494 DISEASES OF THE EAR 



Sebaceous Tumors or Cysts.— These are recognized by 

 their rounded, well-defined appearance, absence of inflam- 

 matory symptoms, and the character of the contents. 



Treatment.— The cyst should be opened well, all of the 

 secretions pressed out, and tincture of iodin applied to 

 destroy the gland. It may be necessary in some cases to 

 open into the gland and destroy it by silver nitrate or the 

 actual cautery. 



PARASITES IN THE EAR. 



In the rabbit and dog the Otodectes cvnotis and the 

 Dermatophagus canis are frequently found producing a more 

 or less intensive form of otitis. 



Symptoms.— During the early stage of invasion the symp- 

 toms are not very pronounced. Later as the parasites 

 increase in numbers and they extend farther down into the 

 canal, the patient carries its head at an angle, whines, and 

 rubs its ears against objects. Rabbits often show marked 

 nervous symptoms from the irritation of the internal ear and 

 auditory nerve direct. On examination there will be found a 

 similar condition as in otitis. Tiny white or reddish specks 

 will be visible in the discharge and when examined under a 

 low power microscope or reading glass, the parasites are seen 

 and recognized without difficulty. 



Diagnosis.— This is made positive by the presence of the 

 parasites in the discharge. 



Prognosis.— Favorable. Most cases will recover unless 

 nervous symptoms are present indicating the involvement 

 of the internal ear. Such cases should be considered hopeless, 

 especially in rabbits. 



Treatment.— Local applications have proved quite satis- 

 factory in these cases. Remove all crusts, secretions and 

 debris with a solution of alcohol or ether. Dry the surface 

 by using a swab of cotton or gauze. Apply paraffin oil to 

 the entire surface, or a solution of carbolic acid (5 per cent.) 

 in paraffin oil. Other oleaginous compounds may be used. 

 Thoroughness in the application is important in order to 

 destroy all parasites present. Daily applications are advis- 

 able. 



