428 PLANTAR SYSTEM. 



The Sole. 



The sole is the arched plate entering into the formation (as its 

 name implies) of the bottom of the hoof: or, to adopt Sainbel's 

 definition, "it is that part which covers the whole inferior sur- 

 face of the foot, excepting the frog." It is a very just practical 

 observation of Mr. Coleman's, that although a knowledge of 

 every part of the foot is indispensably necessary to render us 

 scientific overseers of the farrier's art, no individual part re- 

 quires such undivided attention, as regards shoeing, as the sole, 

 since the success of this mechanical operation mainly depends 

 on the paring and defence of this arched horny plate. 



Situation and Connexion. — It fills up the interspaces between 

 the outer and inner walls (or bars) of the crust. I differ in 

 opinion from those who describe it to surround the toe of the 

 frog. I hold its circumferent support and connexion to be 

 the wall of the hoof, to which it is firmly cemented by an inter- 

 stitial horny matter, filling the crevices between the laminae. 



Figure. — The circumferent outline of the sole measures about 

 two-thirds of a circle, the remaining third being omitted to form 

 a triangular-shaped hiatus or opening for the reception of the 

 frog and bars. This circular form, however, is by no means 

 true, or even invariably the same, in its dimensions. Ge- 

 nerally, the longitudinal exceeds the transverse diameter. 

 Its greatest diameter is shewn by a line extended from either 

 heel across its middle to the opposite point of the toe. 



Aich. — Commonly, the sole presents an arch of more or less 

 concavity inferiorly, and convexity superiorly. But it is not a 

 regular or uniform arch, being one that rather waves or undu- 

 lates, so as to bear a comparison, made of it by Mr. Clark, 

 '* to the mouth of a bell extremely extended or flattened." Like 

 that of the bell, the arch is highest in the middle, from which 

 it slopes, laterally, down to a flat, subsequently to rise again 

 around its border, in order to present a dilated surface for attach- 

 ment towards the wall. There is, however, vast variety in the 

 degree of arc of the sole: in some feet it is of surprising depth; 

 in others, the arch is converted into a flattened surface ; and yet 

 both seem to perform equally well. In the hind feet the sole is 

 generally more arched than in the fore, and approaches in figure 

 nearer to the oval than the circle. 



Division. — In the sole we distinguish an anterio?' part or toe; 

 a middle or central part ; two points or heels ; and two suffaces. 

 These divisions are not very well defined : but they prove ser- 

 viceable in aid of our descriptions. — The toe of the sole is the 

 part encircled by the toe of the wall, against which it abuts, and 



