main of blood- vessels, lympluilu-s, aud nerves extending Ix'tween tlie 

 notch on the inner border of the kidney to and from the oviter vascular 

 portion, in which the secretion of urine is almost exclusively carried 

 on; and ((/) a large saccular reservoir in the center of the kidney, into 

 which all uriniferous tubes pour their secretions and from which the 

 urine is carried away through a tube y (ureter), which passes out of 

 thenotcli at the inner 1)order of the kidney and which opens by a valve- 

 closed orifice into the roof of the bladder just in front of its neck. The 

 bladder is a dilatable reservoir for the retention of the urine until the 

 discomfort of its presence causes its voluntary discharge. It is kept 

 closed by circular muscular fibers surrounding its neck or orifice, and 

 is emptied by looped muscular fibers extending in all directions for- 

 ward from the neck around the blind anterior end of the sac. From the 

 bladder the urine escapes through a dilatable tube (urethra) which 

 extends from the neck of the bladder backward on the floor of the pel- 

 vis, and in the male through the penis to its free end, where it oi)ens 

 through a pink conical papilla. In the mare the urethra is not more 

 than an inch in length, and is surrounded by the circular muscular 

 fibers closing the neck of the bladder. Its opening may be found 

 directly in the median line of the fl(X)r of the vulva, about 4i inches 

 from its external opening. 



General symptoms. — These apjjly especially to acute inflammations 

 and the irritation caused l>y stone. The animal moves stiifly on the 

 hind limbs, straddles, and makes frequent attempts to -pass urine, 

 which may be in excess, deficient in amount, liable to sudden arrest 

 in spite of the straining, passed in driblets, or entirely suppressed. 

 Again, it may be modified in density or constituents. Difficulty in 

 making a sharp turn, or in lying down and rising with or without 

 groaning, dropping the back when mounted or when pinched on the 

 loins is suggestive of kidney disease, and so to a less extent are 

 swelled legs, dropsy, and diseases of the skin and nervous system. 

 The oiled hand introduced through the rectum may feel the bladder 

 beneath and detect any over-distension, swelling, tenderness, or stone. 

 In ponies the kidneys even may be reached. 



Examinaiion of the urine. — In some cases the changes in the urine 

 are the sole sign of disease. In health the horse's urine is of a deep 

 amber color and has a strong odor. On a feed of grain and hay it may 

 show a uniform transparency, while on a green ration there is an 

 abundant white deposit of carbonate of lime. Of its morbid changes 

 the following are to be looked for: (1) CoJor: White from deposited 

 salts of lime ; bro-rni or red from blood clots or coloring matter; yellow 

 or orange from bile or blood-pigment; pale from excess of water, or 

 variously colored from vegetable ingredients (santonin makes it red, 

 rhubarb or senna, brown; tar or carbolic acid, green). (2) Density: 

 The horse's urine maybe 1.030 to 1.050, but it may greatly exceed this 

 in diabetes and may sink to 1.007 in diuresis. (3) Chemical re-action, 



