DISEASES OF THE HORSE. 195 



cases tlie symptoms are analogous to those of apoplex}''. The character 

 of the S3'mptoms depends upon the seat of the softening or abscess 

 within the brain. 



Cerebral sclerosis sometimes follows inflammation in the structure 

 of the brain affecting the connective tissues, which eventually become 

 hypertrophied and press upon nerve cells and fibers, causing their 

 ultimate disappearance, leaving the parts hard and indurated. This 

 condition gives rise to a progressive paralysis and may extend along 

 a certain bundle of fibers into the spinal cord. Complete paralj^sis 

 almost invariably supervenes and causes death. 



Lesions. — On making postmortem examinations of horses which have 

 died in the first stages of either of these diseases we will find an exces- 

 sive engorgement of the capillaries and small blood vessels, with corre- 

 spondingly increased redness and changes in both the contents and the 

 walls of the vessels. If death has occurred a^ a later period of the 

 disease it will be found that, in addition to the redness and engorge- 

 ment, an exudation of the contents of the blood vessels into the tissues 

 and upon the surfaces of the inflamed parts has supervened. If the 

 case has been one of encephalitis, there will usually be found more or 

 loss watery fluid in the ventricles (natural cavities in the brain), in the 

 subarachnoid space, and a serous exudation between the convolutions 

 and interstitial spaces of the gra}" matter under the membranes of the 

 brain. The amount of fluid varies in different cases. Exudations of 

 a membranous character ma}^ be present and are found attached to the 

 surface of the pia mater. 



In meningitis, especiall}^ in chronic cases, in addition to the serous 

 effusion, there are changes which maybe regarded as characteristic in 

 the formation of a delicate and highl}^ vascular la3^er or layers of mem- 

 brane or organized structure on the surface of the dura mater, and also 

 indications of hemorrhages in connection with the membranous forma- 

 tions. Hematoma, or blood tumors, may be found embedded in this 

 membrane. In some cases the hemorrhages are copious, causing 

 paralj'sis or apoplexy, followed by speedy death. The meningitis may 

 be suppurative. In this case, a pus-like exudate is found between 

 the membranes covering the brain. 



In cerebritis, or inflammation of the interior of the brain, there is a 

 tendency to softening and suppuration and the formation of abscesses. 

 In some cases the abscesses are small and numerous, surrounded with 

 a softened condition of the brain matter, and sometimes we may find 

 one large abscess.. In cases of recent development the walls of the 

 abscesses are fringed and ragged and have no lining membrane. In 

 older or chronic cases, the walls of the abscesses are generally lined 

 with a strong membrane, often having the appearance of a sac, or 

 C5'st, and the contents have a very offensive odor. 



Treatment. — In all acute attacks of inflammation involving the mem- 

 branes or cerebral masses, it is the pressure from the distended and 



