uncomplicated by septic infection, these symptoms rapidly
subside, and resolution occurs.

Always, however, the presence of septic infection must be suspected and
looked for. When this has occurred, the inflammatory swelling becomes
larger and more diffuse, and the animal fevered. This is then followed by
a slough of the injured part. A portion of the skin first becomes gray, or
even black, in appearance, and around it oozes an inflammatory exudate, or
even pus. The skin immediately adjoining the spot of necrosis is swollen
and hyperaaemic, and extremely painful and sensitive. Later, the necrosed
portion becomes cast off, and an open wound remains. This as a rule marks
the turning-point in the case. The pain and other symptoms rapidly abate,
and the wound, with proper attention, is not more than ordinarily difficult
to treat.

In the case of an actual wound the symptoms are probably less severe. The
injury is, in this instance, the sooner detected, and remedial measures put
into operation. In this manner the formation of septic material is often
checked, and nothing but the treatment of a simple wound demands attention.

There are, however, complications.

_Complications--(a) Diffuse Purulent Inflammation of the Sub-coronary
Tissue_.--This condition is brought about by the spread into the loose
tissue of the coronary cushion of the septic material introduced by the
tread. The whole coronet in this instance becomes excessively swollen, hot,
and painful, and the dangerous nature of the complication is evident enough
when the structure and situation of the parts involved is considered. The
amount of tendinous and ligamentous material in the neighbourhood offers
a strong predisposition to necrosis, and the necrosis, with its attendant
formation of pus, offers a further danger when the close proximity of
the pedal articulation and the unyielding character of the horny box is
considered with it.

The pus formed in this condition may remain confined to the coronet and
break through the skin as an ordinary abscess, or it may, before so doing,
burrow beneath the wall, and invade the sensitive laminae. In this case,
whenever portions of the secreting layer of the keratogenous membrane are
destroyed, or perhaps only temporarily prevented from fulfilling their
horn-producing functions, then corresponding cavities in the horn are the
result (see Fig. 109).

_(b) Purulent Arthritis_.--Only too readily the pus so formed tends to