the bladder
it must be washed out by injecting water through a catheter by means of
a force pump or a funnel, shaking it up with the hand introduced through
the rectum and allowing the muddy liquid to flow out through the tube.
This is to be repeated until the bladder is empty and the water come
away, clear. A catheter with a double tube is sometimes used, the
injection passing in through the one tube and escaping through the
other. The advantage is more apparent than real, however, as the
retention of the water until the magma has been shaken up and mixed with
it hastens greatly its complete evacuation.

To prevent the formation of a new deposit any fault in feeding (dry
grain and hay with privation of water, excess of beans, peas, wheat
bran, etc.) and disorders of stomach, liver, and lungs must be
corrected. Give abundance of soft drinking water, encouraging the animal
to drink by a handful of salt daily. Let the feed be laxative,
consisting largely of roots, apples, pumpkins, ensilage, and give daily
in the drinking water a dram of either carbonate of potash or soda.
Powdered gentian root (3 drams daily) will also serve to restore the
tone of the stomach and system at large.

_Urethral calculus (stone in the urethra)._--This is less frequent in
horses than in cattle and sheep, owing to the larger size of the urethra
in the horse and the absence of the <b>S</b>-shaped curve and vermiform
appendix. The calculi arrested in the urethra are never formed there,
but consist of cystic calculi which have been small enough to pass
through the neck of the bladder, but are too large to pass through the
whole length of the urethra and escape. Such calculi therefore are
primarily formed either in the bladder or kidney, and have the chemical
composition of the other calculi found in those organs. They may be
arrested at any point of the urethra, from the neck of the bladder back
to the bend of the tube beneath the anus, and from that point down to
the extremity of the penis. I have found them most frequently in the
papilla on the extreme end of the penis, and immediately behind this.

_Symptoms of urethral calculus._--The symptoms are violent straining to
urinate, but without any discharge, or with the escape of water in drops
only. Examination of the end of the penis will detect the swelling of
the papilla or the urethra behind it, and the presence of a hard mass in
the center. A probe inserted into the urethra will strike agai