DISEASES OF THE NERVOUS SYSTEM. 313 



tion, are among the chief causes of sclerosis. It has 

 been observed that the families of animals so affected 

 were subject in some instances to various nervous affections, 

 such as spasms, which were generally of a choreic nature. 

 Sclerosis may also follow as a sequel of some affections, such 

 as certain fevers or inflammatory actions involving various 

 parts of the nervous system. 



Symptoms. — When the sclerosis involved the lobes of 

 the cerebellum, it was noticed that the animal showed a 

 tendency to execute gyratory movements, and had spas- 

 modic contractions of the muscles of the eyeballs. 



In all scleroses in the first instance, the motor power 

 appeared to be more affected than the sensory. 



Morbid Anatomy. — Pale greyish patches of varying 

 extent may be found at the seat of disease. These changes 

 have been observed especially on the lateral lobes of the 

 cerebellum. In one case under our notice these changes 

 were confined [to the left lobe of the cerebellum ; the 

 cerebral hemispheres were healthy. 



Sclerosis of the nerve-tissue is characterized by the growth 

 of a large quantity of fibrous tissue, and by atrophy and de- 

 generation of the nerve-elements themselves. 



The tissue resembles such as is formed in productive in- 

 flammation, and sclerosis has in consequence been regarded 

 as of inflammatory origin. 



Some authorities, however, view the increase of connective- 

 tissue as due to hyperplasia of the neuroglia, the cause 

 being unknown (Green). 



Treatment. — Nux vomica, or its alkaloid strychnine, with 

 other vegetable tonics and iron, in conjunction with a good 

 nutritious diet, are likely to prove beneficial, though com- 

 plete recovery is perhaps only to be expected in very excep- 

 tional instances, where the nervous changes have not made 

 any great progress. 



