487 
ON SANDCRACK. 
By Mr. J. P. Cheetham, V.S., Edinburgh. 
Having had numerous cases of sandcrack under treatment 
during the last twelve months, and those of the worst descrip¬ 
tion I have ventured to forward you a few lines respecting t , 
and this disease of the foot generally. The: cases that I parte,, - 
larly allude to were chiefly m the centre of the toe of *Je 
feet • extending from the coronet to the ground, with a complete 
division of the crust, and some of which had been isc.foryears.. 
Few of them exist without the hinge motion, and that P ri 
pally seen in the superior part of the fissure, and when extern, , 
the laminae connected with it become inflamed the effects of 
which often are suppuration, and separation of the horny covering, 
this is also frequently produced by sand and wet getting to 
llV Auhis rt Jtage the animal is frequently unable to put the foot to 
the ground ; considerable irritative fever is often present, so muci 
so in some instances, I believe, as to destroy life. Sandcrac 
is more severe in the London dray horse than any other I am ac¬ 
quainted with, which is in part accounted for from the motion 
being more extensive in the crack than in horses of a lighter 
description, and they being unable to support themselves ong 
upon the opposite leg. Another reason why sandcrack should 
be so common in the heavy dray horse of London I was soon 
convinced arose from the mode of shoeing their hind feet, w 11 c 
is by putting on heels without adding the tips (nobs), to keep 
the toe the same height with the heel. When the animal is 
driven with this kind of shoe, the whole weight is directed and 
thrown on the toe; the crust in front becomes nearly perpen- 
dicular ; there is a tendency to knuckling produced ; the toot (1 
I may be allowed the mode of comparison) is going down hill, 
by which means the weight is directed more towards the anterior 
and'superior part of the crust, at which situation the ciack 
usually commences. The best explanation I can give o ic 
foregoing opinion is the following : „, , 
Let us suppose that a horse has from two to three tons of load 
behind him, and, proceeding down a declivity, the horse 
finding that the heels of the shoes are the best parts for resistance, 
the heels then being fixed points, the coffin bone act on the 
laminee covering the quarters and heels, so much so, that they 
are actually pressed between the coffin bone and crust, while 
those at the toe are relieved ; but by that very relier from pres¬ 
sure they are stretched or expanded, and it is tms too great ex- 
