230 DISEASES OF THE BRAIN 



tonoclonic spasms (epileptoid), forced movements, or there 

 may be paralysis (general, hemiplegia, etc.). (5) Changes 

 in the pulse. Variations in the frequency and rhythm of 

 the pulse are observed. Quite often the pulse is slow, due 

 to the effect of increased intracranial pressure upon the 

 vagus. If excitement, fever or heart weakness be present, 

 however, the pulse will be fast and irregular. Marked 

 variations in the frequency and rhythm of the pulse are 

 noted in acute meningitis. (6) Eye symptoms. These are 

 manifested by contraction or, on the other hand, marked 

 dilatation of the pupils. One pupil may be dilated, its 

 fellow contracted. Rolling of the eyeballs (nystagmus) 

 and amaurosis are not unrarely observed. (7) Tendon, 

 skin and pupil reflexes. The tendon reflexes may be 

 increased, especially in chronic brain diseases, if the inhib- 

 itory action of the cortex is out of function. The reflexes 

 may be reduced in some acute brain diseases where the 

 inhibitory function of the cortex becomes on the contrary 

 increased. When coma is present both the skin reflex and 

 pupil reactions become nil and the tendon reflex (patellar, 

 Achilles) reduced to a minimum. 



B. Focal or Topical Symptoms. The knowledge of topical 

 symptoms in animals is very limited. Localized nervous 

 diseases in animals are, however, much rarer than in man. 

 Topical symptoms produce, generally speaking, sensory or 

 motor disturbances. 



The sensory disturbance consists in (a) decreased sensi- 

 bility or hypesthesia; (6) absence of sensibility or anesthesia; 

 (c) increased sensibility or hyperesthesia. 



The motor disturbance induces (a) spasms which may be 

 clonic or tonic; (6) involuntary (forced or unphysiological) 

 movements; (c) disturbance of the muscular sense, causing 

 loss of coordination, unphysiological attitudes, and irregu- 

 larities in gait, or paralysis, which may be complete or 

 partial (paresis), unilateral (hemiplegia), bilateral (para- 

 plegia), or in a single organ or part (monoplegia). Hemi- 

 plegia has its origin m the brain, paraplegia in the spinal 

 cord, and monoplegia may have a central (brain) origin, or 

 may be due to disorder of peripheral nerves. 



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