LUXATION OF THE PATELLA. 325 
It consists of a bursa, which, as in the former instance, has been 
injured, and has consequently enlarged; in appearance and in its subse- 
quent 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 encir- 
cle the elbow-joint, and then its size seems to render the removal appar- 
ently impossible. It, however, may be extirpated. All said of capped 
hock applies to capped elbow. : 
A 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. 
When the whirl-bone is displaced, it is always found as an unnatural 
