Blue litmus paper immersed in urine turning red, shows that urine is acid.
Red litmus paper immersed in urine, turning blue, shows that urine is alkaline.
Red litmus paper immersed in urine, turning blue and returning to red on drying shows that the urine contains a volatile alkali (ammonium carb.)
Scanty and high colored urine is associated with acute, febrile and inflammatory diseases; pale urine with diseases of relaxations.
Deposits, ropy and viscid. Add a drop of nitric acid; if wholly or partly dissolved it is composed of phosphates, but is slightly affected with mucus. If deposits fall like a creamy layer to the bottom of a vessel, the supernatant urine being coagulable by heat, it consists of pus.
Opaque from presence of a light flocculent matter, diffused through it, having neither the tenacity of mucus nor dense opacity of pus, a little placed in a tube with equal bulk of liquor potassae will often become a stiff, transparent jelly. This shows presence of the exudation or large organic globules formed under the influence of irritation, providing the urine does not coagulate by heat; should it do so minute quantities of pus may be suspected.
Deposits, flocculent, easily diffused on agitation, scanty, not disappearing on addition of nitric acid, are chiefly made up of healthy mucus, epithelial debris or occasionally in women of secretion from vagina, leucorrheal discharge, etc. Heat urine over a spirit lamp, if white deposits occur albumen or an excess of the earthy phosphates is present. Albumen, if a drop of nitric acid does not redissolve the deposits; phosphates, if it does.
Highly colored urine not rendered opaque by boiling, the coloring matters of bile, or purpurine are present. To determine which pour a thin layer of urine on the back of a white plate and drop a few drops of nitric acid in center. An immediate and rapidly ending play of colors from bluish green to red will be observed if bile; but not if purpurine exists alone.
Highly colored. If it alters in color and transparency by heat the presence of blood must be suspected. If addition of nitric acid to deep red urine unaffected by heat, produces a brown deposit, excess of uric acid exists.
Pale urine: Immerse the urinometer, if specific gravity is below 1012, there is excess of water, if above 1025 the presence of sugar or superabundance of urea is indicated. To determine which, place a few drops of urine in a watch crystal and add equal quantity of nitric acid and allow glass to float on cold water. Crystals of nitrate of urea will appear in 2 or 3 minutes, if a super-abundance of urea exists. If this change does not occur urine must be examined for sugar which may exist in small quantities without raising specific gravity of the fluid. For this "Haines' Sugar Test" is the best at the present. We therefore give the full formula:
Haines' Sugar Test:
Sulphate of copper, 30 grains.
Distilled water and glycerine, 1/2 ounce each.
Liquor potassae, 5 ounces.
First thoroughly dissolve the sulphate of copper in the distilled water, then add glycerine and mix well, then add your liquor potassae. When ready, use as follows: Put one drachm in a test tube and gently boil. To this add 8 to 10 drops of urine and again gently boil the liquid. If sugar is present a copious yellow precipitate is formed. If not, color of the liquid will remain as before.
An excess of coloring matter rich in carbon must always be sought after on account of its pathological importance. Boil some of the urine in a test tube; while hot add a few drops of hydrochloric acid. If an average proportion of pigment exists a faint red or lilac color will be produced, but if an excess is present it will be indicated by the dark red or even purple tint assumed by the mixture.
The Materia Medica and Clinical Therapeutics, 1905, was written by Fred J. Petersen, M.D.