It consists of a bursa, which, as in the former instance, has been injured, and has consequently enlarged; in appearance and in its subsequent course it greatly resembles capped hock, from which it differs only in a greater liability to ulcerate and become sinuous when allowed to remain until it is of extreme magnitude. It is said to derive that unenviable peculiarity from being situated nearer to the center of circulation. Capped hock is so little disposed to take on such a form of disease that the author cannot remember having seen a case of the kind; with a tumor on the elbow, however, ulceration is unfortunately too common. That probability should forbid the owner to allow the tumor to attain any great size; when large, moreover, it is apt to encircle the elbow-joint, and then its size seems to render the removal apparently impossible. It, however, may be extirpated. All said of capped hock applies to capped elbow. LUXATION OF THE PATELLA. That is displacement of the whirl-bone of the stifle, (which answers to the knee-cap of the human being.) Such an accident, fortunately, few horses incur; there are many veterinary surgeons who, during a practice extending over many years, have not encountered a single case; whereas other gentlemen will have hardly started in their profession before =luxation of the patella= is submitted to their notice. It is not peculiar to any district, it is not confined to any special breed; it may affect all kinds of horses in all sorts of places; for it is produced more by the parsimony or the uncharitableness of mankind than by any fault in the structure of the animal. In several localities throughout the country agriculturists, under the notion of saving money, determine to rear horses on short grass. The creatures are out in the fields during all kinds of weather; the body becomes debilitated under such a starvation system; those parts which are naturally weak become weaker, while those structures which were originally endowed with strength grow comparatively stronger. The beautiful balance of nature is overthrown, and each portion becomes at discord with all the rest; any trivial disease may destroy the life thus at war within its own dominion. Colts frequently exhibit luxation of the patella before they are broken; but it is always provoked by weakness, and commonly only seen where the management is faulty or the food is stinted.