The term canker is certainly a convenient one, as the older authors found it quite sufficient to designate a variety of affections of the ear, distinct in character, occurring in different locations, and arising from a variety of causes. Some recent writers have attempted a different classification, but their selections are equally objectionable, and it seems expedient to still recognize the term canker sanctioned by common acceptation.

The disease is really an inflammation of the lining membrane of the auditory canal or passage, which extends from the large cavity of the external ear inward to the drum membrane.

Causation

Among the many causes which may be assigned as inducing canker are cold, digestive disorders, improper food, over feeding with insufficient exercise, the accumulation of the natural secretion in the ear, and possibly, blows.

It may accompany skin diseases, or it may be a sequel of any exhausting illness. During a long run and when overheated, dogs will frequently plunge in stagnant pools, and dirt and mud will lodge in the outer ear and give rise to the affection.

Eruptions sometimes appear on dogs suffering from a prolonged and severe attack of distemper.. The passages to the ears are often invaded by these pustules, and canker results.

Symptoms

Unless the ears of dogs are frequently and carefully examined, the affection is likely to have existed for some days before attention is attracted. The symptoms observed in an animal suffering from canker are his restlessness, frequent scratching of his ear, and violent shaking of his head. On examination the skin in the outermost part of the ear passage is found red, hot, and some swollen.

The irritation may be confined to the parts forming the external cavity, a condition designated by some as " external canker".

The tendency of the disease is to invade the innermost portions of the tube, becoming then the so called "internal canker".

The disease may have its origin either without or deep within the passage. In the latter little or no redness or swelling will be visible, but an offensive odor and a discharge is characteristic evidence.

The inflammation if uncontrolled results in an ulceration, recovery from which is often tedious and delayed.

Treatment

It is difficult for the writer to appreciate why the older authors gave to canker that importance with which they invested it in their works on canine diseases.

No less amazing is the treatment they employed, which possibly is a solution of the enigma, for remedies such as many advised, could only have aggravated the disease and retarded recovery.

The first law to be religiously complied with is perfect cleanliness; very many oases in their early stages will yield to that treatment alone.

This fact must bo remembered in the selection of medicines to be applied within the ear, no more delicate organ exists in the body, and none are more easily injured by wanton applications. An eminent aurist once thus advised a patient, who was addicted to using a small ear spoon to clear the passage "Never put anything into your ear but your elbow," advice which if followed, would materially lessen suffering and save many their hearing unimpaired.

To insure cleanliness the outer ear should be frequently sponged with soap of an unirritating nature, and warm water. If the passage has been invaded by the inflammation, water must be gently injected, sufficient in quantity to remove all discharge and everything foreign within. It matters little the syringe used, provided it be large and easily managed; those small glass affairs are an abomination. The ear should be syringed several times daily and after the operation the following used. -

℞ Acid. Carbolici ℥ ss Glycerinae ℥ ss.

Aquae ℥ ijss.

Ft. Mist. Sig. Drop a little in the ear.

Neither this nor any other application should be used cold, but it should be of the same temperature as the body.

In syringing the water should be warm; a good method to estimate properly how hot it can be comfortably borne by the animal, is for the operator to inject some against his own cheek, which is far more sensitive than his hand.

If frequent syringing does not relieve the pain and itching, it will be well to use the following -

℞ Bromo-Chlorali.

Tr. Opli aa ℥ i.

Aquae ℥ vi.

Ft. Mist. Sig. Drop in the ear.

This preparation can be alternated with the first one advised, using one, then two or three hoars later the other.

When there is much discharge the powdered boracic acid dropped in the ear is productive of good results.

If canker is confined to the outer cavity and flap of the ear, accessible to direct application, stronger remedies can be safely used. If the parts are simply red and inflamed, cleanliness and applications of the following will suffice. -

℞ Acid Carbolici ℥ i Glycerines ℥ i.

Ft. Mist. Sig. Faint the affected part several times daily after sponging.

If an ulceration exists, it will be well to cauterize with the stick nitrate of silver or concentrated carbolic acid, after which the paint can be applied.

While recognizing the fact that in a majority of cases of canker there is some associate general affection which demands treatment, the need to follow the stereotyped rule of first giving a cathartic is not appreciated by the writer, unless the conditions are favorable and there is good and sufficient reason for it.

If the animal is overfed and plethoric, or if some fever attends, then certainly a purgative is demanded; but if on the other hand he is debilitated by a long illness, or some rapidly exhausting disease, it were much better withheld.

In debility, iron, quinine, or cod liver oil with a generous and nutritious diet is indicated.

Whatever disease may be associated, its treatment is not influenced by the presence of canker, but constitutional remedies are to be administered as the need is manifested.