346 NATURAL THEOLOGY. 



Bernouilli found that when a small tube, b, 

 was inserted into the side of a horizontal conical 

 tube, A, in which the water was flowing towards 

 the wider end c, not only did no water escape 

 through the smaller tube, but water in a vessel, 

 at a considerable distance below, was drawn up 

 through the lesser tube into the greater. 



With these facts before us, we turn with inte- 

 rest to the curves of the arteries and veins, seeing 

 that the contained fluids flow in the one from the 

 trunk to the branch, in the other in an opposite 

 direction from the smaller to the greater vessel. 



And now, if, instead of taking the artery as 

 the important vessel, and the vein as less so — 

 and therefore negligently contrived, we consider 

 both of them to be important and perfect — we 

 ought to expect that their course and curves 

 should differ. 



In the artery, where the blood is passing from 

 the heart towards the extremities — that is, from 

 trunk to branch — the branches slightly diverge 

 from the direction of the stream in the trunk ; 

 whilst the branch of the vein, where the blood is 

 passing from the lesser into the larger vessel, 

 enters abruptly and at right angles. From this 

 it appears, that if we could imagine such a mal- 

 formation as that the offices of these vessels were 

 changed, congestion would immediately take place, 

 and the circulation could not be carried on. 



