t are not so well defined as is the circumference of fibrous
tumors, which they most resemble.

_Treatment._--The means recommended to bring the acute abscess "to a
head" are but rarely effectual with this variety; or, if successful, too
much time has been occupied in the cure. We must look for other and more
rapid methods of treatment. These consist, first of all, in carefully
exploring the tumor for the presence of pus. The incisions must be made
over the softest part and carried deep into the tumor--to its very
bottom, if necessary--and the matter allowed to escape. After this, and
whether we have found matter or not, we must induce an active
inflammation of the tumor, in order to promote solution of the thick
walls of the abscess. This may be done by inserting well into the
incision a piece of oakum or cotton saturated with turpentine, carbolic
acid, tincture of iodin, etc., or we may pack the incision with powdered
sulphate of zinc and keep the orifice plugged for 24 hours. These agents
set up a destructive inflammation of the walls. Suppuration follows, and
this should now be encouraged by hot fomentations and poultices. The
orifice must be kept open, and should it be disposed to heal we must
again introduce some of the agents above described. A favored treatment
with many, and it is probably the best, is to plunge a red-hot iron to
the bottom of the incision and thoroughly sear all parts of the walls of
the abscess. This is to be repeated after the first slough has taken
place if the walls remain thickened and indurated.

It is useless to waste time with fomentations, poultices, or blisters in
the treatment of cold abscesses, since though apparently removed by such
methods, they almost invariably return when the horse is put to work.
Extirpation by the knife is not practicable, as the walls of the tumor
are not sufficiently defined. If treated as above directed, and properly
fitted with a good collar after healing, there will not remain any track
or trace of the large, unsightly mass.

FISTULAS.

_Definition._--The word fistula is applied to any ulcerous lesion upon
the external surface of the body which is connected by ducts, or
passages, with some internal cavity. Because of this particular
formation the term fistulous tract is often used synonymously with the
word fistula. Fistulas may exist in any part of the body, but the name
has come to be commonly accepted as applicable only to such lesions when
fou