MOTION. 



her of spools on end ; the column is more lightened than it is weak- 

 ened by the hollowing out of the sides of each spool. And the central 

 hollow of the spool does not greatly weaken it. A given weight of 

 material has more strength when in the form of a hollow cylinder. The 

 bones combine well two very desirable quali- 

 ties, lightness and strength. If in our col- 

 umn of spools we place a wide rubber band 

 around the junction of two spools, we have 

 something very similar to the capsular liga- 

 ment, which surrounds the joints. 



Joints. The ends of the bones, where 

 they fit together in the joints, are covered 

 with a layer of smooth, elastic, whitish or 

 transparent cartilage. The motion in the 

 joints is made still more easy by the synovia, 

 resembling white of egg. The ends of the 

 bones are held together by tough bands and 

 cords of ligament, a form of connective 

 tissue very much like tendon. Bones are 

 closely covered by a tough coat of connective 

 tissue called the periosteum. 



All these structures can easily be found 

 by dissecting a sheep shank gotten from the 

 butcher, or in the hind leg of a rabbit. 



Locomotion. Locomotion is mov- 

 ing from place to place and should 

 be distinguished from mere motion. 

 By continuing such observations as 

 we made when we began to study 

 our motions, we can analyze and 

 understand many of the common 

 movements which we habitually 

 make. 



Standing. Although we are not ordinarily conscious of 

 the fact, when we are standing still we are using many 

 muscles. The accompanying figure illustrates how some 



Action of the Muscles 

 in Standing. 



