214 CALCULI. 
are as yet unknown in the horse. Cystic calculus signifies a stone which 
resides in the cavity of the bladder. Urethral calculus denotes a stone 
which was detected within the passage leading from the bladder. Of 
these the cystic are altogether the largest, and the renal, at a consider- 
able distance, rank as the next in magnitude. All consist of carbonate 
of lime or of common chalk, held firmly together by the secretion of the 
mucous membrane. 
The symptoms which characterize renal calculus are not well marked. 
The urine may become purulent, thick, opaque, gritty or bloody. Exer- 
tion may provoke extreme anguish, resembling a severe fit of colic; but 
the attack is distinguished from genuine gripes by the back, during the 
pain, being always roached. However, the most decided symptom is 
of a negative nature; being the absence of stone in the bladder to 
account for the diseased urine. The inference is, moreover, strengthened 
if, when the hand within the rectum is carried upward, pain and alarm 
are elicited; or if pressure made upon the loins causes the animal to 
shrink. 
Cystic calculus is denoted, as is the previous kind of stone, by certain 
conditions of the urine. Added to these general signs, the water, when 
flowing forth, will often be suddenly stopped, 
and every emission is followed by violent 
straining. Abdominal pains also are pres- 
ent; but the back is rather hollowed than 
roached. The point of the penis is, in par- 
ticular instances, constantly exposed; and 
the horse, when going down hill, sometimes 
pulls up short, either to recover from torture 
or to relieve the bladder. 
The way to ascertain the presence of cystic 
, calculus is to make an examination per rec- 
[ete oui, Make the investigation with all gen- 
tleness. The foreign body may then be dis- 
tinctly felt; even its size, form, and irregularities can by this means be 
discovered. 
Urethral calculus is a small stone which, during the flow of urine, 
has been carried out of the bladder and is spasmodically grasped by the 
muscle of the urethra. The passage is effectually closed and great suf- 
fering is induced. Should the stone be impacted within the exposed 
part of the canal, the precise situation is easily told. Behind the stop- 
page the passage is distended by fluid; while before it all is natural. 
The calculus should be cut down and removed; the wound being after- 
ward dressed with a solution of chloride of zinc—one grain to the ounce 
