whether, however, as a result of the
treatment adopted or by reason of the structures within accommodating
themselves to the condition, we would not care to say.

[Illustration: FIG. 133.--OS PEDIS SHOWING THE GROOVE IN IT CAUSED BY
ATROPHY AND ABSORPTION INDUCED BY PRESSURE OF A KERAPHYLLOCELE.]

Other writers advocate the removal of that portion of the wall to which the
tumour is attached, after the manner described on p. 182, and illustrated
in Fig. 98. This, however, should be a last resource, and should be adopted
only when weighty reasons, such as excessive and otherwise incurable
lameness, appear to demand it.

4. KERATOMA.

In our nomenclature the terms 'Keratoma' and 'Keraphyllocele' are both used
to indicate the condition we have just described. There are some, however,
who reserve the term 'Keratoma' for horny tumours occurring only on the
sole, and for that reason we draw special attention to the word here.
Keratoma may thus be used to describe what we have called keraphyllocele
directly that growth makes its appearance at the sole, and is there able
to be cut with the knife. Similar hard and condensed growths may, however,
make their appearance on the sole in other positions quite removed from the
white line, plainly being secreted by the villous tissue of the sensitive
sole, and having no connection whatever with the sensitive laminae.
They appear as circular patches, varying in size from a shilling to a
two-shilling piece. Compared with the surrounding horn, they stand out
white and glistening, while in structure they are dense and hard, and
offer a certain amount of resistance to the knife. They are of quite minor
importance, and, beyond keeping them well pared down, need no attention.
Keratoma probably offers us the best analogy we have to corn of the human
subject.

5. THRUSH.

_Definition_.--A disease of the frog characterized by a discharge from it
of a black and offensive pus, and accompanied by more or less wasting of
the organ.

_Causes_.--The primary cause of this affection is doubtless the infection
of the horn, and later the sensitive structures, with matter from the
ground. Those factors, therefore, leading to deterioration of the horn, and
so exposing it to infection, may be considered here. Such will be changes
from excessive dampness to dryness, or _vice versa_; work upon hard and
stony roads; prolonged standing in the accumulated wet and filth of
insanitary stables, or long standin