292 MANUAL OF EQUINE MEDICINE. 



CHRONIC DISEASES OF THE BRAIN, 



CHRONIC MENINGITIS. —Chronic inflammatory changes 

 are sometimes met with in horses in the membranes of the 

 brain, but during life they are not usually diagnosed. 

 They may give rise to general dulness, a staggering gait, 

 slow pulse, and other symptoms, as well as sometimes to 

 the more active manifestations of cerebral disturbance. 



Chronic meningeal inflammation is usually the sequel of 

 acute attacks of inflammation, or it may follow recovery 

 from various injuries to the brain. 



CEREBRAL SOFTENING.— Cerebral softening is usually 

 the result of embolism of the cerebral arteries, but it may 

 also follow inflammation of the brain substance. It some- 

 times occurs as a result of plugging of the cerebral arteries 

 in pink eye or pneumo-enteritis. 



The symptoms manifested during life, though not diag- 

 nostic, are similar to those met with in tumours and chronic 

 meningeal disease of the brain, and were spoken of by the 

 older writers as * coma,' or ' sleepy staggers.' 



If the softened patch of the brain substance be examined, 

 it will be found variously altered. 



It will be white, yellow, or pinkish in colour, and of 

 variable consistency. 



Softening, due to arterial plugging and atheroma, is 

 usually met with in old animals. 



HYDROCEPHALUS. — Hydrocephalus {boojp, water ; 

 zi(paXri, the head), or efl'usion of fluid into the ventricles of 

 the brain alone, or into or beneath the arachnoid in addi- 

 tion, is of not uncommon occurrence in the horse. 



In rare instances it is said to be met with sometimes in 

 old animals, but is more frequently met with as a congenital 

 defect in foals. 



