PLANTAR SYSTEM. 427 



appeared to afford an increase of actual surface more than the 

 simple internal area of the hoof would give of about twelve times, 

 or about 212 square inches, or nearly one square foot and 

 a half. 



The lamellae exhibit no differences but in their dimensions. 

 In length they correspond to the respective depths of the wall; 

 being longest, and likewise broadest, around the toe, and gra- 

 dually decreasing towards the hinder parts. 



In composition, they are horny. Viewed through a microscope, 

 Mr. Clark discovered in their substance two planes of fibres, 

 " the one running in parallel lines to the axis of the hoof, the 

 other obliquely intersecting these." When stretched, they ex- 

 hibit signs of elasticity; but this appears greater in the trans- 

 verse than in the perpendicular direction. 



By means of its lamellae, the wall presents a superficies of ex- 

 traordinary amplitude for the attachment of the coffin-bone. A 

 structure consisting of similarly formed lamellae envelops the 

 bone, and these are dovetailed in such a manner with the horny 

 lamellae, as to complete a union wliich for concentrated strength, 

 combining elasticity, may vie with any piece of animal mecha- 

 nism at present known to us. 



THE BARS are processes of the wall, inflected from its heels 

 obliquely across the bottom of the foot. For a long time, by far- 

 riers, they were confounded with the substance of the sole, an 

 error that owed its origin and perpetuation to the malpractice 

 they exercised in paring the foot — in cutting both bars and sole 

 down, without any distinction, to a common level. In the na- 

 tural healthy foot the bars appear, externally, as elongated 

 sharpened prominences, extending from the bases of the heels 

 into the centre of the foot, between the sole and the frog : pos- 

 teriorly, they are continuous in substance with the wall, with 

 which they form acute angles ; anteriorly, they stretch as far 

 as the point of the frog, constituting two inner walls or lateral 

 fences between that body and the sole. Sainbel conceives, from 

 their position, that they offer resistance to the contraction of the 

 heels. Their internal surfaces exhibit rows of lamellae, continued 

 from those lining the wall, but which are here short, and in their 

 direction transverse, two circumstances referrible to the narrowness 

 and inflection of the bar: towards the extremity of the bar they 

 gradually grow shorter, and less distinctly marked, until we at 

 length lose all vestige of any more of them. While the prominence 

 of the bars is such as to give them a secondary bearing upon 

 the gi'ouiid, their sharpened forms will sink them more or less 

 deeply into every impressible surface. 



