abscess. The eflPect of tLis squeezing of the sensil^le sole is 

 most commonly witnessed at the angle of the inner heel, 

 where the descending heel of the coffin bone, forcibly pressing 

 the vascular sole upon the horny sole, ruptures a small blood 

 vessel, and produces, what is called, a corn, but which is in 

 fact a bruise. 



The horny frog occupies the gTeater part of the triangular 

 space between the bars, and extends from the hindermost 

 part of the foot to the centre of the sole just over the 

 point, where the bars meet ; but is united to them only at 

 their upper edge ; the sides remain unattached and separate, 

 and form the channels, called the " Commisures.'"'- 



The frog is evidently designed for very important uses ; 

 but as our object is purely practical, and not speculative, 

 we will not stop to inquire, whether it is designed to expand 

 the foot, and prevent contraction, or whether its chief office 

 is to protect the navicular joint from injvuy ; but proceed to 

 consider it in a point of view, bearing more usefully on our 

 subject, viz., as the part, which offers us the best criterion, 

 whereby to judge of the effect of our shoeing upon the 

 foot generally ; for no part undergoes so much change from 

 bad shoeing, or exhibits it so soon, as the frog. If we 

 carefully observe the form and size of the frog in the foot 

 of a colt of from four to five years old at its first shoeing, 

 and then note the changes, which it undergoes, as the 

 shoeings are repeated, we shall soon be convinced, that a 

 visible departure from a state of health and nature is taking 

 place ; at first it will be found large and full with consider- 



* Plate 1, fig. 1. 



