648 ON THE SENSE OF TOUCH IN THE HORSE’S FOOT. 
owing to a considerable bundle of the fifth pair of nerves, which, 
according to Duges, expend themselves in the superior jaw, at 
the origin of the beak, between the bone and the horn. 
So that it is not drawing too largely on vraisemblance to assert 
that, notwithstanding their removed situation from the ground, the 
papillse of the frog are its organs of touch. 
The use, therefore, we assign to the papillary processes of the 
foot seems demonstrated. But, is the tactile property exclusively 
confined to these parts ] No ! The plantar papillae are no more, so 
to speak, than appendices to the nervous textures of the tegument- 
ary membranes, sorts of processes designed to penetrate the hoof 
and endow it with participation in their own sensorial property, and 
we may add, in no slight degree. But are the membranes from 
which the papillae proceed very sensible, and does the podophyllous 
or laminated tissue, which only takes on the papillary form at the 
extremities of the laminae, enjoy any very marked sensibility 
throughout its extent/? Its lamellated processes may be considered 
as issuing out of the general sensitive covering of the foot, and as 
designed, in the same manner as the papillae themselves, to pene- 
trate the hoof, with the intention of diminishing, in effect, its thick- 
ness without detracting from its solidity, by placing the nervous 
tissue more directly under the contact of the body intended to make 
impression upon it. 
The exquisite sensibility of the papillae, as well as of the pro- 
cesses issuing out of the laminae is, moreover, rendered evident in 
a variety of ways telling in favour of our views. Does not the 
animal manifest sharp pain whenever the frog is cut away down 
to the substance of the horn which is traversed by the papillary 
prolongations I Or is any thing more painful to him than the squeez- 
ing of the lamellated substance between the lips of a fissure in the 
crust I And, lastly, cauterization by the red hot iron, through the 
thickness of the hoof, of the extremities of the papillary processes 
perforating it, as happens on occasions in shoeing, is always ex- 
tremely painful, and sometimes proves the cause of fearful inflam- 
matory accidents. 
The sensitive faculty is not confined to the membranous en- 
velopes of the foot; every component part of it is, in a measure, 
possessed of sensibility. It is in the papillary tissue, however, 
that resides in a particular manner the sense of touch. 
A sense of this kind specially developed at the extreme ends of 
the limbs of the horse, taking cognizance of objects through the 
thickness of the hoof, became necessary to enable the animal to 
regulate, in the different paces, the percussion of the foot against 
the ground ; to estimate the momentary position of the solar sur- 
face of the foot ; and to dispose the axes of its bony columns 
