Here there is urine that requires to be discharged; but either the expulsive power is wanting, or the natural channel is obstructed.

The causes of retention are, -

1. Paralysis Of The Bladder

This may occur in various ways. For instance, a dog was shut up in a room for two days, and, being a cleanly animal, would not urinate until he was liberated. The muscular coat of the bladder was, of course, over-distended, and when the animal attempted to make water, he had lost the power to do so - the bladder could not contract upon, and expel its contents. Because there was dribbling of urine - an event which always follows chronic retention - Youatt incorrectly gives this case as an example of "incontinence of urine," which, in this instance, was merely a symptom of retention due to paralysis. Again, this paralysis may be the consequence of disease and injuries of the head, or of the spine; accompanies constitutional debility from any cause, such as distemper; co-exists with paralysis of the hind legs; and may follow the distention of the bladder, which disease of the prostate gland has been known to cause.

2. Stone In The Urethra

Another cause of retention of urine is, a Stone in the Urethra. The stone is arrested in its passage outwards, and becomes impacted in the canal.

Here it may fill up the passage and prevent the discharge of urine. The urine is retained in the bladder. There are frequent and strong efforts to pass the fluid, but none comes. There is pain and distress, and the bladder becomes distended. A case of this kind occurred in Blaine's experience. A Newfoundland dog had from forty to fifty stones in the bladder; one of them had passed into the urethra, and became fixed there; the flow of urine was consequently prevented, and mortification ensued.

The calculi of the urethra are cylindrical, with tapering ends; pale yellow in colour, and smooth on some parts of the surface, rough on others; the strata are irregularly arranged around a sedimentary nucleus. Silicic acid, carbonate of lime, and animal matter are the chief constituents.

The urgent symptoms may be relieved by pushing the stone backwards into the bladder, by means of the catheter.

3. Chronic Enlargement Of The Prostate Gland

Chronic Enlargement Of The Prostate Gland gives rise to retention. At first, when the swelling is small, there is no other symptom, except some difficulty in urinating; but, afterwards, as the enlargement increases, the posterior part of the urethra is pressed upon externally, and its calibre diminished. In proportion to the obstruction is the difficulty of passing water, and the pain and distress attending the act. At length, there is complete retention; the bladder is distended; the urine dribbles away incontinence as a symptom of retention. Rupture of the bladder may follow. Professor Simonds met with a case of this kind, in which rupture of the bladder, extravasation of urine into the peritoneal cavity, and fatal peritonitis, took place from the mechanical impediment to the flow of urine caused by prostatic hypertrophy, in a dog that had been affected with symptoms like the above for about two years.

Supposing this disease were correctly made out, Mercurius corrosivus, or Iodium, would be the most appropriate remedy.

4. Warm In The Urethra

In the Journ. Pratique for February 1828, M. Seon, veterinary surgeon, states that he was requested to examine a dog which was straining in vain to urinate, uttering loud cries, and then licking the penis. After having tried in vain to abate the irritation, he was on the point of passing an elastic bougie, when he discovered a something protruding from the urethral orifice with each effort at urinating, and then returning into the urethra. This something was seized with the forceps and withdrawn; it turned out to be a worm. The dog passed its urine freely and soon recovered. The worm was a strongylus.

Symptoms

The symptoms are: - First, Distention of the bladder; a state of things which any experienced person can satisfy himself of, by making the proper examination either through the walls of the belly, or through the rectum; in a word, the bladder is found full of urine. Secondly, There is pain on pressing over the bladder in the pubic region, and dulness when percussing it. Thirdly, The dog lies, and shifts about from one place to another; when made to walk, he does so unwillingly, with back arched and straggling gait. Fourthly, There are frequent, strong, straining, distressing efforts to urinate, but inability to do so; these efforts gradually abate as the bladder loses its sensibility. Fifthly, Not only is there inability to pass urine - retention of urine - but there is no power to hold it, and the fluid slowly dribbles away - incontinence of urine. This happens when the resistance to escape at the neck of the bladder is overcome by the pressure of the fluid behind; showing, as before stated, that incontinence is, in the majority of cases, a symptom of retention.

Treatment

The most successful remedies are Cantharis,* Nux vomica, and cold-water douches. If necessary, catheterism should be practised to evacuate the bladder.