and any disease of the lungs subjected to appropriate treatment.
If the crystals are triangular prisms of ammonia-magnesium phosphate or
starlike forms with feathery rays, the indications are to withhold the feed
or water that abounds in magnesia and check the fermentation in the urine
by attempts to destroy its bacteria. In the latter direction plenty of
pure-water diuretics, and a daily dose of oil of turpentine in milk, or a
dose thrice a day of a solution containing one-tenth grain each of biniodid
of mercury and iodid of potassium would be indicated.

In considering the subject of prevention, it must never be forgotten that
any disease of a distant organ which determines the passage from the blood
into the urine of albumin or any other colloid (uncrystallizable) body is
strongly provocative of calculus, and should, if possible, be corrected.
Apart from cases from geological formation, faulty feeding, and other
causes, the grand preventive of calculus is a long, summer's pasturage of
succulent grasses, or in winter a diet of ensilage or other succulent feed.

The calculi formed in part of silica demand special notice. This agent is
secreted in the urine in the form of silicate of potash and is thrown down
as insoluble silica when a stronger acid displaces it by combining with the
potash to its exclusion. In cases of siliceous calculi, accordingly, the
appropriate chemical prevention is caustic potash, which being present in
the free state would attract to itself any free acid and leave the silica
in its soluble condition as silicate of potash.

STONE IN THE BLADDER (VESICAL CALCULUS, OR URETHRAL CALCULUS).

Stone in the bladder may be of any size, but in the ox does not usually
exceed half an inch in diameter. There may, however, be a number of small
calculi; indeed, they are sometimes so small and numerous as to form a
small, pulpy magma by which the bladder is considerably distended.

_Symptoms._--The symptoms of stone in the bladder may be absent until one
of the masses escapes into the urethra, but when this occurs the escape of
urine is prevented, or it is allowed to pass in drops or driblets only, and
the effect of such obstruction becomes manifest. The point of obstruction
is not always the same, but it is most frequently at the S-shaped curve of
the penis, just above the testicles or scrotum. In cows and heifers the
urethra is so short and becomes so widely dilated during the urination that
the calculi e