NATURAL THEOLOGY. 175 



mal. We may here likewise repeat, what we 

 before observed concerning some of the ligaments 

 of the body, that they could not be formed by any 

 action of the parts themselves. There are cases 

 in which, although good uses appear to arise from 

 the shape or configuration of a part, yet that shape 

 or configuration itself may seem to be produced 

 by the action of the part, or by the action or pres- 

 sure of adjoining parts. Thus the bend and the 

 internal smooth concavity of the ribs may be at- 

 tributed to the equal pressure of the soft bowels ; 

 the particular shape of some bones and joints, to 

 the traction of the annexed muscles, or to the po- 

 sition of contiguous muscles. But valves could 

 not be so formed. Action and pressure are all 

 against them. The blood, in its proper course, 

 has no tendency to produce such things ; and in 

 its improper or reflected current has a tendency 

 to prevent their production. Whilst we see, 

 therefore, the use and necessity of this machinery, 

 we can look to no other account of its origin or 

 formation than the intending mind of a Creator. 

 Nor can we without admiration reflect, that such 

 thin membranes, such weak and tender instru- 

 ments, as these valves are, should be able to hold 

 out for seventy or eighty years. 



Here also we cannot consider but with grati- 

 tude, how happy it is that our vital motions are 

 involuntary. We should have enough to do, if 

 we had to keep our hearts beating and our 

 stomachs at work. Did these things depend, we 



