CHAPTER VII. 

 CONTROL OF CIRCULATION. 



Circulation controlled by the Nervous System. We 

 know that fear often causes the face to turn pale and that 

 shame makes it red. Certain emotions also 

 quicken or retard the action of the heart. 

 Great grief or joy has caused sudden 9eath 

 by stopping the action of the heart. 



Nervous Control Involuntary. 



But this control is not volun- 

 tary. The will has nothing di- 

 rectly to do with it. We often wish to keep 

 from getting red in the face when embar- 

 rassed, but cannot prevent it. Neither can 

 we keep from turning pale through fright 

 or pain. We cannot keep the heart from 

 beating faster when we are excited. Instead 

 of being controlled by the brain, circulation 

 is chiefly under the control of a special part 

 of the nervous system, known as the Sym- 

 pathetic Nervous System. 



The Sympathetic Nervous System. The 

 sympathetic nervous system consists of two 

 rows of ganglions in the body cavity, one p . g 43 Ront Vje ^ 

 along each side of the spinal column, re- of spinal cord with 



. . , -'" .. Sympathetic Gang- 



ceivmg branches from the spinal nerves, nons of one side. 



70 



