252 DISEASES OF THE NERVOUS SYSTEM 



spinal cord, found as a result of syphilis in man. Friedberger and Froh- 

 ncr thought they found it in the spinal cord of several dogs that had 

 ataxia. The writer is of the opinion that it does not occur in the canine 

 race, for among the thousands of dogs he has posted he has yet to see a 

 case that he could consider was affected with the disease. 



Syringomyelia. — Lienaux describes one case of this peculiar disease, 

 which is characterized by fissures and hollows in the cord. The disease 

 developes very slowly; at the onset we find disturbances of mobility, 

 weakness, paralysis of the posterior extremities, the animal has a peculiar 

 hyena-like walk, urination and defecation remain normal, the appetite 

 is good, sensation in the posterior extremities and later in the anterior 

 extremities is gradually lost. On examining the spine, it is found to 

 contain a number of cavities filled with clear serum; these cavities are in 

 the gray matter, particularly in the posterior section, and in the com- 

 missures of the anterior section of the cervical and dorsal regions. 



Paralysis of the Nerves. 



Paralyzed nerves may be due to some morbid process of the central 

 nervous system, also to traumatisms, such as tearing or bruising of the 

 nerves, or compressing the nerves by neoformations, hemorrhagic ex- 

 travasations, exudates, enlarged lymphatic glands, swollen tissues, dis- 

 located bones, etc. Inflammation and subsequent paralysis of the nerves 

 may also be caused by cold (neuritis rheumatica), by paralysis or paresis, 

 causing an atrophy of a muscle or group of muscles, and in the case of a 

 mixed nerve going to a certain part, to have disorder of sensation, neu- 

 ralgia, or anaesthesia. Convulsions are extremely rare and if they appear 

 would indicate some central pathological process. 



We will take up particularly paralysis of the peripheric nerves. 



Paralysis of the Facial Nerve. — The most frequent cause of this 

 condition is disease of the middle ear, caries of the petrous bone, neo- 

 formations or inflammatory processes of the region of the parotids, 

 traumatisms at the place where the nerve goes around the maxillary 

 or the periphery of the nerve, cold — this latter cause, however is rare; 

 also to pathological processes in the skull and base of the brain, or it may 

 follow as a result of distemper. Generally the affection is unilateral 

 (monoplegia facialis). A bilateral paralysis (diplegia facialis) is in- 

 variably of central origin. 



In the case shown in the accompanying figure (Fig. 97) the symptoms 

 were as follows: The end of the nose, the superior and inferior lip and 

 the chin turned to the right side, the left eye was wide open and could 

 not be closed, the left cheek was relaxed and sunken, the left ear hung 

 downward and backward and could not be lifted by the animal, as was 



