BRAIN AND NERVOUS SYSTEM. 



327 



brain. This wing is attached to tke bone, and gives support 

 to the brain, and protects it from the injury that might come 

 from jars ; and it also prevents the upper and larger organ 

 from pressing upon the smaller organ below. 



750. The spinal cord extends from the FIG. LXIII. 

 brain through ihe whole length of the Brai and Cord, 

 back-bone, (Fig. LXIII. 6.) In the bottom 



of the skull there is a large hole, which 

 is placed directly over, and opens into, 

 the channel in the spine. This channel 

 is formed by the rings of the successive 

 vertebrae. It is closed on all its sides, 

 and gives a sufficient and secure place 

 for this great nerve or extension of the 

 brain. This spinal cord is composed of 

 pulpy, nervous matter, like that of the 

 brain, and is protected by the same deli- 

 cate and strong membranes that cover 

 the organ above. 



751. The brain sends nerves to the 

 wlia 1 !' body. There are holes in the base 

 of the skuil through which twelve pairs 

 pass outward. These are alike on the 

 two sides. The optic nerves pass for- 

 ward to the eyes. The auditory nerves 

 pass sidewise to the ears. The others 

 pass through other holes to the fafce, and 

 to some other parts of the body. Twelve 

 pairs go directly from the brain, (Fig. 

 LXIII. a,) and thirty pairs go from the 

 spinal cord, (Fig. LXIII. <, <, c.) These 

 nerves divide and multiply until their 

 branches reach every part of the body, 

 and every organ, muscle, and blood-ves- 

 sel is connected with the brain by its appropriate nerve. The 

 nerve of the face passes out from the skull below the ear, 

 (Fig. LXIV. ,) and sends its branches and filaments over the 



a, Brain. 



b, Spinal cord. 



c, c, c, c, Roots of 

 spinal nerves. 



