INFLAMMATION OF THE EXTERNAL AUDITORY MEATUS. 361 



Symptoms. Otorrhoea may be acute or chronic, and unilateral 

 or bilateral. The acute affection develops in the dog as a sequel 

 to eczema of neighbouring parts, or follows infection of the meatus. 

 The lining of the external ear is hot, red and painful. An offensive 

 yellowish-brown secretion, usually mixed with pus, runs from the 

 ear, and excoriates the skin below. The dog frequently shakes the 

 head, and rubs or scratches the ear. Some patients vomit ; others 

 exhibit symptoms of nerve irritation. Proper treatment often. results 

 in recovery in eight to fourteen days. 



In neglected cases chronic otorrhoea develops. It may be divided 

 into two forms, superficial and deep. The first is commonest in dogs, 

 and owes its origin to irritation produced by infection and decomposing 

 secretions. Abnormal pruritus is present ; the unpigmented skin 

 of the meatus is reddened, and covered with a blackish-brown fatty 

 material ; light pressure at the base of the cartilage produces an 

 agreeable sensation, the animal leaning towards the operator, and 

 holding the head on one side. A bubbling sound may perhaps be 

 heard, owing to motion of the fluid contents of the ear. After some 

 time the secretions become yellowish-brown, and excoriated spots 

 appear in the depths of the meatus. In the deep form one meets 

 with a purulent discharge ; granulations appear on the surface of the 

 diseased meatus, and necrosis of the petrous temporal bone may ensue. 

 Sometimes pus formation preponderates ; sometimes the formation 

 of granulations. The latter may obliterate the external opening. 

 Perforation of the tympanum and otitis media are rare. Whilst 

 irritation disappears early in the chronic superficial form, the deep 

 form is usually accompanied by greater pain. Frohner records 

 vomiting in dogs, which he referred to irritation of the ramus 

 auricularis of the vagus nerve. Implication of the middle ear or 

 brain may produce epileptiform fits and other brain symptoms ; 

 but, considering the frequency of such ear diseases in dogs, these 

 complications are seldom observed. Masch describes such a case 

 in the horse, which showed a purulent discharge containing fragments 

 of bone from the external ear. The horse was killed, and on post- 

 mortem examination was found to be suffering from necrosis of the 

 petrous temporal bone and an abscess under the dura mater. 



Prognosis. Acute otorrhoea is readily curable, but the chronic 

 form is often extremely obstinate. In the superficial form care and 

 perseverance will usually succeed, but the deep form in old dogs 

 may be incurable ; the more profuse the discharge of pus, the less 

 the chance of recovery. 



The treatment of acute otorrhoea consists in repeated cleansing 



