Part 35

Cutting the nerves of this plexus causes excessive vaso-dilation, renal pulsations synchronous with heart beats and arterial pulse, and great increase of urine. A similar increase comes from the application of cold to the surface, from fatigue, from heat exhaustion, from irritation of the floor of the fourth ventricle just in front of the origin of the vagus and from section of the splanchnic nerve. This last is, however, much less marked and more transient than from section of the renal nerve noted above; the latter causing dilation of the renal vessels only, and increased pressure, whereas the former causes dilation of the abdominal organs generally, diverting the blood largely to other parts than the kidney and preventing the same increase of pressure in the vessels of the latter. For the same reason transverse section of the medulla oblongata, or of the spinal cord as far back as the seventh cervical vertebra, lessens or interrupts the urinary secretion, the pressure in the kidney being reduced by the diversion of much of the blood elsewhere. This influence of the nervous system on the urinary secretion seems to be mainly or entirely one of increase or decrease of blood pressure in the kidney. For this reason a weak heart tends to lessen urinary secretion.

=Excessive increase= of urine is only important when continuous and in the absence of visible cause, such as diuretics.

PHYSICAL PROPERTIES OF THE URINE.

Color, yellow, red, brown; horse, ox, calf, sheep, goat, dog, cat, bird. In disease: pale yellow, with water in excess; deep yellow, red, brown with solids in excess, urobiline, biliverdin, hæmoglobin. Extraneous colors. Bilharzia. Translucency: Turbidity: horse, ruminants, carnivora, pig. In disease, horse, other animals. Consistency, viscous, stringy, tarry; odor, horse, dog, cat, ammoniacal, fœtid, drug odor. Specific gravity, estimate of solids; reaction, acid, alkaline, neutral; morbid chemical changes, sodium chloride, phosphate, alkaline, earthy, indican, urea, uric acid, hippuric acid, phenol, creatinin, acetone, oxalic acid, allantoin, xanthin, hypoxanthin, cyanuric acid, leucin, albumen, glucose, bile salts and pigments, blood, hæmoglobin, epithelium, pus, casts.

=Color.= In estimating the color we must note the various shades of yellow, red and brown and compare these with the normal in different genera of animals, on different food and water, and in different conditions of health. Grades of color may be stated as follows:

=Yellow=: Pale, clear and deep yellows.

=Red=: Reddish yellow, yellowish red, and red.

=Brown=: Brownish red, reddish brown and brownish black.

=Color of Normal Urine.= This varies with the species of animal, food, quantity of water drunk, and time of retention in the bladder.

=Horse=: Urine is normally clear yellow, brownish yellow, or deep citron yellow, and the color is deepened by rich and abundant food (excess of solids) and by exposure to the air (changes in pigments). It may be sulphur white and sedimentary from precipitation of CaCO_{2} when on green food.

=Ox, Calf, Sheep and Goat=: Normal urine clear yellow to wine yellow. In the ox especially it is a pale straw tint, but varies to a deep brown on nitrogenous food (clover, peas, beans, cotton seed, lentils, pea or bean straw). Color may be due to indican and sometimes to indicanin or indigo blue, which explains the blue urine sometimes described.

=Dog=: Normal urine is yellow, straw colored, aniline yellow, honey yellow, to brownish yellow in hot season or on dry nitrogenous food. Is always relatively deeper than in ruminants.

=Cat=: Straw yellow to honey yellow, with variation as in the dog.

=Pig=: Very pale yellow, more highly colored on dry feeding, nuts, peas, etc.

=Birds=: White or yellow, sedimentary. Mixed with fæces in cloaca.

=Color of Pathological Urine=: =Pale yellow= with excessive secretion glycosuria, polyuria, cryptogamic polyuria, chronic interstitial nephritis, under diuretics, or after excessive drinking. The free secretion of a crisis in a fever is pale yellow.

=Deep yellow=, =deep red=, =deep brown color=, indicates excess of urinary pigment (urobiline) and is deepened by nitric acid. This is seen in all hyperthermias with suppressed or diminished secretion, in privation of water, or food. This urine is acid even in herbivora.

=Yellow=, =saffron yellow=, =brownish yellow=, =greenish=, =olive=, =or brownish red= indicate the presence of bile pigments (biliverdin, bilirubin) as in jaundice or cholyuria. Bile salts should be tested for. A similar coloration may come from free consumption of carrots, or other yellow pigmentary matters.

=Red=, =brownish red=, =blood red=, =or deep brown color= implies the presence of blood or blood coloring matter in the urine (hæmaturia, hæmoglobinuria). Exposed to the air this becomes brown or chocolate in ratio with the amount of blood or blood pigment present. Some such cases are complicated by blood clots.

Color due to Foreign Constituents.

=Bronze or black color= may come from injection of =phenic acid=.

=Deep green or olive green= may come from =tar=, =carbolic acid=, =salol=, =creosote=, or =derivatives of benzine= taken in.

=Brownish green= comes from =thallin= and reddens with iron chloride.

=Brown or blood red= from =rhubarb= or =senna=.

=Purple red from santonin=, if alkaline (if acid, is reddish yellow).

=Red= from =madder= (it is alleged from indigo).

=Yellow= from =carrots=.

=Blue= (indigo blue) may occur in urine of horse or ox when exposed to the air.