230 DISEASES OF THE HORSE'S FOOT 



opposite foot, and may happen in a variety of ways. More 

 often than not it is met with in the feet of heavy draught 

 animals, and is there caused by the calkin, either when 

 being violently backed or suddenly turned round. It may 

 also occur in horses with itchy legs, as a result of the 

 animal rubbing the leg with the shoe of the opposite limb. 

 The irritation in this case is nearly always due to parasitic 

 infection (Symbiotes equi), and becomes sometimes so un- 

 bearable as to render the animal unmindful of the injury 

 he may be inflicting so long as he experiences the relief 

 obtained by the rubbing. 



Self-inflicted tread is also sometimes met with when 

 horses are worked abreast at plough. The animal in the 

 furrow, with one foot sometimes in and sometimes out of 

 the hollow, is caused to make a false step, and so brings 

 the injury about. 



Animals worked in pairs are further liable to receive a 

 tread from the foot of their companion. This is commonly 

 seen in heavy animals at agricultural labour in fields, 

 where the walking is uneven, and abrupt turning constant. 

 It is not uncommon either in animals at work in vans in 

 town, and is occasionally met with in the feet of carriage- 

 horses. 



' Overreach ' is the term used to indicate the injury in- 

 flicted on the coronary portion of the heel of the fore-foot 

 by the shoe of the hind. Ordinarily, overreach occurs 

 when the animal is at a gallop, and is thus met with in its 

 severest form in hunters and steeplechasers. It can only 

 occur when the fore-foot is raised from the ground and the 

 hind-foot of the same side reached right forward. When 

 the feet separate the injury takes place. In its movement 

 backwards the inner border of the shoe of the hind- 

 foot catches the coronet of the fore, and tears it backwards 

 with it. Quite frequently a portion of the skin is removed 

 entirely, but often it hangs as a triangular flap. The flap 

 in such a case is always attached by its hindermost edge, 

 and indicates plainly enough that the direction of the blow 

 that cut it must have been from before backwards. 



