600 Inflammation of the Pia Mater. 



mater and petechiae, the majority of wliicli are caused by the 

 escape of blood from vessels that have been cut throngh and 

 which may be wiped away. More rarely there are small hem- 

 orrhages which cannot be wiped off. In exceptional cases there 

 may be smaller or larger softened centers. 



Almost without exception the venous plexuses in cases of 

 inflammation of the pia mater appear gelatinous, while the ven- 

 tricles of the brain contain a yellowish, turliid liquid which 

 sometimes contains flocculi or fibrin or even pus (hydrocephalus 

 internus acutus). If the inflammation is confined to the venous 

 plexuses and the choroid plexuses (meningitis internal) the ven- 

 tricle wall is sometimes softened. 



In chronic inflammation of the pia the membrane ap- 

 pears thickened and opaque, especially along the course of the 

 vessels, and it is closely adherent to the cortex. 



Symptoms. Acute meningitis is accompanied by general 

 symptoms of brain disturbance which gradually reach their 

 maximum within a shorter or longer period. At the commence- 

 ment disturbance of consciousness shows itself by the dullness 

 of the animal; they take less notice of their surroundings, but 

 stand wdtli staring eyes and frequently take up unnatural posi- 

 tions. They do not respond to accustomed calls, a sudden noise 

 startles them, but they promptly fall into a sleepy state again. 

 Animals can only be induced to move with difficulty, and while 

 moving are difficult to lead; their movements may be clumsy 

 and stumbling, or in some cases the feet are lifted high and 

 the head is held up. Dogs are particularly restless and fre- 

 quently change their position and attempt to hide themselves. 

 They make no response wdien called and do not recognize their 

 owners. They are likely to snap at one 's hand. 



From time to time and frequently within a few hours of the 

 onset of the disease there are symptoms of excitement and even 

 of mania. Horses attempt to walk through or over any object 

 that may stand in their way; they sometimes stand with their 

 heads pressed up against a wall and move their limbs as if they 

 were w^alking. In many cases they kick and bite at the manger, 

 neigh, rear, move in circles, and finally collapse, or in some cases 

 fall over backwards, by which time they, as a rule, have several 

 wounds about the head and face. In cattle there is sudden rest- 

 lessness, stamping of the feet, the head is held up and the ap- 

 pearance is wild and staring. They bellow, stagger, strike out 

 at any object or person near them with their horns, lash their 

 tails, and climb into the manger. Finally, they go down and 

 general convulsions set in which may be started by a very sliglit 

 external stimulus, and which recur a number of times. In cases 

 of tuberculous meningitis, SA,aiiptoms of excitement are, as a gen- 

 eral rule, absent. Swine utter piercing squeals, root al)out in 

 the straw, and try to climb the walls of the sty, S^miptoms of 

 mania occur far more rarely in the other species of animals. 



