748 GENITO-UKINARY ORGANS. 



portion of the urethra, or directly to remove one from the spongy- 

 portion opposite the ischial curve. 



Calculi fixed in the intra-pelvic region are detected by rectal 

 exploration. 



The exact position of the foreign body is determined by inspec- 

 tion and palpation, whilst distension of the urethra by urine may 

 be noted even before more striking symptoms appear. 



The urethra can be incised by one of three methods. 



The animal should be secured, if possible, in the standing 

 position. 



The first method, which dates back to very early times, consists 

 in puncturing the urethra at one stroke with the fleam or lancet, 

 and Oldening it more freely, after introducing a grooved director. 

 This method is very useful where rupture of the bladder is 

 imminent. 



The extraction of a calculus fixed in the ischial region, or the 

 manipulation of an obstruction at any other point, can afterwards 

 be undertaken. 



Second method. A second method consists in incising the sub- 

 cutaneous tissues, layer by layer, until the urethra is reached at 

 the ischial arch. 



The operation is terminated by puncturing the urethra and 

 enlarging the incision in an upward direction after passing a grooved 

 director. This method minimises haemorrhage and urinary infiltra- 

 tion. By previously injecting cocaine, the operation may be made 

 practically painless. 



Third method. Puncture of the urethra by a single sti'oke with 

 a straight bistoury at the ischial arch. 



The opening is enlarged in an upward direction with the same 

 instrument. 



SCROTAL URETHROTOMY. 



Scrotal urethrotomy is necessary when the calculus is situated 

 in one of the S-shaped curves of the penis or nearer the glans. 



The operation is facilitated by casting the animal and with- 

 drawing the penis from the sheath, but as there is considerable 

 danger of rupturing the bladder when casting an animal with 

 marked distension of that organ, the more serious operation should be 

 preceded by puncturing the urethra with a fleam at the ischial arch. 



By repeated moderate traction on the extremity of the glans, the 

 S-shaped curve can be obliterated and the anterior portion of the 

 penis withdrawn beyond the sheath. 



One of two conditions may exist, 



