DISEASES OF THE HOKSE. 209 



disease of peripheral nerves, to spinal irritation or congestion caused 

 by blood poisons, etc. 



Symptoms. — When due to mechanical injury of the spinal cord, from 

 a broken back or spinal hemorrhage, it is generally progressive in its 

 character, although it may be sudden. When it is caused by agents 

 in the blood, it may be intermittent or recurrent. 



Paraplegia is not difficult to recognize, for it is characterized by a 

 weakness and imperfect control of the hind legs and powerless tail. 

 The urine usually dribbles away as it is formed and the manure is 

 pushed out, ball by ball, without any voluntary effort, or the passages 

 may cease entirel}^. When paraplegia is complete, large and ill- 

 conditioned sores soon form on the hips and thighs from chafing and 

 bruising, which have a tendency to quickly weaken the animal and 

 necessitate his destruction. 



Locomotor' ataxia, or hicoordlnation of onovement. — This is charac- 

 terized by an inability to control properly the movement of the limbs. 

 The animal appears usually perfectly healthy, but when he is led out 

 of his stall his legs have a wobbly movement, and he will stumble or 

 stagger, especially in turning. When this is confined to the hind parts 

 it may be termed a modified form of paraplegia, but often it may be 

 seen to affect nearly all the voluntary muscles when they are called 

 into play, and must be attributed to some pressure exerted on the base 

 of the brain. 



Local j)aralysis. — This is frequently met with in horses. It may 

 affect many parts of the body, even vital organs, and it is very fre- 

 quently overlooked in diagnosis. 



Facial jparalysls. — This is a frequent type of local paralysis, and is 

 due to impairment of function of the motor nerve of the facial muscles, 

 ihcj^ortlo dura. The cause may exist at the base of the brain, compres- 

 sion along its course after it leaves the medulla oblongata, or to a 

 bruise after it spreads out on the great masseter muscle. 



Sy7nptoms. — A flaccid condition of the cheek muscles, pendulous lips, 

 inabilit}^ to grasp the food, often a slow and weak movement in chew- 

 ing, and difficulty and slowness in drinking. 



Laryngismus paralytieiis, or roaring. — This condition is characterized 

 by roaring, and is usually caused by an inflamed or hypertrophied 

 bronchial gland pressing against the left recurrent laryngeal nerve, 

 which interferes with its conducting power. A similar condition is 

 occasionally induced in acute pleurisy, where the recurrent nerve 

 becomes involved in the diseased process or compressed by plastic 

 exudation. 



Paralysis of the rectum and tail. — This is generall}^ the result of a- 

 blow or fall on the rump, which causes a fracture of the sacrum bone 

 and injury to the nerves supplying the tail and part of the rectum and 



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