CHAPTER X. 



Diseases of the Brain and ^fervous System. 



While the nervous system of the lower order of animals* 

 possibly is not quite so sensitive as that of the human, it is found 

 that the finer bred the animal is the more sensitive the nervous 

 arrangment becomes. Each of the divisions of the nervous sys- 

 tem have phenomena peculiar to themselves, enabling the ob- 

 server to ascertain which becomes involved in disease. The dif- 

 ferent classes of disease being divided according to the parts in- 

 volved, those of the brain being called cerebral, of the spinal cord 

 the spinal, and of the nerves the peripheral. When the brain is 

 involved in disease there is a loss of perception, volition and 

 special sensation. In paralysis of one side of the body, either 

 motor or sensory, the brain is affected, but in cases of transverse 

 paralysis, where the hind limbs are affected or a posterior portion 

 of the carcass, then it is due to disease of the spinal cord, also in 

 cases of incontinence of urine or retention, we conclude the cord 

 to be affected. Where certain localized parts only are paralized, 

 such as a muscle or set of muscles of one portion of the leg, it is 

 due to an affection of the nerves supplying the part, and is 

 termed peripheral. 



Injui-y to the outer or corticle portion of the brain will 

 affect the voluntary motions of the animal, while injuries to 

 the deeper portions affect the involuntary or automatic motion, 

 and severe injury to the vital parts produces instant death by 

 causing paralysis or suspension of the vital functions. All in- 

 juries embracing the whole system produce either excitation and 

 increased nervous excitability or paralysis. One of the greatest 



