454 
OBSERVATIONS ON SOUNDNESS. 
Gamgee, Sen., which are well worth the attention of every 
student and practitioner of veterinary medicine. 
The frog is a structure which has always come in for a share 
of discussion when speaking of the foot. I remember having 
heard that the frog caused expansion of the heels, &c., and this, 
I dare say, even at the present time, is an opinion ac¬ 
cepted by numberless individuals. If expansion of the heels 
was a fact , it may be received as the principal cause in 
performing that function, but we have sufficient reason to 
doubt that the feet have the expansive power attributed to 
them by some members of the profession, therefore we shall 
have to assign some other function to the frog. On looking at 
the frog, and taking into account its component parts, as well 
as its situation and connection with other tissues with which 
it is in immediate contact, it will strike us that in the first 
place it is intended to make up quantity. Secondly, it is to 
prevent or ward off concussion ; to this I think we may give 
all our attention. It is not too much to state that this is the 
most it has to do, namely, give protection to the structures above 
it. The same may be said of the elastic tissue. It is placed 
there to make up quantity , in a similar manner as India rubber 
would be employed where concussion is met with in in - 
organized materials. Something has been said about the 
movements of the foot during progression. I do not intend at 
present to open up that question, but merely to state that 
the movements of the foot are not universally understood, 
with reference to the front foot more particularly. If we 
look at the various structures, we shall find the elastic por¬ 
tions are susceptible of compression; we know that there is 
sufficient room within the hoof for a certain amount of 
displacement to take place, if required, and it is required, 
I have no doubt, under some circumstances. It has been 
denied there is any downward movement at all of the bones of 
the foot. If we will take a little trouble, we shall however clear 
up this question in a short time. Smear some black oil upon 
the hoofs and allow the horse to walk upon a dusty road, and 
it will soon be found that the hair has wiped away a consider¬ 
able portion of the dust from the upper part of the hoof, 
much below the situation of the hair when the foot is at 
rest. This, I think, fully demonstrates the fact that there 
must be downward movement; and with reference to the long- 
talked-of expansion, it will be found that the greatest expansion 
is observable in connection with the lateral cartilages, and 
not in the horny structures. 
Nature seems to have provided the foot with those struc¬ 
tures which do not assume the state other soft parts of the 
