186 DISEASES OF THE HORSE’S FOOT 
as a rule content to confine his operations to the sole alone. 
In addition, the frog and the bars also suffer from the too 
lavish use of his knife. His main object is doubtless that 
of giving a broad and open appearance to the foot. It 
follows from this that his operations are confined more to 
the posterior than the anterior parts of the foot, and that 
the toe is therefore left too long. This gives us a com- 
bination of causes leading to pressure and bruises upon the 
sensitive structures at the seat of corn. 
By this unequal paring of the toe and the heels greater 
weight is thrown upon the posterior half of the foot. 
What then happens to the structures thinned as we have 
described is this: the pared frog, lessened in volume, does 
not meet the ground. It therefore fails to expand laterally 
with weight, and cannot assist, as normally it should, in 
aiding the heels generally in their movements of expansion. 
The weakened bars and the thinned sole, meeting with no 
opposition from the frog, give downwards and inwards with 
the body-weight at the precise moment these movements 
should be directed mainly outwards. As a further result 
of non-resistance on the part of the frog, this time in a 
lateral direction, the bars, the sole, and the wall at the heels 
all contract at the exact time they should expand. The 
end result must mean abnormal pressure and bruising of 
the sensitive structures in that particular region. Naturally, 
also, the excessive thinning of the horn renders direct 
injury to the sole from stones or other objects in the road 
far more probable. 
For this one reason alone—the manner in which it 
favours the production of corn—too great a condemnation 
cannot be placed upon excessive paring of the sole, the 
bars, and the frog. 
When corns are already present, as they may be from 
other causes, the same remarks will again apply to ex- 
cessive paring. It is the custom with many smiths to 
carefully pare down the discoloured horn in every case of 
corn they meet with, and at the same time to again weaken 
the bars and even part of the wall at the heels, with the 
