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SOFTENING AND ABSCESS OF THE BRAIN. 



This is one of the terminations of cerebritis. It may also be dne to 

 an insiiflicient supply of blood as a result of diseased cerebral arteries 

 and of apoplexy. 



Sympioms. — Drowsiness, vertigo, or attacks of giddiness, increased 

 timidity, or fear of familiar objects, paralysis of one limb, hemiplegia, 

 imperfect control of the limbs, and usually a weak, intermittent pulse. 

 In some cases the symptoms are analogous to those of apoplexy. The 

 character of the symptoms depends upon the seat of the softening or 

 abscess within the brain. 



CEREBRAL SCLEROSIS. 



This is a result of an inflammation in the structure of the brain 

 affecting the connective tissues, which eventually become hypertro- 

 phied and press upon nerve cells and fibers, causing their ultimate 

 disappearance, leaving the parts hard and indurated. 



Sijmpfoms. — This condition gives rise to a progressive paralysis, 

 and may extend along a certain bundle of fibers into the spinal cord. 

 Complete paralysis almost invariably supervenes and causes death. 



PATHOLOGY OF ACUTE BRAIN AFFECTIONS. 



On making post mortem examinations of horses which have died in 

 the first stages of either of those diseases, we will find an excessive 

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

 spondingly increased redn^ess and molecular changes in both contents 

 and the walls of the vessels. If the death has occurred at a later 

 period of the disease, in addition to the redness and engorgement we 

 will find that an exudation of the contents of the blood-vessels into 

 the tissues and upon the surfaces of the inflamed parts has super- 

 vened. If the case has been one of encephalitis we will usually find 

 more or less watery fluid in the ventricles (natural cavities in the 

 brain), in the sub-arachnoid space, and a serous exudation between 

 the convolutions and interstitial si^aces of the graj^ matter under the 

 membranes of the brain. The amount of fluid varies in difl'erent 

 cases. In some where the animal's l)lood was very plastic, exudations 

 of a membranous character may be present and are found attached 

 to the surface of the pia mater. 



In meningitis, especially in chronic cases, iii addition to the serous 

 effusion, we find changes which may be regarded as characteristic in 

 the formation of a delicate and highly vascular laj'er or layers of 

 membrane or organized structure on the surface of the dura mater, 

 and also indications of hemorrhages in connection with tlio mem- 

 branous formations. Haematoma or blood tumors may be found 

 embedded in this membrane. In some cases the hemorrhages are 

 copious, causing paralysis or apoplexy, followed by sjjeedy death. 

 5961— HOR 7 



