Normal urine is a clear, watery fluid, with an acid reaction and a
specific gravity of from 1018 to 1020. It is composed of inorganic
salts, organic constituents, together with some coloring and a small
amount of mucus.
The most important of these inorganic salts are chlorid of sodium,
phosphate of potassium, and the sulphates of calcium and magnesium.
The inorganic constituents are chiefly urea, uric acid, and poisonous
inorganic substances found in the body. The normal amount of urine
voided by an adult weighing 160 pounds is from 40 to 70 ounces in
twenty-four hours. The amount may be increased by drinking large
quantities of fluid, especially water, and diminished by perspiration,
emotion, and copious bowel movements.
_Normal urine_ is aromatic. In health it may be faintly alkaline at
certain times of the day. Urine passed in the morning has an acid
reaction, a high specific gravity, and a dark color. After a hearty
meal it may be turbid—perhaps alkaline, and of low specific gravity.
Large quantities are pale, and vary with concentration. When just
passed it is clear; then it collects a cloudy material made up of
mucous corpuscles, which can be easily shaken up. Concentrated urine,
when it cools, deposits a pinkish (brick-dust) precipitate. Gentle heat
clears it up. When highly concentrated the crystals are red. When they
collect and adhere together they become stones; if all precipitate on
heating it is normal urine.
_Alkaline urine_ throws down phosphates that are held in solution
and clears up on addition of any acid; if urine is cold and acid in
reaction, sediment, if present, may be urates, but is not phosphates;
if urine is alkaline, they are normal phosphates.