360 
URETHRAL CALCULI IN THE HORSE. 
ordinary forceps passed into the urethra. Sometimes strong pressure on 
the penis with the hand is sufficient, or the urethral orifice may be 
enlarged, and the calculus thus removed. Urine then generally flows 
away in large quantities, if not, a catheter must be passed, to discover 
whether other calculi remain in the urethra. 
Landvatter removed from a gelding, by means of forceps, a calculus about 
If inches in length and £ inch thick, which lay in the terminal portion of the 
urethra. Two years later he took from the same animal a still larger one, 
which was fixed in the urethra 4 inches from the anus. Ueicherter grasped a 
calculus, lying If inches in front of the opening of the urethra, with a pair of 
dressing forceps and broke it down ; fragments were afterwards passed with 
the urine. In a case seen by Bother, the calculus, which lay about 2£ inches 
behind the glans, had caused ulceration and perforation of the urethra, in con¬ 
sequence of which urine had extensively infiltrated into the neighbouring 
tissues. The animal died from rupture of the bladder. Muller cured a horse 
apparently suffering from colic by removing two chalky concretions from the 
urethra; one from just behind the urethral orifice, the other about 4 inches 
further back. Concretions of inspissated smegma around the glans may also 
cause dysuria in the horse. 
Two cases of urinary calculi passed per urethram are related in The 
Veterinarian for 1896, pp. 29 and 30. A. M. McFarlane saw a horse 
apparently suffering from colic pass a stone weighing 20 grammes (about 5 
drachms), and of the size of the illustration (see fig. 159). Thos. Mellis saw a 
three months old foal, which was violently straining to micturate and was 
evidently in great pain. On examination the body illustrated (fig. 160) was 
found protruding from the meatus urinarius, and was without much difficulty 
removed. The figure is natural size, but Mr. Mellis states that nearly 1 inch 
was broken off in removal, and the total size was therefore much greater. 
This was probably a cystin calculus. 
As a rule, in the horse, the calculus lies at the height of the ischial 
arch, where the urethra turns downwards and forwards. As casting an 
animal with distended bladder is open to danger, it is usual to operate 
in the standing position, the patient being controlled by twitches and its 
hind legs extended. To prevent accidents it is best to place the animal 
in slings or stocks, so that it cannot lie down. Should a really dangerous 
horse require to be cast, every precaution must be taken, and a very thick 
straw bed provided. It is best to operate with the animal on the left 
side or back; the latter is perhaps preferable. 
After plaiting the tail and cleansing the skin, a catheter is passed, 
and an incision 1J to 2J inches long made through the skin immediately 
over the urethra, that is, in the middle line of the body and over the 
point where the calculus can be felt. This is successively carried through 
the retractor penis muscle, the accelerator urinse, the corpus spongiosum 
of the penis, and, finally, the urethra itself. The incision should 
gradually become smaller as it penetrates deeper, so as to favour the 
free exit of wound discharges and of urine. The incision into the wall 
of the urethra must be as small as will allow exit of the calculus, which 
