210 DISEASES OF THE HORSE. 



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

 the base of the brain. 



Local paralysis. — This is frequently met with in horses. It may- 

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

 frequently overlooked in diagnosis. 



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

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

 muscles, the portio dura. The cause may exist at the base of the 

 brain, compression along its course after it leaves the medulla oblon- 

 gata, or to a bruise after it spreads out on the great masseter muscle. 



Symptoms. — A flaccid condition of the cheek muscles, pendulous 

 lips, inability to grasp the food, often a slow and weak movement in 

 chewing, and difficulty and slowness in drinking. 



Laryngismus paralyticus., or roaring. — This condition is character- 

 ized by roaring, and is usually caused by an inflamed or hypertro- 

 phied bronchial gland pressing against the left recurrent laryngeal 

 nerve, which interferes with its conducting power. A similar con- 

 dition 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 generally 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 muscles belonging thereto. This facture would not be suspected 

 were it not for the loss of motion of the tail. 



Intestinal paralysis. — Characterized by persistent constipation; 

 frequently the strongest purgatives have no effect whatever on the 

 movement of the bowels. In the absence of symptoms of indigestion, 

 or special diseases implicating the intestinal canal, torpor of the 

 bowels must be attributed to deficient innervation. This condition 

 may depend upon brain affections or be due to reflex j^aralysis. Sud- 

 den checks of perspiration may induce excessive action of the bowels 

 or paralysis. 



Paralysis of the hladder. — This usually affects the neck of the blad- 

 der, and is characterized by incontinence of urine; the urine dribbles 

 away as fast as it is secreted. The cause may be of reflex origin, 

 disease of the rectum, tumors growing within the pelvic cavity, injury 

 to the spinal cord, etc. 



Paralysis of the optic nerve, or amaurosis. — A paralysis of eyesight 

 may occur very suddenly from rupture of a blood vessel in the brain, 

 acute local congestion of the brain, the administration of excessive 

 doses of belladonna or its alkaloid atropia, etc. In amaurosis the 

 pupil is dilated to its full extent, the eye looks clear, but does not 

 respond to light. 



