Examination 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 in an abundant white deposit of carbonate of lime. Of its morbid changes the following are to be looked for: (1) Color: White from deposited salts of lime; brown 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 may be 1.030 or 1.050, but it may greatly exceed this in diabetes and may sink to 1.007 in diuresis. (3) Chemical reaction, as ascertained by blue litmus or red test papers. The horse on vegetable diet has alkaline urine turning red test papers blue, while in the sucking colt and the horse fed on flesh or on his own tissue (in starvation or abstinence during disease) it is acid, turning blue litmus red. (4) Organic constituents, as when glairy from albumen coagulable by strong nitric acid and boiling, when charged with microscopic casts of the uriniferous tubes, with the eggs or bodies of worms, with sugar, blood, or bile. (5) In its salts, which may crystallize out spontaneously, or on boiling, or on the addition of chemical reagents.

PLATE VIII.
LONGITUDINAL SECTION THROUGH KIDNEY.

PLATE IX.
MICROSCOPIC ANATOMY OF KIDNEY.

PLATE X.
MICROSCOPIC ANATOMY OF KIDNEY.

Albuminous urine in the horse is usually glairy, so that it may be drawn out in threads, but its presence can always be tested as follows: If the liquid is opaque, it may be first passed through filter paper; if very dense and already precipitating its salts, it may be diluted with distilled water; add to the suspected liquid acetic acid drop by drop until it reddens the blue litmus paper; then boil gently in a test tube; if a precipitate is thrown down, set the tube aside to cool and then add strong nitric acid. If the precipitate is not dissolved, it is albumen; if dissolved it is probably urate or hippurate of ammonia. Albumen is normally present in advanced gestation; abnormally it is seen in diseases in which there occurs destruction of blood globules (anthrax, low fevers, watery states of the blood, dropsies), in diseases of the heart and liver which prevent the free escape of blood from the veins and throw back venous pressure on the kidneys, in inflammation of the lungs and pleurae, and even tympany (bloating), doubtless from the same cause, and in all congestive or inflammatory diseases of the kidneys, acute or chronic.

Casts of the uriniferous tubes can be seen only by placing the suspected urine under the microscope. They are usually very elastic and mobile, waving about in the liquid when the cover glass is touched, and showing a uniform, clear transparency (waxy) or entangled circular epithelial cells or opaque granules or flattened, red-blood globules or clear, refrangent oil globules. They may be even densely opaque from crystals of earthy salts.

Pus cells may be found in the urine associated with albumen, and are recognized by clearing up, when treated with acetic acid, so that each cell shows two or three nuclei.

Fonte: Diseases of the Horse