LOCAL DISEASES. 329 



diseases being specific or peculiar only in so far as tliey have 

 this common morbid action, in their case modified in its mode 

 of development, course, or results, or in their having some- 

 thing added thereto. 



In this group of diseases we have not to look for any defi- 

 nite or specific morbid condition of the blood ; nothing extra 

 and morbid added to the circulating fluid, and propagating 

 itself indefinitely in it, or transformed and eliminated in the 

 diseased local process ; nor yet to a peculiar disturbance of the 

 equihbrium usually subsisting amongst the constituent ele- 

 ments of the blood. The diseased action is simple, uncompH- 

 cated, and unattended with the formation or development of 

 any material capable of continuing in a healthy animal body 

 a similar disordered process. 



CHAPTER 11. 



diseases of the nervous system. 



General Remarks — Localization of Nervous Diseases. 



Although the functions presided over by the organs or struc- 

 tures entering into the formation of the nervous system are 

 both numerous and varied, embracing perception, volition, 

 special sense, motor-power, and common sensation, the list of 

 diseases taken cognizance of in veterinary pathology as in- 

 trinsically or primarily belonging thereto, is less extensive than 

 that connected with the majority of the other systems or 

 groups of organs of which the animal machine is made up. 

 From this alone, however, we are not to imagine that the 

 diseases of this system are of so much rarer occurrence ; the 

 reason of this paucity in description is rather to be looked for 

 in the fact that with its physiology or functional activity in. 

 health, the pathology or conditions of action in disease are yet 

 less fully and accurately known than that of many other 

 organs and systems. Owing to the absence of psychical in- 

 fluences, the number and variation of diseases originating in 

 the mass of nervous matter situated within the cranium is 

 much fewer in our patients than in ourselves. 



