482 ANIMAL PHYSIOLOGY. 
rises suddenly without a special effort of will power ; he experi- 
ences pain, and has certain thoughts about the object, etc. 
Fie. 343.—Group of cells in connection with anterior roots of spinal nerves, as seen in trans- 
verse section of spinal cord of sheep (after Flint and Dean). A, emergence of anterior 
roots from gray matter ; b, b, b, cells connected both with each other and with fibers of 
anterior roots. 
Now, in reality this is very complex, though it can be ana- 
lyzed into its factors. Thus, afferent nerves are concerned, the 
spinal cord as a reflex center, efferent nerves to the muscles 
called into action, the cord as a conductor of impulses which re- 
sult in sensations, emotions and thoughts referable to the brain; 
so that if we would grasp the state of affairs it is of importance 
