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the posterior part of the hoof, and their healthy and normal action
doubtless contributes in an important degree to the perfect performance
of the functions of that part of the leg. These organs are, however,
liable to undergo a process of disease which results in an entire change
in their properties, if not in their shape, by which they acquire a
character of hardness resulting from the deposit of earthy substance in
the intimate structure of the cartilage, and it is this change, when its
consummation has been effected, that brings to our cognizance the
diseased growth which has received the designation of sidebones. They
are situated on one or both sides of the leg, bulging above the superior
border of the hoof in the form of two hard bodies composed of ossified
cartilage, irregularly square in shape and unyielding under the pressure
of the fingers.

_Cause._--Sidebones may be the result of a low inflammatory condition or
of an acute attack as well, or may be caused by sprains, bruises, or
blows; or they may have their rise in certain diseases affecting the
foot proper, such as corns, quarter cracks, or quittor. The deposit of
calcareous matter in the cartilage is not always uniform, the base of
that organ near its line of union with the coffinbone being in some
cases its limit, while at other times it is diffused throughout its
substance, the size and prominence of the growth varying much in
consequence.

_Symptoms._--It would naturally be inferred that the degree of
interference with the proper functions of the hoof which must result
from such a pathological change would be proportioned to the size of the
tumor, and that as the dimensions increase the resulting lameness would
be the greater in degree. This, however, is not the fact. A small tumor
while in a condition of acute inflammation during the formative stage
may cripple a patient more severely than a much larger one in a later
stage of the disease. In any case the lameness is never wanting, and
with its intermittent character may usually be detected when the animal
is cooled off after labor or exercise. The class of animals in which
this feature of the disease is most frequently seen is that of the
heavy draft horse and others similarly employed. There is a wide margin
of difference in respect to the degrees of severity which may
characterize different cases of sidebone. While one may be so slight as
to cause no inconvenience, another may develop eleme