250 DISEASES OF THE LIPS AND CHEEKS. 



covered with iodoform collodion or wound gelatine. Tempel removed 

 a dentigerous cyst from a horse's upper lip. With the exception of 

 those named, new growths on the cheeks and lips are comparatively 

 rare in domesticated animals. Fibromata, sarcomata, carcinomata 

 and melanomata have been seen and operated on with varying success, 

 depending on the kind and age of the tumour. 



Treatment consists in careful removal of the new growths, which 

 is seldom very difficult if the knife be used early and boldly. 



(4.) PARALYSIS OF THE LIPS. FACIAL PARALYSIS. 



The facial is the motor nerve of the muscles of the ears, eyelids, 

 nose, lips, cheeks and subcutaneous muscle of the neck. Arising 

 from the pons, it enters the inner ear with the N. acousticus, passes 

 through the Fallopian canal, and outwards through the stylomastoid 

 foramen of the petrous temporal bone, penetrates beneath the 

 parotid gland, and then passes over the posterior border of the lower 

 jaw, on the external surface of which it divides into several branches 

 which join the superficial temporal nerve to form the subzygomatic 

 plexus. 



Paralysis of the facial nerve occurs rather frequently in horses, 

 but is rarer in oxen and dogs. It is commonly confined to one side, 

 often to the nerve supply of the upper lip ; the deformity consequently 

 is slight, and the mischief may be overlooked. But double-sided 

 paralysis interferes very noticeably with feeding, and therefore with 

 nutrition, while at a later stage the respiration in fast paces may 

 be impeded owing to paralysis of the nostrils. 



The cause is most frequently external injury impairing the con- 

 ductivity of the nerve. The malady is therefore common in horses 

 which, in consequence of colic or injuries to the feet, lie a great deal. 

 Siedamgrotzky first noted that this nerve often becomes bruised at 

 the point where it turns round the lower jaw. The cheek-straps 

 of the head-collar, and especially the buckle at the left side, may 

 easily injure the nerve when the animal is lying. The double-sided 

 paralysis described by Grebe, and erroneously regarded as reflex 

 paralysis, is similarly produced. In earlier times facial paralysis 

 was often caused by inserting hair setons in the cheeks as a remedy 

 for disease of the eye. It occurs during the progress of serious 

 infectious disorders, such as influenza, petechial fever, etc., and may 



