704 ANATOMY AND PHYSIOLOGY OP THE HORSe’s FOOT. 
nishing the capacity of the hoof, and inducing irremediable 
pathological alterations. But we will have more to say of 
this reserve keratogenetic faculty in general shortly. 
The horny sole is produced from the membrane covering 
the corresponding portion of the pedal hone. This also is a 
fact demonstrable by daily observation. When by accident, 
design, or disease, this portion of the hoof becomes removed 
or detached from the living surface, which is covered by 
myriads of villi, like the coronary cushion, new horny matter 
is generated from it, which after a time acquires sufficient 
thickness and firmness to protect the sensitive parts from 
external injury, and to sustain pressure on the ground. On 
examination, it is found that this new sole is composed of 
fibres arranged in a vertical manner, as in that which had 
been removed, and though at first these fibres are not quite 
straight, but follow a more or less undulating course, and while 
the whole corneous mass is more or less discoloured from the 
injury to the membrane which secreted it, yet in a few months 
the fibres generally become perfectly rectilinear, and the horn 
wears its normal tint. 
In this way, then, the formation of the wall, white line, 
bars, frog, and sole takes place simultaneously on the derm 
covering the horse’s foot, and their fusion with each other at 
their point of junction, while the epidermic material is yet in 
a plastic and agglutinative condition being ensured, we have 
produced the important case or horny box called the hoof. 
It only remains for us now to consider the part played by the 
villi in the production, formation, and characteristic features 
of the horn texture with which they appear to be so in- 
timately related — a subject which has engaged the attention 
of Professors Delafond, Chauveau, Bouley, Gourdon, and 
other continental veterinarians of note, who have not come 
to a perfectly unanimous conclusion on some of the points 
discussed. 
We have seen that the whole of the hoof, with the excep- 
tion of the laminae, is nothing more or less than a fibrous 
epiderm of varying thickness and consistency in particular 
situations ; and that this fibrous character, if not dependent 
upon, is at any rate coincident with, the presence of the 
myriads of villi projecting from the living surface contained 
within the dense envelope, each villus being received into 
the upper extremity of a horn tube or fibre. But some 
veterinary authors have been of opinion that these villi are 
the real and sole agents in the production of the hoof, ex- 
cepting, of course, the laminge ; others have asserted that 
such is not their office, and that they are merely instruments 
