Heart and Blood 57 



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 dis- 

 persed ; 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. But of these things we 

 shall speak more opportunely when we come to specu- 

 late 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 com- 

 monly 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 undeservedly, 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 nutrition ; the former transmits the digested, perfect, 

 peculiarly nutritive fluid. 



