352 DISEASES OF THE HORSE'S FOOT 



of the operation as originally introduced. In all, however, 

 the preliminary steps are the same. We shall therefore 

 describe them collectively, as applying correctly to either of 

 the three methods of operating we are about to show. 



Preparation of the Subject and Preliminary Steps in the 

 Operation. — On the day previous to the operation the horn 

 of the wall immediately over the cartilage must be so 

 thinned with a rasp as to yield readily to pressure of the 

 thumb in any position. It should be so thin as to only 

 just avoid wounding the sensitive structures below. 



The whole of the foot must then be thoroughly cleansed, 

 and rendered as nearly aseptic as possible. The use of 

 warm water, soap, and a stiff brush is the readiest means 

 of removing the surface dirt. Afterwards the foot should 

 be soaked for some time in a reliable antiseptic solution, 

 a 1 in 1,000 solution of perchloride of mercury being 

 the most suitable. When removed from the solution the 

 foot must be packed round with wool or tow impregnated 

 with corrosive sublimate, and then bandaged, the whole 

 afterwards wrapped in a thick cloth, or protected with a 

 boot. 



On the following day the animal is brought out and cast, 

 and the foot desired to be operated on firmly secured, after 

 the manner described on p. 81. The bandages and subli- 

 mate pads are then removed, and the skin of the coronet 

 over the seat of operation shaved of hair. An Esmarch 

 rubber bandage is next run up the limb, and the tourniquet 

 applied, thus rendering the operation a nearly bloodless one. 



This done, the animal is chloroformed, and an antiseptic 

 douche played over the foot. 



So far, the steps in the operation are common to all 

 methods. There are now, however, three slightly differing 

 modes of extirpating the cartilage, which modes vary simply 

 according to the structures severed by the knife. 



First Method. — This is the oldest method of the three, 

 and consists in making ( 1 ) a horizontal incision through the 

 sensitive laminae along the lower border of the cartilage, 

 and (2) a vertical incision through the skin of the coronet, 



