ON THE EXPANSION OF THE HORSE’S FOOT. 
201 
must have bent, and consequently make it stronger; but, to their 
astonishment, the same thing occurs as before, by which they are 
quite disconcerted. 
In another part of the same work, the author says, the heel of 
the foot must be in contact with the shoe; for the hoof is flexible ; 
and, further on, the hoof by its flexibility follows the heel of the 
shoe. But this means nothing more than the downward motion 
of the heels ; certainly not lateral expansion. The celebrated 
Bourgelat, some years after, in his Traitt de Ferrure, says — The 
elasticity by which the hoof is endowed, pervades every part of 
it; and this assertion of the author is supported by some experi- 
ments, which are neither happily selected nor very conclusive ; 
but, like the former writer, he makes not the slightest allusion 
either to lateral expansion or descent of the sole, which are first 
mentioned by Mr. Bracy Clark in his PODONOMY, the edition of 
which was published in 1809, and of which the following short 
extract will convince us. “ It appears also, in fact, that it is not 
so much from the upward pressure against the frog as from the 
downward pressure of the limb, and weight of the body, upon the 
bones of the foot, that should produce this effect of expansion 
upon the yielding contents of the hoof; timely assisted, and in due 
time prevented from too much depression in this direction — by 
meeting with the support of the frog, then brought to the ground 
at the time the strain and weight is greatest ; the sides of the foot 
then expanding laterally through the whole extent , and springing 
back again to their places, on the removal of the exertion and 
weight. And they must in any violent exertion, as galloping, 
&c., where the force is tenfold that of the mere weight, make 
these parts, if at liberty, play or expand to an extent that, merely 
considering the hoof in the hand, can give us but a faint concep- 
tion of.” — Page 35-6. 
From page 92 the following extract may be taken : — “ Again, 
the lower circumference of this arch of the sole, which may be con- 
sidered in the light of the heels of the arch, is everywhere abutting 
against the sides of the wall, which, as we have formerly shewn, 
are rendered yielding to its impression against them, and the sides 
of the frog dilating (which retracts and shortens this part), affords 
full opportunity for the extension, and which is necessarily accom- 
panied with a descent and flattening of the sole, in which action 
all parts of the hoof combine ; and in this manner, we maintain, is 
performed the elastic movement of the hoof, and which we appre- 
hend to be essential to its well being and healthy existence.” 
This opinion has been followed, with very slight deviations, by 
all subsequent writers on the horse’s foot. Many controversies 
have arisen as to the priority of these views; but very few experi- 
VOL. XXIII. E e 
