726 ANATOMY AND PHYSIOLOGY OF THE HORSE’S FOOT. 
the lower border of the os pedis, all around its wide sloping 
surface to the wings, and reflected on the inner aspect of 
these, is seen the assemblage of- thin ridges which have been 
designated as the “ vascular” or “ sensitive laminae,” or 
“ podophyllae ( ttovoq , 7 roSog, foot, and cpvWov leaf). These 
are of a bright or deep red colour, and resemble nothing so 
much, perhaps, as the crimping of a lady’s frill, the leaves 
of a partially opened book, or the folds of a fan when nearly 
closed. They are arranged in the nicest order, and with 
mathematical precision ; in health they are of an equal thick- 
ness from top to bottom, and uniformly parallel, looking as if 
the dermo-perioste had been evenly and regularly puckered 
up around the front and lateral aspects of the os pedis. Their 
number has been variously estimated at from 500 to 600. 
The longest, of course, are in front, to correspond with the 
depth of the bone and hoof in this situation, and the shortest 
are placed towards the heels and within the wings of that 
bone, where they terminate. Their upper ends abut on the 
white zone of the plantar cushion, and their lower extremi- 
ties, reaching the inferior border of the bone, end in com- 
paratively large papillae, becoming continuous with the in- 
tegument covering the sole, with the exception of those inside 
the wings, which do not so terminate. The width of each leaf, 
or rather the depth of each interspace, varies to a degree some- 
what proportionate to its length, being greatest in the front 
laminae, and least in those behind. But even the widest are 
narrower above, towards the white zone, than they are nearer 
the bottom of the foot. Not only is this the case, but as we 
turn over leaf after leaf, and get well round towards the heels, 
we occasionally come upon some which are not one half the 
width of their fellows. 
The free edge or border of each is much thinner than that 
next the foot, and though all the laminae in front are com- 
pletely separated from each other by what appears to be a 
wide channel or groove, yet at their base they approach each 
other so closely as to convert this groove into an angular or 
Y-shaped space. Into these interspaces there closely fit, and 
are retained, similar horny processes or laminae that belong to 
the inner surface of the lioof-wall. The consideration of the 
relations between the two series of laminae will be adverted 
to shortly. 
Before their minute structure was properly understood, 
it was estimated that, through their duplications, the external 
superficies of the cylinder of the foot was enlarged six, seven, 
or even twelve times : that is, the laminae, if spread out, would 
cover a surface twelve times larger than the actual superficies 
