544 THE MECHANICAL FUNCTIONS. 



a person blindfolded cannot walk far in a straight 

 line ; for, even on a level plane, he will incline 

 unconsciously either to the right or to the left. 



In all quadrupeds, and even also in the quad- 

 rumana, the fore extremities more or less contri- 

 bute to the support and progression of the body : 

 it is only in man that they are wholly exempted 

 from these offices, and are at liberty to be applied 

 to other purposes, and employed as instruments 

 of prehension and of touch. In the power of 

 executing an infinite variety of movements and 

 of actions, requiring either strength, delicacy, or 

 precision, the human arm and hand, considered 

 in their mechanism alone, are structures of un- 

 rivalled excellence ; and, when viewed in rela- 

 tion to the intellectual energies to which they 

 are subservient, plainly reveal to us the divine 

 source, from which have emanated this exquisite 

 workmanship, and these admirable adjustments, 

 so fitted to excite in our breasts the deepest 

 veneration, and to fill us with never ceasing 

 wonder. 



To specify all the details of express contrivance 

 in the mechanical conformation of the hand 

 would alone fill a separate treatise : but I must 

 refrain from pursuing this interesting subject, 

 as, fortunately, the task has devolved upon one 

 far more able than myself to do it justice. 



