434 DISEASES OF THE EAR 



there is no doubt that the quickest results may be obtained l^y cutting 

 off a portion of the diseased IoIdc of the ear; this, however, disfigures the 

 animal very much. This operation is generally performed on animals 

 under the influence of ether. First remove the hair and thoroughly 

 disinfect the parts and cut off a circular piece from the ear that will 

 include the torn portion, being careful not to remove any more of the 

 lobe than is actually necessary. Another method is to cut off the edges 

 of the slit ear a thin section about one-eighth of an inch in thickness, 

 so as to insure two raw fresh surfaces. The two edges of the wound 

 must then be drawn together by means of sutures. These should not 

 be inserted too close to the edge of the wound, as they are apt to tear 

 through. The stitched line is then powdered with sulphonal. The 

 external ear is covered with wadding, turned over the top of the head, 

 and held in position by means of a bandage, as indicated in Fig. 152 

 and 153. 



The writer has been able to obtain satisfactory results in slight cases 

 of external otitis and canker by covering the ulcer with oxide of mercury 

 and tying the ear in a cap. 



Inflammation of the External Auditory Canal — Internal Canker. 



{Otitis Externa.) 



This consists of an inflammatory irritation of the external canal of 

 the ear. It occurs most frequently in dogs with long ears. It is gen- 

 erally of an eczematous nature and appears in a diffuse form, extending 

 over a larger part of the lining of the ear. It is accompanied by redness, 

 swelling of the membrane, and an exudation of a serous, and, later in 

 the chronic course, a purulent secretion. It involves the papillary 

 body and the wax secreting glands of the ear. The skin is tumefied, red 

 and warm; there is abundant epithelial desquamation; the ceruminous 

 glands secrete a very much increased amount of al^normal wax, which 

 collects with the secretion of the ear. In some cases the discharge becomes 

 purulent and is found lying in the ear in the form of a viscous fluid, vary- 

 ing in color from yellowish-brown, gray-brown, yellow-brown, or dark 

 brown. This discharge may irritate the skin of the lower part of the ear, 

 causing an erythema. We may also have the formation of abscesses 

 and contraction of the meatus (caused by thickening of the cutis, by 

 granulations, and by polypus malformations). We may have acute 

 inflammation of the canal extending deep into the lining, and perforations 

 of the tympanum and irritation of the Eustachian canal and discharge of 

 pus into the pharynx. Abscesses of the parietal bone have been observed. 



Etiology. — The causes are similar to those mentioned under eczema. 

 It is due to an accumulation of cerumen, dirt, cutaneous scabs, and 



