EXTERNAL CANKER. 359 



on the pillar reins. If the dressing remain dry, it should be left in 

 position for about a week. In ulceration of the cartilage, it is of 

 first importance to prevent the head being shaken. This can be 

 effected by bandaging the ears to the head, but preferably by the 

 treatment recommended in inflammation of the external auditory 

 meatus. Careful cleansing of the ulcer, followed by cauterization 

 with the iron or strong carbolic acid, and dressing the sore with 

 iodoform-collodion may prove successful. 



Cellulitis in dogs usually subsides in a few days after the appli- 

 cation of Goulard's extract or dilute solution of lead acetate. 

 Scarification and disinfectant applications are of assistance in the 

 early stages in pigs, but, if somnolence has appeared or suppuration 

 set in, destruction of the external or even of the middle ear often 

 follows and treatment is hopeless. For this reason fat pigs should 

 be slaughtered at an early stage. 



(2.) OEDEMA OF THE EXTERNAL EAR. OTHEMATOMA. 



Rupture of blood-vessels, and extravasation of blood between 

 the cartilage and skin of the external ear, is often brought about in 

 long-eared dogs by the ears being rubbed or bitten, but more frequently 

 from their being vigorously shaken to allay irritation arising from 

 otitis or caused by a foreign body. As a rule, the rupture occurs 

 under the perichondrium, and the condition, therefore, in the dog 

 consists of sub-perichondrial blood extravasation. This usually 

 remains fluid for a time, appears oftenest on the inner surface, less 

 frequently on the outer, at times on both. From the position of the 

 lesion, absorption is slow and usually incomplete. 



Hoffmann, misled by the above facts, erroneously regarded the 

 extravasate as consisting of lymph. 



Symptoms. The dog holds its head on one side, and examination 

 reveals a slightly painful, fluctuating swelling, sharply defined, 

 rounded or longish, and varying in size from a bean to an orange. 

 An incision liberates fluid or clotted blood, and displays the yellow 

 white surface of the cartilage, which later becomes covered with 

 granulations, which appear as little discrete red flecks, and gradually, 

 during perhaps several weeks, spread over the exposed surface. 

 Healing is tardy, and the parts generally remain thickened. Where 

 the swelling is not opened it may persist indefinitely, and produce 

 marked distortion. 



Treatment. In slight haematoma, absorption may be produced 

 by massage, though operation is usually preferable. The inner 



