NATURE OF MUSCULAR ACTION. 105 



harmony between effort and resistance. The loss 

 of equilibrium, and the concussion and disturbance 

 of the system consequent on taking a false step, as 

 it is called, are a specimen of what we would always 

 be subject to without the guidance of the muscular 

 sense. When we imagine we have one step more of 

 a stair to descend than really exists, we are placed 

 nearly in the same circumstances as if we had no 

 muscular sense to direct the extent of our intended 

 movement ; because the sense is then misled by an 

 erroneous impression, and, accordingly, we make 

 an effort grievously unsuited to the occasion : and 

 yet, so habitually are we protected from this error 

 by the assistance of the sense alluded to, and so 

 little are we conscious of its operation, that it is only 

 after mature reflection that we perceive the neces- 

 sity of its existence. 



In chewing our food, in turning the eyes towards 

 an object looked at, in raising the hand to the mouth, 

 and, in fact, in every variety of muscular movement 

 which we perform, we are guided by the muscular 

 sense in proportioning the effort to the resistance to 

 be overcome ; and where this harmony is destroyed 

 by disease, the extent of the service rendered us 

 becomes more apparent. The shake of the arm and 

 hand which we see in drunkards, and their conse- 

 quent incapability of carrying the morsel directly to 

 the mouth, are examples of what would be of daily 

 occurrence, unless we were directed and assisted by 

 a muscular sense. 



Life and the nervous stimulus are essential to 

 muscular power. Separated from the body, and 

 deprived of both, the muscle which formerly con- 

 tracted with a power equal to 100 pounds would be 

 torn asunder by a weight of ten. This fact is of 

 itself sufficient to give a tolerable notion of the ex- 

 tent to which muscular contraction depends on 

 other causes than the mere structure of the fleshy 

 fibres, for these continue the same after death, or 



