d by the condition of his case. He should see that it is
not too far advanced, and that a great deformity of the hoof, or actual
exploration, does not indicate disease of the greater part of the wall.

_Treatment_.--From what has gone before, it will be seen that the
eradication of canker is no easy task, that it is, in fact, a most
difficult matter, and one not to be lightly undertaken. At the risk of
recapitulating what we have said before, we may mention here the two points
which the veterinarian must bear in mind. (1) That there is no actual
disease or alteration in structure of the deep layers of the keratogenous
apparatus. It is only the superficial, or horn-secreting, layer that
concerns us. (2) That the disease of this superficial layer is infection
with a material that may reasonably be presumed to be infective.

Put thus, treatment of canker would at first sight appear to be easy. One
would imagine that a simple and long-continued soaking of the entire foot
in a strong enough antiseptic would be all that was needed. Clinical
observation, however, shows that this is not so, and for this there must be
reasons.

The reasons are these: (1) Between us and the diseased layer upon which our
attention must be directed is often a layer of normal horn, effectually
protecting the tissues beneath from any dressing which we might consider
beneficial. (2) Anything applied with the object of destroying septic
material, but strong enough, or caustic enough, to injure the membrane upon
which we are working, only makes the case worse. The superficial layer of
the keratogenous membrane in which we have judged the disease to exist is,
after all, but a delicate structure. When attacked by the application of
too potent a drug its horn-secreting layer is easily destroyed, and thus,
although we may succeed in establishing asepsis, we cannot expect at the
point of injury a growth of horn. In its place we are confronted with large
outgrowths of inflammatory fibrous tissue. (3) Shedding of the diseased
horn and removal of the pressure exerted by the hoof faces us with
hypertrophy of the exposed villi. The difficulty of meeting this with an
adequate and evenly-distributed pressure is well enough known, and we find
in that a further reason that the treatment of canker is superlatively
difficult. (4) The material on which the animal has to stand is a distinct
bar to the maintaining of a strict asepsis.

When we have said this, it is easy