212 DISEASES OF THE HORSE'S FOOT 



opening thus found should be carefully probed, and its 

 depth and situation noted. 



At other times the prick is not so readily apparent. The 

 nail or other object has penetrated and afterwards with- 

 drawn itself. The natural elasticity of the horn, especially 

 that of the frog, causes it to contract upon the puncture, 

 and to largely obliterate the hole made. What, therefore, 

 may look to be but a simple injury to the horn alone may 

 in reality be the only evidence of a stab complicating the 

 sensitive structures. It thus behoves the veterinary sur- 

 geon to follow up and carefully cut out any unnatural- 

 looking mark in the horn, more especially if the horn is dis- 

 coloured, or if blood is extravasated into its fibres, or there 

 is moisture exuding from the part. 



In some cases of this description the knife in the act of 

 paring comes into contact with the cause of the trouble. 

 Sometimes this is a nail, sometimes a sharp and small 

 piece of flint, so deeply penetrated as to have become quite 

 buried. When met with in this manner, however, the 

 foreign body is more often than not a splinter of wood 

 deeply embedded in the cleft of the frog or in the frog 

 itself. 



The fact that multiple punctures may occur should here 

 be remembered, and the remainder of the inferior surface 

 of the foot thinly pared. 



On withdrawal of the foreign object blood may immedi- 

 ately follow. Should the former have been fixed in position 

 for some time, however, pus is nearly always found at the 

 bottom of the wound. As a rule, its removal is compara- 

 tively easy, but one case recalls itself to the author's mind 

 iii which the extraction was a matter of considerable diffi- 

 culty. The offending object was a large, flat-headed nail, 

 some 2 inches long. This was driven fast into the os pedis, 

 and necessitated the employment of a pair of pincers and 

 the exertion of some amount of force to move it from its 

 position. 



In this connection it must be remembered that the pene- 

 trating object sometimes breaks off after entering the foot. 



