URINE (Lat. urine, urine; connected with Gk. apop, ouron. urine. Skt. rani, rir, water, Av. yam rain, Icel. fir, drizzling rain, AS. aver, sea). The fluid which is secreted by the kid neys, stored in the bladder, and evacuated through the urethra in the act of micturition. The epithelium lining the tubules of the kidneys elaborates from the blood urea and other products of retrograde metamorphosis. and a transudation or osmosis of water occurs from the interior of the convoluted blood vessels into the cavity of the tubules.
In a healthy human being, urine is a clear yellowish or amber fluid of a salty taste and a peculiar aromatic odor, normally acid, and with a specific gravity of about 1.020, and generally containing sonic mucus. In 24 hours such a person discharges about 50 fluid ounces, or 1500 cubic centimeters. of urine. The amount of the several urinary constituents passed in 24 hours are as follows, according to Parkes: These constituents, other than water, appear in the urine as ( 1 ) inorganic salts, including sodium chloride; calcium chloride; potassium and sodium sulphates; sodium, calcium. and mag nesium phosphates: traces of silicates; alkaline carbonates; nitrates in small quantity; traces of iron. (2) Nitrogenous crystalline bodies, in cluding urea, uric acid, kreatiuin, %anthill, hypo xanthin, and occasionally allantoin; hippuric acid, ammonium oxalate; and rarely taurin, cystin, 'mein. and tyrosin. (3) Non-nitrogenous bodies, including lactic, succinie, formic, oxalic, and phenylie acids; and rarely sugar in minute amount. (4) Pigments, including urobilin, pur purin, and indican. (5) Other bodies, including ferments from the various digestive fluids of the body. (6) Gases, rarely, in very small quan tities, chiefly nitrogen and carbonic acid.
The acidity of normal urine is due to the pres ence of the acid sodium biphosphate. At times the urine of digestion is alkaline, and frequently urine decomposes rapidly and becomes alkaline. Upon standing and cooling, it frequently becomes cloudy from the uratcs, and a sediment of pink urates occurs; or in other cases an increase of oxalate of ammonium, together with mucus, forms a thick precipitate or deposit. This occurrence by no means indicates disease of the kidneys, as is claimed by ignorant quacks. Among the ab normal constituents of urine are blood, pus, epithelium from bladder, kidney, ureter or vagina, spermatozoa, albumin, fibrin in the form of 'casts,' fats, sugar, etc., during various con ditions or diseases. In Bright's disease (q.v.) albumin and casts are generally found.
Urea is determined most easily by a test with hypobromate of potassium. The total excretion per day should be between 300 and 600 grains. Uric acid generally precipitates in a few days if the urine be allowed to stand. It may be de termined by a hydrochloric acid procedure. Sugar is generally detected by using a solution of sul phate copper, which is reduced and precipitated in the form of the orange-colored oxide in the presence of glucose. Albumin responds to boiling or the nitric acid test, either of which causes a permanent cloud in the urine if albumin be present. Phosphates cause a white cloud on boiling the urine, which is dissolved and cleared away by adding a drop of acetic acid. Chlorides, ammonia, and urates have their special chemical tests.