210 DISEASES OF THE BRAIN 



plegia, 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 intra- 

 cranial 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 

 inhibitory 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. Where coma is present both the skin reflex and 

 pupil reactions become nil and the tendon reflex (patellar, 

 Achilles) reduced to a minimum. 



(5) Topical or focal 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 ; (b) absence of sensibility or anesthesia; 

 (c) increased sensibility or hyperesthesia. 



The motor disturbance induces (a) spasms which may.be 

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

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

 loss of coordination, unphysiological attitudes, and irregulari- 

 ties in gait, or paralysis, which may be complete or partial 

 (paresis), unilateral (hemiplegia), bilateral (paraplegia), or 

 in a single organ or part (monoplegia). Hemiplegia has its 

 origin in the brain, paraplegia in the spinal cord, and mono- 

 plegia may have a central (brain) origin, or may be due to 

 disorder of peripheral nerves. 



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