The Structure of the Horse'tf Foot and Principles of Shoeing. 653 
dancer does sometimes, after long and painful training, and the 
horse does always without any efibrt at all. 
After grasping the idea which the woodcuts are meant to 
convey, it will be easy to go on a little further, and find out 
how the toe of the horse is made to serve the purpose of a foot 
chiefly by the extra growth of the nail, which instead of being 
a mere horny scale on the top of the toe, covers the part all 
over like a case or box of horn. The bones of the fore foot may 
in like manner be compared with those of the hand and wrist of 
man. But as the human hand is not used to support the weight 
of the body nor to assist in moving it, the human foot furnishes 
the best type of the foot of the horse. 
In beginning the inquiry about the structure and uses ot 
the foot of the horse, it is most natural and easy to take the 
outside part of the organ, and in so doing it will be best to com- 
pare the foot of the horse with that of the foal at birth, before 
the organ has been used to bear the animal's weight. Plates 3 
and -i. on pages 662 and 663, show the external foi'm of the foot of 
an adult horse, and Plate 5, on page 664, that of a foal, and it will 
be noted at once that there is a great difference in the state of the 
horn, especially at the bottom of the foot in the two specimens. 
In the adult foot, as it is seen resting on the ground, the 
wall of horn «, from the hair at the coronet down to the ground, 
is first noticed, and for the purpose of description it is divided 
into several parts. Exactly where the skin joins the hoof is the 
coronary ring d. The outside of the hoof is the wall or crust. 
At the back of the hoof are the heels, c c. A portion in the 
front a. is called the toe. and the sides of the wall are the inside 
and outside quarters. Only imaginary lines mark the points of 
separation of these different parts from each other. 
In thickness, the wall of the foot varies according to the 
size of the animal and the treatment it has met with from the 
rasp of the shoeing smith. An average of half an inch may be 
taken as near enough for practical purposes. 
Having made out the general characters of the outer surface 
of the hoof as it rests on the ground, the next thing to be done 
is to lift it off" the ground and look at the bottom of it, which 
can be seen in the next figure (Plate 4, on page 663). The 
parts exposed to view are the crust (2), bars (3), sole (1), and 
frog (4). The crust is turned in at each heel to form the two 
bars which meet nearly in the centre of the circle, leaving a 
triangular space behind which is filled up by the mass of soft 
horn called the frog, and a half-circular space in front, in which 
is the sole. In form the sole is concave at the bottom and 
convex above, as may be proved by dissection. But in the foot 
