352 DADD’S VETERINARY MEDICINE AND SURGERY. 
SAND-CRACK. 
“The name of sand-crack seems of questionable upplication. It 
ws, evidently, a compound of the word sand and erack, as though 
it denoted a crack with sand in it, or a crack occurring in a sandy 
eountry, or in a dry, sandy season, which several derivations have 
Deen ascribed to the term. May not the word sand admit of res- 
olution iato its primitive signification, and mean in this, as in 
other ins‘ances, a sundered crack? A sand-crack may be defined 
to be a Icngitudinal division in the fibers of the wall of the hoof, 
amounting to a flaw simply, or else to a cleft or fissure through 
the substance of the horn. 
The direction of the crack is slanting, from above downward, 
aud from behind forward, following the course of the fibers of the 
nvof. A sand-crack in the side of the wall slants more than one 
in front, owing to the greater obliquity of the course of the horny 
fibers, as we proceed from the toe to the heel of the foot. 
There are two kinds of sand-crack, quarter sand-crack and toe 
sand-crack, the former occurring in the fore, the latter in the hind 
foot. At least this is generally the case. It is rare to find the 
reverse, though there are occasions on which we meet with sand- 
srack in the toe of the fore-foot and the quarter of the hind foot, 
It is possible for cracks to occur in other parts of the hoof; but 
in these two situations it is that veritable sand-crack occurs, and 
there are here, as we shall find hereafter, special causes for their 
production. Let us first consider 
QUARTER CRACK. 
The situation of this crack is the slanting line of the wall of 
the hocf, directly opposed to the extremity of the wing of the 
coffin “ore; and it is oftener found in the inner than in the outer 
quarter, added to which the hoof in which sand-crack occurs is 
always s contracted one, quarter sand-crack, no more than toe 
sand-crack, never happening in a hovf disposed to obliquity and 
flatness, The same description of foot which is predisposed te 
eontraction is, for the same reasons, predisposed to sand-crack. 
There is an obvious connection between contraction and quarter 
eand-crack. The light, near-the-ground stepping horse, with 
strong, parrow, upright hoofs. will be equally likely, under cer 
