776 ANATOMY AND PHYSIOLOGY OF THE HORSE’S FOOT. 
dividing the extensor and flexor tendons and lateral ligaments, 
and penetrating the articulation of the foot. The pedal bone 
being detached, the lower extremity of the second phalanx, 
with its articular face, was removed by the saw, and the re- 
maining portions of the lateral fibro-cartilages were excised 
by dissection, so that the face of the large wound was bordered 
by the intact coronary cushion, still covered by a thin layer of 
horn. With regular dressings the wound gradually became 
studded by granulations, the horn on the coronary cushion 
grew down, and at its inner border a continually increasing 
secondary zone of horny matter was developed, until in about 
a month it had attained a width of fifteen millimetres. While 
its breadth always increased towards the centre, it at the same 
time gained in thickness, and the growth from the coronet 
went on regularly. In about two months the wound was 
scarcely the size of a centime, and the horse was able to rest 
somewhat firmly on the plate of horn which had formed. 
Nine months afterwards, the growth from the coronet had 
assumed the shape of a complete cylinder fifteen centimetres 
in height, and five or six in diameter ; it was not perpendicular 
to the ground, however, but curved forward and upward like 
a • cow’s horn, and in such a manner that the weight was 
thrown on the heel of the stump. 
It must, therefore, be concluded that upon exceptional 
emergencies — as when they are suddenly denuded of their 
external covering — all the textures entering into the compo- 
sition of the foot are endowed with the faculty of generating 
horn to an almost unlimited amount, no matter how diminished 
in superfices they may be, or how little of the organ remains. 
It would seem as if the blood sent to the foot contained a 
certain quantity of the horn-producing element which it 
must deposit there in some form or other, no matter if this 
extremity of the limb be ever so severely mutilated or cur- 
tailed. 
But though the proper secreting membrane is not abso- 
lutely indispensable to the generation of horn, it must, never- 
theless, be conceded that it is the essential agent in giving 
the hoof its normal shape and structure. To its peculiar 
constitution is due the circumstance that the epidermic cells, 
as they are developed, instead of accumulating in an irregular 
manner around the foot, are so ingeniously arranged as to 
form a comparatively light but dense and resisting insensitive 
case, which perfectly protects the vital tissues that compose 
this part of the limb, and yet leaves them all the liberty 
necessary for the exercise of their functions without impair- 
ing the stability of the organ as it rests upon the ground. 
