MUSCLES 167 



332. How to see muscles. Shut the hand tightly, and 

 notice that the arm just below the elbow becomes harder 

 and larger. This is because the muscles which shut the 

 hand are situated upon the arm. You can feel and see 

 the ridges formed by each bundle of muscle while it is 

 acting. You can feel their tendons as they cross the wrist. 

 Some end in the palm of the hand, and some go on to the 

 fingers. There are a few small muscles in the palm of 

 the hand, but most of the finger muscles are in the arm. 

 There are no muscles at all in the fingers. 



The muscles of the foot are upon the leg below the 

 knee. They end in tendons which go to the toes like the 

 tendons to the fingers. The tendon above the heel sup- 

 ports the weight of the body when we stand on tiptoe. It is 

 the largest in the body, and is called the tendon of Achilles. 



Muscles which bend a joint are usually much stronger 

 than those which straighten it, for most of our work is 

 done by bending the joints. 



333. Strength of muscle. Lean meat seems soft and 

 almost like jelly, yet it can contract with great force. The 

 muscle upon the front of a man's arm can put forth a force 

 of nearly a thousand pounds, but its tendon is attached so 

 near the elbow that we can really lift about a hundred 

 pounds with the hand. Most muscles have to put forth a 

 strength more than equal to the weight which they move. 



A grasshopper seems to be very strong, for it can jump 

 a hundred times its own length. But a grasshopper is 

 very light, and has but little weight to carry. A piece of 

 man's muscle of the size of a grasshopper's is really far 

 the stronger. 



334. How to increase the strength. By use, a muscle 

 becomes larger and stronger. When a boy wishes to go 

 into a race, he uses the muscles of his legs every day until 



