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.) 
T have made a number of post mortem examina- 
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 
detect 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. 
