In neglected cases of canker, ulcers form low down in the ear, causing a mattery, offensive discharge. In these cases different treatment is required. The ear should be syringed night and morning with a tablespoonful of methylated spirits added to half a tumbler of tepid water, and then after letting the dog shake his head, the ear should be thoroughly dried with some medicated wool twisted around a bodkin, and then be filled with some finely powdered boracic acid. This is best done by the means of a quill attached to an indiarubber tube, the quill being filled up by being dipped into the powder, and then inserted into the ear, and deposited there by means of blowing through the tube.
Some of these cases are difficult to cure, but with perseverance they get all right in time.
There is another form of canker due to an insect, which I call psoroptes auricularis canis. This is a very minute insect, which collects in large numbers in the canal of the ear, causing the dog to shake his head frequently, and scratch the ear. The canal of the ear looks as if it were full of dry grey powder, but if looked at carefully it will be noticed to be full of very small insects, the size of tiny cheese mites, and they will be seen running about as they are very active. This form of canker is contagious.
Treatment: Syringe the ear thoroughly with a teaspoonful of Pearson’s fluid added to six ounces of tepid water, then carefully dry, and anoint with the following ointment.
The syringing should be repeated about twice a week, and the ointment applied night and morning for a time.
Recipe: The Ointment:
| Salicylic Acid, | 10 grains. |
| Vaseline, | 1½ drachms. |
| Carefully mix. Apply with camel’s-hair brush. | |
As it is very difficult to destroy the eggs of these parasites, it is advisable, even after the irritation has ceased, to continue the ointment two or three times a week for some time, so as to destroy the parasites as they hatch.