The following is a singular case of this disease:--1st July, 1820 a dog was sent with a tumour, evidently containing a fluid, in the flap of the ear. A seton had been introduced, but had been sadly neglected. The hair had become matted round the seton, and the discharge had thus been stopped. Inflammation and considerable pain had evidently followed, and the dog had nearly torn the seton out. I removed it, washed the ear well, and applied the tincture of myrrh and aloes. The wound soon healed. On the 14th the ear began again to fill. On the 17th the tumour was ripe for the seton, which was again introduced, and worn until the 9th of August, when the sides of the abscess appeared again to have adhered, and it was withdrawn. Canker had continued in the ear during the whole time; and, in defiance of a cold lotion daily applied, the ear was perceived again to be disposed to fill. The seton was once more inserted, and the cyst apparently closed. The seton was continued a fortnight after the sinus was obliterated, and then removed. Six weeks afterwards the swelling had disappeared, and the canker was quite removed. This anecdote is an encouragement to persevere under the most disheartening circumstances. All dogs that are foolishly suffered to become gross and fat are subject to canker. It seems to be a natural outlet for excess of nutriment or gross humour; and, when a dog has once laboured under the disease, he is very subject to a return of it. The fatal power of habit is in few cases more evident than in this disease. When a dog has symptoms of mange, the redness or eruption of the skin, generally, will not unfrequently disappear, and bad canker speedily follow. The habit, however, may be subdued, or at least may be kept at bay, by physic and the use of Goulard lotion or alum. Sportsmen are often annoyed by another species of canker Pointers and hounds are particularly subject to it. This species of canker commences with a scurfy eruption and thickening of the edges of the ear, apparently attended by considerable itching or pain. The dog is continually flapping his ear, and beating it violently against his head. The inflammation is thus increased, and the tip of the ear becomes exceedingly sore. This causes him to shake his head still more violently, and the ulcer spreads and is indisposed to heal, and at length a fissure or crack appears on the tip of the cartilage, and extends to a greater or less distance down the ear. The narration of one or two cases may be useful, as showing the inveteracy of the disease. 8th Feb. 1832.--A Newfoundland dog, very fat, had dreadful canker in both ears, and considerable discharge of purulent matter. He was continually shaking his ears, lying and moaning. Apply the canker lotion, and give the alterative balls. 13th. The discharge considerably lessened from one ear, but that from the other has increased. Continue the lotion and apply a seton.