118 NATURAL THEOLOGY. 



OF THE JOINTS. 



I. The above are a few examples of bones made 

 remarkable by their configuration ; but to almost 

 all the bones heloBg joints ; and in these, still more 

 clearly than in the form or shape of the bones them- 

 selves, are seen both contrivance and contriving 

 wisdom. Every joint is a curiosity, and is also 

 strictly mechanical. There is the hinge-joint and 

 the mortice and tenon-joint ; each as manifestly 

 such, and as accurately defined, as any which can 

 be produced out of a cabinet-maker's shop ; and 

 one or the other prevails, as either is adapted to the 

 motion which is wanted — e.g., a mortice and ten- 

 on, or ball and socket-joint, is not required at the 

 knee, the leg standing in need only of a motion 

 backward and forward in the same plane, for which 

 a binge-joint is sufficient ; a mortice and tenon, or 

 ball and socket-joint, is wanted at the hip, that not 

 only the progressive step may be provided for, but 

 the interval between the limbs may be enlarged 

 or contracted at pleasure. Now observe what 

 would have been the inconveniency — i. e., both 

 the superliuity and the defect of articulation, if the 

 case had been inverted : if the ball and socket-joint 

 had been at the knee, and the hinge-joint at the 



the fore-less with an clastic rebound, the trunk hanging upon the 

 muscles, the muscles supponted by the scapula, and the scapula 

 sustained upon the bones of the extremity. There is no solid sub- 

 stance to receive the shock. Were the collar-bone introduced here, 

 it would be snapped across by the percussion, as happens to a man 

 ivhere he is thrown upon his shoulder. 



