Circulation of the Blood 115 



denies that the contents of the branches in continuation 

 of the vena portae circulate ; but he could neither 

 oppose nor deny this, did he not conceal from himself 

 the force of his own arguments ; for he says in his 

 Third Book, chap, viii., "If the heart at each pulsa- 

 tion admits a drop of blood which it throws into the 

 aorta, and in the course of an hour makes two thousand 

 beats, it is a necessary consequence that the quantity 

 of blood transmitted must be great." He is farther 

 forced to admit as much in reference to the mesentery, 

 when he sees that far more than single drops of blood 

 are sent into the cceliac and mesenteric arteries at 

 each pulsation; so that there must either be some 

 outlet for the fluid, of magnitude commensurate with 

 its quantity, or the branches of the vena portae must 

 give way. Nor can the explanation that is had recourse 

 to with a view of meeting the difficulty, viz. that the 

 blood of the mesentery ebbs and flows by the same 

 channels, after the manner of Euripus, be received as 

 either probable or possible. Neither can the reflux 

 from the mesentery be effected by those passages and 

 that system of translation, by which he will have it to 

 disgorge itself into the aorta; this were against the 

 force of the existing current, and by a contrary motion ; 

 nor can anything like pause or alternation be admitted, 

 where there is very certainly an incessant influx : the 

 blood sent into the mesentery must as inevitably go 

 elsewhere as that which is poured into the heart. And 

 this is obvious ; were it otherwise, indeed, everything 

 like a circulation might be overturned upon the same 

 showing and by the same subterfuge ; it might just as 

 well be said that the blood contained in the left 

 ventricle of the heart is propelled into the aorta during 

 the systole, and flows back to it during the diastole, 

 the aorta disgorging itself into the ventricle, precisely 

 as the ventricle has disgorged itself into the aorta. 

 There would thus be circulation neither in the heart 

 nor in the mesentery, but an alternate flux and reflux, 



