h which the flexor
tendons slide. The dilatation of this articular synovial sac is what is
denominated bog spavin, the term thoroughpin being applied to the
dilatation of the tendinous capsule.

The bog spavin is a round, smooth, well-defined, fluctuating tumor
situated in front and a little inward of the hock. On pressure it
disappears at this point to reappear on the outside and just behind the
hock. If pressed to the front from the outside it will then appear on
the inside of the hock. On its outer surface it presents a vein which is
quite prominent, running from below upward, and it is to the
preternatural dilatation of this blood vessel that the term blood spavin
is applied.

The thoroughpin is found at the back and on the top of the hock in that
part known as the "hollows," immediately behind the shank bone. It is
round and smooth, but not so regularly formed as the bog spavin, and is
most apparent when viewed from behind. The swelling is usually on both
sides and a little in front of the so-called hamstring, but may be more
noticeable on the inside or on the outside.

In their general characteristics bog spavins and thoroughpins are
similar to windgalls, and one description of the origin, symptoms,
pathological changes, and treatment will serve for all equally, except
that it is possible for a bog spavin to cause lameness, and thus to
involve a verdict of unsoundness in the patient, a circumstance which
will, of course, justify its classification by itself as a severer form
of a single type of disease.

We have already referred to the subject of treatment and the means
employed--rest, of course--with liniments, blisters, etc., and what we
esteem as the most active and beneficial of any, early, deep, and
well-performed cauterization. There are, besides, commendatory reports
of a form of treatment by the application of pressure pads and peculiar
bandages upon the hocks, and it is asserted that the removal of the
tumors has been effected by their use. Our experience with this
apparatus, however, has not been accompanied with such favorable results
as would justify our indorsement of the flattering representations which
have sometimes appeared in its behalf.

OPEN JOINTS, BROKEN KNEES, SYNOVITIS, AND ARTHRITIS.

The close relationship which exists among these several affections,
their apparently possible connection as successive developments of a
similar, if not an essentially identical, origin, together wit