Pathological technique; a practical manual for the pathological laboratory

Front matter

Chap*.„\„. 'Copyright No.

3helf„,iAA(o

UNETED STATES OF AMERICA.

Preface

This book is designed especially for practical use in pathological laboratories, both as a guide to beginners and as a source of reference for the advanced. We believe that the book will also meet the wants of practitioners who have more or less opportunity to do general pathological work.

Every autopsy presents for solution a problem which may be simple or complex. The known quantities are certain clinical symptoms and physical signs ; the unknown quantities are not only the gross and microscopic lesions that may or may not have given rise to the symptoms and signs, but also the etiology of the lesions and the order of their sequence. The solution of the problem often requires the highest skill in post-mortem, bacteriological, and histological technique, but in its solution lies the fascination of pathological work.

It has seemed advisable to us to present, so far as possible, a consecutive statement of the methods employed in solving the various problems that arise, so as to avoid the repetitions that necessarily occur when the three usual divisions of the subject are separately considered by different writers. It is hoped that this method of presenting the subject will bring the student to the realization that the mechanical performance of a post-mortem examination and the inspection of the gross lesions constitute usually only the beginning

of the solution of the problem, which should be investigated

12 PREFACE.

bacteriologically, histologically, and chemically as far as our present knowledge will permit.

We should particularly advise the routine bacteriological and histological examination of the more important organs in all suitable cases. Naturally, the autopsies in which the lesions are due to a single etiological factor are the most valuable and instructive for a clear understanding of the pathological processes present.

Besides the methods of post-mortem examinations and of bacteriological and histological investigations connected with autopsies, we have added the special methods employed in clinical bacteriology and pathology.

In the parts devoted to Bacteriology and to Pathological Histology we have not endeavored to make an exhaustive collection of methods and formulae, but rather to select those which have been found of the greatest service in practical work.

To Dr. A. H. Wentworth, Assistant in Children's Diseases in the Harvard University Medical School, we are indebted for the sections on the Blood and on Malaria, and for the notes in regard to Lumbar Puncture.

Boston, August, 1897.

Part I. Post=mortem Examinations

Introduction, 17. — Instruments, 18. — General Rules, 21. — Suggestions to Beginners, 23. — Private Autopsies, 24.

I. EXTERNAL EXAMINATION OF THE BODY.

Inspection of the Body as a Whole, 26. — Special Inspection of the Different Parts of the Body, 27.

II. INTERNAL EXAMINATION OF THE BODY.

Opening of the Abdominal Cavity, 27. — Inspection of the Abdominal Cavity, 29. — Opening of the Thorax, 30. — Inspection of the Pleural Cavities, 31. — Opening of the Pericardium, 32. — External Inspection of the Heart, 32. — Opening of the Heart, 33. — Removal of the Lungs, 37. — Organs of the Neck, 39. — The Abdominal Cavity, 40. — The Spleen, 41. — The Gastro-intestinal Tract, 41. — The Liver, 44; The Kidneys and Adrenals, 45. — The Pelvic Organs, 47. — Removal of the Brain, 50. — External Examination of the Brain, 55. — Section of the Brain, 56.— Virchow's Method, 58; Pitre's Method, 59. — Removal of the Spinal Cord, 60.— The Eye, 62.— The Ear, 63.— The Nasopharynx, 64. — Examination of New-born and Very Young Children, 65. — Restitution of the Body, 67.

Part II. Bacteriological Examinations

I. BACTERIOLOGICAL APPARATUS.

Steam Sterilizer, 70. — Hot-air Sterilizer, 70. — Blood-serum Coagulator, 70. — Gas-stove, 71. — Test-tubes, 71. — Hypodermic Syringes, 71. — Cornet Coverglass Forceps, 71. — Dropping-bottles, 71. — The "Platinum Wire" or "Loop," 72.— Bacterial Filtering Apparatus, 72. — Wire Baskets, 72. — Tin Cups, 73. — Thermo-regulator, 73.

14 CONTENTS.

II. CULTURE=MEDIA.

The Preparation of Test-tubes, 74. — Preparation of Culture-media : Bouillon, 75 ; Glucose Bouillon, 76; Agar-agar (Plain), 77; Glucose Agar-agar, 79. — Glycerin Agar-agar, 80; Gelatin (Plain), 80; Glucose Gelatin, 81 ; Blood-serum (Lofflers Mixture), 81 ; Litmus-milk, 85; Potato- cultures according to Bolton, 85 ; Dunham's Pepton Solution, 86. — The Filling of Test-tubes, 86. — Sterilization of Culture-media, 87.

III. BACTERIOLOGICAL EXAMINATIONS AT AUTOPSIES.

Cover-glass Preparations, 89. — Staining Methods for Cover-glass Preparations : Gram's Method of Staining, 91 ; Stain for the Bacillus Tuberculosis (Gabbet's Method), 92; Welch's Method of Staining the Capsule of the Pneumococcus, 93; Curry's Method of Staining the Capsule of the Pneumococcus, 93. — Examination by Cultures, 94. — Method of Preparing Cultures on Blood-serum, 94; The Inoculation of Animals, 96.

IV. THE METHODS OF STUDYING BACTERIA IN CULTURES.

1. Cover-glass Preparations from Cultures, 98. — The Staining of Spores, 100.— -The Staining of Flagella, 100 : Loffier's Method. 102; Pitfield's Method, 103; Bunge's Method, 103; Van Ermengem's Method, 104. — 2. Methods of Obtaining Pure Cultures, 105. — Method of Isolation of a Bacterium in Pure Culture from a Mixed Growth, 107 : The Plate Method of Petri, no; Esmarch's Method of Roll-cultures, no. — The Determination of the Motility of Bacteria, in. — 3. The Inoculation of Animals, 112. — Guinea-pigs, 112. — Rabbits, 113. — Mice, 115. — The Care of Animals, 117. — 4. Cultivation without Oxygen (Anaerobic Cultures) : Method of Liborius, 117; Method of Buchner, 119; Esmarch's Method, 119; Bouillon Cultures under Hydrogen, 119.

V. BACTERIOLOGICAL DIAGNOSIS.

Staphylococcus Pyogenes Aureus, 121. — Staphylococcus Pyogenes Albus and Citreus, 1 24. — Staphylococcus Epidermidis Albus, 124. — Staphylococcus Cereus Albus and Flavus, 124. — Streptococcus Pyogenes, 124. — Pneumococcus, 128. — Gonococcus, 130: Special Culture-media, 131 ; Serum Agar-agar, 131 ; Urine- Sei-um-Agar-agar, 132. — Micrococcus Tetragenus, 133. — Diplococcus Intracellularis Meningitidis, 135. — Bacillus Diphtherial, 137. — Bacillus of Typhoid Fever, 141 : Differential Diagnosis between the Bacillus of Typhoid Fever and the Bacillus Coli Communis, 143. — Bacillus Coli Communis, 145. — Bacillus Tuberculosis, 148. — Spirillum of Asiatic Cholera (Comma Bacillus), 152. — Bacillus of Anthrax, 156. — Bacillus Pyocyaneus (Bacillus of Green Pus), 160. — Bacillus of Influenza, 162. — Bacillus of Glanders (Bacillus Mallei), 164. — Bacillus Proteus (Proteus Vulgaris), 167. — Bacillus Mucosus Capsulatus, 168. — Bacillus of Tetanus, 171. — Bacillus Aerogenes Capsulatus, 173. — Bacillus of Malignant Edema, 175. — Actinomyces, 176.

CONTENTS. 1 5

VI. CLINICAL BACTERIOLOGY.

General Considerations, 178; Cover-glass Examinations, 180; Preparation of Cultures, 180; Animal Inoculations, 181. — Suppurative Processes, 181. — Erysipelas, 181. — Peritonitis and Appendicitis, 181. — Pleural, Pericardial, and Joint Exudates, 182. — Anthrax, or Malignant Pustule, 182. — Diphtheria, 182: Special Methods of Staining the Bacillus Diphtheria?, 184. — Influenza, 185. — Examination of Sputum for Tubercle Bacilli, 186. — Tubercle Bacilli in Urine, 188. — Surgical Tuberculosis, 189. — Cultures from the Blood during Life, 190. — Gonorrhea, 190: Method of Staining for Gonococci, 191. — Gonorrheal Conjunctivitis, 192. — Pyosalpinx, 192. — Cerebro-spinal Meningitis, 192. — Glanders, 193. — Tetanus, 193: Method of Isolation, 193. — Asiatic Cholera, 195. — Typhoid Fever, 198: Isolation of the Typhoid Bacillus from the Feces, 198; Capaldi's Culture-medium, 200; The Blood-serum Reaction in Typhoid Fever, 201. — Rabies (Hydrophobia), 201. — Leprosy, 203. — Actinomycosis, 203.

Part III. Histological Methods

Introduction, 204. — Laboratory Outfit : Microscopes, 204. — Freezing Microtome, 206. — Celloidin Microtome, 209. — Paraffin Microtome, 210. — Paraffin Bath, 2IO. — Vulcanized Fiber, 211. — Knives, 212. — Running Water, 213. — Slides, 213. — Cover-slips, 214. — Staining Dishes, 214. — Metal Instruments, 215. — Bottles, 216. — Examination of Fresh Material, 216. — Indifferent Fluids, 217. — Macerating Fluids, 218. — Examination of Fluids, 218. — Injections, 218. — Cold Injection-masses, 219. — Warm Injection-masses, 219. — Fixing Reagents, 220. — -Alcohol, 222. — Zenker's Fluid, 223. — Orth's Fluid, 224. — Flemming's Solution, 224. — Hermann's Solution, 225. — Pianese's Solution, 225. — Rabl's Chromo-formic Acid Solution, 225. — Corrosive Sublimate, 225. — Formaldehyde, 226. — Boiling, 227. — Miiller's Fluid, 227. — Marchi's Fluid, 228. — Erlicki's Fluid, 228. — Decalcification, 228. — Directions for Using Nitric Acid, 229. — Phloroglucin and Nitric Acid, 229. — Picric Acid, 230. — Trichloracetic Acid, 230. — Imbedding Processes, 230. — Celloidin, 231. — Imbedding in Celloidin, 231. — Imbedding in Paraffin, 234. — Serial Sections by the Celloidin Method, 237. — Serial Sections by the Paraffin Method, 239. — Staining Solutions : Hematoxylin and Hematein Stains, 239. — Carmine Stains, 244. — Aniline Dyes, 245. — Diffuse Stains, 249. — Combination Stains, 250. — Pianese's Staining Solutions and Staining Methods, 250. — Orcein, 253. — Iodin, 253. — Lugol's Solution, 254. — Acid Alcohol, 254. — Aniline Water, 254. — Carbolic-acid Water, 255. — Mayer's Glycerin-albumin Mixture, 255. — Clearing Reagents, 255. — Mounting Reagents, 258. — Metallic Stains or Impregnations, 258. — Silver, 258. Gold, 260. — Osmic Acid, 261. — Staining Methods, 262. — Nuclear Stains, 265. — Alum-hematoxylin Stains, 266. — Aqueous Alum-hematoxylin ; Delafield's Hematoxylin; Ehrlich's Acid Hematoxylin, 267. — Mayer's Hemalum, 268. — Hcidenhain's Hematoxylin Stain, 268. — Carmine Stains, 268. — Aniline Dyes as

1 6 CONTENTS.

Nuclear Stains, 269. — Diffuse or Contrast-stains, 271. — Combination Stains, 272. — Staining in Mass, 273. — Mitosis, 273. — Directions for Staining Karyomitotic Figures with Safranin, 274. — The Staining of Bacteria in Tissues, 275. — Pathogenic Bacteria which do not Stain by Gram, 277. — Gonococcus, 278. — Typhoid Bacillus, 278. — Influenza Bacillus, 279. — Glanders Bacillus, 279. — Friedlander's Capsule-bacillus, 280. — Pathogenic Bacteria which Stain by Gram, 280. — Bacillus of Rhinoscleroma, 282. — Actinomyces, 282. — Bacteria that Stain by the Tubercle-bacillus Method, 283. — Tubercle Bacillus, 283. — Bacillus of Leprosy, 285. — Syphilis Bacillus, 286. — Smegma Bacillus, 286. — Methods of Examination of Animal Parasites, 287. — Protozoa, 287. — Malaria] Organisms, 287. — Ameba Coli, 292. — Sporozoa, 294. — Round-worms, 294. — Trichinae, 295. — Tape-worms, 296. — Taenia Solium, 296. — Taenia Mediocanellata s. Saginata, 298. — Taenia Echinococcus, 298. — Bothriocephalus Latus, 298. — Special Stains for Certain Tissue-elements other than Nuclei, 298. — Mastzellen, 298. — Plasma-cells, 300. — Connective-tissue Fibrillae, 300. — Elastic Fibers, 301. — The Central Nervous System, 303; General Stains, 305 ; Stains for Ganglion-cells, 307; Stains for the Myelin-sheath, 316; Stains for the Neuroglia-fibers, 321. — Degenerations of the Nervous System, 325. — Examination of the Blood, 326.— Apparatus Used in the Examination of the Blood, 327. — Preparation of Apparatus, 330. — Obtaining the Blood, 331. — The Hemoglobin Test, 332. — Estimation of Number of Red Corpuscles, 333. — Cover-glass Preparations, 336. — The Elements of the Blood, 338. — Methods of Staining, 342. — Methods of Fixing and Examining Special Organs and Tissues, 344. — Acute Inflammatory Exudations; Granulation-tissue, 345. — Lung, Spleen, Bone-marrow, Kidney, 346. — Gastro-intestinal Tract, 347. — Liver, 347. — Bone and Cartilage, 348. — Museum Preparations, 350. — Pathological Products, 352. — Cloudy Swelling; Albuminous Degeneration, 352. — Fatty Degeneration, 352; Necrosis, 354. — Caseation, 355. — Demonstration of Fibrin, 355. — Mucin, 356. — Pseudo-mucin, 358. — Colloid and Hyaline, 358. — Glycogen Infiltration, 361. — Amyloid Infiltration, 362. — Pigmentation, 365. — Petrifaction, 368. — Clinical Pathology, 368. — Examination of Tissues from Clinical Cases for Diagnosis, 369. — Uterine Scrapings, 369. — Examination of Fluids obtained by Puncture, 370. — Lumbar Puncture, 371. — Ovarian and Parovarian Cysts, 374. — Pancreatic Cyst or Fistula, 374. — Dropsy of the Gall-bladder, 375. — Hydronephrosis and Renal Cysts, 375. — Echinococcus Cysts, 375. — Examination of the Sputum, 376: Macroscopic Examination, 376; Microscopic Examination, 378. — Examination of the Gastric Contents, 380. — Examination of the Feces, 382. — Examination of the Urine, 382.

PATHOLOGICAL TECHNIQUE.

Part I. Post-mortem Examinations

Introduction. — The method of making post-mortem examinations as originally taught by Virchow has been variously modified in its details by his pupils and followers. We have endeavored, while following in general his plan, to select those modifications that have proved simplest and of greatest value. In certain instances we have not hesitated to adopt, or at least to call attention to, useful methods of procedure originating in the Rokitansky school of pathology, as now best exemplified by Chiari.

The problem offered by an autopsy is often solved in part or wholly by the macroscopic post-mortem examination. More frequently, however, the complete and final solution is reached only after careful bacteriological and histological study. The post-mortem examination may, therefore, be looked upon as the beginning of the solution of the problem. Its particular function is to demonstrate in the individual case all congenital or acquired abnormalities, all macroscopic lesions, and to explain all gross mechanical questions. It furnishes the material for bacteriological and histological study. Perfectly to accomplish its purpose a post-mortem examination must be made in a careful, systematic manner.

While a general method of procedure is advisable, it will often be found advantageous, or even necessary, to depart 2 17 from it. According to Orth, " the chief requisite of every exact post-mortem examination is this, that no part shall be displaced from its position until its relations to the surrounding parts are established, and that no part shall be taken out by whose removal the further examination of other parts is affected."

The order and method of procedure in making a post-mortem examination, including the various incisions, may be said to have been planned for the routine examination of normal or diffusely diseased organs. As soon as a noticeable focal lesion is present the order of procedure and the customary method of removal and of incision must be so altered as best to display the lesion.

Instruments. — The following instruments will be found extremely useful in the autopsy-room, although not all of them are necessary :

The autopsy-table should be large, so as to accommodate on it the instruments and several dishes in addition to the body. It should have a slightly raised edge, and should slope gently toward an opening in the center for the escape of fluids. The table is best made of zinc, and along one edge should have a centimeter scale. The water for use on the table is best supplied by a rubber tube from an overhead pipe reaching to within 60 to 100 cm. of the table.

The scales for weighing the various organs should have a large pan and gram and kilogram weights.

A band-saw will be found very useful for sawing bones for the inspection of the marrow, and for calcified and osseous tumors.

The best autopsy-knife is a stout, broad-bladed knife with bellied edge and heavy handle. The blade should measure about 12 cm. in length and 3 cm. in width ; the handle should be 12 cm. in length. Many operators prefer a somewhat smaller knife than this.

Amputating-knives of different sizes are useful for long, deep cuts into organs and tumors.

A myelotome is a short, thin, narrow knife-blade, 1.4 cm. long and 4 mm. wide, set obliquely on a slender steel stalk

POST-MORTEM EXAMINATIONS.

ending in a wooden handle (Fig. 2). It is used only for cutting the cord squarely across in removing the brain.

Fig. i.-Instruments for use in the autopsy-room: a, saw; b, holder for the head ; c, steel hammer with wedge end and blunt hook on the handle ; d, costotome ; e, bone-cutter ; /, hatchet-chisel ; gt autopsy-knife.

Cartilage-knives and scalpels of different sizes are used for a variety of purposes.

Scissors, both straight and curved, should be of various sizes. A medium-sized and a fine pair should each have one probe-pointed blade.

An enterotome is a long, straight pair of scissors, of which

FIG. 2. — Myelotome.

one blade is longer than the other and blunt at the extremity (Fig. 3). A hook at the end is not advisable. The instrument is used in opening the heart and the intestines.

Fig. 3. — Enterotome.

A saw with movable back and rounded end will be found the most generally useful for opening the skull and the

Luer's double rachiotome.

spinal canal. An ordinary meat-saw is preferred by some, but cannot be used on the vertebrae.

Luer's double rachiotome, or adjustable double saw (Fig. 4), is very useful in removing the cord, and is the safest instrument to put into the hands of beginners.

Forceps : several sizes, large and small, mouse-toothed.

Costotome : heavy bone-shears for cutting the ribs.

A powerful bone-cutter ; with short blades, 5 cm. long, set at an angle of about 45 ° to the handles, which are 36 cm. in length, is employed for dividing the arches of the cervical vertebrae and for other purposes where ordinary bone-cutters will not do.

A chisel with 2 cm. cutting edge, for exposing the marrow of the long bones, removing portions of the base of the skull, etc.

A hatchet-chisel of steel for starting the calvaria and spinous processes after sawing the skull and the vertebral column.

Soft-iron hammer with wooden handle.

Steel hammer with wedge end, and blunt hook on the handle.

Holder for the head while sawing the skull.

Autopsy-needles, long and a little curved.

Prohes of flexible metal ; also fine glass probes for small blood-vessels or ducts.

Grooved director.

Pans for holding water, organs, etc.

Boards, square or oblong, 30 X 30 or 30 X 50 cm., on which to lay instruments or cut organs.

Sponges.

Catheters.

Strong hemp twine is the best for sewing up the body.

Glass graduates for measuring fluids.

A block of wood with shallow depression for the neck ; for use while opening the head.

Vise.

Small cup or dish for removing fluid from cavities.

General Rules. — The room for an autopsy should be well lighted, otherwise the finer changes in the tissues cannot be recognized. Artificial illumination is not good, because the colors of the tissues are entirely changed by the yellowness of the light.

Before beginning an autopsy the necessary instruments should be arranged on a short board on the autopsy-table in the order in which they are most likely to be used.

The operator stands on the right side of the body. This position he rarely leaves except for some definite purpose ; for example, in opening the skull he stands at the head.

Order and cleanliness are the first points to be insisted upon at every autopsy. Clean water should always be at hand for washing the instruments and for keeping the hands free from blood and pus. The cut surface of an organ should not be washed with water except to remove blood ; gently scrape the surface with the knife held obliquely.

In cutting, the knife should be drawn, not pressed or shoved into the tissues. According to Virchow, a broad, clean cut into an organ, even if incorrectly made, is much better than several short cuts which leave a ragged surface.

The autopsy-knife should be grasped in the hand as if to cut bread. In using this knife the main movement should be from the shoulder, not from the wrist as in dissecting. It goes without saying that the sharper the knife the better.

In cutting the brain and cord, especially if their consistency is lessened, moisten the knife to prevent the tissue from sticking and tearing.

Before beginning an autopsy it is important to know the main points in the clinical history of the case, as they may greatly lighten the work of investigation by calling attention to those organs that require special examination.

The record of an autopsy should be dictated by the operator as he proceeds with the examination of the case, and should be as nearly as possible an objective description of the appearances found. Only the anatomical diagnosis should express the opinion of the operator. If it is not convenient to dictate the autopsy during its performance, the description of the lesions certainly ought to be made with the organs in sight, and not from memory after the lapse of hours or even days, when many of the details may be forgotten. Later, the results of the bacteriological and histological examinations should be added to the autopsy report, so as to make the case complete.

Rubber gloves are sometimes worn to protect the hands while making a post-mortem examination ; but they greatly dull the sense of touch, and cannot be recommended for routine work except while opening the stomach and intestines. Rubber cots for the fingers are often useful.

For cuts on the fingers use celloidin dissolved in equal parts of alcohol and ether, instead of flexible collodion, because the latter will not stick. A cut received during an autopsy should immediately be washed thoroughly, and then sucked so that the blood will flow freely. For protection during the rest of the autopsy use a rubber glove or cover the cut with celloidin.

It is always well to wash the hands after an autopsy with an antiseptic solution, such as corrosive sublimate (i : 2000). For removing odors from the hands turpentine will often be found serviceable, or a saturated solution of permanganate of potassium followed by oxalic acid. Orth highly recommends a dilute solution of formaldehyde for this purpose.

Suggestions to Beginners. — In a case of general miliary tuberculosis the older focus from which the organisms have spread must always be found. Look especially for tubercular thrombi in the pulmonary veins as the frequent source of the general infection.

In a case of embolism hunt for the thrombus, bearing in mind, however, that the whole of a thrombus may become free and form an embolus. An arterial embolus may be due to a venous thrombus, in which case it must have passed through an open foramen ovale, except in the case of thrombi of the pulmonary veins.

In acute peritonitis always seek for a source of infection (appendix, female genitals, gastro-intestinal tract, etc.). It cannot always be found.

In hemorrhage from the stomach associated with cirrhosis of the liver look for rupture of dilated esophageal veins.

In cases of more or less sudden death, especially if preceded by signs of asphyxia, always examine the pulmonary artery in situ for possible emboli. In cases of instantaneous death examine the coronary arteries.

Private autopsies must often be made under many disadvantages, and, when out of town, not infrequently in a short space of time. It is always important to warn the attending physician not to allow the undertaker to inject the body before the autopsy, because the color and consistency of the organs are so changed by most injecting fluids that it is difficult to recognize the pathological processes. If there is danger of post-mortem changes, have the body packed in ice.

A regular autopsy-bag will be found very convenient for carrying to private autopsies. It is made of black leather lined with rubber, and measures about 40 X 1 8 X 20 cm. Loose within it is carried a rubber bag 40 X 24 X 20 cm., shaped like a short envelope with a flap (22 cm. long) on one side, for bringing away any organs that demand further examination. The case of instruments should contain one or two autopsy-knives, two scalpels, a pair of forceps, one or two pairs of scissors, an enterotome, a steel hammer with wedgeend and with a blunt hook on the handle, a small chisel, a saw with detachable handle and back, an autopsy-needle, and a probe ; free within the bag should be carried a spool of strong twine, a costotome, a long slender knife for use in removing the brain, a hammer with soft iron head, and a sponge. In rare cases additional instruments may be required. A white duck apron for personal use will always be found convenient. It is also well to carry along several blood-serum tubes and a platinum needle for making cultures at the autopsy. When there is a lesion of the nervous system it is advisable to bring a jar of a 4 per cent, solution of formaldehyde and to place the tissue in the fluid at the autopsy, as otherwise it is not easily gotten to the laboratory in good condition.

At the house can always be obtained a slop-pail, a washbowl, a pitcher of water, several newspapers, and an old sheet. The body is usually on an undertaker's frame, but it may be in an ice-box or on the bed. The examination of the chest and abdomen can be made in any of these positions. If, however, the body is in an ice-box, it must be raised to the level of the top of the box in case it is necessary to open the head.

The clothing on the body can be removed, or, if only a shirt or a night-dress, is best slit down the middle and turned out over the arms. Tear the sheet into four equal pieces. Fold and tuck in one piece on each side of the trunk and neck, allowing the outer portion to fall over the arms. Fold and lay the third piece on the lower extremities, tucking the upper end beneath the clothing below the pubes. The fourth piece can be placed beneath the head if it is to be opened. This procedure leaves the front of the thorax and abdomen free for operation and protects the rest of the body and the clothing. On the thighs place one or two folded newspapers, and on these the necessary instruments. On the legs place the bowl containing only a dampened sponge. If the undertaker has not put a rubber sheet on the floor beneath the body and on the side where the operator is to stand, newspapers should be spread to protect the carpet. Place the slop-pail on the rubber sheet within convenient reach. Having thus made all arrangements, even to the threading of his needle, the operator is ready to begin.

If the cord and brain have to be examined as well as the body, it is best to do the cord first, so as to avoid the leakage that might otherwise occur from the trunk-cavities if they had been opened first. To support the head while opening it, use a stick of wood, a brick, or, in case of necessity, the instrument-box wrapped in a newspaper.

At a private autopsy cleanliness is extremely important. If there is no undertaker or nurse present, the operator himself must see that everything is cleaned and put in order before leaving, that all the blood-stains are removed from the dishes, and that all papers and soiled cloths are burned or rolled up and left in a neat bundle for the undertaker to dispose of. Ground coffee thrown on a shovelful of burning coals will be found an excellent deodorizer for the room after the autopsy.

EXTERNAL EXAMINATION OF THE BODY.

External examination is often of great importance, especially in medico-legal autopsies, and should never be neglected, as it may throw great light on lesions found within the body. It should be systematic and careful, and is best taken up in the following order :

I. Inspection of the Body as a Whole.

1. Sex.

2. Age.

3. The body-length should be measured on the table beside the body, between points opposite the vertex of the head and the sole of the foot beneath the ankle.

4. The development of the skeleton has reference to the bony framework, which may be powerful, slender, or deformed.

5. The general nutrition is shown by the amount of muscular development and of subcutaneous fat-tissue. The latter is judged by pinching up a fold of skin.

6. The general condition of the skin includes amount of elasticity, bronzing, jaundice, edema, and decubitus.

7. Post-mortem discolorations may be divided into three varieties :

(a) Hypostasis of blood, or the settling of blood into the lowest lying blood-vessels ; this form of discoloration disappears on pressure.

(b) Diffusion of blood-coloring matter out of the vessels into the surrounding tissues (due to blood-pigment being set free by post-mortem decomposition) ; does not disappear on pressure.

(c) The greenish discoloration, usually seen earliest over the abdomen, is due to sulphate of iron formed through decomposition of the tissues. This discoloration is important, as it may modify the interpretation of appearances observed in the internal organs.

8. Post-mortem rigidity, degree and extent. It begins in the maxillary muscles, and spreads gradually from above downward, disappearing later in the same order. It is most marked and lasts longest in muscular individuals who have

POST-MORTEM EXAMINATIONS. 2J

been ill but a short time. Cholera furnishes the most marked cases. The rigor disappears quickest in cachectic diseases. When once it has been forcibly overcome, it does not recur. The time of beginning after death varies widely — from ten minutes to seven hours.

II. Special Inspection of the Different Parts of the Body.

The examination should begin with the head. Any lesion or abnormality found should be carefully noted. Particular attention should be paid to the condition of the pupils and to the color of the sclera. Then follow in order the neck, the thorax (size and shape), the abdomen (distended or retracted), the genitals, and the extremities.

INTERNAL EXAMINATION OF THE BODY.

The opening of the body-cavities is described first, because the brain is relatively much less frequently the seat of disease, and because in this country it is often impossible to obtain permission to open the head. Moreover, the lesions in the body often throw much light on those to be expected in the brain. The advantage of examining the brain first, particularly in those cases in which the important lesions are cerebral, is said to be that the amount of blood in the cerebral vessels can be more accurately determined. After the heart has been removed some of the blood in the brain may escape through the severed vessels below.