DISEASES OF THE NERVOUS SYSTEM 117 



mixed infectious; constipation brought on by improper feed- 

 ing and insufficient exercise is a predisposing cause; injuries 

 such as strains and blows in the region of the back may also cause 

 it ; compression of the spinal cord by the vertebmp is no doubt a 

 very connnon cause ; dislocation, enlargement of the disks between 

 the vertebra", bony enlargements resulting from strains and in- 

 juries, rickets, tuberculosis and actinomycosis and tumors com- 

 monly cause compression of the cord. It is rarely caused by 

 parasites. Young, fat animals are especially prone to injuries 

 in the region of the back. Such animals may suffer from mal- 

 nutrition of the bones, and complete fractures of the thigh bones 

 may occur. Extreme heat from the sun's rays and close, hot 

 quarters are probable causes. 



The symptom that is most prominent is the partial or com- 

 plete loss of control over the movements of the hind parts. The 

 appetite may be little interfered with. The animal may sit on 

 the haunches, with the limbs projecting forward, or swing the 

 hind quarters from side to side in walking or trotting. Irregu- 

 larity in the animal's movements is especially noticeable when 

 turning or backing. In case the animal suffers pain, the spine 

 is held rigid or arched, and when forced to move, marked evi- 

 dence of pain occurs. There may be a decrease or increase in the 

 sensibility of the part. The increase in sensibility is noticed on 

 striking the muscles with the hand or rubbing the hair the wrong 

 way. Spasmodic twitching or contractions in the muscles some- 

 times occur. There is frequent elevation of temperature. The 

 animal is unable to pass urine or fa?ces, or there may be an 

 involuntary passage of the body excretions. 



The outcome of this disease is unfavorable. Acute inflam- 

 mation of the covering of the cord may subside within a few days. 

 Cases that do not recover within a few weeks should be destroyed. 

 Paralysis of the hind parts should not be confused with rheuma- 

 tism, azoturia and other disorders that may interfere with the 

 movements of the posterior portion of the body. 



