122 DISEASES OF THE EAR. 



Otitis, Me<di& o<R Interna. 



It is to be understood that the membrana tympani, or drum membrane 

 of the ear, is the division between the so-called external and middle ear. 

 In treating of the affection which we were obliged to call canker, owing 

 to the difficulty and inconvenience of displacing it, inflammations of the 

 external ear were alone considered. There remains affections of the tym- 

 panum and internal ear to be described. 



Otitis is strictly the proper name to apply to inflammations of the ear in 

 general ; to this may be added terms to distinctly designate the particular 

 locality and structure affected. 



In a general way the ear may be divided thus : external, middle or inter- 

 nal. Still other subdivisions might be made, but they are needless in this 

 work and would simply tend to confuse the reader. The middle ear is the 

 space internal to the drum membrane, and the internal ear is beyond that 

 and comprises the deeper structures. Properly inflammations of the ear 

 should be denominated thus : otitis externa, media or interna. 



As the first has already been considered as canker, there now remains to 

 be described otitis, media or interna. In this disease the cavity of the ear 

 becomes inflamed, involving the drum and generally the external ear, and 

 invading the cells and inner structures. The inflammation may be con- 

 fined to the mucous membrane alone, or with it the membrane covering 

 the bone and even the bone itself may become affected. 



Causation . —The usual causes are exposure to cold, sudden chills such 

 as may result from plunging into the water and remaining too long, vio- 

 lent injuries and blows in the region of the ear, and foreign bodies in the 

 external passage. Powerful chemical liquids which have been poured 

 into the ear, accidentally or for the purpose of treatment, may so irritate 

 the drum that deep seated inflammation will result. 



The disease may have its origin in the middle ear or it may follow the 

 profuse purulent discharge of a severe attack of canker, which Anally 

 ulcerates through the drum and gains entrance to the cavity within. 



Certain constitutional conditions and disturbances furnish predispos- 

 ing causes for this affection. When the blood is impoverished and the 

 system debilitated by long tedious illnesses, otitis is more prone to occur. 



Symptoms . —The disease almost always commences suddenly, attack- 

 ing one ear, but never both at the same time. Pain which marks the inva- 

 sion of the inflammation is intense and rapidly increasing in severity, 

 eventually becoming so torturing as to cause the animal to shake his head 

 violently, rub his ear along the ground, and utter incessant, sharp, shrill, 

 car piercing cries. He seems distracted and cannot be tranquillized. 



These violent local symptoms are attended with disturbances of the 



