Examination of the urine; a manual for students and practitioners

Front matter

Copyright^ .

COPYRIGHT DEPOSIT:

Plate i

Preface

The object of this manual is to furnish a concise guide to the examination of urine for the practitioner in his daily work and for the student in his laboratory course, as well as in his study for examinations.

In accordance with this aim, an effort has been made to treat the important and practical parts of the subject as fully as possible, while theory, discussion of moot-points, and cumbersome analytic details have been either omitted or treated in the briefest possible manner.

The theory of urinary secretion and the methods of functional examination of the kidneys have been given a rather more prominent place than has been done in other text-books, for the reason that a knowledge of these themes, while still of little practical use, adds materially to a grasp of the modern status of uranalysis and of the directions in which advances may be expected in this science.

Special attention has been paid to technics and to the interpretation of findings. In this connection some hints as to the methods of working that developed in my own experience have been inserted, which I trust may prove helpful to the beginner.

In a text-book of this scope, it is not necessary to

6 PREFACE.

mention in detail the authorities consulted, and this has not been done here, except in a few instances. I take occasion, however, to acknowledge my especial indebtedness for material to the works of Neubauer and Vogel, Hammarsten, Von Jaksch, Ogden, F. C. Wood, Simon, Purdy, Heitzmann, and Tyson, and to express my sincere thanks to Dr. Henry T. Brooks, Pathologist to the Postgraduate Hospital, for many valuable hints in the preparation of this book.

The metric system is used in the greater part of the book, but the old system of weights and measures has been retained in some places for the sake of convenience in working, and in order to keep intact the original formulas of certain authorities.

Unless otherwise specified, the reagents and solutions are supposed to correspond to the standard of the United States Pharmacopoeia.

If this little volume will contribute towards a clearer and more precise understanding of the subject of uranalysis on the part of the student or practitioner, my task shall not have been fruitless.

G. A. DeS. S.

Preface To The Second Edition

Time was when those engaged in laboratory work were bidden to " stick to their lasts " when they attempted to come into contact with patients. To-day we see on every hand a clearly defined change in the relations of the laboratory man and the bedside man. In fact, to attain the highest standing in clinical medicine, in surgery, or in any of the specialties, it is now necessary for a physician to be thoroughly trained in laboratory work and to be able to apply laboratory methods in his daily routine, as well as in his search for the unknown in the particular branch in which he is interested. The highest places in the gift of our great universities in the department of clinical medicine and in some of the specialties are now given to men who have made reputations in laboratory research as well as in clinical study. As was well said recently by Dr. Christian, Dean of the Harvard Medical School, "The future of medicine in this country lies in a perfect co-ordination of the laboratory and the ward, both of which should be under the same head. ' ' 1

Written by one who is primarily devoted to clinical work in a branch of surgery in which the greatest dependence is placed upon urine examinations, this book is, therefore, addressed to the clinical worker, the practitioner, who aims to make the laboratory his

1 Quoted from memory by the author.

8 PREFACE

daily guide and counselor. Whether he himself examines the specimens, or whether he is fortunate enough to have this work done for him, the practitioner will require a thorough knowledge of the urine when he comes to interpret the findings of the microscope or of the test-tube.

In the new edition the clinical side of urine analysis has been still more markedly emphasized than in the first. The book has not only been revised and amplified, but many of the chapters have been entirely rewritten, to meet the important advances in the field of physiologic chemistry and chemical pathology in the midst of which we live to-day. In many respects this second edition also represents the fruits of individual experience in urinalysis and in clinical work in urinary diseases, covering now a period of ten years, as well as the results of the author's published researches on urethral shreds, prostatic and vesicular elements in the urine, etc.

Among the chapters which have been practically rewritten are those on acidity, albuminuria, albumoses, mucin, nucleo-albumin, indican, phosphates, sulphates, and the nitrogenous bodies, including uric acid. A number of new subjects have been introduced — e. g., a short section on the pentoses, a brief account of Cammidge's reaction, a detailed description of the methods of preserving and staining urinary sediments and of preparing sediments for bacteriologic examinations. New chapters have also been inserted on urethral shreds, vesicular sago-bodies, etc. ; on diabetes, and on the toxemias of pregnancy. A complete yet concise account of the present-day methods of functional renal diagnosis has been incorporated.

PREFACE 9

In every instance tests which have proved valueless have been dropped. Few new tests have been admitted, and only such as have proved useful in the author's own work. A number of new and original illustrations have been added. In order to make the volume compact, in spite of the numerous additions, smaller type has been used for the parts that are not apt to be required for daily reference.

The favorable reception of the first edition and its adoption as a text-book in a number of the medical schools of this country leads the author to hope that this edition will prove even more useful than its predecessor to the student and the practitioner.

G. A. DkS. S. 130 West 71ST St., New York City.

October „ 1909.

Part I— General Considerations

I. Introduction. Composition of Urine in Health.... 17 II. Selection of a Specimen of Urine 21

III. Physical Properties of the Urine 25

Part Ii— Chemic Examination Of The Urine Organic Constituents

PROTEIDS

IV. Serum-albumin 50

Quantitative Tests for Albumin 70

V. Other Proteids in the Urine 77

Serum-globulin 77

Fibrin 79

Mucin (Moerner's Mucoid) 87

Substances Formerly Taken for " Nucleo-albumin " . . . 89

CARBOHYDRATES

VI. Glucose. . . . '. 96

Quantitative Determination of Sugar in

VII. Other Carbohydrates in the Urine 122

Lactose 122

Levulose 123

Laiose 123

Pentoses 124

Other Substances Allied to Glucose 125

Cammidge's Reaction 128

n

12 CONTENTS

NITROGEN GROUP : UREA, URIC ACID, ETC.

VIII. The Excretion of Nitrogen in the Urine 131

Urea 133

IX. The Purin Bodies — Uric Acid and its Chemical Congeners 145

Urates 154

Purin (Xanthin or Alloxur) Bases 155

Quantitative Test for Purin Bodies (Uric Acid + Purin

Bases) 157

Creatin and Creatinin 160

Allantoin 161

Nucleic Acid 161

Hippuric Acid 162

ACETONE GROUP : INDICAN AND OTHER ETHEREAL SUL- PHATES ; DIAZO-REACTION

X. Acetone and Diacetic Acid 165

Diacetic Acid 170

Beta-oxybutyric Acid 172

XL Indican and Other Ethereal Sulphates; Diazo-

reaction 174

Other Ethereal Sulphates 181

Ehrlich's Diazo-reaction 182

COLORING-MATTERS? BILE? BLOOD; OTHER ORGANIC CONSTITUENTS

XII. Urinary Coloring-matters 186

Normal Coloring-matters 186

Biliary Pigments and Acids 189

Bile-pigments 189

Bile-acids 191

Blood Pigments 193

XIII. Leucin, Tyrosin, Fatty Matter, and Other Organic

Constituents 201

Leucin and Tyrosin 201

Fat and Cholesterin in the Urine 203

Other Organic Constituents of Minor Importance 204

CONTENTS 13

INORGANIC CONSTITUENTS

XIV. Chlorids 208

XV. Phosphates 215

XVI. Sulphates, Carbonates, and Less Important Inorganic

Constituents 223

Carbonates 229

Inorganic Constituents of Minor Importance 229

Accidental Inorganic Constituents 231

XVII. Urinary Concretions '. 232 part hi— microscopic examination

XYIII. General Considerations 235

Methods of Obtaining Sediments 235

Methods of Examining Sediments 239

Preservation and Mounting of Sediments 242

Staining of Sediments 244

Extraneous Materials in Sediments 245

Classification of Sediments 250

Sediments in Acid and Alkaline Urines 251

XIX. Unorganized Sediments 255

XX. Organized Sediments 274

Pus 281

Connective -tissue Shreds 284

False Casts or Cylindroids 309

Mucous Threads 310

Prostatic Plugs 311

Amyloid Bodies 312

Spermatozoa 313

Sago Bodies and Other Vesicular Elements in Massage-urine 314

14 CONTENTS

Part Iv— Urinary Diagnosis

XXI. Characters of the Urine in Diseases of the Kidney

and Renal Pelvis 342

Acute Congestion 343

Chronic Congestion 345

Acute Diffuse Nephritis 346

Chronic Diffuse Nephritis 349

Chronic Parenchymatous Nephritis 351

Chronic Interstitial Nephritis 353

Amyloid Kidney 356

Tuberculosis of the Kidney 358

Stone in the Kidney 360

Tumors of the Kidney 362

Cysts and Cystic Degeneration of the Kidney 364

Abscess of the Kidney 364

Embolism of the Kidney 365

Acute Pyelitis and Pyelonephritis 365

Chronic Pyelitis and Pyelonephritis 366

Hydronephrosis 366

Pyonephrosis 367

Ureteritis 368

XXII. Characters of the Urine in Diseases of the Lower

Urinary Tract and of the Genital Organs . . 369

Cystitis 369

Tuberculous Cystitis 371

Tumors of the Bladder 373

Stone in the Bladder 373

Prostatitis 373

Tuberculosis and Cancer of the Prostate 375

Seminal Vesiculitis 376

Spermatorrhea 377

Urethritis 377

XXIII. The Urine in Abdominal States of Metabolism 380

Diabetes Mellitus 380

Diabetes Insipidus 385

The Toxemias of Pregnancy 386

CONTENTS 15

Part V-functional Renal Diagnosis

XXI Y. General Considerations; The Secretion of Urine. . 389

The Objects of Determining the Renal Function 389

Theories of Renal Secretion 391

XXV. Methods of Determining the Functional Efficiency

of the Kidneys 395

Determining the Freezing-point of the Urine (Cryoscopy) 395

Determining the Electric Conductivity of the Urine .... 400

The Methylene-blue Test 401

The Indigo-carmin Test 403

The Phloridzin Test 404

Experimental Polyuria 408

XXVI. The Toxicity of the Urine 410

Ptomains. 412

Leukomains 412

Appendix

Routine Examination, Reagents, Apparatus, etc 414

Routine of Examination 416

Lists of Reagents, Apparatus, Etc 421

Liquid Reagents 422

Solid Reagents 423

Bacterial Stains 423

Apparatus 424

Thermometric Equivalents 425

Relations of English to Metric Systems 425

Index 427

Chapter I

INTRODUCTION. COMPOSITION OF URINE IN HEALTH

A knowledge of the characters of the urine in health and disease is of the greatest importance to the physician, inasmuch as this fluid constitutes one of the most valuable aids to both medical and surgical diagnosis. Next to the pulse and the temperature, the urine offers the greatest possibility for an insight into the workings of the human system. Aside from its purely clinical value, urinalysis is essential to the study of the physiologic processes of the body and the determination of changes in its metabolism produced through normal or abnormal influences.

The urine is a watery fluid secreted by the kidneys, and in health contains a large variety of constituents which are derived from the wasting and decomposition of the fluids and tissues of the body and from certain elements of the food.

The constituents of normal urine are difficult to classify 2 17 i8 systematically on account of their complexity, but a useful division of the dissolved elements of the urine (modified from Hoppe-Seyler) is as follows:

i. Gases.

2. Inorganic salts.

3. Urea and its congeners.

4. Aromatic substances.

Fatty and other non-nitrog- j enous substances -{

6. Other organic substances. . . .

Oxygen, nitrogen, and carbonic acid (very small quantities; dissolved). f (a) Chlorids of sodium and potassium.

(b) Potassium sulphate.

(c) Sodium, calcium, and magnesium

phosphates.

(d) Calcium carbonate.

(e) Silicic acid.

k (/) Ammonium compounds.

Urea, uric acid, xanthin, creatinin, allantoin, oxaluric acid, sulphocyanic acid, etc. ethereal sulphates of phenol, cresol, pyrocatechin, indoxyl, and skatoxyl; hippuric acid and aromatic oxyacids. acids; oxalic, lactic, glycerophosphoric acids, and a very minute amount of certain carbohydrates. j Pigments; ferments, especially pepsin; \ mucoid substances.

'The

The following table (Parkes) gives an idea as to the character and general quantitative relations of the urinary constituents, but it cannot serve as a clinical guide for the interpretation of urinary analyses. For this reason other tables (pp. 19, 20) have been compiled by the author, as exhibiting the chief points necessary for judging the results of quantitative estimations in urine. The figures given in these tables correspond with results of analyses carried on in the author's laboratory, and in the main are in accordance with the figures given by other writers on urine analysis.

The composition of normal urine, according to Parkes, is as follows:

COMPOSITION OF URINE IN HEALTH

COMPOSITION OF THE URINE

Amount of Urinary Constituents Passed in Twenty-four Hours (Parkes)

Constituents.

Water

Total solids

Urea

Hippuric acid

Creatinin

Pigments and other organic matters.

Sulphuric acid

Phosphoric acid

Chlorin

Potassium

Sodium

Calcium

Magnesium

Average Man,

Weight, 66 Kilograms.

1500.00

72.00

33-^

°-55

0.40

0.91

10.00

2.01

3.16

7-8.00

0.77

2.50

11.09

0.26

0.21 grams

a

a

gram grams gram grams

gram

Per Kilogram of Body-weight.

ANALYSIS OF NORMAL URINE FROM THE CLINICAL VIEWPOINT

I. General Characters oe Normal Urine

Transparency. — Clear or faintly cloudy.

Color. — Amber-yellow.

Specific Gravity. — 1015 to 1020 at 15 ° C.

Reaction. — Acid (depending on diet, etc.).

Acidity (total) may be expressed in one of the following ways (see p.

35):

1. Equivalent to from 3 to 5 cc. jo-normal NaOH in 10 cc. of urine.

2. Equivalent to from 2 to 4 gm. of oxalic acid in twenty-four hours.

3. Equivalent to from 1.15 to 2.3 gm. of HC1.

4. Equivalent to from 0.4 to 20 parts per thousand of acid phosphates.

Amount voided in twenty-four hours (average) : 1200 to 1500 cc. (50 fluidounces).

24.0 cc. of urine in twenty-four hours per each kilo of body-weight; a kilo being equivalent to 2.3 pounds.

II. Normal Constituents of Urine

Total solids.

Chlorids (NaCl)

Phosphates (P 2 5 )

(total)

/ i earthy

Parts in iooo Per Cent. | (Grams in Liter).

Sulphates.

Urea

Uric acid.

Indican. . .

3.49-4.66

0.6-1.0 0.17-0.26

0.1-0.2

1.5-2.0

0.016-0.083

trace

Grams in

Twenty-four

Hours.

20.0-30.0

0.2-1.25

(average 0.7)

0.0045-0.0195

Grains per Ounce

(Approximate).

16.80-22.08

2.88-4.80

0.8-1.25

0.48-0.96

7.20-9.60

0.048-0.384

III. Graphic Expression of Quantities in Urine For comparing normal and abnormal conditions of excretion, there is nothing more convincing than the graphic method. A simple chart for this purpose is shown herewith. The solid line shows the proportions of urea, chlorids, phosphates (phosphoric acid), and the specific gravity in normal urine. The dotted line shows an abnormal urine plotted in the same way (a case of cancerous cachexia). (See Plate 2.)

The urea, chlorids, phosphates, sulphates, and uric acid are expressed in grams per twenty-four hours; the specific gravity is shown by the two last figures of the hydrometer reading, the normal average being taken as 1020. The quantity voided in twenty-four hours is indicated " in terms of 100 cc." — i. e., by the number of times 100 cc. are voided.

z o * °

Grams

IN 24

Hours

H

Z a

Hi o

Urea.

NaCl.

q o

Uric Acid.

Albumin.

.': ! ! .3^

1 _ Pg j~"pp^

~p

— , l jpl

S

^gfe

]jziiii m iSiji

^=fizg::

rsjrs4.'-A^:

gH~j£:

^j^S

EggNl j-p^

Hgi s,U H-S

£EHH r E ^rg

:5rzij3r£i5 i^

JH^iijiip

=gzz^±d

Mfjj

^3

Graphic Expression of Quantities in the Urine.

Solid line, normal urine; dotted line, an example of pathologic urine

in a case of cancerous cachexia.

Chapter II Selection Of A Specimen Of Urine

For accurate quantitative work it is absolutely necessary to obtain the total amount of urine passed in twenty-four hours or, at least, a sample obtained after mixing thoroughly the entire quantity so collected. In the latter case the quantity eliminated in twenty-four hours must be measured and made known to the examiner. A perfectly clean bottle, holding about \ gallon, should be used for collecting the twenty-four-hour quantity. It should be well corked after each addition, and should be kept in a cool, dry room to avoid decomposition. It is important that no foreign matter whatever, such as dust, feces, sputum, etc., be introduced into the sample, and the urine should never be allowed to stand in open or dirty vessels.

The reason for collecting the twenty =f our=hour quan= tity is that the proportion of the constituents and the amount of albumin, etc., vary a good deal at different hours of the day and night, and that the object should be to obtain the average composition of the urine in the twenty- four hours.

The best time to obtain a sample of urine when we do not want the twenty-four-hour quantity, but merely wish to test qualitatively for sugar, albumin, etc., is during the day, about three hours after a meal. It is a mistake to take the morning urine, as is so commonly done; for in slight albuminuria the urine passed in the morning is the least likely to contain albumin, and the same is true of sugar in glycosuria. Sometimes, when a case requires careful study, a comparison of the day urine and the night urine is desired; in that case we collect the urine from 7 a. m. to 7 p. m. in one bottle, and from 7 p. m. to 7 a. m. in another bottle, each being appropriately marked.

If a more concentrated urine is desired than is obtained in a given case w T ith ordinary diet, it may be advisable to

^3

Fig. 1. — Stoppered graduate .

Fig. 2. — Cylindric graduate.

reduce the amount of water and other fluids ingested for a day or so, and thus a urine with greater concentration and more abundant sediment may be obtained for microscopic examination.

The urine is subject to rapid decomposition after being voided, as the result of the action of molds and other micro-organisms, and also as the result of reactions between its various constituents. On standing, a normal urine precipitates, as a rule, first, some amorphous urates,

SELECTION OF A SPECIMEN OF URINE 23

then some uric-acid crystals, and sometimes calcium oxalate. If allowed to stand open, and if exposed to high temperature, as in hot weather, the urine becomes clouded from a large number of bacteria and fungi. At th3 end of a few days it becomes ammoniacal — that is, the urea is gradually transformed into ammonium carbonate, according to the following formula:

In consequence of this the urine grows alkaline and the sediment contains ammonium urate, triple phosphate, and amorphous masses of calcium phosphate. Urines of normal concentration and acidity do not decompose so rapidly as urines of low density and slight acidity.

While this series of changes is known as alkaline fermentation, there is another form that has been known as acid fermentation. This change is sometimes seen as a preliminary stage of alkaline fermentation. It consists of an increase in acidity, a darkening in color, and the deposition of uric acid and urates, and occasionally of calcium-oxalate crystals, together with many yeast fungi and bacteria. This change is probably caused by the mucus, which acts as a ferment and induces an acetic-acid or lactic-acid fermentation. The reason for this increase of acidity has been also attributed to a reaction between the biurates and MH 2 P0 4 , dihydrogen phosphate (Hammarsten) .

Preservation. — It is very important, therefore, that the urine be examined in as fresh a state as possible. In order to preserve it during the collection of the specimen or during the transportation to the laboratory, etc., a number of substances have been used as antiseptics. The most practical is the addition of a crystal or two of thymol, or an ounce of cold saturated solution of boric acid to the quart of urine. With thymol, however, the urine may give a test suggesting the presence of bile. Chloroform (a few drops) will preserve urine well for chemic analysis (save that it gives a deceptive precipitate with Fehling's solution), but it makes the sediment unfit for microscopic examination. The use of formalin, of which 2 or 3 drops are added to the urine, has been advocated of late, but it is apt to cause a reduction of Fehling's solution which may be taken for glucose; besides, it is apt to affect the organized sediment, shrinking the cells and distorting the casts. The addition of formalin to urine also obscured the microscopic examination, in the author's experience, by the production of innumerable gas-bubbles if the urine was allowed to stand for any length of time. The addition of 5 grains of salicylic acid to 4 ounces of urine is favored by some, and is said to be very efficient. In warm weather urines should be kept on ice.

QUESTIONS ON CHAPTERS I AND II

Name the principal groups of constituents in the normal urine.

What gases are found in it?

What inorganic salts? What organic substances?

What is the average amount of total solids in urine in twenty-four hours? The average amount of chlorids, phosphates, sulphates, urea, uric acid ? Describe a graphic method for recording quantitatively the constituents of urine.

Give the rules in selecting a specimen of urine.

How is the specimen collected?

Why do we insist upon the twenty-four-hour quantity ?

At what time should urine be taken if it is not possible to obtain the twenty-four-hour quantity, and why?

Describe the processes of decomposition occurring in urine on standing.

What constitutes alkaline fermentation?

What is known as acid fermentation?

How should urine be preserved from decomposition?

Chapter III Physical Properties Of The Urine

Amount. — The amount of urine passed during twenty-four hours by a healthy adult is from 1200 to 1600 cc, the average being about 1500 cc. or about 50 fluidounces. Women pass smaller quantities than men, and smallsized persons void less than large-sized individuals. One kilogram of body-weight produces on the average 1 cc. of urine in the course of one hour. The average amount is obtained by multiplying the body-weight in kilos by 24 (60X24 = 1440 cc). Children eliminate 28.0 cc. per 5 kilograms per hotir. The drinking of large quantities of liquids increases, while the taking of violent exercise, through free perspiration, diminishes, the average amount. The physiologic limits are 800 to 3000 cc. In health the largest amount is usually passed in the afternoon, a moderate amount in the forenoon, and the smallest amount during the night.

In warm weather considerably smaller quantities are passed than during the cold months. In disease the quantity of urine may be diminished or increased, or the urine may be suppressed through obstruction, or retained in the bladder through an impediment in the region of its neck or in the urethra.

Oliguria is a term used for diminished quantity of urine (below 800 cc. in twenty-four hours). Anuria is used to designate cases in which no urine, or a very small quantity, is passed — i. e., when there is a partial or complete suppression of urine. Polyuria is a term used for a markedly increased quantity of urine (over 3000 cc).

The increase or decrease must, however, be constant, as attested by several examinations, and must be independent of ingested fluids to justify the terms polyuria or oliguria. Polyuria must be distinguished from pollakuria (frequent urination) and refers only to the quantity passed, not the frequency of voiding the bladder.

Diminution in quantity is noted in fevers; in shock after anesthesia or after operations on the genito-urinary organs; in stasis in the kidney due to heart disease, etc.; in acute congestion of the kidney; in acute nephritis and in the acute phases of chronic nephritis; in diseases accompanied by diarrhea and vomiting, such as cholera or yellow fever, and in all diseases in the last stages before death.

Increased quantity is observed in diabetes mellitus and insipidus, in some diseases of the nervous system, such as hysteria and convulsions, and in cerebral hemorrhage; in convalescence from acute and inflammatory diseases; in convalescence from acute congestion and from acute diffuse nephritis; in chronic nephritis, both interstitial and diffuse, and in amyloid kidney; in hypertrophy of the heart and in all conditions causing increased blood-pressure; also in cases in which diuretics have been freely used or a large amount of water drunk.

With the exception of the chronic diffuse and interstitial varieties of nephritis, in which there is an increase, there is a tendency to diminution in all forms of Bright's disease. A marked diminution in the urine in chronic nephritis, if accompanied by low specific gravity, is a very grave sign and usually precedes death.

Color. — The normal color of urine is of a pale-yellow, straw, or amber tint, but even in health it may vary considerably according to the amount of water drunk, etc. Dilute urines are usually pale; concentrated urines are deeply colored. The action of the skin in perspiration, the quantity of water drunk, and sometimes the quality of the food may have to do with changing the color of the urine in health. Color is not a very trustworthy sign in urine examinations.

In disease the color of urine may be changed, owing to the increase or diminution of the normal coloring-matters or the addition of abnormal pigments. The general rule, stated before, about the proportion of color to concentration usually holds good in disease. An exception, however, is the urine of diabetes mellitus, which is characteristically pale, but has a high specific gravity owing to the presence of sugar. Very pale-colored urine occurs in diabetes insipidus, hysteria, interstitial nephritis, etc. Highly colored urine occurs in acute fevers and in inflammations, and is due to concentration and also to the presence of uroerythrin (see p. 186). Reddish urine is always due to the presence of abnormal coloring-matters, usually blood. A brown or reddish color is seen in urines after ingestion of rhubarb and senna; a yellow color, after santonin. A dark-brown urine may be a sign of hemorrhage from the kidney, and be due to the presence of methemoglobin or hematin. Smoky and dark urine is often seen after carbolic acid has been used internally or sometimes after its external use, as well as after the taking of large doses of salol or guaiacol. These urines show the black color, especially on standing, owing to the formation of hydroquinon as the result of decomposition of the phenol (see Phenol, p. 181). A dark urine is also seen in the presence of alkapton (see p. 127).

Bile-pigments , when present in excess, give a dark color with a yellowish-green foam, and on standing the urine becomes greenish. In cholera and typhus the urine may be blue. In melanotic cancer the urine is almost black, especially after standing, owing to the presence of melanin. A greenish-blue urine is eliminated after methylene-blue has been taken. A greenish tint is also sometimes seen after the use of a large quantity of milk, also in chronic Bright's disease and in diabetes with large amounts of sugar.

Odor. — The odor of normal urine is peculiar, aromatic, sometimes styled " urinous. " It is due to the presence of volatile acids — phenylic, taurylic, and damaluric — in very minute quantities, and partly also to urea. The odor is strongest in concentrated urine. On standing, normal urine acquires a disagreeable odor which is both putrid and ammoniacal. The putrid odor is due to decomposition of mucus or other organic matters. The ammoniacal odor is due to the formation of ammonium carbonate. It is important to note the odor of freshly passed urine, for if it is putrid or ammoniacal the urine must have decomposed within the body — e. g. y in the bladder. A urine which contains a large amount of pus or albumin may suffer decomposition of its proteid matter to such an extent as to evolve an odor of sulphuretted hydrogen. A fecal odor is noted when there is contamination of the urine by the feces through a fistula, etc.

Certain vegetable foods and certain drugs, when taken internally, very quickly produce a peculiar odor in the urine. Thus, turpentine produces the odor of violets;

cubebs, copaiba, sandalwood oil, asparagus, etc., produce their characteristic odors in the urine.

In disease the only abnormal odors to be noted are the increased odor, usually styled "strong," in concentrated urine; the sweet or fruity smell of diabetic urine; the foul odor of cystitis, and the "sulphuretted" odor of urine containing much pus. A peculiar odor, intense in its foulness, is noted in pyelitis. A sulphuretted odor is noted in the presence of cystin in decomposing urines containing this substance.

Consistence. — Normal urine is always of the consistence of water. When the urine contains much pus or mucus, especially if it has become alkaline, it becomes very thick and stringy. Urine containing much sugar or albumin tends to froth when shaken. Chylous urine which contains fat in fine emulsion is thickened in consistence.

Transparency. — Normal freshly voided urine is always perfectly clear, but on standing a few minutes there is generally a faint cloud which floats usually in the center of the urine or settles at the bottom if the urine is dilute enough. This cloud or "nubecula" consists of mucus, epithelium, bacteria, and debris of cells. It is much more pronounced in women on account of the admixture of vaginal mucus, which becomes washed away from the genitals in the passage of the urine from the urethra. In catarrhal conditions of the genito-urinary tract, especially in cystitis, prostatitis, and urethritis, the normal mucous cloud is markedly increased, so that the urine appears cloudy soon after being voided, and the cloud sinks more rapidly to the bottom. The mucous cloud may be distinguished from other causes of turbidity by the fact that it tends to float in the center of the fluid, and is precipitated on the addition of an excess of acetic acid.

A cloudy urine may be the result of the presence of bacteria, phosphates, urates, or pus.

Bacteria, when present in large numbers (bacteriuria) , give rise to a faint cloud which tends to float in the middle of the vessel and does not settle, even when the urine stands for a long time. This cloud, unlike the mucous cloud, remains unchanged on the addition of acetic acid.