URINARY APPARATUS. 179 



groan, and void urine in drops or thin streams. The seat 

 of the pain may be in the bladder or in the urethra (concre- 

 ments, strictures, inflammations). Sometimes the pain is 

 caused by abdominal pressure in peritonitis. 



d. Retention of urine (ischury) is attended with accu- 

 mulation of urine in the bladder. It is observed: 



1. In obstruction of the urethra (concre- 

 ments, swellings, strictures, tumors). In such cases the urine 

 is voided in drops or thin streams, and frequently with symp- 

 toms of pain. 



2. In paralysis of the bladder; frequently 

 associated with paralysis of the rectum and of the tail. 



e. Inability to retain urine, incontinentia urinae, occurs 

 as a result of paralysis or weakening of the sphincter of the 

 bladder, or as a result of diminished sensitiveness of the 

 urethral mucous membrane, thus suspending the reflex ex- 

 citability of the sphincter. Most frequently observed in dogs 

 in the course of distemper (spinal affection) but otherwise 

 rare in animals. 



II. Examination of the Urine. 



A. Macroscopical Examination. 



a. The quantity of urine voided depends on the same 

 conditions that regulate the frequency of voiding it: on the 

 average horses secrete 4-5 liters, cattle 6-1? and dogs %-l 

 liter per day. As a rule we determine the quantity of urine 

 voided daily by making an estimate. Collecting the urine for 

 actual measurement is cumbersome and, besides, not exact. 



An increase in the quantity of urine occurs in : 



Diabetes insipidus [polyuria] (very marked) diabetes 

 mellitus (which is rare), the daily average may be 40 liters. 



Most forms of chronic nephritis. 



During reabsorption of profuse exudates and in the criti- 

 cal stage of severe infectious diseases. 



