PARALYSIS OF THE URINARY BLADDER. 



639 



the urethra must not be injured internally, nor must infective or 

 decomposing material be introduced into it. Failure to observe 

 the latter precaution may result in decomposition of the urine, 

 inflammation of the bladder (cystitis), or even fatal pyelonephritis, 

 on account of the inflammatory processes spreading as far as the 

 pelvis of the kidney. 



In Germany elastic rubber tubes are generally employed ; the 

 outer opening is somewhat dilated, whilst the opposite end possesses 

 one or two lateral openings (eyes), by which the urine may enter 

 the catheter. A suitable stilette serves to assist the introduction 

 and cleansing of the instrument. 



For large male animals one large catheter generally suffices ; 



Fig. 437. — Median section of the bladder, urethra, vagina, and vulva of a cow. 

 a, Vagina ; 6, vulva ; d, bladder ; e, urethra ; /. blind sac below urethra ; g, clitoris. 



for dogs, flexible and metal catheters of varying calibre must be 

 kept. For mares and cows a slightly bent tube with a well-rounded 

 end is used, though in case of need the index or middle finger may 

 replace the catheter. The introduction of the catheter is seldom 

 difficult in these animals, if it be borne in mind that the outer opening 

 of the urethra lies on the lower wall of the vagina, over which the 

 instrument is allowed to glide forwards until it enters the urethra. 

 For cows Imminger uses a special instrument about 13 inches in 

 length and T 3 e inch in diameter, with a pointed end and a small round 

 head ; he also employs a metal catheter 12 inches long and I inch 

 thick, slightly bent towards the rounded point, which is f inch long. 

 Before passing the catheter, the cow's head is firmly tied to a ring 

 or the animal is thrust against a wall. The hand is oiled and passed 

 into the vagina, where the opening of the urethra is soon discovered 

 and is slightly dilated by passing the forefinger into it. The catheter 

 is then passed in and slipped beneath the finger into the urethra 

 and so into the bladder. As, in young animals, the forefinger can 



