CHAPTER XXXVIII. 



SPORADIC DISEASE S—conti7iued. 



LOCAL DISEASES. 



Local diseases are those wliich have their primary seat and 

 origin in any one tissue, function, or organ. They are sporadic 

 diseases, and are generally, but not always, associated with con- 

 stitutional disturbance, which, however, depends upon, and is 

 secondary to, the original local affection. 



(A.) DISEASES OF THE NEEVOUS SYSTEM. 



EPILEPSY — CHOREA. 



Compared with the nervous diseases of man, those which 

 affect the lower animals are few and insignificant. This can be 

 accounted for in a variety of ways, but more particularly by the 

 absence of the higher mental functions in the lower animals, and 

 " in the way of life," from their non-participation in the excite- 

 ments, jjleasures, hopes, and fears, as well as in the indidgences 

 of the human race. 



There are certainly some instances of what might be considered 

 aberrations of intellect or morbid fancies in the lower animals, 

 more particularly in the dog, by which the docile become fero- 

 cious, the good-tempered extremely irritable, the intelligent 

 stupid or listless. 



Animals also vary in degree of mental power: some are 

 sharp, intelligent, easily taught, possessed of good memories, and 

 are capable of manifesting a great degree of affection to those 

 around them ; while others are dull, hard to teach, liave bad 

 memories, and seem to live for themselves only. Notwith- 



