Circulation of the Blood 117 



difficulty that is experienced with all the aid supplied 

 by compresses, bandages, and a multiplied apparatus, 

 in restraining the flow of blood from the smallest 

 artery when wounded, with what force it overcomes all 

 obstacles and soaks through the whole apparatus, he 

 will scarcely, I imagine, think it likely that there can 

 be any retrograde motion against such an impulse and 

 influx of blood, any retrograde force to meet and over- 

 come a direct force of such power. Turning over these 

 things in his mind, I say, no one will ever be brought 

 to believe that the blood from the branches of the 

 vena portae can possibly make its way by the same 

 channels against an influx by the artery of such 

 impetuosity and force, and so unload the mesentery. 



Moreover, if the learned anatomist does not think 

 that the blood is moved and changed by a circular 

 motion, but that the same fluid always stagnates in the 

 channels of the mesentery, he appears to suppose that 

 there are two descriptions of blood, serving different 

 uses and ends ; that the blood of the vena portae, and 

 that of the vena cava are dissimilar in constitution, 

 seeing that the one requires a circulation for its 

 preservation, the other requires nothing of the kind ; 

 which neither appears on the face of the thing, nor is its 

 truth demonstrated by him. Our author then refers 

 to "A fourth order of mesenteric vessels, the lacteal 

 vessels, discovered by Asellius," l and having mentioned 

 these, he seems to infer that they extract all the 

 nutriment from the intestines, and transfer this to the 

 liver, the workshop of the blood, whence, having been 

 concocted and changed into blood, (so he says in his 

 third book, chapter the 8th), the blood is transferred 

 from the liver to the right ventricle of the heart. 

 " Which things premised," he continues, 2 " all the 

 difficulties which were formerly experienced in regard 

 to the distribution of the chyle and blood by the same 

 channel come to an end ; for the lacteal veins carry 



1 Enchiridion, lib. ii, cap. 18. 2 Ibid. 



