ON SHOEING HORSES. 
573 
both sides 1 Nay, further, why does a shoe which has not a level 
seated surface but is bevelled inwards, cause so many horses to go 
lame] though many feet may resist injury from it, one instance in 
ten thousand upsets the conclusion. There is in many feet an appre¬ 
ciable expansion in action; and further, expansion takes place inde¬ 
pendently of growth above, as 1 this day (Sep. 3d) saw a horse which 
was shod under my own inspection on the 30th July, who has been 
since in a loose box and at grass, in which the shoes some days 
ago had to be taken off and made wider at the heels, nearly half 
an inch , in consequence of the spreading of the heels : growth 
from above would not account for this. 
Conclusion 2d :—Difficult to criticise, from its mixture of error 
and truth, and from the ambiguity and obscurity in which it is 
expressed. As far as I can understand it, much of the remarks 
on conclusion 1st, will apply to this; but further, the frog does 
descend at the posterior part in a greater degree than at the toe, 
and expansion takes place in the bars, or, more properly, between 
the bars and frog, that portion of the frog-band covering the junc¬ 
tion of the bulbs of the frog and the angles of the heels, when in a 
healthy condition, yielding in a slight degree, or why do horses 
in which this part has become rigid and preternaturally thick, go 
lame, and upon its removal (even to the starting of the blood) go 
sound at once I Further, why is it that in these kind of feet we so 
often find that Nature has relieved herself by a fissure, even down 
to the secreting surface. 
Conclusion 3d :—A contradiction in itself to the preceding con¬ 
clusion ; and the observation on the springing of the heels of the 
shoe I shall remark on when on the subject of shoeing in particular. 
Conclusion 4th :—I have already shewn that the descent of the 
frog is not entirely governed by the descent of the heels. Except 
in the case of a bar shoe pressing directly on the frog, ordinary 
shoeing does not render the base of the frog a fixture: the part 
that is the most thrown out of action (that is descent) is the an¬ 
terior part of the frog, as is shewn, first, by the small quantity of 
elastric material to be acted on, and, secondly, mechanically de¬ 
monstrable by the fact of the sole being arched from side to side, 
the extremities of such arch abutting against the crust, which is 
buttressed, as it were, by the nails driven through the crust, and 
held in their places by the unyielding iron shoe. 
Conclusion 5th:—If “ no appreciable descent of the horny sole 
in moderately concave feet” means, that such descent is not visible 
to the eye, f agree with it; but, as a general rule, the sole does 
appreciably descend, as is shewn by the necessity that exists to 
avoid any pressure to that part: it may not be more than a 50th 
or even an 100th part of an inch, an extent hardly appreciable to 
VOL. XXII. 4 G 
