RETENTION OF URINE. 155 
bath. The great object is to arrest the efforts of the animal to urinate ; and 
when they are stopped, sometimes the bladder will empty itself. After the 
opium a dose of castor-oil should be administered. 
If these measures are unsuccessful, a surgeon should be called and the 
catheter used to evacuate the bladder. 
Retention associated with true paralysis demands the use of this instrument, 
and the employment of treatment elsewhere advised for the latter. 
A dog to be catheterized should be placed on his side or back, and held firmly 
by assistants, of whom there must be a sufficient number to keep the patient in 
position. 
Unless the operator is equally skilful with both hands, it would be well for 
him to grasp the external organ with the left and introduce the instrument with 
the right hand. : 
Catheters designed for use on man must generally be used, and the best form 
for him who has not had much experience in catheterizing dogs is that made of 
soft rubber. It should be of small size, and constantly rotated while it is entering. 
In the absence of a soft rubber catheter one made of hard rubber should be 
used, and with the wire stylet in place. This, however, should be first removed, 
and much of the bend taken from it, so that it will be nearly straight, the curve 
remaining being a long one—not short and confined to the end as when 
intended for use on man. 
When the patient is a female, the ordinary metallic or German silver catheter, 
appropriate for women, may be used, if she is‘of small breed ; but if of the largest, 
the male catheter of hard rubber will be much the best. The stylet of this 
should be bent at its outer end until it has that same short curve that is on the 
metallic female catheters. 
The catheter, having been well lubricated with sweet-oil, vaselin, or fresh lard, 
should be inserted with gentle force. The patient being a male, after passing 
easily for a short distance, the instrument will encounter an obstruction. Here 
the canal narrows a little, there is a bend in it, and a spasmodic contraction 
of its walls is generally excited. But steady pressure will soon cause this to yield, 
and the catheter will again pass in quite easily for a short distance, — until the 
so-called arch of the perineum is reached. 
If a hard rubber catheter is being used, the wire stylet must now be with- 
drawn at least one-third, to allow the instrument to make the curve. 
When the neck of the bladder is reached the muscles controlling the opening 
contract and resist further advance; but they soon relax under gentle pressure, 
and allow the bladder to be entered. The stylet should then be entirely with- 
drawn. 
In cases in which much difficulty is encountered in passing the catheter, the 
forefinger may be inserted in the rectum and the point of the instrument guided 
by it around the bend, where the trouble is located. 
