URINARY APPARATUS. 169 



In adult male dogs only do we observe frequent and 



-voluntary urina ion. For this act they prefer places used for the 



same purpose by other dogs. Their choice places are trees the 



corners of '- — '--- -^-^ ^ i-iccs, mc 



ises. etc. 



When urme is voided the bladder contracts and this is aided 

 by the abdominal muscles. Every species of animal manifests 

 peculiarities of its own m this act, but it is a rule that all animals 

 stand while urinating. 



Horses (both sexes) urinate only while resting and cease feed- 

 ing tor the time; not infrequently they emit loud groans. 



Cows urinate similarly to mares, male cattle on the other 

 hand urinate not only while feeding but also while walkijig- in 

 tact, in these animals the act seems almost to be a passive one 

 _ Old dogs and pigs (male) void the urine in an interrunted 

 lerky stream. ^ 



a. The frequency of urination depends on the amount of 

 water imbibed, the amount of water lost by respiration, perspira- 

 tion, and per intest nal tract; accordingly it varies very consider- 

 ably. Healthy horses ordinarily urinate 5-G times a day. 



1. Abnormal frequency of urination occurs during in- 

 creased secretion of urine (polyuria) in the course of dia- 

 betes, and in chronic inflammation of the kidneys, temporarily 

 in the crisis of severe diseases (contagious pleuro-pneumonia 

 of horse). 



2. Urination is suppressed, when rupture of 

 the bladder has occurred (urethral calculus) in oxen; to 

 determine (in doubtful cases) whether or not an ox urinates 

 a clean cloth is tied in front of the opening of the urethra. 



b. Abnormally frequent attempts to urinate, only 

 slight quantities of urine being passed at each attempt, 

 stranguria. The cause of this is an abnormal irritability of 

 the mucous membrane of the bladder and urethra. Such 

 conditions are most frequently observed in the course of 

 colic in horses where the distended intestines (impaction, con- 

 stipation, tympanitis) exert a pressure on the bladder, or the 

 sense of fulness of the abdomen causes the animals to make 

 these attempts. Inflammatory conditions of the bladder 

 (bladder diseases, stone and gravel, neoformations, poison- 

 ing with irritating substances) or of the urethra (applica- 

 tions of pepper) are much le.ss common causes. Mares in 



