the part that intervenes 

 between the fingers and the heart almost immediately to become 

 empty, the blood being exhausted by the action of the heart ; 

 at the same time the heart will become of a much paler colour, 

 even in its state of dilatation, than it was before ; it is also 

 smaller than at first, from wanting blood ; and then it begins 

 to beat more slowly, so that it seems at length as if it were about 

 to die. But the impediment to the flow of blood being removed, 

 instantly the colour and the size of the heart are restored. 



If, on the contrary, the artery instead of the vein be com- 

 pressed or tied, you will observe the part between the obstacle 

 and the heart, and the heart itself, to become inordinately dis- 

 tended, to assume a deep purple or even livid colour, and at 

 length to be so much oppressed with blood that you will believe 

 it about to be choked ; but the obstacle removed, all things im- 

 mediately return to their pristine state the heart to its colour, 

 size, stroke, &c. 



Here then we have evidence of two kinds of death: extinction 

 from deficiency, and suffocation from excess. Examples of both 

 have now been set before you, and you have had opportunity of 

 viewing the truth contended for with your own eyes in the heart. 



CHAPTER XI. 



THE SECOND POSITION IS DEMONSTRATED. 



THAT this may the more clearly appear to every one, I have 

 here to cite certain experiments, from which it seems obvious 

 that the blood enters a limb by the arteries, and returns from 

 it by the veins ; that the arteries are the vessels carrying the 

 blood from the heart, and the veins the returning channels of 

 the blood to the heart ; that in the limbs and extreme parts of 

 the body the blood passes either immediately by anastomosis 

 from the arteries into the veins, or mediately by the pores of 



