These are more or less spherical, dark brownish green, and usually found
in the gall bladder or larger bile ducts. They may vary in size from a
pea to a hazel nut. Their chemical analysis is wanting.
_Symptoms._ There may be evidence of biliary obstruction and if this
occurs intermittently and is associated with colic, it becomes somewhat
characteristic. Constipation, emesis, icterus, and sometimes tenderness
of the right hypochondrium would indicate the source of the colic. A
pre-existing and concurrent catarrh of the bowels corroborates these
indications.
Cadeac explains that the obstructing calculus is called on to resist the
impulse of the bile forced upon it by the spasmodic contraction of the
bile ducts, which distends the bile duct immediately back of the stone
to perhaps ten times its normal size. Then under a suspension of the
spasm or even an antiperistaltic contraction of the duct, the calculus
is forced back into the dilated portion or even into the gall-bladder,
and the attack is relieved. Under repeated irritations of this kind the
inflammation of the bile ducts extends into the liver and determines
cirrhosis. The irritation further through the sympathetic produces a
reflex constriction of the pulmonary capillaries, with the natural
results of increasing tension of the pulmonary artery and right heart,
and dilatation and degeneration of the walls of the latter even in the
best nourished animals. Thus dyspnœa and modified heart sounds (murmurs)
may be symptoms of biliary calculi.
_Treatment._ Three or four ounces of olive oil were found to greatly
increase the quantity and fluidity of the bile in from thirty to
forty-five minutes. Bile, sulphate of soda and salicylate of soda are
excellent cholagogues, and the latter at the same time an antiseptic.
Anti-spasmodics are especially indicated to relieve the colics, but they
must be used in relatively smaller doses than in the herbivora. Potassic
and sodic carbonates or tartrates (Vichy) may be used as enemas if they
cannot be administered by the mouth. Fomentations may be resorted to.
The food must be laxative and aqueous, and exercise must be imposed as
far as the animal can bear it.