All water-dogs, and some others, are subject to a disease designated by this name, and which, in fact, is inflammation of the integumental lining of the inside of the ear. When the whole of the body, except the head and ears, is surrounded by cold water, there will be an unusual determination of blood to those parts, and consequent distension of the vessels and a predisposition to inflammation. A Newfoundland dog, or setter, or poodle, that has been subject to canker, is often freed from a return of the disease by being kept from the water. The earliest symptom of the approach of canker is frequent shaking of the head, or holding of the head on one side, or violent scratching of one or both ears. Redness of the integument may then be observed, and particularly of that portion of it which lines the annular cartilage. This is usually accompanied by some enlargement of the folds of the skin. As soon as any of these symptoms are observed, the ear should be gently but well washed, two or three times in the day, with lukewarm water, and after that a weak solution of the extract of lead should be applied, and a dose or two of physic administered. If the case is neglected, the pain will rapidly increase; the ear will become of an intenser red; the folds of the integument will enlarge, and there will be a deposition of red or black matter in the hollow of the ear. The case is now more serious, and should be immediately attended to. This black or bloody deposit should be gently but carefully washed away with warm water and soap; and the extract of lead, in the proportion of a scruple to an ounce of water, should be frequently applied, until the redness and heat are abated. A solution of alum, in about the same quantity of alum and water as the foregoing lotion, should then be used. Some attention should be paid to the method of applying these lotions. Two persons will be required in order to accomplish the operation. The surgeon must hold the muzzle of the dog with one hand, and have the root of the ear in the hollow of the other, and between the first finger and the thumb. The assistant must then pour the liquid into the ear; half a tea-spoonful will usually be sufficient. The surgeon, without quitting the dog, will then close the ear, and mould it gently until the liquid has insinuated itself as deeply as possible into the passages of the ear. Should not the inflammation abate in the course of a few days, a seton should be inserted in the poll, between the integument and the muscles of the occiput, reaching from ear to ear. The excitement of a new inflammation, so near to the part previously diseased, will materially abate the original affection. Physic is now indispensable. From half a drachm to a drachm of aloes, with from one to two grains of calomel, should be given every third day.