94 CIRCULATION OF THE BLOOD. 



it overcomes all obstacles and soaks through the whole appa- 

 ratus, 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 overcome 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 portse 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 

 portse, and that of the vena cava are dissimilar in consti- 

 tution, seeing that the one requires a circulation for its pre- 

 servation, 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 " 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 pre- 

 mised," 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 

 the chyle to the liver, and as these canals are distinct, so may 

 they be severally obstructed." But truly I would here ask: 

 how this milky fluid can be poured into and pass through the 

 liver, and how from thence gain the vena cava and the ven- 

 tricle of the heart? when our author denies that the blood 

 of the vena portse passes through the liver, and that so a cir- 

 culation is established. I pause for a reply. I would fain know 

 how such a thing can be shown to be probable; especially 

 when the blood appears to be both more spirituous or subtile 



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



