as
exposed the soft tissues of the foot, the wound shows no tendency to
heal, but instead there is secreted from the inflamed parts a profuse,
thin, fetid, watery discharge, which gradually undermines and destroys
the surrounding horn, until a large part of the sole and frog is
diseased. The living tissues are swollen, dark colored, and covered at
certain points with particles of new, soft, yellowish, thready horn,
which are constantly undergoing maceration in the abundant liquid
secretion by which they are immersed. As this secretion escapes to the
surrounding parts, it dries and forms small, cheesy masses composed of
partly dried horny matter, exceedingly offensive to the sense of smell.
When the disease originates independently of an injury, the first
evidences of the trouble are the offensive odor of the foot, the liquid
secretion from the cleft and sides of the frog, and the rotting away of
the horn of the frog and sole.

In the earlier stages there is no interference with locomotion, but
later the foot becomes sensitive, particularly if the animal is used on
rough roads, and, finally, when the sole and frog are largely destroyed
the lameness is severe.

_Treatment._--Since canker does not destroy the power of the tissues to
produce horn, but rather excites them to an excessive production of an
imperfect horn, the indications for treatment are to restore the parts
to a normal condition, when healthy horn may again be secreted. In my
experience, limited though it has been, the old practice of stripping
off the entire sole and deep cauterization, with either the hot iron or
strong acids, is not attended with uniformly good results.

I am of the opinion that recovery can generally be effected as surely
and as speedily with measures which are less heroic and much less
painful. True, the treatment of canker is likely to exhaust the
patience, and sometimes the resources, of the attendant; but after all
success depends more on the persistent application of simple remedies
and great cleanliness than on the special virtues of any particular
drug.

First, then, clean the foot with warm baths and apply a poultice
containing powdered charcoal or carbolic acid. A handful of the charcoal
or a tablespoonful of the acid mixed with the poultice serves to destroy
much of the offensive odor. The diseased portions of horn are to be
carefully removed with sharp instruments, until only healthy horn
borders the affected parts. The e