ANATOMY AND PHYSIOLOGY OF THE HORSe’s FOOT. 149 
obtuse angular cavity on each side, named the “ lateral la- 
cunae/’ or “ commissural cavities.” The lower border of the 
bar, on the unpared foot, projects more or less above the 
sole, from which it differs in consistency, and most frequently 
in colour. 
These are, then, the most striking features to be noticed in 
the disposition of the wall of the hoof. For the convenience 
of the veterinary surgeon in his science, and also to facilitate 
the teaching and practice of the farrier’s art, this part has 
been divided into several regions, between which there is in 
reality no natural limit. This artificial division, however, 
possesses such important advantages as to be indispensable in 
everyday experience. 
For example, the anterior or central part of the wall is 
designated the “ toe,” an appellation scarcely correct, but 
which custom has sanctioned. This toe, with the English, 
extends to the sides of the hoof, where the quarters begin. 
With the French, however, there is an intermediate portion, 
named the inamelle (“ mammilla,” or “ breast ”), in con- 
sequence of its symmetrical situation on each side of the 
toe ; this division should be accepted by us, as it would 
greatly facilitate description. Behind this “ mammilla,” or 
“ breast,” is the “ quarter,” so named because of its consider- 
able extent, each quarter occupying no less than one fourth 
of the entire circumference of the foot. After the quarter 
comes the “ heel,” or angle of inflection, and within this the 
(t bar.” So that for practical purposes the wall is artificially 
divided into “ toe,” “ mammillae ” (or, as they are more fre- 
quently designated in this country, the “ outside 99 and “ in- 
side toe ”), “ quarters,” “ heels,” and “ bars.” 
All these parts of the wall do not follow the same direc- 
tion. We have seen that, as a general rule, the geometrical 
outline of the hoof is slightly conical, its lower circumference 
being a trifle larger than its upper ; hut even this outline is 
not regular, in consequence of the outer circumference being 
more salient in the unshod, and also in the shod horse, than 
the inner. The toe and mammillae of a well-formed hoof 
should be inclined from above to below at an angle of from 
50° to 60°, according to the inclination of the phalanges of 
the foot, and in conformity, to some extent, with the obliquity 
of the head and shoulder of the horse. The quarters of the 
hoof are not so oblique, and the heels are still less so ; in- 
deed, it is by no means rare, and is perhaps the rule, to see 
hoofs in which the obliquity towards the heels is altogether 
reversed, the inclination being from above downwards and 
inwards. This peculiarity is very striking, as it gives this 
