162 DISEASES OF THE HORSE. 
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 laxa- 
tive, 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 (8 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 S-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. J 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 strain- 
ing 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 against the gritty calculus. If the stone has been arrested 
higher up, its position may be detected as a small, hard, sensitive 
knot on the line of the urethra, in the median line of the lower sur- 
face of the penis, or on the floor of pelvis in the median line from 
the neck of the bladder back to the bend of the urethra beneath the 
anus. In any case the urethra between the neck of the bladder and 
the point of obstruction is liable to be filled with fluid, and to feel 
like a distended tube, fluctuating on pressure. 
Treatment of urethral calculus may be begun by an attempt to 
extract the calculi by manipulation of the papilla on the end of the 
penis. This failing, the calculus may be seized with a pair of fine- 
pointed forceps and withdrawn from the urethra; or, if necessary, a 
probe-pointed knife may be inserted and the urethra slightly dilated, 
or even laid open, and the stone removed. If the stone has been 
arrested higher up it must be extracted by a direct incision through 
the walls of the urethra and down upon the nodule. If in the free 
