92 CIRCULATION OF THE BLOOD. 



viz., that the whole of the blood, wherever it be in the living 

 body, moves and changes its place, not merely that which is 

 in the larger vessels and their continuations, but that also 

 which is in their minute subdivisions, and which is contained 

 in the pores or interstices of every part ; that it flows from and 

 back to the heart ceaselessly and without pause, and could not 

 pause for ever so short a time without detriment, although I 

 admit that occasionally, and in some places, its motion is 

 quicker or slower. 1 



In the first place, then, our learned anatomist only denies 

 that the contents of the branches in continuation of the vena 

 portse 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 

 pulsation 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 refer- 

 ence to the mesentery, when he sees that far more than single 

 drops of blood are sent into the coeliac 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 portse must give way. Nor can the ex- 

 planation that is had recourse to with a view of meeting the dif- 

 ficulty, 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 alterna- 

 tion be admitted, where there is very certainly an incessant in- 

 flux : 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 con- 

 tained in the left ventricle of the heart is propelled into the 

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

 1 Vide Chapter III. 



