uinus_ or a related species, may be
found in the renal artery or in the kidney itself.

SPASM OF THE NECK OF THE BLADDER.

This affection consists in spasmodic closure of the outlet from the
bladder by tonic contraction of the circular muscular fibers. It may be
accompanied with a painful contraction of the muscles on the body of the
bladder; or, if the organ is already unduly distended, these will be
affected with temporary paralysis. It is most frequent in the horse, but
by no means unknown in the mare.

_Causes._--The causes are usually hard and continuous driving without
opportunity for passing urine, cold rainstorms, drafts of cold air when
perspiring and fatigued, the administration of Spanish fly or the
application of extensive blisters of the same, abuse of diuretics, the
presence of acrid, diuretic plants in the fodder, and the presence of
stone in the bladder. As most mares refuse to urinate while in harness,
they should be unhitched at suitable times for urination. Spasms of the
bowels are always attended by spasm of the bladder, hence the free
passage of water is usually a symptom of relief.

_Symptoms._--The symptoms are frequent stretching and straining to
urinate, with no result or a slight dribbling only. These vain efforts
are attended by pain and groaning. On resuming his natural position the
animal is not freed from the pain, but moves uneasily, paws, shakes the
tail, kicks at the abdomen with his hind feet, looks back to the flank,
lies down and rises, arches the back, and attempts to urinate as before.
If the oiled hand is introduced into the rectum the greatly distended
bladder may be felt beneath, and the patient will often shrink when it
is handled.

It is important to notice that irritation of the urinary organs is often
present in impaction of the colon with solid matters, because the
impacted intestine under the straining of the patient is forced backward
into the pelvis and presses upon and irritates the bladder. In such
cases the horse stands with his fore limbs advanced and the hind ones
stretched back beyond the natural posture and makes frequent efforts to
urinate, with varying success. Unpracticed observers naturally conclude
that the secondary urinary trouble is the main and only one, and the
intestinal impaction and obstruction is too often neglected until it is
irremediable. In cases in which the irritation has caused spasm of the
neck of the bladder and overdistention of that