452 DISEASES OF THE PERIPHERAL NERVES 



or abscesses are present they should be operated at once, 

 care being taken to avoid injuring the nerve. In the central 

 form nerve stimulants (strychnin sulphate 0.001 daily), or 

 electricity should be employed. Usually in the course of 

 ten days to two weeks improvement will be noticed. If 

 after one month to six weeks no improvement is noted the 

 chances are that the nerve trunk has been completely 

 destroyed and further treatment is useless. Spasm of the 

 muscles supplied by the facial nerve occurs occasionally, 

 especially in dogs, no doubt due to the infection from dis- 

 temper producing irritation to the nerve. It may also occur in 

 meningitis. and encephalitis. When present the condition is 

 characterized by clonic convulsions of the muscles supplied 

 by the nerve. Sedatives would be indicated to reduce the 

 irritation. 



Trigeminal Nerve. — Paralysis of this nerve is observed 

 most often in dogs. 



Etiology. — (a) Rabies produces the greatest number of 

 cases. Therefore, all cases of trigeminal paralysis should 

 be handled with caution Until the exact cause is known, (b) 

 Occurs in some cases from distemper, (c) Inflammation of 

 the brain and concussion of the brain also cause it. (d) 

 Injuries in which the motor branch is pressed or crushed. 

 This happens not uncommonly in dogs from extreme open- 

 ing of mouth, or carrying large heavy objects in the mouth. 

 (e) Tumor formations, such as sarcomata in close proximity 

 to the nerve, or abscesses. These conditions may either 

 injure the nerve directly or by external pressure. (/) Rheu- 

 matic conditions involving the muscles supplied by the nerve. 

 (g) Neoplasms at the base of the cranium (angioma). 



Symptoms.— The most pronounced symptom is dropping 

 of the lower jaw, the mouth remaining open constantly. In 

 such cases rabies should be suspected. In unilateral paralysis 

 the animal may be able to close the mouth and masticate on 

 one side. If all three branches of the nerve are paralyzed 

 mastication and sensibility are lost. In case any individual 

 branch of the nerve is paralyzed that part supplied by that 

 branch only will be affected. When the mouth -remains 

 open the tongue will protrude, become dry and discolored, 



