_Prep._ (Thenard.) Fresh urine, gently evaporated to the consistence of a syrup, is treated with its own volume of nitric acid of sp. gr. 119; the mixture is shaken and immersed in an ice bath, to solidify the crystals of nitrate of urea (p. 1689); these are washed with ice-cold water, drained, and pressed between sheets of blotting paper; they are next dissolved in water, and the solution is decomposed and precipitated with carbonate of pota.s.sium (or carbonate of barium); the whole is then gently evaporated nearly to dryness, and the residuum is exhausted with pure alcohol, which dissolves the urea, which crystallises out as the solution cools.

=Urea, Fact.i.tious.= Mix 28 parts of well-dried ferrocyanide of pota.s.sium with 14 of black oxide of manganese (both in fine powder), and heat them to dull redness on an iron plate. Lixiviate with cold water, add 22-1/2 parts of dry sulphate of ammonia, concentrate by evaporation with a heat not exceeding 212 F., decant the concentrated liquid, treat it with rectified spirit, and crystallise. This is intended as a cleanly subst.i.tute for the preceding.

=Urea, Ni'trate of.= _Syn._ UREae NITRAS, L. _Prep._ From urine, as described above; or it may be prepared by saturating artificial urea with nitric acid. Diuretic.--_Dose_, 2 to 5 gr. twice or thrice daily; in dropsy.

=U'RIC ACID.= C_{5}H_{4}N_{4}O_{3}. _Syn._ LITHIC ACID; ACIDUM LITHIc.u.m, A. URIc.u.m, L. A substance discovered by Scheele, and peculiar to the urine of certain animals, and the excrement of serpents and several birds. The faeces of the boa constrictor consist of little else than urate of ammonium. It const.i.tutes one of the commonest varieties of urinary calculi, and of the red gravel or sand which is voided in certain morbid states of the urine. Guano derives its princ.i.p.al value as a manure from the presence of urate of ammonium. The gouty concretions of the joints, popularly known as chalk-stones, consist chiefly of urate of sodium.

_Prep._ Dissolve the chalk-like excrement of serpents, reduced to fine powder, in a solution of caustic pota.s.sa, by boiling; then add hydrochloric acid in excess, again boil for 15 minutes, and well wash the precipitate with water.

_Prop., &c._ Brilliant, very minute, white and silky scales, which are tasteless, inodorous, slightly soluble in boiling water, and dissolve in strong sulphuric acid, but are again precipitated by water. It forms salts with the bases called urates, all of which are very sparingly soluble. The characteristic reaction of uric acid is, that when moistened with nitric acid and heated, it dissolves, and by evaporation yields a red compound, which, upon the addition of a drop or two of solution of ammonia, a.s.sumes a magnificent crimson colour, being converted into murexide.

Uric acid is a const.i.tuent of healthy human urine, in which it exists combined with bases in the form of urates, which, being in small quant.i.ty, are soluble in the urine. 1000 grains of the urine contain from 1/2 grain to 1 grain of the acid. Drs Beale and Thudichum respectively estimate the amount of uric acid excreted in twenty-four hours by a healthy adult man at from 5 to 8 grains. To determine the amount of uric acid in urine proceed as follows:--To a certain weight of the urine, hydrochloric or nitric acid is added, and the urine set aside for some hours, at the end of which time, the insoluble crystals of uric acid which are formed, are washed, dried, and weighed.

With the exception of the urates, uric acid is one of the deposits most frequently met with in abnormal urine, wherein it occurs as a small reddish powder adhering to the bottom or sides of the containing vessel.

As a urinary deposit, uric acid a.s.sumes a great variety of forms, that of most frequent occurrence being the rhombic, modified in many of the crystals by the rounding of two of the angles, as shown in the engraving on next page.

[Ill.u.s.tration: Uric acid. (Beale.)]

=URINARY DISEASES.= This cla.s.s of disorders, which in general terms may be said to embrace affections of the kidneys, bladder, ureters, &c., comprises diseases of these parts varying greatly in character and pathological importance.

The most serious forms of kidney disease are CONGESTION of the kidney, a very frequent accompaniment of heart or lung disease; PYELITIS, or inflammation of the pelvis of the kidney; SUPPURATIVE NEPHRITIS, or inflammation of the substance of the kidney, which ends in suppuration; ACUTE NEPHRITIS, or ACUTE BRIGHT'S DISEASE, acute inflammation of the kidney, frequently arising from scarlatina or cold; CHRONIC NEPHRITIS, or CHRONIC BRIGHT'S DISEASE, a formidable and incurable variety of kidney affection, giving rise to dropsy, and, owing to the disintegration of the organ, to poisoning of the blood by urea. In advanced cases of this disease the urine contains a large quant.i.ty of alb.u.men and casts of the urinary tubes.

CALCULUS OF THE KIDNEY. The most dangerous diseases of the bladder are those caused by the deposition in it of earthy and other concretions, known as URINARY CALCULI, which are described in the present work under CALCULUS. The presence of these calculi is indicated by acute pain in the bladder and urinary pa.s.sages, extending to the adjacent parts, the pain being excruciating immediately after pa.s.sing the urine. Sometimes during the act of excretion the stream of water is suddenly stopped.

Inflammation is another dangerous disease of the bladder, calling for the prompt summoning of the medical pract.i.tioner wherever possible.

The following particulars as to its symptoms and treatment are offered for adoption to emigrants and others so placed as to be beyond the means of medical succour.

Inflammation of the bladder commences with pain in the region of that organ, the pain becoming continuous and increasing in violence, and being accompanied with a sense of burning heat and of tenderness on pressure.

The urine is frequently voided. The inflammation is sometimes so acute as to give rise to suppuration and the consequent discharge of pus with the urine. Sometimes the disease a.s.sumes a chronic character.

In the acute form of the disease recourse should be had to leeches, hot fomentations, and warm baths; a dose of calomel, to be followed by a brisk dose of castor oil, should likewise be administered. Alcoholic drinks of any kind must be carefully avoided, the patient being allowed to drink only cool demulcent beverages. With these should be combined effervescing draughts, frequently repeated, and small doses of Dover's powder. Great relief will also be derived from the use of enemas of gruel containing laudanum. Where inflammation of the bladder arises from gout or rheumatism, it must be treated as for these diseases. A suppository, consisting of two grains of opium, combined with twenty grains of soap, is frequently of great benefit.

Should the disease become chronic, the best method of treatment will be the repeated use of mild aperients, the combined employment of uva ursi in infusion or powder, with either tincture of perchloride of iron, or the mineral acids. Spirituous liquors of any kind must be avoided. Demulcent drinks form the best beverage, and a farinaceous or milk diet the most desirable food.

NEURALGIA OF THE BLADDER. The pain which attends this disease is unaccompanied either by inflammation or irritation, and is recurrent in character. It may generally be arrested by tincture of perchloride of iron, or of iron and quinine, administered three times a day.

IRRITATION OF THE BLADDER. The patient affected with this disorder gratifies the frequent desire he has to pa.s.s his urine, the operation being accompanied with pain and forcing, the most severe pain being experienced after the excretion has taken place. The tincture of perchloride of iron will also be found the best remedy for this disorder.

It should be given in conjunction with the infusions of uva ursi, Pareira brava, or buchu.

Mucilaginous drinks should also be had recourse to.

CATARRH OF THE BLADDER. The symptoms of this disease are irritation, and the presence of much mucus in the urine. The same treatment may be adopted as recommended for irritation of the bladder. If there be an absence of pain, spirits of nitre and copaiba balsam in moderate doses frequently afford relief.

STRANGURY. Constant micturition, only a few drops of urine pa.s.sing at the time, occasioning burning and cutting pains around the parts. Strangury is generally due to some irritating cause, which should, if possible, be discovered and removed. Cantharides taken either internally, or applied externally, as in the form of a blister, will sometimes give rise to it.

The patient should drink copiously of mucilaginous beverages, such as linseed tea, slippery elm bark, barley water, with gum Arabic dissolved in it. An injection consisting of thirty or forty drops of laudanum in a spoonful of gruel will be found to afford immediate relief. If the above means fail, a pill containing a grain of camphor in five grains of extract of henbane should be given, and a warm bath taken. See GRAVEL.

=U'RINE.= The density of the urine varies from 1005 to 1030;[247] the average, in health, being 1020, when it contains about 380 gr. of solid matter in the pint. According to Berzelius, the proportion is about 6-3/4%, the rest being pure water. It exhibits a decidedly acid reaction, and is never alkaline, except during disease, or the use of large quant.i.ties of alkaline salts of the vegetable acids. The average quant.i.ty secreted during 24 hours may be taken at 2 pints to 3 pints; as might be supposed, a larger quant.i.ty is pa.s.sed during the summer than in the winter months.

[Footnote 247: From 1015 to 1025, Beale.]

Miller gives the following as the composition of healthy urine:--

In 100 Specific gravity 1020 parts of solid Water 95680 matter.

{ { Urea 1423 3300 { { Uric acid 037 086 { Organic matters, 2979 { Alcoholic extract 1253 2903 { { Watery extract 250 580 { { Vesical mucus 016 037 { { { Sodic chloride 722 1673 A { { Phosphoric anhydride 212 491 { { Sulphuric anhydride 170 394 { Fixed salts, 1335 { Lime 021 049 { { Magnesia 021 028 { { Potash 193 447 { { Soda 009 012 { Loss 003 ------ ------ 100000 10000 A = Solid matters, 432.

The presence of bile in urine, or other like fluids, may be detected as follows:--Put a small quant.i.ty of the suspected liquid into a test-tube, and add to it, drop by drop, strong sulphuric acid, until it becomes warm, taking care not to raise the temperature above 122 Fahr.; then add from 2 to 5 drops of syrup (made with 5 parts of sugar to 4 of water), and shake the mixture. If the liquid contain bile, a violet coloration is observed.

Acetic acid may be subst.i.tuted for sugar.

Another test for bile consists in pouring a little of the suspected urine into a test tube, and adding to it a few drops of tincture of iodine, when if bile be present the fluid becomes distinctly green. Rosenbach says that urine containing bile, when pa.s.sed through white filtering paper, imparts a yellow or brown colour to the paper. On allowing one drop of strong nitric acid to run down the side of the moist filter it leaves a yellow streak, soon changing to orange, with a violet border, on the outside of which blue and emerald-green zones may be observed. These colours remain visible for some time.

Dark-coloured urine, owing to substances other than bile, does not produce this play of colours.

The reagents most generally employed for detecting the presence of sugar in urine are Trommer's (_see_ SUGAR) and Fehling's solutions. For the effective application of Fehling's test, Dr Roberts[248] advises the following method of procedure:--Pour some of the Fehling's solution into a narrow test tube to the depth of 3/4 of an inch; heat until it begins to boil; then add 2 or 3 drops of the suspected urine. If the sugar be abundant, a thick yellow opacity or deposit of yellow suboxide are produced (and this changes to a brick-red at once if the blue colour of the test remains dominant). If no such reaction ensue, go on adding the urine until a bulk nearly equal to the test employed has been poured in; heat again to ebullition, and no change occurring, set aside without further boiling. If no milkiness is produced as the mixture cools, the urine may confidently be p.r.o.nounced free from sugar, or, at any rate, it contains less than 1/40th percent.

[Footnote 248: 'Urinary and Renal Diseases,' by Dr W. Roberts.]

If the quant.i.ty of sugar is very small, viz. from a 1/2 to 1/40th per cent., the precipitation of the yellow or cuprous oxide does not take place immediately, but occurs after some time as the liquid cools, and the manner of the change is peculiar. First, the mixture loses its transparency, and pa.s.ses from a clear bluish green to a light greenish opacity, just as if some drops of milk had fallen into the tube. This green milky appearance is quite characteristic of sugar.

Before using the Fehling's solution it should be always examined previously to the addition of the urine, by being first boiled alone, when if it remains clear it may be p.r.o.nounced in fit condition. On the contrary, should the preliminary boiling give a deposit, the solution must be discarded, and some freshly made employed instead.

Bottger has proposed the following quant.i.tative test for the presence of sugar in urine:

He first adds some potash to the sample of urine, and then a small quant.i.ty of subnitrate of bis.m.u.th, and boils the mixture. If sugar is present, the suboxide is reduced, and metallic bis.m.u.th being liberated is precipitated as a black powder.

Another method of applying the bis.m.u.th test is as follows:--One part of crystallised carbonate of soda is dissolved in three parts of water, and added to an equal quant.i.ty of the urine. A small quant.i.ty of basic nitrate of bis.m.u.th is then added to the mixture, which is then heated to the boiling point. A black precipitate is formed if the urine contains sugar.

Horsley's test consists in boiling with the suspected urine a mixture of equal parts of neutral chromate of potash and solution of potash, when, if sugar be present, a green colour will be produced, owing to the formation of the sesquioxide of chromium.

M. Luton's, which is a modification of Horsley's test, a solution of bichromate of potash is decomposed by excess of sulphuric acid, and upon the urine being boiled with the mixture, a splendid green colour is imparted to it. Urea, alb.u.min, and the urates do not interfere with this reaction.

Vidau has observed that a mixture of equal parts of hydrochloric acid and oil of brune (oil of sesame), either in the cold, or when slightly heated, a.s.sumes a distinct rose colour in the presence of cane or grape sugar, provided 0001 gramme of sugar is present for every c.c. of mixture.

One of the best methods for the accurate and quick estimation of the amount of sugar in urine is, perhaps, the volumetric, devised by Fehling, who employed a standard copper solution, known as 'Fehling's solution,' of the following composition:

Sulphate of copper 90-1/2 grains.

Neutral tartrate of potash 364 "

Solution of caustic soda, sp. gr. 112 4 fl. oz.

Add water to make up exactly 6 "

Of this solution 200 grains are exactly decomposed by one grain of sugar.

The following is the mode of performing the a.n.a.lysis given by Dr Roberts[249]:--Measure off 200 grains of the above standard solution in a 200-grain tube, pour this into a flask, and add about twice its volume of water; then place over a spirit lamp to boil. While the copper solution is being heated the urine to be a.n.a.lysed should be diluted with water to a known degree. In the case of ordinary diabetic urines the best dilution is one in ten. This is obtained by carefully filling a 6-ounce measure with water to the depth of 4-1/2 ounces, and then adding urine so as to make up exactly 5 ounces. The mixture will then contain exactly one tenth of urine (when the quant.i.ty of sugar in the urine is very small, a dilution of one in five, or even the undiluted urine may be employed). The next step is to fill a burette (which must be graduated to grains) with the diluted urine to 0. Then proceed to add it in successive small portions to the boiling copper solution until the blue colour has entirely disappeared. After each fresh addition from the burette, the mixture should be raised to the boiling point, and then allowed to stand a few seconds, so that the precipitated copper may subside, and the observer may see, by holding the flask between the eye and the light, whether the mixture still retains any blue colour.

[Footnote 249: 'Urinary and Renal Diseases,' by Dr W. Roberts.]

As soon as the blue colour has disappeared the a.n.a.lysis is complete, and the quant.i.ty of diluted urine may be read off. The percentage of sugar in the urine can now be readily calculated. Suppose 125 grains had been added from the burette, this represents one tenth, or 125 grains of undiluted urine, and contains exactly one grain of sugar; by dividing 125 into 100 the per-centage of sugar is obtained, or 100/125 = 8; the urine contains 8 per cent. of sugar.