Clinical diagnosis and urinalysis. A manual for students and practitioners

Front matter

RB 37 .A74 Copy 1

Medical Epitome Series

CLINICAL DIAGNOSIS

Author's Preface

The great importance of laboratory examinations in all branches of medicine and surgery has come to be universally recognized ; but the ability to put the methods into practice, and to derive the information they can give, has not yet been as widely acquired by the profession. This brief volume, covering the essentials, is intended to serve the needs of physicians and students rather than those of experts.

The practical side of laboratory work in its relation to the diagnosis of disease is emphasized. Many of the time-consuming quantitative analyses are intentionally omitted or merely mentioned. To be of value they should be made by experienced chemists. An attempt is made to explain fully the most important tests and procedures, and to anticipate many of the difficulties and mistakes of the inexperienced worker. No claim is made for originality or completeness. Many of the standard works have been freely consulted — such as Simon, Von Jaksch, Nichols, Ewing, Cabot, Musser, DaCosta, Vierordt, Purdy, Peyer, Osier, and others.

Numerous practical suggestions also have been obtained from the work in the clinical laboratory of the University of Michigan as instituted by Drs. Dock and Cowie. I am greatly indebted to Mr. Charles L. Bliss, late instructor in physiological chemistry in the University of Michigan, now government physiological chemist at Manila, for very valuable aid in the preparation of the section on Urinalysis.

J. R. A.

Denver, Colorado.

EDITOR'S PREFACE,

In arranging for the editorship of The Medical Epitome Series the publishers established a few simple conditions, namely, that the Series as a whole should embrace the entire realm of medicine ; that the individual volumes should authoritatively cover their respective subjects in all essentials ; and that the maximum amount of information, in letterpress and engravings, should be given for a minimum price. It was the belief of publishers and editor alike that brief Avorks of high character would render valuable service not only to students, but also to practitioners who might wish to refresh or supplement their knowledge to date.

To the authors the editor extends his heartiest thanks for their excellent work. They have fully justified his choice in inviting them to undertake a kind of literary task which is always difficult — namely, the combination of brevity, clearness, and comprehensiveness. They have shown a consistent interest in the work and an earnest endeavor to cooperate with the editor throughout the undertaking. Joint effort of this sort ought to yield useful books, brief manuals as contradistinguished from mere compends,

6 EDITOR'S PREFACE.

In order to render the volumes suitable for quizzing, and yet preserve the continuity of the text unbroken by the interpolation of questions throughout the subject-matter, which has heretofore been the design in books of this type, all questions have been placed at the end of each chapter. This new arrangement, it is hoped, will be convenient alike to students and practitioners.

Chapter I. Genekal Considerations

EQUIPMENT AND SCOPE OF WORK.

In purchasing laboratory supplies one should deal with an absolutely reliable firm. Because of the technical skill and experience required in the preparation of some of the solutions and stains, it is well for beginners to purchase them already prepared. This statement refers especially to the decinormal sodium hydrate solution and the like, and such stains as Wright's, Gram's, and Ehrlich's triacid stains.

Griibler's stains (powders) have the reputation of being the best on the market.

Laboratory tables should be painted black.

Laboratory diagnosis includes examination of the blood, stomach-contents, sputum, feces, urine, transudates and exudates, and of the various secretions and excretions of the body.

Special apparatus and reagents are required for some of this work, but the same apparatus may be employed in many of the foregoing subdivisions.

Among the general utility articles are to be mentioned the following :

Microscope (triple nose-piece, 2 eye-pieces, 3 objectives) — i. e. y oil-immersion and high and low dry lens.

Thermostat.

Glass rods, different sizes.

Glass tubing, different sizes.

Filter-paper, 4 inch, 6 inch, 8 inch, etc.

Funnels, different sizes (2 inch, 4 inch, etc.).

Graduates, different sizes (100 c.c, 500 c.c, 1000 c.c).

Centrifuge.

Two-gallon syphon bottle with distilled water*

Teasing needles.

Platinum loop.

Cover-glass forceps.

File.

Canada balsam (for mounting permanent specimens ; keep in wide-mouthed bottle).

Turpentine.

Cedar oil.

Xylol.

Glass slides — w T hite, not green glass.

Cover-slips are sold in four thicknesses, Nos. 0, 1, 2, 3. No. 1 is best for general work, since it is thin enough for use with the oil-immersion lens, and is not so easily broken as No. 0. The square f-inch cover-glass should be used.

Cleaning Glassware. — In cleaning glassware that has never been used, Cabot, after a long experience with various chemicals, has given them up, and uses nothing but soap and water, with thorough polishing.

The glassware may be placed in acetic acid for twenty-four hours, more or less (if in a hurry, a minute will do), then thoroughly washed in water and transferred to a largemouthed bottle containing alcohol. When wanted, it is dried and polished with a clean soft cloth.

The following cleaning fluid for glassware is recommended by Nichols as especially useful for glassware that has been soiled :

Potassium bichromate, 10 parts ;

Sulphuric acid (commercial), 10 "

The glassware is left in this fluid for twenty-four hours, then thoroughly rinsed with water and transferred to alcohol, to be used as wanted.

EQUIPMENT AND SCOPE OF WORK. 19

Carbol Fuchsin. —

Fuchsin (S.), 1 part ;

Absolute alcohol, 10 parts ;

5 Der cent, solution of carbolic acid, 100 "

Lbffler's Methylene-blue. —

Concentrated alcoholic solution of methylene-blue, 30 parts ; 1 : 10,000 aqueous solution of potassium hydrate, 100 "

Gram's method requires the following solutions :

1. Aniline Water. — Prepare by adding aniline oil to 10 c.c. of distilled water, drop by drop, shaking thoroughly after the addition of each drop, until the solution becomes opaque. Filter through moistened filter-paper.

2. Aniline Water Gentian-violet. — Treat the foregoing solution with 10 c.c. of absolute alcohol and 11 c.c. of a concentrated alcoholic solution of gentian-violet. This combined solution keeps only a few days, and should, therefore, be made up fresh.

3. LugoVs Solution. —

Iodine, 1 part ;

Potassium iodide, 2 parts ;

Gram's method is employed for the differentiation of certain bacteria, especially the gonococcus, and for staining the capsule of diplococeus pneumonice and other germs.

Application of Gram's Method. — 1. Cover spread with aniline water gentian-violet (made within two weeks) and heat to steaming-point.

2. Wash in water.

3. Cover with LugoPs solution for one-half to two minutes to decolorize.

4. Rinse in 95 per cent, alcohol until the violet color disappears to the naked eye.

5. Wash in water and mount.

When thus treated, certain bacteria retain the stain, such as diplococcus pneumoniae, diphtheria bacillus, tubercle bacillus, anthrax bacillus, streptococci and staphylococci.

The bacteria which become decolorized are the following : gonococcus, typhoid bacillus, colon bacillus, influenza bacillus, and cholera spirillum.

Fat-detection by Sudan III. — Test-solution. — Make a saturated alcoholic solution of Sudan III. Let stand for several days ; then mix 1 part of this solution with 1 part of alcohol and 1 part of water. The mixture is at once turbid, but clears on standing. Sudan III. stains fat red and leaves everything else unstained. Do not treat specimens with alcohol or ether before or after staining.

Test — A drop or two of the solution is run under the cover-glass covering the specimen ; under the microscope the neutral fat is seen to take on a red color.

Iodine Test for Starch. — Starch in granules or in solution strikes a deep-blue color in the presence of iodine. The stock test-solution is Lugol's. A drop or two of this solution is allowed to run under the cover-glass covering the specimen. In testing liquids for the presence of starch, dilute a few drops of this solution with water to a light-yellow color, and add a few drops of the suspected fluid. A deep blue indicates starch, a deep brown indicates erythrodextrin.

Glycogen granules treated by the first method turn a deep mahogany brown under the microscope.

Iodide Test for Starch. — Starch does not react to iodides in combination, but on setting free the iodine with nitric acid a deep-blue color develops.

Technic. — A strip of starch-paper is moistened with the fluid to be tested and then touched with a drop of nitric acid. The characteristic blue color develops in the presence of iodides.

Ethereal Extracts. — In certain tests the watery solution of the substance is shaken with ether or chloroform in order to extract the substance from the water. On standing the two fluids separate. Either the water or the ether may be removed by means of a pipette. Another method is to place the mixture in a filter which has been previously moistened

EQUIPMENT AND SCOPE OF WORK. 21

with water. The watery portion will then filter through. If ether is used for moistening the filter, the ethereal portion will filter through.

Guaiacum Test for Blood. — To 4 or 5 c.c. of tincture of guaiacum add from ^ to \ as much hydrogen peroxide, or an equal amount of " ozonized" turpentine (expose turpentine to light and air for a long time). The suspected fluid — in a long glass tube placed at the bottom of a test-tube — is allowed to run slowly out and underlie the reagent. At the junction of the two liquids a robin's egg blue layer forms, either immediately or in the course of a few minutes, if hsemoglobin is present.

Iodides and iodine also give a blue color.

Hsemin Test for Blood. — A drop of a 0.6 per cent, salt solution is evaporated on a slide. A small bit of the suspected materia], well teased, is placed upon the layer of crystallized salt. Place a cover-slip over it, and allow glacial acetic acid to run in under the slip, filling the spaces. Heat carefully (three-quarters to one minute) till bubbles of gas begin to form

Fig. 1.

Hsemin crystals.

beneath the cover. During evaporation glacial acetic acid is further added, drop by drop, from the edge of the slip, until a faint reddish-brown tint appears. Now hold specimen farther away from the flame, and slowly evaporate the last traces of acid. Add a drop of glycerin and examine under the microscope. If blood is present, heemin (or Teichmann) crystals form, in the shape of light- or dark-brown rhombic plates or columns. The size of the crystals varies with the manner in which they are produced. The more slowly the acetic acid is evaporated the larger the crystals.

G ENSEAL CONSIDERATIONS.

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It is often desirable to convert Centigrade (C.) into Fahrenheit (F.). The following formula will be found useful :

QUESTIONS.

Mention the various methods of cleansing glassware.

Describe the method of preparing carbol-fuchsin and Loffler's methylene-blue.

Describe Gram's stain, its practical application, and its special value.

Describe a method for the detection of fat.

What is the iodine test for starch ?

What is meant by ethereal extracts ?

Describe the guaiacum and hsemin tests for blood.

Give the formulas for converting Fahrenheit into Centigrade, and vice versa.

Chapter II. Blood

THE TECHNIC OF BLOOD- WORK-PRACTICAL SUGGESTIONS.

Blood-Stickers. — The German blood-sticker, illustrated in Fig. 2, is the most satisfactory made ; it costs 50 cents. The pen-sticker costs 5 cents and is very good. A pen with one nib broken is a useful substitute. The Hagerdorn needle is also used by many.

Gleaning Blood Pipettes. — In hospitals and laboratories where a great deal of blood-work is done an aspirator (Fig. 3) will be found extremely useful.

The cold-water faucet is threaded and the appliance screwed on. A rather large bottle with a doubly perforated rubber cork is attached, on one side by noncollapsible rubber tubing to the aspirator, and on the other to the blood-counter. The water is turned on, and its rush through the aspirator produces a suction which is felt in the blood-counter. This instrumentis placed for a few seconds in a bottle of dilute acetic acid, then in alcohol, and finally in ether, and these fluids sucked through it, thereby thoroughly cleaning and drying it. It is

Fig. 2.

A convenient to keep these four bottles grouped together in a rack.

Common Method of Cleaning a Blood Pipette. — Remove the rubber tubing attached to the blood-counter. Apply the

Fig. 3.

<S*gfc3 mouth and suck dilute acetic acid, alcohol, and ether through the pipette, thus cleaning and drying it.

THE TECHNIC OF BLOOD-WORK. 25

The dilute acetic acid and alcohol may be forced out by blowing through the pipette, but the ether must be expelled by forcible, downward, jerking movements of the hand, since moisture would be forced into it by the mouth. If clean and thoroughly dry, the glass ball in the bulb will roll about freely on moving the pipette. Compressed air furnishes a handy means for drying the pipette.

Coagulated Blood in Pipette. — This accident occasionally happens to beginners because of slow manipulation. In order to remove the coagulum do not insert a needle or pen into the lumen, as there is danger of breaking off the tip of the instrument. It is best to place the pipette in a test-tube filled with sulphuric acid and allow it to digest the coagulum for twenty-four to forty-eight hours. Then pursue the ordinary method of cleaning. If this is not successful, as sometimes happens, break up the coagulum by the careful insertion of a fine hypodermatic wire. Even with careful routine cleansing a film of coagulated albumin is apt to adhere. This should occasionally be removed by cleansing with sulphuric acid.

Rubber Tubing for Blood- counters. — Small rubber catheters are much better than the rubber tubing supplied with the blood pipettes. When thickening of Canada balsam occurs, it should be thinned with xylol.

Cleansing Lenses. — Cedar oil should be removed from the oil-immersion lens immediately after using by touching it with filter-paper or rice-paper. It frequently happens that cedar oil dries on the objective, obscuring the field of vision. It may be removed by rubbing the lens with a soft cloth or absorbent cotton moistened with either alcohol or xylol. A camePs-hair brush is useful for dusting slides and cover-slips.

Diluting Fluids for Counting Red Corpuscles. —

Toisson's :

Methyl-violet, 5 B, 0.025 gm. ;

Sodii chlor., 1.000 gm.;

Sodiisulph., 8.000 gm.;

Neutral glycerin, 30.000 cm. ;

Aqua dest., 160.000 cm.

Gowers' :

Sodii sulph., gr. cxij ;

Acid, acet., 3v ;

Aqua dest., §iv.

Hayem's :

Hydrarg. bichlor., 0.5 gm,

Sodii sulph., 5.0 gm.

Sodii chlor., 1.0 gm.

Aqua dest., 200.0 gm.

Toisson's fluid is most commonly used, but is dirty and deposits considerable sediment. It should be filtered. Its only advantage is that it stains the white corpuscles and makes it possible to count them along with the red cells. However, if one has a white counter, the cells are best counted separately.

Diluting Fluid for Counting Leukocytes.— 0.3 to 0.5 per cent, of glacial acetic acid in distilled water.

Wright's Stain. — (1) 0.5 per cent, solution of sodium bicarbonate. Dissolve thoroughly.

(2) To (1) add 1 per cent, of inethylene-blue (Griibler's B X or Ehi;lich ? s).

(3) Steam (2) 1 hour in steam sterilizer.

(4) Cool mixture.

(5) Pour into large flask and add to it, stirring, enough 1 : 1000 watery solution of eosin (Griibler yellow, watersoluble) until the mixture becomes purple in color, and a yellow metallic scum forms on the surface and a finely granular precipitate appears in suspension. This takes about 500 c.c. of eosin solution to 100 c.c. of alkaline solution.

(6) Filter (5) ; do not wash ; let filter dry and collect dry powder.

(7) With powder make a saturated solution in methyl alcohol — i. e. } 0.3 gram in 100 c.c. of methyl alcohol.

(8) Filter (7) and add to filtrate 25 per cent, of methyl alcohol. This is the staining fluid,

THE TECHNIC OF BLOOD-WORK, 27

The Ehrlich Tricolor Mixture. —

Saturated watery solution of orange-green, 6 c.c. ; Saturated watery solution of acid fuchsin, 4 c.c.

Mix these and then add a few drops at a time, shaking between each addition,

Saturated watery solution of methyl-green, 6.6 c.c. ;

Then add :

Glycerin, 5.0 c.c. ;

Absolute alcohol, 10.0 c.c. ;

Water, 15.0 c.c.

Shake well for one to two minutes. Let stand for twenty-four hours. Do not filter.

This formula is suggested by Cabot, though there are many other methods of making it.

Eosin. —

Eosin, 0.5 gram ;

Alcohol (70 per cent.), 100.0 c.c.

Hsematoxylon (Delafield's). — To 400 c.c. of a saturated solution of ammonium alum add 4 grammes of hsematoxylon crystals dissolved in 25 c.c. of strong alcohol. Leave this exposed to the light and air in an unstoppered bottle for three or four days. Filter and add 100 c.c. of methyl alcohol. Allow the solution to stand until the color is sufficiently dark. Then filter and keep in tightly stoppered bottles. The stain should ripen for at least two months before using.

Eosin and Methylene-blue. — (a) A saturated alcoholic solution of Ehrlich's blood eosin. (b) A saturated watery solution (1 per cent.) of Ehrlich's rectified methylene-blue. The latter should be at least one week old.

After several weeks, methylene-blue in solution diminishes in staining power, while the alcoholic eosin absorbs water and becomes less selective and more powerful.

Ehrlich's Dahlia Solution. —

Absolute alcohol, 50.0 c.c. ;

Glacial acetic acid, 12.5 c.c. ;

Distilled water, 100.0 c.c.

Add dahlia to saturation.

Iodophilia Mixture. —

Iodi. sublim., 1 gm. ;

Pot. iodidi, 3 gm. ;

Aq. dest., 100 c.c.

Acacia ad syrupum.

Nocht-Romanowsky Stain for Malarial and other Parasites. — 1 . To 1 ounce of polychrome methylene- blue (Grubler) add 5 drops of a 3 per cent, solution of acetic acid (U. S. P., 33 per cent.).

2. Make a saturated 1 per cent, watery solution of methylene-blue, preferably Ehrlich's (Grubler) or Koch's, dissolving the dye by gentle heat. This solution improves with age, and should be at least one week old.

3. Make a 1 per cent, watery solution of Grubler's icatenj eosin.

The mixture is prepared as follows : To 10 c.c. of water add 4 drops of the eosin solution, 6 drops of neutralized polychrome blue, and 2 drops of a 1 per cent, methylene-blue solution, mixing well. The specimens may be fixed either in alcohol or by heat, and are immersed, specimen side downward, for one to three hours, and will not overstain in twenty-four hours.

THE BLOOD AS A WHOLE.

The blood as a whole consists of a fluid portion, the plasma, in which are suspended cells of three kinds : red blood-cor-

THE BLOOD AS A WHOLE. 29

puscles (erythrocytes), white blood-corpuscles (leukocytes), and blood-plates.

Total Volume.— Most text-books give the total volume of the blood as about one-thirteenth of the body weight. If the recent researches of Haldane and Smith prove to be trustworthy, this deeply rooted idea will be modified. Smith estimates the average volume of blood in health as 3240 c.c., or 3420 grammes. In the 14 normal cases studied, the bloodmass varied from 2830 to 4550 grammes, or one-thirtieth to one-sixteenth of the body weight. A correct knowledge of the total blood volume would be of remarkable clinical value in diagnosing an anaemia and plethora. The methods employed by these observers will be referred to in another chapter. Unfortunately they are not sufficiently easy of application to be put into general use.

Color. — The red color of the blood is due to an albuminous iron-containing substance called hcemoglobin, which is combined in the red blood-corpuscles. It has an extremely strong affinity for oxygen, combining with it to form oxyhemoglobin. The excess of oxyhemoglobin in the arterial blood over that in the venous blood gives the former its bright-red color and the latter its bluish appearance. The hemoglobin of normal blood, represented by its red color, is arbitrarily placed at 100 per cent. The varying color of blood in disease is dependent upon the amount of hemoglobin and oxyhemoglobin present ; a great excess of the leukocytes, however, tends to give the blood a whitish or creamy appearance, such as is seen in leukemia.

Reaction. — The reaction of the blood during life is alkaline, owing to the presence of disodium phosphate (Na 2 HP0 4 ) and sodium carbonate. It is lower in women and children than in men, and is influenced by physiological processes, such as digestion, exercise, etc. In a large number of pathological conditions it is diminished, such as the prolonged use of acids, and in pernicious anemia, leukemia, nephritis, diabetes, hepatic disease, carcinoma, high fevers, and toxic conditions. An increase in the alkalinity is brought about by the prolonged use of alkalies and by cold baths.

Coagulation. — The most striking phenomenon which the blood exhibits on exposure to the air is the formation of a clot. If a bit of this clot be examined microscopically, it will be found to consist of a dense network of fibres which is filled with blood-corpuscles. These may be washed out, leaving the fibrin network intact.

Fibrin belongs to the class of the so-called coagulated albumins, and probably does not occur in the circulating blood, but is formed during the process of coagulation.

Blood-serum is the straw-colored fluid which separates from the clot during the process of coagulation. It differs from blood-plasma in the absence of fibrinogen and the presence of large quantities of fibrin-ferment and traces of fibrinoglobulin in the blood-serum.

In the plasma the following albumins are found : fibrinogen, serum-globulin, and serum-albumin.

Agglutinins are very important constituents of the blood-serum ; they are susceptible to examination, and furnish valuable clinical information, as is seen in the Widal test in typhoid fever. They appear in the blood-serum as a result of bacterial infection, each variety of germ elaborating a special agglutinin, which has a specific agglutinating effect only upon that species of germs.

Pigment-granules are sometimes present in the plasma, as in malaria, melanosis, and sometimes in Addison's disease.

Haemoglobin occasionally passes into solution in the blood-plasma — i. e. 9 hcemoglobincemia.

The following additional substances are found in the blood : fats, soaps, cholesterin, sugar, glycogen, and at times lecithin. Numerous extractives have been found in the blood, such as urea, uric acid, kreatin, carbamic acid, sarcolactic acid, hippuric acid, and, under pathological conditions, xanthin, hypoxanthin, paraxanthin, adenin, guanin, leucin, tyrosin, lactic acid, cellulose, /9-oxybutyric acid, acetone, and biliary constituents. These numerous substances are of practically no clinical importance.

Chemical analysis of the blood shows the following com-

PHYSIOLOGY OP THE BLOOD. 31

position, calculated for 1000 parts, according to the table of C. Schmidt :

Man. Woman.

Haemoglobin and globulins 159.60 120.10

Mineral salts 3.70 3.55

Albumin and extractives 39.90 44.79

Mineral salts 4.14 5.07

Specific gravity of normal blood varies from 1056 to 1060, being somewhat higher in men than in women. It varies greatly in disease, running practically parallel to the haemoglobin per cent.

PHYSIOLOGY OF THE BLOOD.

Examination of a fresh drop of normal blood under the microscope reveals chiefly two things, red corpuscles and white corpuscles ; less prominently blood-plates, Muller's " blood-dust," and a fibrin network.

Red Corpuscles. — Under normal conditions the number of red corpuscles per cubic millimetre is quite constant, averaging about 5,000,000 in the male and 45,00,000 in thfc female. This number is greatly increased or diminished in disease. In vigorous health the number often reaches 6,000,000. High altitudes increase the number of cells up to 8,000,000 or 9,000,000. In the newborn the number of cells is high for a few days, 7,000.000 to 8,000,000. The red corpuscle is a round biconcave disk, with a yellowish or greenish-yellow appearance. It varies considerably in size under normal conditions, but the average may be taken as 7.5/^. It seems to be larger in northern than in southern latitudes. Red blood-cells are all of the same round shape, except as they are indented, bent, and curved by striking against each other, or against white corpuscles, as they are moved in the plasma-currents. These corpuscles tend to form rouleaux, rows of cells standing on end or slightly tilted, like piles of

BLOOl).

coins. The cells also become crenated with great facility. One should become thoroughly familiar with all forms of crenation, since the early stage of this process produces a deceptive appearance in the cell, which resembles the young form of the malarial parasite.

White corpuscles attract attention by their color, size, granules, amoeboid movements, or by the fact that they are not moved by the blood-current like the red cells. In healthy adults they vary considerably in number, averaging

Fig. 4.

Normal and abnormal red blood-corpuscles : a, Normal corpuscles, side and edge view; b, vacuole formation; c, crenated corpuscles; </, rouleau formation; r, pale corpuscles, deficient in haemoglobin;/, poikilocytes ; g, macrocyte ; h, microcyte; i, normoblast ; k, megaloblast. (Nichols.)

about 7500 per cubic millimetre. The normal ratio of red to white cells is about 1 : 600. They vary much in size, from 10 fjt to 13.5 /i, depending on the variety.

Blood-plates are small irregularly shaped disks, about half the size of a red cell, and having a tendency to clamp in bunches. They are seldom noticed in normal unstained blood, probably because of slow manipulation. Their number is variously estimated at from 180,000 to 860,000 per cubic

PHYSIOLOGY OF THE BLOOD.

millimetre. They do not contain haemoglobin, and show no signs of a nucleus.

Blood-dust. — Muller has given the name " hsemokonia " to small round colorless granules (\ to 1 [x in diameter) which may be found in normal and pathological blood. They are highly refractile, have a rapid dancing movement, but are without power of locomotion.

Fig. 5.

Normal blood. X 350. (Cabot.)

Fibrin Network. — If a fresh blood-drop preparation is exposed to the air for some time, a network of fine fibrin threads forms, and may be seen under the microscope, running between the corpuscles and sometimes radiating from a centre which is perhaps a mass of blood-plates. Under certain conditions this network is increased or diminished. 3— c. D.

QUESTIONS.

Describe the method of cleansing the blood pipette. How should coagulated blood be removed from the pipette? Describe the method of cleansing lenses.

Mention the diluting fluids used in counting red and white blood-corpuscles.

Mention the important blood-stains.

What is the total volume of blood in man ?

The colors of the blood are due to what substance?

What is the reaction of the blood and upon what does it depend?

Upon what does the coagulation of the blood depend ?

What is the specific gravity of the blood ?

What are agglutinins?