DISEASES OF THE LATEEAL CARTILAGES 361 



only of the cartilage, and do so in what appears at first 

 sight a comparatively rough-and-ready manner. 



The apparent roughness is that they do not concern 

 themselves with conserving the coronary cushion, and 

 hesitate but little in cutting portions of it bodily away. 

 One would imagine that in this case the quarter of the side 

 operated on would be always more or less bare of' horn. 

 Such, however, is not the case. 



To perform this operation the animal is again cast and 

 chloroformed. Some operators, however, use the stocks 

 and dispense with the anaesthetic. The foot is first well 

 cleaned with soap and water and a stiff brush, and the hair 

 of the coronet over the seat of operation shaved. Again, 

 too, the horn of the affected quarter is rasped until it yields 

 easily to pressure of the thumb, and the whole of the foot 

 washed in an antiseptic solution. 



A probe is now inserted into the opening at the coronet, 

 and the direction of the fistula noted, after which the foot 

 is firmly secured, and an Esmarch bandage and tourniquet 

 applied to the limb. 



This done, a triangular or wedge-shaped portion of skin, 

 coronary cushion, and thinned horn is removed with a 

 strong sage-knife or scalpel. 



The base of the wedge-shaped portion removed contains 

 the opening of the fistula, and the apex of the wedge should 

 reach to the bottom of the sinus (see Fig. 142). 



After the horn is removed and the fistula followed up, it 

 is sometimes found that what we at first thought was its 

 end, it may now be continued in an altogether different 

 direction. 



It is again followed up with the probe, and the horn and 

 sensitive structures excised until we are quite certain we 

 have reached its furthest extent. 



Attention should next be paid to the cartilage. "Where- 

 ever spots of necrosis are found, as indicated by the pea- 

 green colour of the affected parts, they must be carefully 

 excised. Care should be taken in so doing to carry the line 

 of excision some little distance around the visibly affected 



