THE MUSCLES. 



5. The Tendons. Tendons, or sinews, are the ex- 

 tremities of muscles, and are compactly fastened upon 

 bone. They are very strong, and of a silvery whiteness. 

 They may be felt just beneath the skin, in certain parts of 

 the body, when the muscles are being used, as at the bend 

 of the elbow or knee. The largest tendon of the body is 

 that which is inserted into the heel, called the tendon of 

 Achilles, after the hero of the Grecian poet, the fable relat- 

 ing that it was at this point that he received his death- 

 wound, no other part of his body being vulnerable. The 

 muscles "which extend into the leg unite to form a single 



FIG. 10. -VIEW OF KNEE-JOINT. A. Thigh bone: B, Knee-pan : C, D, Leg bones. 



and very powerful tendon, and enclose a small bone called 

 the knee-pan, which, acting like a pulley, greatly increases 

 their power, and at the same time protects the front of the 

 knee-joint (Fig. 10). 



6. Muscular Contraction. The muscles, when acted 

 upon by the appropriate stimulus, contract, or so change 



5. What are the tendons or sinews? Their strength? Color? Location? 

 Tendon of Achilles ? The fable ? Muscles of the leg ? 



6. Contraction of the muscles ? Bending of the arm or finger ? Other agencies ? 

 Automatic movements ? In cold-blooded animals ? 



