DISEASES OF THE BEAIN AND NERVOUS SYSTEM. 151 



peculiarities of this system is that there may be a great derange- 

 ment of function without perceptible alteration of structure. 



fvcnzy, encephalitis, or Ccnbritis. 



This is inflammation of the brain substance. It is fre- 

 quently seen occurring as a sequela to the operation for gid, or 

 following an attack of apoplexy or fractures of the cranium. It 

 is also caiised by exhaustion and exposure or as the result of some 

 specific fever from the blood becoming poisoned. Food of too 

 stimulating a nature, or an excess of coarse, innutritions food- 

 stuffs. Eye-grass tops are apt to cause the disease, especially 

 when overripe. Plethora and exposure to the hot rays of the 

 sun in the summer season are predisposing influences. Lambs 

 are more often afflicted with this disease than grown sheep. 



Sjtnptoms. 



The prmiary symptoms are stupor, the animal being dull 

 and unwilling to move. This stage is rapidly succeeded by more 

 active symptoms. The animal becomes frantic, throwing itself 

 ■about with great violence, the miTcous linings of the eyelids be- 

 come red and congested, the eyes appear to bulge from their 

 sockets, the pupils of the eyes contract, respirations become 

 irregular and bowels constipated. In lambs the violent symp- 

 toms are most marked. They jvimp about continually, their 

 motions appearing ridiculous. A few generations ago when thus 

 affected they were said to be bewitched, and burned alive by good 

 churchmen to exorcise the fiends. Grown sheep when attacked 

 may suddenly spring from the ground and fall dead, or should 

 the attack be prolonged the periods of excitability are alternated 

 with intervals of exhaustion and quiet. During the acute 

 periods the sheep breathes hard and runs about in all directions 

 Avith its tail carried upwards. It will butt in its delirium at men 

 or other sheep or anything which comes in its way. 



