NATURAL THEOLOGY. 133 



tion, and pull in such a direction, as to produce the 

 motion of which the joint admits. For instance, 

 the sartoriusor tailor's muscle, rising from the spine, 

 running diagonally across the thigh, and taking hold 

 of the inside of the main bone of the leg a little 

 below the knee, enables us, by its contraction, to 

 throw one leg and thigh over the other, giving ef- 

 fect, at the same time, to the ball and socket-joint 

 at the hip, and the hinge-joint at the knee. There 

 is, as we have seen, a specific mechanism in the 

 bones for the rotatory motions of the head and hands : 

 there is, also, in the oblique direction of the muscles 

 belonging to them, a specific provision for the put- 

 ting of this mechanism of the bones into action. 

 And mark the consent of uses : the oblique muscles 

 would have been inefficient without that particular 

 articulation ; that particular articulation would have 

 been lost without the oblique muscles. It may be 

 proper, however, to observe, with respect to the 

 head, although I think it does not vary the case, 

 that its oblique motions and inclinations are often 

 motions in a diagonal produced by the joint action 

 of muscles lying in straight directions. But whether 

 the pull be single or combined, the articulation is 

 always such as to be capable of obeying the action 

 of the muscles. The oblique muscles attached to 

 the head are likewise so disposed as to be capable 

 of steadying the globe as w^ell as of moving it. The 

 head of a new-born infant is often obliged to be 

 filleted up. After death the head drops and rolls 

 in every direction. So that it is by the equilibre 



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