AN ANATOMICAL STUDY ON THE 



Nature, making nothing in vain, would not have 

 given these vessels such relative greatness uselessly. 

 Then I thought of the arrangement and structure of • 

 the valves and the rest of the heart. On these and 

 other such matters I pondered often and deeply. 

 For a long time I turned over in my mind such 

 questions as, how much blood is transmitted, and 

 how short a time does its passage take. Not deeming 

 it possible for the digested food mass to furnish such 

 an abundance of blood, without totally draining 

 the veins or rupturing the arteries, unless it some- 

 how got back to the veins from the arteries and re- 

 turned to the right ventricle of the heart, I began 

 to think there was a sort of motion as in a circle. 



This I afterwards found true, that blood is pushed 

 by the beat of the left ventricle and distributed 

 through the arteries to the whole body, and back 

 through the veins to the vena cava, and then re- 

 turned to the right auricle, just as it is sent to the lungs 

 through the pulmonary artery from the right ventricle 

 and returned from the lungs through the pulmonary 

 vein to the left ventricle, as previously described. 



This motion may be called circular in the way 

 that Aristotle says air and rain follow the circular 

 motion of the stars. ^ The moist earth warmed by 



* In spite of his own extraordinary discoveries, Harvey was re- 

 markably conservative. N. Copernicus (1473-1543), J. Kepler (1571- 

 1630), and G. Galilei (1564-1642) had overthrown the Ptolemical 

 theory of the circular motion of the stars in the heavenly spheres, 

 but Harvey seems never to have heard of their studies. 



I70I 



