514 



APPLIED BIOLOGY 



spinal cord with the brain. Most of these structures can 

 be identified on a sheep's brain, obtained from a meat-market, 

 and hardened in strong alcohol or formalin solution. 



Microscopic study of 

 sections shows that most 

 of the nerve-cells of the 

 brain are near the 

 surface (cortex), while in- 

 side are the fibers con- 

 necting with the spinal 

 cord and also connecting 

 various parts of the brain. 

 Hence a cut across a fresh 

 brain shows gray matter 

 (with nerve-cells) on the 

 outside and white matter 

 (nerve-fibers) inside, just 

 the reverse of the spinal 

 cord. 



The cerebral hemi- 

 spheres are the center of 

 mental life, conscious- 

 ness, and voluntary 

 action. The cerebellum 

 is the center of coordina- 

 tion, causing muscles to 

 work in definite and con- 

 trolled ways. The nerve- 

 cells which control the 

 respiratory movements 

 and the circulatory or- 



FIG. 163. Diagram showing nerve con- 

 nections of ear, eye, lips, and hand with 

 centers in the cerebrum of the brain. 

 The ear and eye have only sensory fibers 

 which carry impulses to the brain, while 

 the lips and hand have both sensory and 

 motor fibers (m, s) carrying impulses as 



shown by the arrows. 

 and Stirling.) 



(From Landois 



are in the spinal 



gans 

 bulb. 



Localized centers in the cerebrum are known to exist. 

 So far our knowledge is limited, but there are areas in the 



