518 DISEASES OF THE BLADDER. 



Ischial urethrotomy is the promptest method of affordmg rehef, 

 and should always be preferred whenever there is danger of rupture 

 of the bladder. 



It is performed in the standing position, but is only possible when 

 the animal is not too fat. 



In other cases urethrotomy is performed opposite the point where 

 the calculus is fixed, and aims at removing the obstruction. It can 

 only be practised after casting the animal ; but, in this case also, it is 

 indispensable that the animal should not be excessively fat, as in such 

 cases a secondary urinary abscess is almost certain to form. 



Should the animal be so fat as to render treatment difficult, it is 

 best to slaughter it at once. 



URINARY CALCULI IN SHEEP. 



Urinary calculi are commoner in sheep than in oxen, and seem to 

 depend more on the breed and on conditions of feeding. They are 

 almost exclusively confined to animals which are richly fed, to show 

 animals, and to males. In exceptional cases they are seen, under 

 ordinary conditions of feeding, in aged subjects. 



Calculus formation can moreover be induced experimentally, and in 

 a relatively short time, by giving certain rations — e.g., 7 lbs. per day 

 of maize, lentils and beans for adults, and 3 lbs. for lambs. The other 

 favouring circumstances, viz., hereditary gouty diathesis and infection, 

 are less well established than they are in the case of the ox. 



In sheep the symptoms are still less characteristic than in oxen, 

 for which reason gravel in sheep merits special description. 



It shows itself in the passage of turbid urine, forming a deposit at 

 the extremity of the sheath, which becomes somewhat inflamed. The 

 colic resulting from retention of urine is shown by depression, want 

 of appetite, dysuria, and generalised convulsive shivering fits. 



The patients lie down in the sterno-abdominal or sterno-lateral posi- 

 tion. They constantly suffer from attacks of general violent shivering, 

 and die after twelve, twenty-four, or forty-eight liours. 



On post-mortem examination the bladder is found to be ruptured, 

 or the urethra obstructed. 



Diagnosis. The diagnosis involves no difficulty, provided the method 

 of feeding is understood. In many cases the shepherds themselves per- 

 fectly recognise the cause of the symptoms. 



Prognosis. The prognosis is very grave, it being impossible to pass 

 the catheter on account of the perineal valve in the urethra, while it is 

 difficult to operate, the urethra being very small and deeply embedded 

 in a thick layer of fat. 



