than to imperfectly pare, since
canker, if undestroyed, develops far more rapidly under thin horn than
under thick.

'In conclusion, I would again urge the necessity, at the very first
operation, when the horse is down, of removing _every single particle_ of
the diseased tissue, either by excision or effectual cauterization, but at
the same time taking very great care to guard against the latter being
too destructive. The cautery should be laid aside as soon as the tissue
cauterized ceases to _burn white_. The moment at which the canker has
thus been eradicated without destroying sound tissue is indicated by
the appearance of healthy horn, by the intimate union of that with the
secreting surface, and by the healthy aspect of the exuded blood when
paring has been carried to the quick.

'Should subjacent healthy structures be destroyed during the process,
that is shown by the production of a raw sore, or of a sore to which a
"sit-fast," coextensive to the injury, is firmly attached. This seriously
retards recovery. The secreting surface having been destroyed, no new horn
can be produced directly from the part, and a new secreting surface and new
horn have now to grow inwards from the surrounding undestroyed tissue, and
that is a slow process. At the same time, on the principle of choosing
the least of two evils, practical experience teaches that it is better to
produce a small sore or a "sit-fast" than to leave a part of the canker
undetected; but, on the other hand, it is better to leave a small part
of canker undetected, which can be recognised and removed at the next
examination, than to cause a large slough. The object of the skilful
surgeon is, naturally, to avoid both extremes; and if trouble be taken to
carry out the procedure described, there need be no fear of the result.'[A]

[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. iv.,
p. 24.]

Treated in this way, the horse with cankered feet may be usually kept at
work during the whole time that treatment is carried out, and a cure is
obtainable in periods varying from six weeks to six or even twelve months.

The same essentials in treatment--namely, removal of diseased horn,
antiseptic dressings, and pressure--are insisted on by other writers.
Bermbach,[A] in 1888, treats canker as follows: The horse having been cast,
the undermined hoof-horn is removed with the knife, and the hypertrophied
sensitive structures, if necessary, reduced in th