124 MECHANISM OF THE MUSCLES. 



so very near the joint. Here is an admirable atten- 

 tion to mechanical laws. 



B. This does not seem very intelligible. One 

 would think the muscle would pull to great disadvan- 

 tage from being inserted so close to the joint. It 

 would seem like drawing to a door with a string; fast- 

 ened just by the hinge, which every one knows would 

 make it very hard to move the door. The elbow 

 certainly appears to be bent with a great loss of me- 

 chanical power. It would seem far better if the mus- 

 cle, which raises the fore arm had reached down to 

 the hand, and been inserted at c. This would have 

 given a greater purchase. 



A. The advantage obtained is this, and the door 

 is a good explanation. When the string is fastened 

 very near the hinge, it requires a strong pull to draw 

 the door ; but then, if the strength is sufficient, it will 

 make the door move much more swiftly than if the 

 string were attached at a greater distance from the 

 hinge. So, w r hen a mechanic is raising a ladder, if 

 he is able to lift it up by taking hold of one of the 

 lower rounds, close to the foot, where the ladder 

 turns upon the ground, — we may say, where the 

 hinge is, in that case he will do the business much 

 more quickly than if he were to begin at the farther 

 end. Thus, the nearer the joint the muscle acts, the 

 swifter the motion produced, provided the strength 

 of the muscles is sufficient. 



T. And for this, provision is made. The Creator 

 has given sufficient vital power to the muscles to ad- 

 mit of this sacrifice of the mechanical or lever power, 



