THE URETERS AND URINARY BLADDER 377 



endings of nerve fibrils were shown. Some authors have claimed renal vaso- 

 constriction following vagus stimulation, but the fact seems not to be uni- 

 versally admitted. 



The Ureters and Urinary Bladder. The duct of each kidney, the 

 ureter, is a tube about the size of a goose-quill and from twelve to sixteen 

 inches in length. It is continuous above with the pelvis of the kidney, and 

 ends below by obliquely perforating the walls of the bladder and opening 

 on its internal surface. It has three principal coats, an outer fibrous, a 

 middle muscular, of which the fibers are unstriped and arranged in three 

 layers. The fibers of the central layer are circular, and those of the other 

 two layers longitudinal in direction. It has an internal mucous lining con- 

 tinuous with that of the pelvis of the kidney above and the lining of the urinary 

 bladder below. The urinary bladder, which forms a receptacle for the tem- 

 porary lodgment of the urine in the intervals of its expulsion from the body, 

 is more or less pyriform. Its widest part, which is situated above and be- 

 hind, is termed the jundus; and the narrow constricted portion in front and 

 below, by which it becomes continuous with the urethra, is called its cervix 

 or neck. It is constructed of four principal coats: serous, muscular, areolar 

 or submucous, and mucous. The fibers of the muscular coat deserve special 

 mention. They are unstriped, are arranged in three principal layers, of 

 which the external and internal have a general longitudinal, and the middle 

 layer a circular, direction. The latter are especially developed around the 

 cervix of the organ, and are described as forming a sphincter vesicae. The 

 mucous membrane is provided with mucous glands, which are more numer- 

 ous near the neck of the bladder. 



The bladder is well provided with blood- and lymph-vessels, and with 

 nerves. The latter are from the sacral plexus (spinal) and hypogastric 

 plexus (sympathetic). Ganglion-cells are found, here and there, in the 

 course of the nerve fibers. 



THE URINE. 



Quantity and General Properties. Healthy urine is a perfectly 

 transparent amber-colored liquid, with a peculiar but not disagreeable odor, 

 a bitterish salty taste, and a specific gravity of from 1020 to 1025. The urine 

 consists of water holding in solution certain organic and saline matters as its 

 ordinary constituents, and occasionally various other matters. Some of the 

 latter are indications of diseased states of the system, and others are derived 

 from unusual articles of food or drugs taken into the stomach. 



The total quantity of urine passed in twenty-four hours is influenced 

 by numerous circumstances. In adults of average size and medium ac- 

 tivity the daily amount of urine may be given as from 1,200 c.c. to 1,500 c.c. 

 In Chittenden's recent observations on nine athletic students and on eight 



