Chapter IX 



The Circulation of the Blood is Proved by 

 a Prime Consideration 



IF ANYONE says these are empty words, broad 

 assertions without basis, or innovations without 

 just cause, there are three points coming for proof, 

 from which I believe the truth will necessarily 

 follow, and be clearly evident. 



First, blood is constantly being transmitted from 

 the vena cava to the arteries by the heart beat in 

 such amounts that it cannot be furnished by the food 

 consumed, and in such a way that the total quantity 

 must pass through the heart in a short tme. 



Second, blood is forced by the pulse in the arteries 

 continually and steadily to every part of the body 

 in a much greater amount than is needed for nutri- 

 tion or than the whole mass of food could supply. 



And likewise third, the veins continually return 

 this blood from every part of the body to the heart. 



These proved, I think it will be clear that the blood 

 circulates, passing away from the heart to the ex- 

 tremities and then returning back to the heart, 

 thus moving in a circle. 



Let us consider, arbitrarily or by experiment, 

 that the left ventricle of the heart when filled in 



[73] 



