HEART AND BLOOD. 47 



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

 perfection. Here it resumes its due fluidity and receives an 

 infusion of natural heat powerful, fervid, a kind of treasury 

 of life, and is impregnated 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 de- 

 signated 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, nou- 

 rishes, cherishes, quickens the whole body, and is indeed the 

 foundation of life, the source of all action. But of these things 

 we shall speak more opportunely when we come to speculate 

 upon the final cause of this motion of the heart. 



Hence, since the veins are the conduits and vessels that 

 transport the blood, they are of two kinds, the cava and the 

 aorta ; and this not by reason of there being two sides of the 

 body, as Aristotle has it, but because of the difference of office; 

 nor yet, as is commonly said, in consequence of any diversity 

 of structure, for in many animals, as I have said, the vein does 

 not differ from the artery in the thickness of its tunics, but 

 solely in virtue of their several destinies and uses. A vein and 

 an artery, both styled vein by the ancients, and that not un- 

 deservedly, as Galen has remarked, because the one, the artery 

 to wit, is the vessel which carries the blood from the heart to 

 the body at large, the other or vein of the present day bringing 

 it back from the general system to the heart ; the former is the 

 conduit from, the latter the channel to, the heart; the latter 

 contains the cruder, effete blood, rendered unfit for nutri- 

 tion ; the former transmits the digested, perfect, peculiarly nu- 

 tritive fluid. 



