90 MECHANISM OF THE BONES. 



place, or that would do, in any other place. Change 

 the situation, proportion, dimensions, shape, of any 

 bone, and we can see at once, we violate some me- 

 chanical principle. Yet the bones are original, fixed 

 parts. They do not take their form from our mo- 

 tions. They do not wear into the right configuration. 

 The limbs of the infant are as perfect as those of the 

 adult. They exhibit examples of almost every kind 

 of mechanical power of which their nature' admits^ 

 and whatever be the instance, anatomists observe, it is 

 invariably the simplest, the most beautiful, and the 

 least subject to derangement, which would have an- 

 swered the purpose. 



The manner in which the bones are articulated, or 

 jointed, affords evidences of contrivance and contriv- 

 ing wisdom still more striking if possible, than those 

 we discover in the configuration and proportions of the 

 bones themselves. There is nothing perhaps in the 

 whole frame a mechanic would be more likely to no- 

 tice. The greatest curiosity and wonder to him would 

 probably be the appearance of selection, that is to say, 

 the employment of chosen joints in the different limbs, 

 and the admirable adaptation of each to the particular 

 motion required, as well as to the particular dangers 

 of injury in the situation in which it is used. Every 

 child knows that the bones are jointed ; but he is not 

 probably aware that no two joints are exactly alike, 

 except in corresponding parts of the frame. We have 

 the ball and socket joint, the pin or pivot joint, the 

 hinge joint, and as perfect in every respect as could 

 be produced from a cabinet maker's shop. One or 



