CEREBKAL TUMOURS. 459 



quite incapable of avoiding obstacles or as though absolutely forced 

 to move to the right or left, etc. 



Attacks of giddiness, moreover, are not unusual under the influence 

 of the slightest excitement. During such attacks the animals thrust 

 the head against a wall, or they involuntarily recoil or make lateral move- 

 ments. In many cases these vertiginous attacks end by the animal 

 falling and showing epileptiform convulsions, during which it may die. 

 The symptoms are never the same in two different animals, but 

 they may easily be classed according to the above indications. The 

 indications furnished by the condition of the eyes and by the peculiar 

 impulsive movements are particularly significant. 



On the other hand, there are modifications in breathing without 

 apparent local cause, and difficulty or even impossibility of swallowing, 

 etc., although there exists no material obstacle. 



Diagnosis. The condition is often confused with meningitis, and 

 the mistake is not serious, because meningitis and encephalitis fre- 

 quently accompany one another. 



Prognosis. The prognosis must be regarded as fatal. The patients 

 very seldom recover, and there is no reason for keeping them alive. 



Treatment. Here, again, bHsters may be applied to the upper 

 extremity of the neck, or setons may be passed. Cooling applications 

 to the cranial region have also been suggested. None of these 

 methods produces more than a temporary palliative effect. 



CEREBRAL TUMOURS. 



The brain may be injured and compressed by various tumours of 

 other than parasitic origin. Such tumours may origniate in the 

 bones, the meninges or the choroid plexus, or they may simply be 

 due to generalisation of a previously existing tumour. Whilst of 

 very varied origin and nature, all tumours of the cranial cavity have 

 one common effect, viz., to compress the brain. This continuous 

 compression causes progressive atrophy of the brain, but its exist- 

 ence is not always suspected, because the lesions may not give rise 

 to any marked symptoms. 



The hind portions of the hemispheres and the white substance 

 are generally very tolerant. The front portions, on the other hand— 

 the frontal lobes and the grey substance— resent compression, which 

 provokes various symptoms in consequence. 



The symptoms of compression and atrophy of the bram differ 

 greatly, a fact which is easily understood, inasmuch as the seat of 

 the change may vary, and therefore it is possible only to trace the 

 chief manifestations, which suggest the existence of a cerebral tumour. 



