NATURAL HISTORY. 



Since God is ever present, ever felt, 



In the void waste as in the city full ; 



And where he vital breathes there must be joy." THOMSON. 



more. In like manner, the muscles which move the toes, and 

 many of the joints of the foot, are disposed in the calf of the 

 leg, instead of forming an unwieldy tumefaction in the foot itself. 

 Thus, also, is it with the nictating membrane over the eye. Its 

 office is in the front of the eye ; but its body is lodged in the 

 back part of the globe, where it lies safe, and where it encumbers 

 nothing. 



65. What cure tendons? 



Tendons are not only necessary as pulleys tc the bones, but to 

 give the limbs a proper form, and preserve their beautiful symmetry, 

 Tendons are seldom required, except where muscles are inserted 

 into bones. There is no tendon in the heart, the stomach, the 

 bowels, or the gullet ; these do not require them, for the motions 

 are wholly contractile, and need no lever power. But where tendons 

 pass over bones and traverse joints, the force is concentrated into 

 narrow bounds, and their long cords being fixed to the extremities 

 of the muscles, pull the bones, and raise them in obedience to our 

 will Tendons have no visible nerves, and little or no motion. 



66. What is cartilage f 



Cartilage is intermediate in hardness with bone, and what are 

 called the soft parts it is firm and resisting, and yet it has 

 a great deal of elasticity. In some parts of the body there are car- 

 tilages serving for continuations of bones, such as those which con- 

 tinue the ribs and connect them to the breast-bone, and they are 

 exactly similar to bones from which the earthy parts have been 

 dissolved by an acid. 



67. The cartilaginous crusts which cover the auricular ends of bones are of a very 

 beautiful and peculiar structure. If a piece of bone be sawn towards its 

 articular end, till all be cut through, and then the remaining part, and the cartilage 

 covering it be torn asunder, the cartilage will be found to present an infinity of 

 fibres set perpendicularly on the surface of the bone. When a portion of the bone 

 v. itli its articular cartilage has been soaked in "water for some weeks, the cartilage 

 i found to have lost its smooth surface and cohesion, and looks exactly as if the 

 b.j.tv !(.ul Uoi covered with white vchx-t. 



