la,' or
little pipe, we have ourselves already indirectly restricted the use of the
word to the two latter conditions, for in those varieties known as Simple
or Cutaneous and Tendinous, the wound is generally broad and open, or,
at any rate, superficial, and can scarcely be strictly described as
'fistulous.' In the two latter, however, a true fistula exists. These,
however, have only one essential difference, and that consists simply in
the position of the lesion and the structures it has attacked. In the main
the symptoms will be the same, the disease in each case about equally
serious, and in each the same essentials of treatment will have to be
regarded.

In our opinion, therefore, a lengthy classification serves no useful end,
and we think matters will be simplified by considering quittor under
two headings only--namely, 'Simple or Cutaneous' and 'Sub-horny,' and
discussing the other varieties as simply complications of either of these
two.

1. SIMPLE OR CUTANEOUS QUITTOR.

_Definition_.--This condition is simply a sloughing of a portion of the
skin of the coronet, together with a portion of the immediately underlying
soft structures.

_Causes_.--This form of quittor has its origin more often than not in
contusions, punctures, or wounds of the region severe enough to cause death
of a small portion of the tissues. In this case the low vitality of the
parts does not allow of the dead portion being removed piecemeal by a
process of phagacytosis, as is usually the case with similar injuries
elsewhere. Instead, the tissues around, aided by a process of suppuration,
cast the offending portion off as a slough. It is the wound remaining after
the slough which we may really regard as a quittor. In this connection may
be considered as causes blows from falling shafts, self-inflicted treads,
or treads from other horses, overreach, etc. On the other hand, simple or
cutaneous quittor may occur without ascertainable cause. In this case we
can only explain its appearance, as we did that of simple coronitis (see p.
231), by attributing it to septic infection through a wound or a blow that
is able to inoculate the skin, yet which is insufficient to cause pain, or
in any other way attract the attendant's notice. Meanwhile, the spot of
infection thus started spreads, and the end result is an abscess in the
coronary region, again accompanied with necrosis and sloughing of more or
less skin and other tissue, which terminates by disc