182 DISEASES OF THE HORSE'S FOOT 



degree of pressure. When haemorrhage has accompanied 

 the operation, this dressing should be removed on the fol- 

 lowing day, the wound dressed, and the pledgets of tow 

 and the bandage renewed. Any after-dressing need only 

 then be practised at intervals of a week. Repair after this 

 operation is rapid, and takes place both from the exposed 

 podophyllus membrane and from the coronary cushion. 



(d) By stripping the Wall from the Coronary Margin to 

 its wearing Edge on Either Side of the Crack. — This is 

 merely a more extensive application of the method just 

 described, and is only indicated in a complete and com- 

 plicated crack that has refused to yield to other modes of 

 treatment (see Fig. 98). 



As in the previous case, a groove is run from a to c. 

 The grooves ab and dc are then continued to the lower- 

 most edge of the wall, and the whole of the wall w T ithin 

 these points removed. To facilitate removal, the white 

 line should be grooved between the points b and d. After- 

 treatment is exactly the same as that just referred to. 



B. COENS. 



Definition. — In veterinary surgery the term ' corn ' is 

 used to indicate the changes following upon a bruise to 

 that portion of the sensitive sole between the wall and the 

 bar. Usually they occur in the fore- feet, and are there 

 found more often in the inner than in the outer heel. 



The changes are those depending upon the amount of 

 haemorrhage and the accompanying inflammatory pheno- 

 mena occasioned by the injury. 



Thus, with the haemorrhage we get ecchymosis, and con- 

 sequent red staining of the surrounding structures. As is 

 the case with extravasations of blood elsewhere, the haemo- 

 globin of the escaped corpuscles later undergoes a series of 

 changes, giving rise to a succession of brown, blue, greenish 

 and yellowish coloration. 



With the inflammation thereby set up we get swelling of 

 the surrounding bloodvessels, pain from the compression of 



