INFLAMMATION OF THE J3EAIN (PHEEN1TIS). 919 



called nerves, which are given out from the brain and spinal cord, 

 and distributed to the different parts of the body, especially those 

 parts endowed with sensibility, and under the control of the will. 

 Besides this system of nerves, there is another set, independent of 

 the cerebro-spinal axis, called the sympathetic or ganglionic sys- 

 tem, which supplies the organs of nutrition and other viscera, blood- 

 vessels, etc. It consists of numerous small centers, called ganglia, 

 extending in two great chains from the head to the tail, on each 

 side of the bodies of the vertebrae, closely associated with the other 

 system by intricate communication. 



INFLAMMATION OF THE BRAIN (PHRENITIS). 



Phrenitis is not a very common disease, though the substance 

 of the brain itself, or, as is 

 more commonly the case, its 

 membranes, or coverings, be- 

 come inflamed. It has received 

 various appellations, such as 

 mad staggers, sleepy staggers, 

 etc. 



Causes. The causes are 

 not thoroughly understood. 

 Injuries to the skull, 'metasta- 

 sis, or the transference of in- 



FIG. 801. Symptom of inflammation of 

 narnmation from some of the the brain 



other organs, high condition 



and overwork, undue exposure to a hot sun, all seem to be fav- 

 orable to its production. Horses that are too highly fed are sub- 

 ject to this, while moderately fed horses are scarcely ever inclined 

 to it. 



Symptoms. It- is usually ushered in by dullness and persist- 

 ent drowsiness ; he stands with his head between his legs, or some- 

 times resting against the manger or leaning against the wall ; the 

 eyes shut, and the pupils dilated ; the pulse is full, soft, and slow ; 

 the breathing is heavy and loud; he is very difficult to arouse, and 

 when startled, he looks dreamily about ; may take a few bites of 

 hay, but soon drops asleep again ; the bowels are costive, and the 

 urine scanty and high colored. 



In a day or two the symptoms are mitigated, or it goes on to 



