118 DR. LEGEAR'S STOCK BOOK. 



CHAPTER IX. 

 THE NERVOUS SYSTEM. 



The nervous system is composed of the brain, spinal cord, and 

 nerves. The brain is situated in the upper part of the skull, the 

 spinal cord in the back-bone, and the nerves branch off, like the 

 limbs of a tree, from the brain and spinal cord and extend to 

 every part of the body. The brain generates the electricity, as 

 it were, and the nerves convey the messages to and from the 

 l)rain. When a nerve is cut, or divided, or if by any means the 

 nervous force is shut off from any part of the body, local para- 

 lysis will take place. Without nervous force there is no motion, 

 nutrition, vitality, or life. If the spinal cord in the region of the 

 back or loins is severed or injured there is immediate paralysis of 

 the whole hind parts; while if the injury takes place in the neck, 

 &s by broken neck, death will soon follow. By piercing the 

 spinal cord a few inches behind the ears with any sharp instru- 

 ment, as a pin or small knife blade, death will immediately fol- 

 low. Below will be found a brief description of the more im- 

 portant diseases and injuries of the nervous system. 



SUNSTROKE. 



Sunstroke occurs during the hot months of summer. It is a 

 greater or less congestion of the brain, causing either partial or 

 complete loss of motion, and often of sensation. 



Causes. Causes which lay an animal liable to suffer from an 

 -attack are high feeding, irregular exercise, an insufficient supply 

 of good water, badly ventilated stables, debility, etc. The direct 

 cause is exposure to the sun during very hot weather, and more 



