The blain is a vesicular enlargement on the lateral and under part of the tongue in horses, oxen, and dogs, which, although not of unfrequent occurrence, or peculiarly fatal result, has not been sufficiently noticed by veterinary authors. In the horse and the dog it is often unaccompanied by any previous indisposition, or by other disease; but suddenly there is a copious discharge of saliva, at first limpid and without smell, but soon becoming purulent, bloody, and exceedingly fetid. On examination, the tongue is found apparently enlarged. It is elevated from its base between the maxillary bones, and on the side and towards the base of it are seen large vesicles, pellucid, red, livid, or purple; and, if the discharge is fetid, having near their bases ulcers, irregular, unhealthy, and gangrenous. In the horse and the dog the progress of the disease is slow, and seldom extends beyond the sides of the tongue. The vesicles are not of such magnitude as to interfere with respiration, and the ulcers are neither many nor foul. In cattle it is sadly different. The vesicles attain an enormous size. They quickly break and form deep ulcerations, which are immediately succeeded by other vesicles still larger. The whole membrane of the mouth becomes affected; the inflammation and swelling extend to the cellular substance of the neighbouring parts, and the head and neck are considerably, and sometimes enormously, enlarged; the respiratory passages are obstructed; the animal breathes with the greatest difficulty, and is, in some cases, literally suffocated. The primary seat of blain, is the cellular substance beneath the integument of the part. As the sublingual glands stretch along the under part of the tongue, and their ducts open on the side of the frænum, it is possible that this disease may proceed from, or be connected with, obstruction or inflammation of these ducts. Dissection, however, has not proved this; and the seat of the disease, when the swellings are first discovered, is chiefly the cellular tissue between the integument and the lateral parts of the tongue, and also that between the membrane of the mouth and the sublingual glands. 'Post-mortem' examination shows intense disease: the small intestines are highly inflamed with red and black patches, which are also found in the c¾cum, colon, and rectum. The blain is more frequent in spring and summer than at other seasons of the year. These are the times when the animal is debilitated by the process of moulting, and is then more than usually disposed to inflammatory complaints. It is usually an epidemic disease. Many cases of it occur about the same time in certain districts, and over a great extent of country. When it appears in towns, the country is rarely exempt from it. I am not prepared lo say that it is contagious either in the horse or the dog. I have not seen any instance of it. At all events, it is not so virulent in these animals as it is in cattle.