48 CLASSICS OF MODERN SCIENCE 

 ward found to be true; and I finally saw that the blood, forced by 

 the action of the left ventricle into the arteries, was distributed to 

 the body at large, and its several parts, in the same manner as it is 

 sent through the lungs, impelled by the right ventricle into the 

 pulmonary artery, and that it then passes through the veins and 

 along the vena cava, and so round to the left ventricle in the manner 

 already indicated. Which motions we may be allowed to call circular, 

 in the same way as Aristotle says that the air and rain emulate the 

 circular motion of the superior bodies; for the moist earth, warmed 

 by the sun, evaporates; the vapours drawn upwards are condensed, 

 and descending in the form of rain, moisten the earth again; and by 

 this arrangement are generations of living things produced; and 

 in like manner too are tempests and meteors engendered by the cir- 

 cular motion, and by the approach and recession of the sun. 



And so, in all likelihood, does it come to pass in the body, through 

 the motion of the blood ; the various parts are nourished, cherished, 

 quickened by the warmer, more perfect, vaporous, spiritous, and, as 

 I may say, alimentive blood ; which, on the contrary, in contact with 

 these parts becomes cooled, coagulated, and, so to speak, effete ; whence 

 it returns to its sovereign the heart, as if to its source, or to the 

 inmost home of the body, there to recover its state of excellence, or 

 perfection. 



Here it resumes its due fluidity and receives an infusion of nat- 

 ural heat — powerful, fervid, a kind of treasury of life, and is impreg- 

 nated with spirits, and it might be said with balsam; and thence it 

 is again dispersed; and all this depends on the motion and action 

 of the heart. 



The heart, consequently, is the beginning of life; the sun of the 

 microcosm, even as the sun in his turn might well be designated the 

 heart of the world ; for it is the heart by whose virtue and pulse the 

 blood is moved, perfected, made apt to nourish, and is preserved 

 from corruption and coagulation; it is the household divinity which, 

 discharging its function, nourishes, cherishes, quickens the whole 

 body, and is indeed the foundation of life, the source of all action. 



