PARASITIC CANKER OF THE EAR. 381 



gent agents, such as salol in alcohol (1 to 40), tannin in glycerin 

 (1 to 30), nitrate of silver (1 to 100), carbolic acid in glycerin (1 

 to 10). This must be repeated several times, and we may also dry 

 up the secretion by means of oxide of zinc or boric acid. Hoff- 

 mann advises us to use subnitrate of bismuth or sulphate of cop- 

 per in starch. Imminger uses a 3 per cent, aqueous solution of 

 chromic acid in auricular catarrh, cleans the ear with tepid water, 

 and drops ten to twenty drops of the solution into the ear, and 

 then massages the base for several minutes; this he. repeats every 

 second day. As a rule, the general treatment with powders is 

 preferable to that with liquids, but the latter must be used when the 

 meatus is much contracted and the ulcers located deeply. An 

 ear-cap is only necessary when the animal is constantly shaking 

 its head and the organ is very sensitive. We remove the numer- 

 ous granular accumulations by means of nitrate of silver. If 

 there are polypous enlargements, they may be touched with a 

 thermocautery. Hoffmann states that in a very obstinate case 

 he excised the entire lower region of the meatus, introduced a 

 drainage-tube, and treated the wound with disinfecting powder. 



External otitis may sometimes produce either partial or entire 

 deafness. Both of these conditions are due to the entire closure 

 of the external auditory canal, either by swelling and filling up 

 with granulations or by polypous formations, etc., and more rarely 

 by extension of the inflammatory process in the middle ear, destroy- 

 ing the tympanic membrane. Of course, any disturbance of the 

 sense of hearing or entire deafness which comes from old age or 

 is hereditary will not show any of the symptoms already described. 

 When a dog is getting deaf he changes his manner very much: he 

 seems strange, does nob answer to the call of his master. 



As a general rule, there is very little result from treatment. 

 We have a contraction of the external meatus, and may try to 

 dilate it by means of the introduction into the canal of cylindrical 

 compressed tampon sponges. 



Parasitic Canker of the Bar. 

 {Parasitic Otitis.) 



The symbiotes auricularis (canis) is a parasite that inhabits the 

 ear of the dog, causing an aggravated form of canker (Nocard and 



