BROKEN KNEES. 409 
horse is down there always exists an impetus which has a tendency to 
propel the body forward. Should the skin of the knees be divided by 
the fall, the after-foree obviously cannot affect the upper line of such 
division; but the lower edge of skin will present an acute obstacle to 
the roughened ground, and will, by the grating of the body, in all prob- 
ability be rent from its attachments. When the animal rises, the action 
and the elasticity natural to the integument will occasion the torn por- 
tion of the skin which has been driven backward to once more assume 
its original position. By this means a kind of bag or purse is formed 
upon the knee. Grit, mud, and all kinds of impurities may be retained 
and concealed within this pouch. These will be disposed to irritate the 
structure with which they are in contact; suppuration is certain to be 
established, and sad consequences have followed such sacs not being 
early detected. 
Such a cavity having been discovered, the next object is to ascertain 
its dimensions. That is done by gradually moving the probe along its 
sides. Should it be small, it will be sufficient that a hole be made 
through its most depending portion with a sharp seton needle. If it 
be large, the needle should be armed with a piece of tape knotted at 
one end. The sac being punctured, the needle is to be drawn through 
the opening, the tape being left in the cavity, and a seton is thus formed. 
PROBING THE SAC OF A BROKEN KNEE. A SETON BEING INSERTED THROUGH 
THE SAC OF THE KNEE. 
The seton should be knotted at the other end, and moved its entire 
length every night and morning. It will prevent all premature attempts 
to heal, will stimulate the soft parts to suppuration, and will remove the 
dirt, as the tape affords a guide to the secretion. When inserting a 
seton into the knee, always use a large curved needle. The size of the 
instruments should never be regulated by any foreign standard, but 
should always be proportioned to the magnitude of the patient and the 
intention of the operator. 
