Circulation of the Blood 113 



my readers not only the places, but the affections of 

 these places, illustrating them as I proceed with obser- 

 vations, and recording the results of my experience 

 derived from my numerous dissections. 



But it is imperative on me first to dispose of those 

 observations contained in the work referred to, which 

 bear upon the circulation of the blood as discovered 

 by me, and which seem to require especial notice at 

 my hands. For the judgment of such a man, who is 

 indeed the prince and leader of all the anatomists of 

 the present age, in such a matter, is not to be lightly 

 esteemed, but is rather to be held of greater weight 

 and authority, either for praise or blame, than the 

 commendations or censure of all the world besides. 



Riolanus, then, admits our motion of the blood in 

 animals, 1 and falls in with our conclusions in regard 

 to the circulation ; yet not entirely and avowedly ; for 

 he says 2 that the blood contained in the vena portce 

 does not circulate like that in the vena cava; and 

 again he states 3 that there is some blood which cir- 

 culates, and that the circulatory vessels are the aorta 

 .and vena cava; but then he denies that the continua- 

 tions of these trunks have any circulation, " because 

 the blood is effused into all the parts of the second 

 and third regions, where it remains for purposes of 

 nutrition ; nor does it return to any greater vessels, 

 unless forcibly drawn back when there is a great lack 

 of blood in the main channels, or driven by a fit of 

 passion when it flows to the greater circulatory vessels ; " 

 and shortly afterwards : " thus, as the blood of the 

 veins naturally ascends incessantly or returns to the 

 heart, so the blood of the arteries descends or departs 

 from the heart ; still, if the smaller veins of the arms 

 and legs be empty, the blood filling the empty channels 

 in succession, may descend in the veins, as I have 



1 Enchiridion, lib. iii, cap. 8. 



2 Ib. lib. ii, cap 21. 



3 Ib. lib. iii, cap. 8. 



