348 



NATURAL THEOLOGY. 



the arrangement in question, instead of being a 

 negligent or irregular joining of the branch to the 

 trunk, is, on the contrary, a provision for the lesser 



tube entering at a proper angle into the side of 

 the greater one. 



If two tubes join to form a larger tube, and a 

 hole be bored at the angle of their union, and if 

 the water flow from the lesser tubes into the 

 greater tube, no water will escape by the hole : 

 in other words, there is a point of negative pres- 

 sure. Now it is remarkable that the vessels which 

 are called absorbents enter into the venous system 

 at the angle of union of the great veins ; that is, 

 at the point of negative pressure. 



