70 VETERINARY STUDIES 



sium, calcium, etc., together with various organic matters, as 

 urea and uric acid, and various aromatic substances which give 

 the odor. Its reaction in herbivorous animals is alkaline. The 

 specific gravity for horse's urine is about 1036, and for cow 

 1025. Either may vary within the normal range. Horses ex- 

 crete about 10 pints in 24 hours, and cattle about 25 pints. The 

 urine is continuously excreted by the kidneys and runs, drop 

 by drop into the bladder. 



Ureters. — These are two slender tubes which conduct urine 

 from the kidneys to the bladder. They are about the size of a 

 goose quill, about one foot long, and they terminate at the blad- 

 der, where they extend for an inch, between its muscular and 

 mucous coats, before reaching the interior, preventing backward 

 flow of urine into the ureters. 



Bladder. — The bladder is a muscular sac, a urine reservoir, 

 ovoid in shape, located in the inferior and anterior part of the 

 pelvic cavity. This organ is supported in place by several liga- 

 ments, which attach to neighboring organs. It is in relation 

 above, in the male, to the rectum ; in the female, to the uterus 

 and vagina and below to the floor of the pelvis. It is covered 

 in front by peritoneum and is in relation to the coiled small 

 intestine. 



Openings. — There are three openings, all on the posterior por- 

 tion of the organ : viz., one leading to the urethra, and two for 

 the ureters. The neck of the bladder contains circular muscle 

 fibers which act as a sphincter and control the outlet to the 

 urethra. 



Coats. — The bladder has three coats, mucous, muscular (of 

 several layers), and serous (peritoneal). The latter covers only 

 a portion of the bladder. 



Urethra. — This canal conducts urine from bladder to exterior 

 of body. 



Practical application. — The kidneys should be seen by the 

 student as a device for bringing a constantly renewed and thin 

 sheet of blood as close as possible to a thin sheet of epithelial 

 cells, lining a suitable device (urine tubules) for carrying off 

 the product. 



The ureters, bladder, and urethra should be seen as mechani- 

 cal devices for disposing of the urine. 



Disorders of the urinary organs are numerous, but not of 

 common occurrence. Diabetes is indicated by excessive and fre- 



