THE EXAMINATION OF A SICK HORSE. 28 
THE EXAMINATION OF THE NERVOUS SYSTEM. 
The great brain, or cerebrum, is the seat of intelligence, and it con- 
tains the centers that control motion in many parts of the body. 
The front portion of the brain is believed to be the region that is most 
important in governing the intelligence. The central and posterior 
portions of the cerebrum contain the centers for the voluntary motions 
of the face and of the front and hind legs. The growth of a tumor or 
an inflammatory change in the region of a center governing the 
motion of a certain part of the body has the effect of disturbing 
motion in that part by causing excessive contraction known as cramps, 
or inability of the muscles to contract, constituting the. condition 
known as paralysis. The nerve paths from the cerebrum, and hence 
from these centers to the spinal cord and thence to the muscles, pass 
beneath the small brain, or the cerebellum, and through the medulla 
oblongata to the spinal cord. Interference with these paths has the 
effect of disturbing motion of the parts reached by them. If all of 
the paths on one side are interfered with, the result is paralysis of one 
side of the body. : 
The small brain, or cerebellum, governs the regularity, or coordi- 
-nation, of movements. Disturbances of the cerebellum cause a totter- 
ing, uncertain gait. In the medulla oblongata, which lies between the 
spinal cord and the cerebellum, are the centers governing the circula- 
tion and breathing. 
The spinal cord carries sensory messages to the brain and motor 
impressions from the brain. The anterior portions of the cord con- 
tain the motor paths, and the posterior portions of the cord contain 
the sensory paths. 
Paralysis of a single member or a single group of muscles is known 
as monoplegia and results from injury to the motor center or to a 
nerve trunk leading to the part that is involved. Paralysis of one- 
half of the body is known as hemiplegia and results from destruction 
or severe disturbances of the cerebral, hemisphere of the opposite side 
of the body or from interference with nerve paths between the cere- 
bellum, or small brain, and the spinal cord. Paralysis of the poste- 
rior half of the body is known as paraplegia and results from de- 
rangement of the spinal cord. If the cord is pressed upon, cut, or 
injured, messages can not be transmitted beyond that point, and so 
the posterior part becomes paralyzed. This is seen when the back is 
fractured. 
Abnormal mental excitement may be due to congestion of the brain 
or to inflammation. The animal so afflicted becomes vicious, pays no 
attention to commands, cries, runs about in a circle, stamps with the 
feet, strikes, kicks, etc. This condition is usually followed by a dull, 
stupid state, in which the animal stands with his head down, dull and 
