THE NERVOUS SYSTEM 385 



651. The phenomena of hearing are very interesting, and worth 

 reading up. The same may be said regarding the phenomena of 

 sight. Fortunately, we have very few diseases of the ear in horses. 

 They may, however, get torn or wounded, and are prone to warty 

 growths, which must be removed by operation. Sometimes we have 

 a sinus running up the edge of the ear, the bottom of which has been 

 found to contain a small rudimentary tooth. 



652. Canker is a foetid secretion in the internal parts of the 

 ear, due to inflammation, of a low type, of the lining membrane. 

 Canker in the ear is mostly seen in dogs that have little to do 

 and are over-fed. Heavy-eared dogs, as spaniels and retrievers, 

 seem to be predisposed to it. When affected, the dog holds its head 

 rather to one side, every now and again shaking it and flapping the 

 ears, which it scratches with its feet. On examination, a nasty, 

 foetid discharge is seen in the hollow of the ear. In some cases 

 minute parasites are at times found infesting the ear, and cause 

 similar symptoms. Treatment. — Washing with warm water seems 

 to aggravate and extend the disease. Wipe the affected part as 

 clean as possible with medicated cotton-wool, then put a few drops 

 of creosote or oil of cloves into the ear, and rub well in from the 

 outside ; but the best and most radical treatment is to puff into the 

 bottom of the ear a small quantity of iodoform every third day, at 

 the same time giving a dose of castor oil and syrup of buckthorn, 

 and changing the diet. 



