RESPIRATION 



225 



column passes the great nerve distributor, the spinal cord. 

 From the spinal cord, 

 nerves are sent to all 

 the muscles of the body, 

 to the skin and to those 

 organs, like the eye and 

 the ear, which trans- 

 mit to the brain im- 

 pressions received 

 from without the body. 

 These nerves give the 

 stimulus which causes 

 the muscles to expand 

 or contract. In fact, 

 all the voluntary move- 

 ments of animals are 

 controlled from the 

 brain just as the move- 

 ments of trains on a rail- 

 road are controlled from 

 the despatched office. 



106. Respiration. 

 All animals must have 

 a way to breathe, or 

 energy cannot be sup- 

 plied to carry on the 

 activities of the body. 

 Different animals 

 breathe in different 



Ways, but in the higher THE NERVOUS SYSTEM OF MAN. 



Vertebrates and in man Notice how the nerves are distributed to 



it is the same. Respira-. a11 *> arts of the bodv ' 



tion in man will, therefore, be taken as the type. 

 Air enters the body through the nose or mouth, and 



