DISEASES OF THE HOG. 183 



PARALYSIS, PARTIAL PARALYSIS. 



This is a very common disease in the pig most 

 usually affecting the hind parts. Pathological 

 condition : In most cases paralysis is a mere symp- 

 tom of a morbid state existing in some other part 

 than the one apparently affected. It may depend 

 upon disease, either in the nervous centers, incapa- 

 citating them for the reception of impressions or 

 the origination of influence, or in the conducting 

 filaments which form the communication between 

 all parts of the body and these centers. But it 

 may also be strictly local and depend on an altered 

 state of the terminal nerves. The nerve centers 

 are probably in the gray matter of the brain and 

 spinal marrow and the ganglia. The conducting 

 filaments probably make up the white matter of 

 the brain, spinal cord, and nerves. It follows that 

 the true seat of the disease may be in the encepha- 

 lon, the spinal marrow, the conducting nerves or 

 the nerve ramifications of the paralyzed part. 

 (Wood.) J 



I have made a number of post mortem examina- 



e 



tions and also examined the spinal cord and have 

 found in some cases the cord and main nerves of 

 the paralyzed parts enlarged and softened with 

 considerable effusion in the sheaths, and in others 

 atrophied and indurated. In some cases I could 

 detec^ very slight change in the nerve structure. 

 It takes a very slight disturbance in the nerve or 

 its sheath to render it unfit for receiving or send- 

 ing impressions from the brain or from the nerves 

 in the immediate seat of the disease. 



