NO. /3 PROPERTY OF The California State Nurses* Association, Inc. JOURNAL LIBRARY Reviewed in. .number, 19/Jr Pacific Coast Journal of Nursing, GIFT OF Pacific Coast Ml OT* "NlJT S 5 T\ I No._/JL_ BOOK REVIEW DEPT. Pacific Coast Journal of Nursing 721 NEW CALL BLDG. Please review this book and return, if possible, on or /O , and oblige, M. Adelaide Waterman, R.N., Editor and Manager THE PACIFIC COAST JOURNAL OF NURSING PLATE I White Cells of the Blood, Leukocytes, acting a^ Phagocytes or 1 Devouring Cells; Streptococci in Chains being Consumed. ELEMENTARY BACTERIOLOGY AND * FOE THE USE OF NURSES BY HERBERT FOX, M.D. DIRECTOR OF THE WILLIAM PEPPER LABORATORY OF CLINICAL MEDICINE IN THE UNIVERSITY OF PENNSYLVANIA; PATHOLOGIST TO THE ZOOLOGICAL SOCIETY OF PHILADELPHIA, ETC. SECOND EDITION, REVISED AND ENLARGED ILLUSTRATED WITH 68 ENGRAVINGS AND FIVE COLORED PLATES LEA & FEBIGER PHILADELPHIA AND NEW YORK 1916 - \o LIBRARY D GIFT' PACIFIC OOAST JOURNAL Entered according to the Act of Congress, in the year 1916, by LEA & FEBIGER, in the Office of the Librarian of Congress. All rights reserved. TO MY WIFE 743537 PREFACE TO THE SECOND EDITION. IN preparing the second edition of this book the same principles have been followed as directed its previous form. It has been found advisable to add some more details concerning general disinfection, the transmission of infection, especially in regard to those diseases spread by insects, and the peculiar phenomena of hypersusceptibility, a subject which becomes wider in its significance as we learn more about it. In regard to the special bacteria and diseases, only such material has been added as was needed to bring the book up to our present information. H. F. PHILADELPHIA, 1916. PREFACE TO THE FIRST EDITION. THE present work has been prepared to give the nurse and the beginner an idea as to the nature of microorganisms and their relation to the world's economy, especially in disease. For this reason much technical material has been omitted, especially in the subject of biological differentiation. Emphasis has been laid upon how bacteria pass from individual to individual, how they enter the body and act when once within, and their manner of exit. Such general information concerning the character of the disease process has been included as seemed necessary to clarify the nature of the microbe action. Indeed, the subject matter in many places is but elementary bacteriological pathology. During the preparation of the work the author has had in mind a question he has been asked repeatedly: How do bacteria produce disease? That this question is answered as simply and as well as our knowledge of today permits is the author's sincerest hope. H. F. CONTENTS. CHAPTER I. INTRODUCTION HISTORY THE PLACE OF MICROORGAN- ISMS IN NATURE 17 CHAPTER II. GENERAL MORPHOLOGY REPRODUCTION CHEMICAL AND PHYSICAL PROPERTIES 23 CHAPTER III. GENERAL BIOLOGY, INCLUDING THE CHEMICAL CHANGES WROUGHT BY BACTERIA . 34 CHAPTER IV. METHODS OF STUDYING MICROORGANISMS STERILIZATION BY HEAT 39 CHAPTER V. DESTRUCTION OF- BACTERIA BY CHEMICALS AND THEIR PRACTICAL USE 52 CHAPTER VI. THE RELATION OF BACTERIA TO DISEASE IMMUNITY . 63 x CONTENTS CHAPTER VII. PREPARATIONS FOR AND PROCURING OF SPECIMENS FOR BACTERIOLOGICAL EXAMINATION 79 CHAPTER VIII. THE ACUTE CHIEFLY LOCALIZED INFECTIONS OF Pus NATURE THE PATHOGENIC Cocci . 85 CHAPTER IX. THE ACUTE SELF-LIMITED INFECTIONS 107 CHAPTER X. THE MORE CHRONIC INFECTIOUS DISEASES .... 149 CHAPTER XL VARIOUS PATHOGENIC BACTERIA NOT ASSOCIATED WITH A SPECIFIC CLINICAL DISEASE 177 CHAPTER XII. YEASTS AND MOULDS 194 CHAPTER XIII. BACTERIA IN AIR, SOIL, WATER, AND MILK .... 202 CHAPTER XIV. DISEASES DUE TO PROTOZOA 214 CHAPTER XV. DISEASES OF UNKNOWN ETIOLOGY 228 GLOSSARY . 235 BACTERIOLOGY AND PROTOZOOLOGY. CHAPTER I. INTRODUCTION HISTORY THE PLACE OE MICROORGANISMS IN NATURE. INTRODUCTION. THE study of disease has brought to light many facts which demonstrate the effect of the association of different forms of life. Chief among these is the fact that minute beings live upon greater ones, either harmlessly or to the detriment of the latter. The study of these small creatures is called microbiology, this being the portion of general biology in which the use of magnification is necessary. Bacteria are classified as plants and their study is called bacteriology. The smallest animals, protozoa, are considered in the sub- ject of protozoology. To explain the causation of infectious diseases the physician has been obliged to study both of these subjects, that is, the large field of microbiology. The lowest forms of life are unicellular bodies capable of leading an independent existence, in contrast to the single units of the cell groups which go to make up the compound organism, a higher animal 18 HISTORY or a plant. Some 'of these single-celled bodies have 'Characteristics placing them without question among the plants, while othevs with equal definiteness belong to the animals. The line between is by no means sharp, and much difference of opinion exists among investigators as to the borderline forms. HISTORY. The existence of more or less independent forms of life invisible to the naked eye was first proven about two and one-half centuries ago by Van Leeuwenhoek and Kircher, who actually saw and described what were called animalcule, living, moving, and multiply- ing bodies in the tartar from teeth and in animal fecal matter. The first conception of the existence of such microscopic forms cannot be accredited to these ob- servers, since so long ago as in the fourth century B.C. Aristotle suggested the possibility. As might be expected, these single-celled bodies were not seen until the development of lens-making per- mitted accurate enlargement. The greatest advances have been made, furthermore, since the perfection of the compound microscope in the early years of the nineteenth century. It is also noteworthy that those who might be considered the founders of this science, so important to physicians, w T ere botanists and chemists. The most important consideration for the early observers was the relation that these minute bodies bore to the spoiling of food and water. Indeed, most physicians of the past and a few of the present have discredited the relation of bacteria to disease. HISTORY * 19 The first opinion upon the relation of specific disease- producing bacteria came in the middle of the eighteenth century, but such a theory could not be proven until about thirty years ago, when Koch made it possible to separate the various individual bacterial species and enabled us, by a series of postulates, to study the relation of the germs to their particular disease. The great proof of the existence of bacteria came from the man who may be considered the founder of the modern science of bacteriology, Louis Pasteur, a French chemist, who demonstrated beyond question that bacteria produce fermentation, and that fer- mentable materials, if protected from the air, remain without bacteria. There succeeded to this proof others to the effect that bacteria are ubiquitous, and that they are carried in dust or probably alone by air currents. His experiments also showed that spontaneous generation (the arising of living forms anew from the elements of nature, and not from preexisting living forms) does not occur. The results of Pasteur's work received practical applica- tion also at the hands of Koch and Lister. The former devised methods for the cultivation and study of the individual species and followed this up by discovering the organisms causing tuberculosis, anthrax, and cholera. Lister, shocked by the appalling mortality in the hospitals from gangrene and septic poisoning, established methods by which bacteria from the air and from infected cases were excluded from healthy surgical cases. To him the basic principles of modern antiseptic and aseptic surgery are due. Throughout all the history of microbiological devel- 20 PLACE OF MICROORGANISMS IN NATURE opment it has been possible to progress more rapidly and definitely with bacteria than with protozoa. Bacterial life and activity can be controlled very largely now, but as yet little or nothing is known of the important vital activities of the minute animals. As in the case of bacteria, so the earliest records of protozoa are those of Van Leeuwenhoek's animalculse. Their natural history has been gradually developed by Jablot, Dujardin, Prowaczek, and Biitschli, and the present leaders in the field, Calkins and Doflein. However, it is only within the last score of years that we have been familiar enough with these lowest animal forms to be sure of their species identity, and we are yet imperfectly informed as to their vital phenomena. PLACE OF MICROORGANISMS IN NATURE. The studies of the life history of bacteria and pro- tozoa have been the work of botanists, chemists, and physicians. Through this combined effort it has become known that these minute forms are present in or upon or have something to do with the life of all the higher animals and plants. The number of species in all is legion. The number of species pathogenic for animals is but small. A microorganism is patho- genic when it is capable of producing some form of disease in the animal in which it is a parasite. In Chapter III some of the known relations of non- pathogenic bacteria will be discussed. It is sufficient here to emphasize the difference between the so-called parasites and saprophytes. Parasites are organisms PLACE OF MICROORGANISMS IN NATURE 21 capable of living and multiplying within the living animal body, sometimes to its detriment, while sapro- phytes live on dead matter and may be found in nature everywhere in air, soil, water. The body upon which a parasite lives is called the host. There are a few of the parasites that can carry on a saprophytic existence for a short time (facultative parasites), while others (obligate parasites), such as the organism of influenza, demand animal juices for their nutriment. Among the protozoa this obligate parasitism exists quite extensively, and many forms cannot live at all if their normal cycle of life within the animal body be dis- turbed. Indeed, we know the existence of many species only because they pass through a certain development in insects, then in higher animals and back again in insects; that is, we only recognize them when they pro- duce disease (see Malaria). The saprophytes include the vast number of organisms having important func- tions among the higher vegetables and the growth of these in soil. It has been suggested that at one time, now long past, all bacteria may have been saprophytic. The general remarks concerning parasites apply alike to protozoa and bacteria, but in medicine there -is at the present time more interest in the bacteria. For this reason only a few diseases caused by protozoa are important. In order that the positions these unicellular forms occupy in the living world may be known and used for reference to large works, their biological classifica- tion is given here. The lowest of the orders among the plants is called Thallophyta. This is divided into Algse, Lichens, and Fungi. The Fungi are divided 22 PLACE OF MICROORGANISMS IN NATURE into Hyphomycetes (moulds), Blastomycetes (yeasts), and Schizomycetes (bacteriaceae or bacteria). This family is divided into Cocci, Bacilli, and Spirilla. Protozoa, the lowest animal class, present the orders Sarcodina, Mastigophora, and Sporozoa, which con- tain nearly all the forms of interest in this work. CHAPTER II. GENERAL MORPHOLOGY REPRODUCTION- CHEMICAL AND PHYSICAL PROPERTIES. GENERAL MORPHOLOGY. Bacteria (sing., Bacterium). In introducing the sub- ject of morphology a few words as to the technic of observing bacteria will not be amiss. The compound microscope is necessary to all microbiological work. Since this book is devoted to principles, a detailed description of the instrument and its operations would be foreign. Let it suffice to say that the compound microscope is a series of finely ground lenses by which exact pictures in definite magnification can be obtained. An object to be examined is placed upon a glass slide and covered with another but much thinner glass cover. This is laid upon the table of the instrument and the tube holding the lens placed at a proper distance to obtain the best light and clearest picture when viewed through the eye-piece end. For nearly all microbiologi- cal observations it is necessary to use a special lens of high magnifying power, called an oil-immersion lens, and to introduce between the lens and the object glass a drop of pure cedar oil into which the lens front dips; this concentrates and filters the light. The microscope is also used to examine the colonies of bacteria. Bac- teria are studied either in the fresh living condition 24 GENERA L MO HP HO LOG Y or when stained by appropriate dyes, especially those derived from coal tar, methylene blue and fuchsin. FIG. 1. Microscope: A, ocular or eye-piece; B, objective; C, stage; D, "iris" diaphragm; E, reflector; F, coarse adjustment; G, line adjustment; H, substage condensing apparatus; /, nose-piece. Bacteria are exceedingly small single cells, in their natural state transparent, colorless, and apparently GENERAL MORPHOLOGY 25 homogeneous, possessing a very low power of refracting light. They consist of nucleus, cytoplasm, and a wall which is probably a simple superficial condensation of the protoplasm. The ordinary animal or vegetable single cell 1 contains an easily distinguishable body, usually central, called the nucleus, whose function it is to control the cell activities, while the space between this body and cell wall is occupied by protoplasm or cytoplasm, a soft, spongy, or gelatinous matter, which 9 S V D D * M CP (f FIG. 2. a, staphylococei; b, streptococci; c, diplococci; d, tetrads; e, sarcinae. (Abbott.) under very high magnification seems to be made up of a delicate meshwork, within the spaces of which a fluid lies. The nucleus is a denser body usually separated from the cytoplasm by a distinct wall or membrane, and w r hen mashed out is seen to consist of a skein of coarse threads. Into the cytoplasm the nourishment of the cell passes. Of bacteria, either in their natural 1 See frontispiece for an example o'f cell. Nearly all living cells are comparable to these leukocytes. 26 GENERAL MORPHOLOGY condition or stained for examination, only the nucleus and the wall can be seen, the intervening layer being exceedingly thin. In shape, bacteria are either spherical, called cocci (sing., coccus), or straight rods, called bacilli (sing., bacillus}, or curved rods, called spirilla (sing., spiril- o -yv- ^ d e / FIG. 3. a, bacilli in pairs; b, single bacilli; c and d, bacilli in threads; e and/, bacilli of variable morphology. (Abbott.) //'v ,'\r- -^ r * i I* / ^ ' V . T ^( a 5 c d FIG. 4. a and d, spirilla in short segments and longer threads the so-called comma forms and spirals; b, the forms known as spiro- chetse, c, the thick spirals sometimes known as vibrios. (Abbott.) lum). Each shape has slight variations, such as the flattening of the sides when two organisms are apposed. The spirilla are, perhaps, subject to more variations than the others, extending from a simple comma shape to that of a long, wavy spiral when looked at from the side. These last are in reality corkscrews, as they twist REPRODUCTION 27 in three planes. In size microorganisms vary consider- ably. Perhaps a proper conception of some organisms can be obtained when one considers that to cover one square inch in single layer it would require 6,250,000,000 influenza bacilli, a very small organism, or 45,000,000 anthrax bacilli, a bacterium of moderate size. Bacteria are measured in terms of microns. The metric unit, a micron, equals about 2Tlro ^ of an inch. REPRODUCTION. Bacteria. Bacteria multiply by a simple dividing of their protoplasm. The spherical organisms divide much as one cuts an apple through the poles, the divided halves rapidly assuming the shape of the mother cell. The rods and spirals divide by simple transverse pinching in at about the middle of their long axis. The new forms may leave each other or may adhere in more or less characteristic groupings, which are taken advantage of in their study and identification. Thus cocci may form pairs or chains, and are known as diplo- or streptococci. Again, the spheres may pro- duce irregular grape-like bunches or staphylococci. These develop in only two planes. Division may occur in the third plane so that packets or cubes of cells result, called sarcincB. Among the rod-shaped bacilli long chains may be formed by a continuous development in the same plane. A single bacterial cell will divide about every twenty minutes, and Fischer says that from one organism 16,000,000,000 may develop in a single day on suitable 28 SPECIAL' CHARACTERS medium. Fortunately, however, foodstuff is used up in the course of multiplication and the waste products of nutritional activity accumulate so that the enor- mous growth of bacteria is limited. Bacteria can no better live in the presence of their excretions than can animals. SPECIAL CHARACTERS. The cell sometimes surrounds itself by an envelope or capsule outside its natural wall, and this is taken advantage of in identification. It is particularly well developed on bacteria when in or lately removed from animal tissues upon which they have been growing. The exact function or importance of these capsules is not known. Some bacteria are able to move from place to place in a fluid medium, and are called, therefore, motile. This is due to the presence of extremely fine filament- ous extensions from the cell wall, which upon micro- scopic examination look like wavy hairs. These are called flagella (sing., flagellurti) . They are arranged either at one end, both ends, or around the whole sur- face of the cell. They propel the bacterium by a quick waving or lashing motion. When bacteria are subjected to conditions unfavor- able for their life they undergo various changes of size and shape, none of which are very characteristic except the so-called spore formation. By this is meant the concentration of the vital powers and some of the physical constituents of the bacterial cell within a very small, homogeneous, highly light-refractive body which is resistant to deleterious agencies and which SPECIAL CHARACTERS 29 may bear little or no resemblance to the parent organ- ism. These spores are not to be considered as evidences FIG. 5. Capsule stained by Hiss's method. Rhinoscleroma bacillus. X 1000. (Thro.) , -.-v .><..: -*- ' f. V-v &:":m*l**^ .*: FIG. 6. Bacilli showing one polar flagellum. (Park.) of reproduction, but merely as a resting or resistance stage. When conditions of life suitable to the normal 30 SPECIAL CHARACTERS appearance of the bacterium are resumed the spore will develop into the same kind of organism as that from which it came. This spore forming is seen FIG. 7. Bacilli showing multiple flagella. (Park.) FIG. 8. Unstained spores in slightly distended bacilli. (The spores are the light oval spaces in the heavily stained bacilli.) (Park.) among bacilli and spirilla, probably never among the cocci. As a rule, only one spore is found in each bacterial cell. These spore formations assist in identi- fication. The practical importance of spores is that SPECIAL CHARACTERS 31 they resist the agencies quickly fatal to the adult or vegetative forms. Bacteria in their ordinary de- velopment are said to be vegetating, and we must differentiate between the vegetative stage and the spore-forming stage. Protozoa (sing., Protozoon). Protozoa are single-cell animals of protean shape. They vary in size from that of the smallest bacterium to nearly one-quarter of an inch in length. They are made up of a fairly well- FIG. 9. Unstained spores in distended ends of bacilli. (Park.) formed wall which may have an appreciable thickness or be merely an immeasurable line. Their cytoplasm, unlike that of bacteria, is usually far in excess of the nucleus. It is sometimes homogeneous, at other times full of granules, septa, or a dividing meshwork. The nucleus is a complex body varying from a simple, bladder-like mass to a dense and intricately wound skein. The vital activity of the protozoan cell seems to lie in a small body, usually in the protoplasm, but originating from the nucleus, called the centrosome. 32 SPECIAL CHARACTERS Protozoa move by several methods. Some possess short, delicate, hair-like projections from the wall, which exhibit a slow, wavy motion. These are cilia. Others have one, two, or three long coarser threads, the flagella (sing., flagellum) arising from various parts of the structure and producing locomotion by a thrashing or whip-like motion. Perhaps the simplest and surely the most primitive form of motion is to be seen in what are called pseudopods or false feet, a phenomenon characteristic of the amebse. This is a pushing out or budding of a portion of the cell wall into which the cytoplasm of the protozoon flow, enlarging the false foot until it embraces all the con- tents of the cell. The space formerly occupied by the protozoon is vacated, the cell having moved to a position directed by the pseudopod. In some protozoa a portion of the body has muscular power and drives the organism. Again, a portion of the cell wall may be fitted with a sucking apparatus, serving either to drive the protozoon or to attach it to another body. Pro- tozoa gain their food by simple absorption through the wall or by possessing definite vacuoles or open- ings for this purpose. Excretion takes place the same way. Reproduction may occur by simple division as in bacteria. Protozoa may divide by simple budding with breaking oft' of the smaller piece similar to the first stages of the pseudopod. The higher protozoa go through a complicated process of division such as is seen in the higher animal cells, or there may be male and female elements with conjugation. CHEMICAL AND PHYSICAL PROPERTIES 33 CHEMICAL AND PHYSICAL PROPERTIES. Bacteria. Chemically the bacterial body is composed chiefly of water (80 to 90 per cent.), the remaining part being made up of protein (see below), fatty matters, including waxes, a trace of the carbohydrates (sugars and starches), and inorganic material. The cellulose supposed to be characteristic of vegetable cells is present in very small quantities. The largest part of the solid matter is comparable to the organic substances which form the most important foodstuff for animals, the proteins. Chlorides and phosphates of the lighter metals form the inorganic salts. The wall of the bacterial cell permits the passage of fluids containing foodstuffs, and is therefore com- parable to the wall of other vegetable and animal cells. Protozoa. The chemical composition is probably like that of bacteria, although little is known of it. Their vital activities are influenced by physical con- ditions, as is the case with all animate beings. They require moisture for their full development, but may live for indefinite times when it is at a minimum. A definite temperature is demanded by each species or genus for its full activity. They are susceptible to high degrees and remain quiescent in nature in the cold for a long time. Desiccation of the germinating forms is usually fatal, but when in sporulation or encystment drying is more easily withstood. Light is not abso- lutely essential for the growth of protozoa, but they are usually attracted or repelled by it; that is, few if any are indifferent to luminosity. CHAPTER III. GENERAL BIOLOGY, INCLUDING THE CHEMICAL CHANGES WROUGHT BY BACTERIA. Bacteria. The bacteria with which the physician is chiefly concerned as disease-producing are but a very small number when compared with the multitude of species in nature. The lay mind is apt to consider any germ as noxious, but instead of this it can be said that without the activity of many saprophytes, life on the earth would soon be extinct. Animals require organic material from plants for their nourishment, but their cells do not possess the power to put together (synthe- size) the elementary constituents necessary for their complex cell composition. Bacteria have the power both of breaking dow r n and building up; that is, they may reduce some compounds to their elements or build up elements into more complex substances. Perhaps the most striking examples of this property are to be found among the earth organisms, some of which break down organic matter into ammonia and liberate nitrogen, others then taking up this gas from the atmosphere and combining it with 'other elements in a form that plants can assimilate. The products of their breaking down and building up are utilized by plants and are presented to animals CHEMICAL CHANGES WROUGHT BY BACTERIA 35 as food in such a form that the animals can use them for their cell needs. It is not the purpose of this book to dwell upon this abstract matter of general biology, but the principles of the activities of non-pathogenic bacteria can well be seen in those inhabiting the intestines. It may be possible for a human being to live without bacteria in the alimentary tract, but some of those present are beneficial in effect. A perfectly healthy young animal may be born without bacteria in the intestines, but organisms soon gain entrance with air and food, since practically no object in the world of life is free of them. The ordinary saprophytes of the intestinal tract assist in making fats more easily assimilable, and destroy some of the pathogenic bacteria. Bacteria require for their life moisture, some degree of heat, and a variety of foodstuffs. The amount of moisture is of little importance pro- vided sufficient is available to make up the physical bulk of the organism and assist in the passage of food- stuffs through the cell wall. The substances used by bacteria in nutrition are dissolved or suspended in water. Temperature requirements are, however, more exact, and every class has its own preferred degree. Those which commonly inhabit the animal body require a temperature of 98 F. (37 C.), while those living naturally in soil or water thrive best at 60 to 70 F. (15 -21 C.) . Foodstuffs must contain the same substances as for the growth of other plants, but the organisms which infest the animal body, grow most luxuriantly when animal tissue or fluid is present. 36 GENERAL BIOLOGY The reaction of the material upon which they are growing is of no small importance. Nearly all bacteria live best when the medium is about neutral or of faintly alkaline or acid reaction. All need carbon, oxygen, nitrogen, hydrogen, and salts. Some organisms cannot live in the presence of free oxygen, but obtain it as they need it by breaking up, or reducing, sub- stances containing this element. These are called anaerobic bacteria, such as the tetanus bacillus. Micro- organisms that can live in the presence of atmospheric oxygen are called aerobic. Most pathogenic forms have this power. The foodstuffs presented to bacteria are seldom in a pure state, so that the power of breaking up the material on which they are existing into the elements necessary for the life of the cell has to be done by some process of cellular activity. To do this, bacteria form what are called enzymes or ferments. An enzyme or ferment is a product capable of changing a chemical combination without itself entering into the product of this change. The bacterial enzymes are comparable to the enzymes found in the digestive juices of the human alimentary canal. There are many kinds of ferments, each having the power of breaking up certain chemical substances. There are ferments splitting up sugars and starches and fats and proteids, and the result of this splitting is simpler in composition than the substance split, thus making it easier of use as food. The ferment activity of bacteria is just like that of yeasts which are used in the industries, especially that of spirituous liquor-making. In this case the organisms and their enzymes are capable of splitting CHEMICAL CHANGES WROUGHT BY BACTERIA 37 sugar with the production of ethyl alcohol, and specific species or strains are kept by vineyards, distilleries, and breweries for the peculiar kind of fermentation desired. Some bacteria have the property of producing light (phosphorescent bacteria on sea water), and many form coloring matter both in nature and when grown artificially (colored mould on preserves). The effect of saprophytes upon pathogenic bacteria in the intestine is that they sometimes destroy the latter. Metchnikoff found that certain bacteria pro- duced so much acid, chiefly lactic acid, that many other bacteria could not live in their presence. He took advantage of this to assist in the treatment of certain cases of putrefaction in the intestinal tract. Bacteria also may produce various simpler products in the course of their enzyme action. Now it happens that some of the bacteria in the intestinal tract, per- haps under the stimulation of irregularity of function, may produce too much fermentation of sugars and starches or too great breaking down of the most important foodstuff, the proteids. From this improper breaking down and absorption of its products comes the so-called intestinal intoxication. 1 MetchnikofTs experiments have show r n that the high acid produced by certain saprophytes, the lactic acid germs in particular, is inimical to the producers of this disturbance. In practice, therefore, cultures of these bacteria are administered by mouth. 1 Auto-intoxication is a term sometimes given to this condition, but it is incorrect and should be limited to disease due to some functional disorder of digestion. 38 GENERAL BIOLOGY Other activities of bacteria and their enzymes are seen in the precipitation and curdling of cream known as cheese. Again, the specific flavor of tobacco and opium for the pipe is due to bacteria. In the pro- duction of indigo and in the preparation of hides for tanning, bacterial enzymes play an important part. Protozoa. Of the saprophytes of protozoa practically nothing is known. Protozoa are parasitic either by the mechanical irritation caused by their presence or by taking their nutriment to the damage of their host. Malaria organisms, for example, may block capillaries and shut off blood supply, although they also disturb the nourishment of the tissues further by destroying red blood cells, which carry oxygen. For optimum development they require, as in the case of bacteria, moisture and a suitable reaction, but rather a higher temperature and more complicated food, as a rule. CHAPTER IV. METHODS OF STUDYING MICROORGANISMS -STERILIZATION BY HEAT. LABORATORY TECHNIC. IN the study of microscopic beings it has been necessary to elaborate a special technic which will supply the requirements of life. Before the epoch- making work of Koch it was necessary to cultivate microorganisms upon broth or bread, and there was little known as to the exact composition of the medium. Koch showed how to control the growth of bacteria in the laboratory. To Pasteur and Kohn credit also is due for the standardizing of the foodstuffs upon which bacteria are cultivated. Let us assume that we have been given a culture of bacteria to study. Since the identification of species is not a part of a nurse's duty it is not necessary to discuss the separation of many germs in a mixture. Bacteria are transferred from one place to another, as, for example, from one culture tube to another or to a glass slide, by means of a piece of platinum wire set into a handle. This metal will withstand great heat and can be sterilized in the flame of a Bunsen burner after every using. The Bunsen burner is an apparatus so arranged that air is thoroughly mixed with the gas and the mixture is completely burned. Starting out with the material 40 METHODS OF STUDYING MICROORGANISMS from which this single organism comes the bacteri- ologist spreads it on a glass slide and colors it by certain aniline or vegetable dyes, of which there is a large number. It is practically impossible certainly to identify any bacterium by a simple examination of a stained preparation under the microscope. The FIG. 10. Culture tubes. (Park.) observer, however, does form a tentative opinion as to its probable nature, and proceeds to introduce some of the material into a nutrient medium which he con- siders best adapted to its development. Among these are broth, milk, potato, coagulated blood serum, and broth stiffened (when cool) with gelatin and the LABORATORY TECHNIC 41 Japanese moss, agar-agar. These foodstuffs, called media for short (sing., medium) are kept in test-tubes or flasks. The worker may also spread into flat glass plates (Petri plates) some of this stiffened broth in order first to see in what form the germs will grow as FIG. 11. Showing certain macroscopic characteristics of colonies. Natural size. (Abbott.) "colonies," and secondly, to see that only one kind of colony, therefore only one kind of germ, is present (Fig. 11). In other words, he wishes to know if his culture be "pure." This means of obtaining a pure culture depends upon the fact that from each single 42 METHODS OF STUDYING MICROORGANISMS organism smeared upon a plate only one kind of colony of organisms will develop. It is the custom to put all material to be examined upon plates of nutrient medium to start with, by which process the worker at once has before him evidence to show how many kinds of bacteria are present and the means of isolating FIG. 12. Platinum needle and loop. (Park.) pure cultures after the first inoculation. These tubes and plates are placed at body temperature (98 F. or 37.5 C.) in the incubator. An incubator is a doubly insulated metal box, heated by gas or electricity and controlled by an automatic device by which the tem- perature is kept constantly where desired. Practically PLATE II Cultures of Bacteria. (Besson.) The jellies upon \vhieh the pure cultures are grown, are hardened in test-tubes in a slanting position. The bacteria are then spread along the oblique surfaces and grow in bands or streaks as shown here. LABORATORY TECH NIC 43 all pathogenic bacteria develop best at this tempera- ture. The bacteria of the soil and water probably grow best at about 70 F. or 20 C. After these tubes and plates have been "incubated" for twenty-four or forty-eight hours the bacteriologist observes them FIG. 13. Method of transferring cultures from one tube to another. (Hiss and Zinsser.) and takes note of the evidences of growth. He will make stained preparations for microscopic observation and note the morphology of the plant. Many stains are in use for demonstrating various characteristics. He will also prepare what is known as a " hanging drop." This consists of a drop of fluid broth culture upon a 44 METHODS OF STUDYING MICROORGANISMS thin inverted glass (Fig. 14). He will discover from this preparation under the microscope the presence of motility and the manner of division of the bacteria. From his tube cultures he chiefly finds out whether the bacteria develop en/ymes. To the solid media (agar-agar) he may add various sugars to discover the fermentative powers of the bacterium. The fermenta- tive powers may also be observed when the germs grow upon bouillon containing the sugars. This broth is placed in an apparatus called a fermentation tube so arranged that the percentage of sugar broken up by the bacteria can be estimated. When he shall have made all his observations he will sum up his results and identify according to the classification of bac- teriologists. f^' ! .. .'"I: v'''^^-!^^..^^.!. *i '..., . .,. . I FIG. 14. Hollow slide with cover-glass. (Park.) The presence of bacteria is searched for in pus and diseased tissues by making a smear from the fluid or affected part upon glass slides and treating it with certain dyes. Before the dyestuff is applied the smear must be fixed by heat or alcohol or formaldehyde. This is for the purpose of killing the albuminous material, keeping it exactly as it was when removed from the body, and rendering it susceptible of taking up and permanently retaining stains, a property living tissues and fluid possess to a very slight degree. Once fixed and stained, examination will reveal the bacteria present, and the observer can form an opinion of the probable nature of the infection. Reference is LABORATORY TECHNIC 45 frequently made in the text to Gram's stain, and it is desirable that the reader be familiar with the term and its significance. It is a combination of aniline oil, water, and gentian violet, which stain can be fixed into some bacteria by after-treatment with iodin solu- tion, so that alcohol will not wash it out. The test is of great importance in determining certain species. Animal Inoculation. Another method of studying bacteria is by injecting them into susceptible animals. Thus can be discovered their power of producing disease, its severity, called virulence, and the nature of their action. When the presence of bacteria in morbid matter cannot be demonstrated by stain or by cultural methods, it may sometimes be shown by injecting the suspected material into animals. If the animal fall sick or die one can then obtain cul- tures of the germs for study. The value of this method of discovering bacteria is increased by the development of changes in the animal's organs peculiar to certain germs. Thus the tubercle bacillus, an organ- ism not easy to find by direct examination, produces definite alterations of organs and special kinds of inflammation by which its presence is indicated and from which it can be obtained. This is also true for other bacteria streptococci, anthrax, and glanders bacilli. Protozoa. The study of protozoa varies according to the source. The parasite of malaria may be found by direct microscopic examination of the fresh blood. This is also true of the organism of sleeping sickness. The protozoa causing dysentery require the mainten- ance of a definite temperature for a long time, and 46 METHODS OF STUDYING MICROORGANISMS this is achieved by the use of a hollow slide filled with warm water. These organisms are cultivated arti- ficially only with great difficulty, and the use of special stains is required for the purpose of practical clinical diagnosis. STERILIZATION. For a better understanding of the technic of laboratory procedure, the preparation of the food- stuffs or media on which bacteria thrive will be briefly considered. They are prepared from meat or its extracts, a substance called peptone, and salt, and adjusted to a suitable reaction of weak alkalinity, according to carefully worked-out formulae, which are the result of long experimentation. They are stored or distributed in glassware, which is of the non-corrosive type. This glassware is cleaned with soap and water, sand or alcohol, and rinsed with distilled water. It is then sterilized by hot air. The glassware and media are sterilized because bacteria are ubiquitous, and apparatus and foodstuffs wholly free from microorganisms are necessary in bacterio- logical technic. In no other way can one be sure of obtaining germs in pure culture, that is, only one kind. After the medium has been put into the glass- ware, steam sterilization is used ; dry heat is ineffect- ual and destroys the medium. The best method of sterilization is by the autoclave or pressure boiler, since all organisms are killed by one atmosphere of pressure to the square inch in addition to the ordinary atmos- pheric pressure. Because of the delicacy of some of the nutrient media it is, however, necessary to sterilize these STERILIZATION 47 at the usual pressure of the atmosphere in streaming steam. For this purpose a double-jacketed boiler with the steam introduced into the inner chamber (Arnold steam sterilizer) is used. FIG. 15. Erlenmeyer flask. FIG. 16. Petri dish. FIG. 17. Fermen- tation tube. SL r> FIG. 18. Autoclave, pattern of Wiesnegg: A, external appearance B, section. 48 METHODS OF STUDYING MICROORGANISMS While this sufficiently indicates the uses of sterili- zation for the preparation of food for bacteria, a few words upon sterilization in general are necessary. This term is usually reserved for the killing of bacteria by means of heat, either dry or moist. For the killing of bacteria by other means see Chapter V. The most widely applicable and efficient physical agent for sterilization is heat. A certain amount of FIG. 19. Arnold steam sterilizer. heat is necessary for the life of bacteria, but there are certain temperatures beyond which they cease to live. While 38 C. or 98.5 F. is their optimum or most suit- able temperature, they find it increasingly difficult to live as the temperature rises to 50 C. or 122 F. Beginning there and extending to 62 C. or 144 F. the commoner pathogenic organisms are killed by ten minutes' expo- sure. For example, the typhoid bacillus dies when STERILIZATION 49 heated to 56 C. or 133 F. for ten minutes, and the pneumonia coccus at 52 C. or 126 F. for ten minutes. The tubercle bacillus is much more resistant and requires from ten to twenty minutes' exposure at 70 C. or 158 F., varying directly with the density of the medium in which it is. The spore-forming organisms are characterized by a vastly greater resistance. This FIG. 20. Laboratory hot-air sterilizer. is due to the peculiar property of spores of resisting deleterious agencies. Low temperatures are much less destructive than high ones. The typhoid and diphtheria organisms may resist 200 below zero C. or 300 F., while some of the more delicate organisms quickly die at zero. In sterilization that method is chosen which will do the least damage to any object to be conserved. 4 50 METHODS OF STUDYING MICROORGANISMS Simple boiling should be undertaken whenever prac- ticable, and immersion for five minutes in boiling water will destroy the vegetative forms of all bacteria. For spores, however, at least of the disease-producing kind, two hours is necessary. It is advisable to add 1 per cent, of sodium carbonate to the water. This assists in killing of spores, and metal objects are not so apt to rust. This simple boiling for ten minutes is sufficient for dry cleaned syringes, trays, dishes, and surgical instruments in the absence of infective material known to contain spores. Sterilization in live steam is the most practical method of killing bac- teria, as it can be carried out in the kitchen. In the laboratory it is done by the Arnold sterilizer (Fig. 19). It is the custom to employ what is called fractional sterilization. This method is the exposure of the material to be disinfected to the temperature of 100 C. or 212 F., which is the temperature reached by the steam in the inner chamber, for fifteen minutes on three successive days. On the first occasion vegetative forms are killed and the spores remaining are permitted to pass into the vegetative state overnight. On the second occasion these will then be killed. A third exposure insures sterility. The exposure of fifteen min- utes is considered to begin when the steam is up and the thermometer registers 100. The foregoing method is practicable for dressings and rubber gloves. For sterilization of objects not injured by pressure the boiler or autoclave is used. The principle of this apparatus is that steam is admitted into the steriliz- ing chamber, the air having been expelled by heating of the walls and displacement by the entering steam. When no air is present the pressure within the appa- STERILIZATION 51 ratus rises and steam penetrates all permeable objects. When the steam escapes and air enters, moisture is absorbed and the objects become dry. By this means as much as two extra atmospheric pressures can be run up, which will be equivalent to 34.5 C. or 74 F. above the boiling point. After starting up steam the apparatus should never be tightly closed at the safety valve until all air is expelled. This method is particu- larly adapted to the sterilization of dressings and infected cast-off clothing. Hot air is suitable for dried glassware and articles injured by moisture, and can be used for domestic sterilization by exposing the articles in the household oven. It is less efficient than moist heat. This is due to the fact that organic sub- stances are less easily coagulated in a dried condition. Spores are more resistant also, as, for example, the anthrax spore, which requires an exposure of three hours at 140 C. or 284 F. dry heat. Hot, dry air penetrates less easily than hot moisture. Burning is the best of all methods, and should be used for every- thing which can be spared, handkerchiefs, dressings, and objects like magazines from the sick room. The two thermometric scales are explained as follows: F. = Fahrenheit, the ordinary scale used in this country. Water just at the freezing point registers 32 F., while just at the boil- ing point registers 212 F. The zero has no relation to physical changes. C. = Centigrade, the French system. Water just at the freezing point is C., and just at boiling point is 100 C. The 100 degrees in the Centigrade scale is equal to the 180 between 32 and 212 in the Fahrenheit scale. To change one system to the other proceed as follows: From Fahrenheit to Centigrade: Given degree F. 32-4-9X5 = same degree in Centigrade scale. Example: 50 F. 32=18-4-9 = 2X5=10. Therefore 50 F. = 10 C. From Centigrade to Fahrenheit: Given degree C. -4-5X9+32 = same degree in Fahrenheit scale. Example: 10 C. -4-5=2X9 = 18+32=50 F. CHAPTER V. DESTRUCTION OF BACTERIA BY CHEMICALS AND THEIR PRACTICAL USE. IT has been shown how bacteria can be killed by heat, and now the chemical methods of destroying infective material will be discussed, and how this may be done practically. Chemicals either in solution or as gas are supposed to kill bacteria by one of several methods. The whole bacterial body may be destroyed or the protoplasm may be entered by a diffusion of the substance through the cell wall with consequent coagulation or solution. It is said also that the rapid withdrawal of water absorbed by some salts may be fatal to the microorganism. There is some confusion as to the terms used for chemical bacteria-killing, and for this reason it may be well to start out with Park's classification. (1) Attenuation is when the pathogenic or vital functions of the bacteria are temporarily diminished. (2) Anti- septic action is when the bacteria are not able to mul- tiply but are not destroyed; they will reproduce when suitable conditions for life are restored. (3) Incom- plete sterilization or disinfection is when the vegetative forms but not the spores are destroyed. (4) Steriliza- tion or disinfection is when both vegetative and spore forms are destroyed ; this implies also the destruction of any products of bacteria capable of producing disease. BICHLORIDE OF MERCURY 53 Practical disinfection must provide not only for superficial action but also for penetrative, and a dis- infectant should be selected which will act as deeply as possible. Formaldehyde gas or its solution has a high penetrating power and is therefore commonly used for the disinfection of rooms, mattresses, and clothing after infectious diseases. Simple air disin- fection is of practically no value, since disease viruses do not live long in the air but may settle upon surfaces where they can be killed either by gaseous disinfec- tants or direct application of germicides. All disin- fection is rendered more efficacious by a good cleansing and a liberal supply of " elbow grease." A chemical is tested for its antibacterial properties in several ways, chief among which is the immersion of some of the pure bacterial growth in solutions of various strengths of the chemicals. Some of the individual disinfectants are: Bichloride of Mercury (corrosive sublimate). This is soluble in 16 parts of cold water. One part in 100,000 inhibits the growth of most bacteria. In twice that strength many kinds are killed in a few minutes. Spores are destroyed in 1 to 500 solution in water within one hour. In order to obtain the best results with this corrosive sublimate it is necessary to have an acid reaction, for which reason most of the tablets now on the market are made up with an acid having no effect upon the mercury salt. The acid reaction is especially demanded when the material to be disin- fected is pus, blood, feces, or the like, substances con- taining albumin w r hich combines with the mercury and renders it inert. It is wise to use a strength of 1 to 54 DESTRUCTION OF BACTERIA BY CHEMICALS 500 for one-half hour when any such organic material is present. The disadvantages of bichloride are, beside that mentioned above, that it corrodes metals and is rather hard on the skin. It is well to add some coloring matter to the solution for the purpose of identification, since this is a rapidly acting, corrosive, deadly poison. Great care should be used in keeping the tablets and solutions, as many accidents have occurred. Being odorless it attracts no attention. Silver Nitrate. Park says that this salt has one- fourth the value of the preceding as a disinfectant, but nearly the same value in restraining bacterial growth. It is not a very practical disinfectant, because of its destructive action on the skin and fabrics, but it can be used with value in diphtheria. Solutions should be freshly prepared in 1-2 per cent, strength. Copper Sulphate. This chemical is potent against typhoid in water in the presence of little organic material in the strength of 1 to 400,000 in twenty-four hours. Sodium Hydroxide (caustic soda). This substance is very destructive to fabric and to the skin, but kills, in the strength of 1 to 100, vegetative bacteria in a few minutes, or spores are destroyed by 4 per cent, solution in forty-five minutes. Sodium Carbonate.- This chemical, advantageous for boiling instruments, kills vegetative forms in 5 per cent, solution very quickly, or spores in boiling water in about five minutes. "Chloride of Lime" (chlorinated lime). This chemical is also known as bleaching powder. There is a differ- ence of opinion as to its composition. Its power de- CRESOLS 55 pends upon the liberation of free chlorine gas, which rapidly disappears when the lime is exposed, so that the dry material must be kept covered and solutions prepared as needed. It is destructive to fabrics. A 1 per cent, solution will kill all non-spore-bearing organisms in five minutes, and a 5 per cent, solution destroys spores in one hour. Calcium hydroxide, made by adding water to quicklime, is efficient against typhoid bacilli in feces when a 20 per cent, solution is added to thoroughly mixed feces in equal parts and exposed one hour. Dr. Daken, working for the British Army, has found that the addition of sodium carbonate to a solu- tion of chlorinated lime, which mixture is neutralized by boric acid, forms a highly efficient germicide for wounds. It is not destructive to tissues, will pene- trate, and may be used in high concentration, 1 to 20. Its value lies in the hypochlorous acid which is liber- ated in the tissues. Carbolic Acid or Phenol. This is a crystalline solid which softens when exposed to the air. It is soluble in 15 parts of water. It must be thoroughly mixed with material to be disinfected. It is not destructive to fabrics or colors. It acts best at about the body tem- perature. It is not much affected by the presence of organic substances. A 5 per cent, solution kills spores in a few hours, and 1 to 1000 inhibits the growth of all bacteria and may be considered as an antiseptic; 3 per cent, solutions kill the pus cocci in one minute. Cresols. These are thick, sticky, brown fluids related to carbolic acid. They make a milky emulsion with water. The best-known ones are tricresol, creolin, 56 DESTRUCTION OF BACTERIA BY CHEMICALS and lysol. The two latter are probably the best, as they mix with water fairly well. All these substances in 5 per cent, emulsion kill the ordinary bacteria within three minutes and the spore-formers within an hour. Other Disinfectants. Ordinary alcohol kills vegeta- tive forms in a few hours. A 70 per cent, alcohol is perhaps the most potent. It has lately been shown that for surface disinfection no method is superior to 10 per cent, iodine in 70 per cent, alcohol. Practical surgical work seems to indicate that for skin disin- fection before operation all bacteria are destroyed in the epidermis. Some defenders of this method maintain that its penetrating powers exceed any other known practical disinfectant. The method, while undoubtedly excellent, must remain for a while su~b judice before one can accept this statement. Chloroform kills vegetative bacteria and restrains spores, even in small quantities. Ordinary soap is a good disinfectant, particularly by its solvent power on the simple organic substances. Its effect is increased by the addition of common washing soda. Acids. The strong mineral acids are not practical disinfectants, but nevertheless are very efficient. Boric acid kills the less resistant organisms in a 2 per cent, solution, but only after some hours' exposure. Gaseous Disinfectants.- There are only three of practical value. They are sulphur dioxide, oxygen from hydrogen dioxide, arid formaldehyde. Chlorine is not included here because it is seldom used in its pure state, since it is highly poisonous and destructive ; it is, however, eminently efficient. DIOXIDE OF HYDROGEN 57 Sulphur Dioxide. Sulphur dioxide is used for hos- pitals, apartments, and ships, and is especially well suited to the destruction of rats and insects. It is more efficient when there is considerable moisture in the air. When conditions are suitable for disinfection, anthrax bacilli in the vegetative condition are destroyed in thirty minutes when there is 1 volume per cent, of the gas in the given space. "Four pounds of sulphur burned for each 1000 cubic feet will give an excess of gas." Some water should be sprayed in the room or an open vessel containing water should be there. It has been suggested that the sulphur candles of com- merce be burned, resting on a brick in a bucket of water. Dioxide of Hydrogen. A 2 per cent, solution of the pure substance will kill anthrax spores within three hours. In 20 per cent, solution it kills vegetative bacteria, pus cocci, and the like in a few minutes. Its activity depends upon the liberation of free oxygen. It should be kept tightly sealed, since it easily gives up this gas. This substance has been widely used in the great European war, in the treatment of gas bacillus infec- tion, its beneficial effects being widely commented upon and attributed to the liberation of oxygen in the tissues with bactericidal effect. It seems to me that this cannot be all the reason, as this gas is soon utilized by the tissues. A much more probable explana- tion is that the liberation of bubbles tears the tissues into large webbed meshes and allows other disinfec- tants free play or permits a penetration of atmospheric oxygen inimical to the anaerobic germs. 58 DESTRUCTION OF BACTERIA BY CHEMICALS Formaldehyde. This is a gas, but is most commonly seen as a solution ordinarily known under its trade name formalin. This contains from 35 to 40 per cent, of the gas and also some wood alcohol. The gas has an affinity for many organic substances, among them some of the dyes, but fabrics are not affected. Of the metals, iron and steel are attacked after long exposure in the presence of moisture. By reason of its affinity for organic substances it is a good deodorizer and disinfectant chiefly because it forms new insoluble odorless compounds. It is not very irritant when taken into the stomach, but its vapors cause considerable annoyance in the eyes, nose, and mouth. The lower animals resist it consider- ably, but insects are not affected. - It is more effective in the presence of moisture and when the temperature is high, up to 120 F. If these conditions cannot be obtained the exposure must be longer. Two and one- half per cent, by volume of the aqueous solution or 1 per cent, by volume of gas are sufficient to destroy fresh virulent cultures of the common non-spore-bearing bacteria in a few minutes. PRACTICAL APPLICATION OF DISINFECTION. Stock Solutions. As given by Park these can be made as follows: 6 ounces of carbolic acid in 1 gallon of hot water this is about a 5 per cent, solution. It is milky at first and must be stirred thoroughly. The addition of a small amount of glycerin keeps the carbolic acid in solution and probably assists in disin- FABRICS 59 fection, in part by absorbing water, in part by making a coating on objects and holding the phenol. Bichloride solution: GO grains of pulverized bichlo- ride and 2 tablespoonfuls of common salt to 1 gallon of hot water = 1 to 1000. Store in glass or earthen vessels. Agate will answer. It is well to color the liquid or to have a prominent label indicating poison. Milk of lime: 1 quart of dry, freshly slaked lime to 4 or 5 quarts of water. Lime is slaked by pouring a small quantity of water on a lump of quicklime. The lime becomes hot, crumbles, and as the slaking is completed a white powder results. Formalin solution: 1 part of formalin to 10 of water is equivalent to 5 per cent, of carbolic acid. Cleansing of Skin. For this purpose a 1 to 1000 carbolic or 1 to 1000 bichloride should be used, allow- ing it to act for at least two minutes. Following this there should be scrubbing with soap and water with a soft brush. It is unwise to roughen the skin with stiff bristles. The newer methods, using iodine-alcohol, require only simple soap and water washing and then a few applications of the solutions to the skin to be disinfected, allowing each application to dry before proceeding. Fabrics. Soiled fabrics should be soaked in carbolic, formalin, or bichloride in this order of preference for at least two hours. Mattresses should be exposed to the sun or removed by health authorities for disinfec- tion. After soaking infected goods in these solutions they should be boiled for at least twenty minutes, preferably with soap. Materials from the sick-room 60 DESTRUCTION OF BACTERIA BY CHEMICALS should never be carried to other parts of the building in a dry state. Utensils. Utensils should be soaked in the solutions and then boiled. Urine, Feces, and Sputum. Urine, feces, and sputum should be received in glass, earthen, or agate vessels already containing carbolic acid solution, milk of lime, or formalin, and they should be allowed to remain for at least one hour. It is well to cover the vessel. FIG. 21. Sanitarj' spit-cups. In the absence of disinfectants, discharges should be burned or boiled for one-half hour. The solid masses of feces should be broken up in order to permit the proper penetration of solutions. Tuberculous Sputum. Perhaps nothing is so impor- tant as the disinfection of tuberculous sputum, as it is the chief means of the transmission of tuberculosis. It should be received preferably in a pasteboard cup within a metal holder, the former being burned. It may be caught in metal or agate cups containing DISINFECTION OF ROOMS AND HOUSES 61 carbolic or milk of lime solution. If caught in hand- kerchiefs they should be burned. The hands must be washed in a disinfectant after catching sputum in a handkerchief. Water-closets and Sinks. They should not receive infective materials until these shall have been thor- oughly disinfected. To disinfect sinks and water- closets, chlorinated lime, cresols, and carbolic acid are the best. Disinfection of Rooms and Houses. The disinfection of rooms and their contents, while not necessarily the nurse's duty, deserves some mention. In case of infectious disease, physical cleaning must be left until after chemical disinfection shall have been done. It is then carried out on the ordinary plan of house-cleaning. The practical methods of house-disinfection today have narrowed down to formaldehyde. There are many forms of apparatus and several methods of producing this gas, but whatever the procedure, certain conditions must be observed. The temperature of the air in the room must not be less than 100 F., and there should be a high percentage of moisture. The most common method now used for the production of formaldehyde gas is the mixture of 1 pint of commercial formalin and 10 ounces of small crystals of potassium perman- ganate in an open vessel for each 1000 cubic feet of air space. These are usually mixed in the centre of the room in a tall metal case of some sort, surrounded by water, which serves the purpose of catching any of the mixture which bubbles over or extinguishing fire which sometimes occurs spontaneously. The cracks of doors and windows are always sealed by 02 DESTRUCTION OF BACTERIA BY CHEMICALS pasting strips of paper over them, and the room left sealed for twenty-four hours; this saves much of the vapor for disinfection and protects inmates of other parts of the house. Any remaining odor may be dis- placed by sprinkling ammonia about. Instruments. Instruments, including syringes, may be boiled for five minutes in a 1 per cent, solution of washing soda. Knives, however, should be kept in alcohol. Gauze should be sterilized at 120 C. or 248 F. and 15 pounds' pressure. Pasteurization. This consists in the heating of a substance, milk usually, to a temperature below the boiling point, usually 140 F. to 56 C., which kills the non-spore-bearing bacilli, and holding there for a few minutes. It is then cooled as rapidly as possible to a point at which bacteria do not usually multiply, that of the ice-chest. This does not sterilize the sub- stance, but in the case of milk may render it more likely to spoil afterward if not properly taken care of. Sunlight. A most admirable disinfectant is sun- light. Direct sunlight will eventually kill all bacteria, and it is wise to expose materials from the sick-room, whether from an infectious case or not, to as much sunlight as possible. CHAPTER VI. THE RELATION OF BACTERIA TO DISEASE -IMMUNITY. THE difference between saprophytes and parasites has already been emphasized, and incidently it has been learned that the latter may for a short time lead a life comparable to that of the former. The organisms that produce disease, pathogenic, are everywhere, particularly in the crowded life of cities. Not only are they on the objects of our environment, but within the entrances to the body. Sometimes organisms are found in the mouth and nose which are classed as pathogenic. Certain organisms are present invariably in the alimentary canal, and under proper circumstances can produce disease. It is often difficult, therefore, to determine precisely how a bacterium enters the body and produces the disease, because it is evident that some factors other than the simple presence of microorganisms are necessary to develop what is termed sickness. A disease might be fairly well de- scribed as the subjective (experienced by the patient) and objective (perceived by the physician) expression of the forces exerted by the bacteria and the defense presented by the body. These two forces must now be considered, and following the natural sequence, bacteria will be traced in their usual seats upon and within the human body, 64 THE RELATION OF BACTERIA TO DISEASE in their course past the primary defences and their manner of awakening the secondary or peculiar immunity resistances which the human system pre- sents. Bacteria gain entrance to the body by introduction through an abraded surface of the skin or mucous membranes. The delicacy of the latter renders infection through them quite easy. They may go in through the intestinal tract and be absorbed by its wall. They may go in through the tonsils, larynx, or trachea. In exposure to cold with the congestion and sensitiveness of the larynx produced thereby we have an opportunity for the absorption of bacteria. Not all bacteria can enter by all ways and produce disease. The pus cocci, if swallowed, are destroyed by the gastric juice, while typhoid bacilli usually pass the stomach uninjured. Typhoid bacilli rubbed into the skin would be followed by no disease, but pus cocci so applied would cause boils. Most of the secretions and excretions, except, of course, the feces, may be said to be mildly inhibitive to bacterial growth. The defences of the body to a local introduc- tion of bacteria depend upon the healthiness of the skin and mucous membranes. The resistance offered has been found to be due to a power supplied by the blood serum. This is discussed later. Any physical condition such as a burn or wound reducing the healthy trim of the body renders invasion easier. Injury and intoxication materially favor the activity of bacteria either previously within the individual or introduced at the time. Normal bodily resistance is impaired by excessive hunger and thirst, by exposure to cold and wet, or by prolonged muscular or mental strains. THE RELATION OF BACTERIA TO DISEASE (35 Conditions resulting after the entrance of bacteria into the body may be defined as follows: Infection is best considered as the presence of disease-producing germs and the evidence of their effects. Intoxication is the condition due to the poisons elaborated by bacteria. Bacteremia is the mere presence of bacteria in the blood while septicemia is the circulation of bacteria and their products in the blood, with some involvement of all the organs in the body. Pyemia is similar to the last but includes the production of many abscesses throughout the body. Fever may be described as a disturbance by bacterial poisons of the mechanism in the brain which controls the heat of the body. Some bacteria merely multiply in the body and exert their effect simply by their mechanical presence without any peculiar poison. Others have the power of elaborating poisons which are specific or individual and whose effect is added to that of the bacterial bodies. The latter form the larger percentage, and it is with them we shall deal chiefly. The ability of bacteria to cause disease is spoken of as their virulence. Each individual kind of bacterium produces only one form of disease, and always that one form. In the early history of pathological bacteriology Koch elaborated certain rules or postulates by which the relation of bacteria to disease is determined. They are essentially that the same bacterium should always be found in the same clinical disease, produce this disease when injected into animals, be recovered again from the animals, and retain its biological characters. By this means the peculiar expression of bacterial disease has 5 66 THE RELATION OF BACTERIA TO DISEASE been found, and thus it becomes possible to separate those diseases which are wholly due to the bacteria themselves and those principally arising from the bac- terial poisoning. Bacterial Toxins. Diphtheria is a disease wherein the bacteria reside and grow on a free surface, such as the pharynx; but their poisons are absorbed and carried in the blood stream, thus producing the peculiar symptoms of the disease. If, however, this toxin is taken, entirely free of diphtheria bacilli, and injected into animals, the same results can be obtained so far as the symptoms are concerned. This is likewise true of tetanus. For the development of typhoid fever and septicemia it is necessary that the bacteria themselves should circulate in the blood stream. The reason for this is that while the poisons of the diphtheria bacilli are soluble in fluids and separable from the germs, the poisons of the typhoid bacillus, for instance, remain within the body of the germ and are only effective when the cell dies and disintegrates. The former poisons are called extracellular toxins and the latter intracellular toxins or endotoxins. In practice the word toxin unqualified means extracellular toxins, while intra- cellular poisons are specifically called endotoxins. Some bacteria (cholera for example) develop both kinds. The local gross effects of bacterial invasion are expressed in inflammation, which is greatest in those which act by their mechanical presence in a confined locality, usually aided by some of the posions men- tioned above. THE RELATION OF BACTERIA TO DISEASE 67 Bacterial poisons, it might be said, usually express some definite predilection for special organs or tissues. For instance, the tetanus toxins attack the brain. The streptococci attack red blood cells, and the typhoid bacillus settles in the lymph glands of the small intestine. Incubation. After bacteria have gained their foot- hold there is a certain lapse of time until their effects become evident. This is the incubation time. Its length depends upon the number of organisms enter- ing, their virulence, and the resistance of the body. Mixed Infection. Sometimes there is more than one kind of bacterium in an infection. This is called a mixed infection, and although there is the expression of both causes, one usually predominates. This usually results from the entrance of the second invader, owing to the lowered resistance of the body produced by the first invader. Transmission of Disease. The transmission of dis- eases from one individual to another takes place in various ways, but it may be said in general that the means of transference must present conditions favorable for the retention of virulence on the part of the bacteria. Some bacteria, notably gonococci and influenza bacilli, die very quickly when dried or exposed to direct light. On the other hand, tubercle bacilli resist drying and diffuse light for several days. Coughing and spitting transfer infective organisms from the mouth to the air, and persons in the vicinity may receive them. Clothes soiled with discharges, both urine and feces, from typhoid patients, contain the bacilli and are capable of carrying the disease. 68 THE RELATION OF BACTERIA TO DISEASE Scales from the skin in the acute eruptive diseases of children may transmit infection. Milk and water have been known to transmit diphtheria, typhoid, scarlatina, and other conditions. Insects transmit disease in two ways, mechanically and specifically. Diseases like typhoid and tuberculosis may be trans- mitted by flies, which soil themselves on excreta or sputum and deposit the infective matter upon food or other objects, which later get into the human body. Other diseases probably to be credited in this category are plague and diphtheria. In the other class of insect-born disease the trans- mission can only take place by this means. Thus malaria is only transmitted from the sick to the unin- fected by the Anopheles mosquito, sleeping sickness only by the tsetse fly, and yellow fever only by the Stegomyia mosquito. In these insects there is a development of the virus to such a degree that it can be infective for an unprotected person, and for each disease this so-called cycle of development is necessary for its further propagation. None of the diseases demanding an insect for its spread can be transmitted by one person to another by the most intimate per- sonal contact. It may be laid down as a law that with the exception of the few infectious disorders only carried by insects, intimate personal contact is the most pro- lific source of the spread of disease. The objects before mentioned clothing, dishes, books, utensils, and so forth called "fomites," were formerly believed of considerable importance in trans- mitting disease, but latterly more weight has been laid upon individuals as carriers of viruses. This has THE RELATION OF BACTERIA TO DISEASE 69 come to pass because it has been found that more per- sons contract disease after having come in contact with persons than with objects from sick-rooms, and for this reason much room and object disinfection has been stopped. The writer still thinks that disinfection of a room should be done before physical cleaning, because of the possible danger to the cleaners of such a room where the virus may lurk in corners and crevices. Persons suffering with an infectious disease are, of course, the greatest danger in communication, but other persons may also carry infection. Attendants upon typhoid, diphtheria, or meningitis patients may carry upon the hands or clothing or in the mouth and nose, bacteria of the respective diseases without themselves having the disease, and may be called " passive" or " accidental" carriers. Doctors and nurses too often innocently are in this class. After recovery from the acute attacks of some diseases, notably typhoid, diphtheria, and dysentery, patients frequently carry the germs for indefinite periods; these are called "chronic carriers." Such persons are great menaces and are usually controlled by health authorities when known, but as certain diseases are endemic among us, particularly such conditions as scarlatina, for which the quarantine is very rigid, the number of so-called "hidden carriers" must be very great. Bacteria are directly the cause of ptomain poisoning, although the ones concerned may not live within the body. Ptomain poisoning is a violent irritation of the gastro-intestinal tract by certain poisons produced from putrefaction of meat and fish by bacteria. The 70 THE RELATION OF BACTERIA TO DISEASE foods may be little or not altered by these poisonous substances in them. They are in small quantity in the food, but are easily and quickly absorbed. It is possible that for a short time after ingestion of the meat the formation of these ptomains may continue. The ptomains are toxins, but they are formed by alter- ing the chemical composition of the meat rather than by any peculiar products of the bacteria- or poisons within their bodies. The condition is not transmissible. IMMUNITY. The resistance offered to the entrance of micro- organisms into the body has already been referred to, and now the method by which our physiology gets rid of the effects of these noxious agents must be con- sidered. It is a well-known fact that illness does not occur every time pathogenic bacteria gain a foot- hold on or within the body. Sometimes a small number of bacteria overcome the primary defences and yield when the reserve powers have been brought into play. Again, a low grade of virulence may be possessed by the. invaders, and although many enter, the specific disease process is halted by the economy. Moreover, some individuals seem to be poor hosts for certain bacteria, while others are received readily. The general resistance of the body to disease is spoken of as immunity. Immunity, as the term is usually used, means that an individual is not susceptible to a disease, but not necessarily that he would not be infected under very severe circumstances. IMMUNITY 71 Types of Immunity. Immunity is classified as (1) natural or racial or species immunity, and (2) acquired immunity, which latter has been further divided into active and passive. Natural immunity is the condition wherein a certain disease does not occur in the type of animal under consideration; as, for example, the dog does not take typhoid fever even when fed a pure culture of the specific germs. There is also a relative natural im- munity. Cats present great resistance to infection with anthrax. Racial immunity is shown by great resistance of the negro to yellow fever. There is also individual immunity, as shown by the passing of a person through a virulent epidemic without the slightest sign of illness. Acquired immunity is that resistance which a person obtains by passing through an attack of disease. That a second attack of measles or scarlatina seldom occurs is well known. This is seen also in typhoid fever. Such an acquired immunity is called active acquired immunity because the economy has had to work for its own protection, and it is only good for the one kind of disease, supplying no protection to any other kind: that is, it is specific. There is also a passive acquired immunity, by which is meant that some protective substances from another individual are added to the natural resistance of the body. This passive acquired immunity is very well shown in diph- theria when the serum of a horse which has been rendered resistant to the toxin of the diphtheria bacilli is given to the patient. This horse is said to possess 72 THE RELATION OF BACTERIA TO DISEASE active artificial immunity because it has been given the poisons themselves in such a manner that its blood has been able to develop anti- or against-poisons or antitoxins, strong enough to neutralize the toxins of the diphtheria bacilli. This blood is suitable to be transferred to another individual, and in the body of the latter offsets the effects of the toxin of the diph- theria bacillus. In other words, the horse's economy has worked actively against the poison, whereas the person receiving the horse's serum has not worked, but merely received a neutralizing substance from the horse's serum; it has been passive. This passive immunity is also seen in the treatment of tetanus by an antiserum (see Antitoxins), and lately Flexner has elaborated a method by which the poisons of the meningitis coccus are neutralized, here again by using the serum of horses injected with this coccus. Artificial immunity is one that has been produced intentionally by the physician. The term may be correctly applied to any form except the natural or active acquired immunities, but it is usually reserved for the various procedures in experimental medicine whereby antiserums or vaccines are manufactured. Anti-endotoxins. These bodies, comparable to anti- toxins, are developed in the blood serum when the system harbors bacteria whose pathogenic power depends upon intracellular poisons. Many kinds of anti-endotoxins or antibodies (a term embracing anti- toxins also but more commonly used, as here) are formed. The important ones are discussed under the Actions of Bacterial Toxins and their Antibodies. IMMUNITY 73 Antitoxins. The production of antitoxins hinges on this subject. Antitoxins may be described as the substances produced in the blood or blood serum of animals injected with the poisons elaborated by bacteria, but soluble and separable from the germ cells. The toxins used to make the injections into animals are obtained by growing the bacteria in broth and then filtering off their bodies. They are distinguished from the poisons described in a preceding paragraph in that no destruction of the germs is necessary to produce these separable toxins. Recapitulation. To recapitulate briefly, active ac- quired immunity is produced by injection of living bacterial cells when incapable of producing disease, or by their endocellular poisons or extracellular separable toxins. In the case of the latter it is possible to take from the blood serum of the immune animals something which will neutralize the toxins introduced, in other words, the principle involved in making of diphtheria and tetanus antitoxin. The former, non- virulent germs or their poisons, is used now as the basis of bacterin treatment. Action of Bacterial Poisons and their Antibodies. This matter is very complicated and not by any means perfectly understood by the most profound scientists. It is, moreover, unnecessary to enlarge upon it in a work of this kind, and tracing the methods as simply as possible is sufficient. The free soluble toxins stimulate the production of antitoxins which have an attraction for the toxin, and for it only. Therefore, when any free toxin and free antitoxin come together they combine, and one neutralizes the other. 74 THE RELATION OF BACTERIA TO DISEASE In the case of the reaction of bacterial cells or their endotoxins the result is more complicated. Many substances are formed, again called anti-, or in general, antibodies. Three will be considered: (1) The anti- bodies which dissolve bacterial cells; (2) those which clump them; and (3) those which encourage the white cells of the blood to eat them. The substances exist in minute quantities in normal blood. 1. Bacteriolysins. The first antibodies cause a dissolving of the bacterial cells. These antibodies are called bacteriolysins (adj., bacteriolytic). There is in all blood, whether normal or subjected to im- munizing procedures, a substance called complement, which makes possible these combinations of antibody and germ. 2. Agglutinins. Agglutinins are substances which cause clumping of bacterial cells, but do not dissolve them. They are made use of in the diagnosis of some acute fevers, notably in the Widal reaction of typhoid (see Typhoid Fever). 3. Opsonins. These are substances which act upon bacteria and prepare them for consumption by certain cells of the body, especially of the blood, called phago- cytes, a term applied because they have the power of devouring foreign substances. Bacteria are such, and it is the task of these phagocytes to remove them. These cells are also migrating cells, as they leave the blood stream and wander over the body. It has been found that in some conditions their power of consuming bacteria is below par, and, further, that if small num- bers of germs incapable of producing disease are intro- duced, the power of these cells may be stimulated for IMMUNITY 75 the particular kind of germ introduced and not for others. The bodies producing this increased eating or phagocytosis, opsonins, are supposed not to act upon the white cells, but upon the bacteria and make them more suitable as food for the leuko- cytes. These phenomena have put a valuable method of treatment in the physician's hands. In sub- acute localized disorders particularly, but also in definitely acute and chronic troubles, injections of dead cultures of the bacteria, responsible for the condition, are made beneath the skin. The progress of treatment is followed by a long, elaborate test of permitting the leukocytes of the blood of the patient, and as a control, those of a healthy person, to feed upon the bacteria in question in test-tubes kept at body heat. If the number of germs consumed by the patient's leukocytes rises during the course of the treatment, he is considered as benefiting from the injections. His general constitutional condition is closely watched also. It is now attempted to use for " vaccination" a culture made from the patient's disease, the so-called "autogenous vaccine." Principles of Vaccine Treatment. To return for a space to active immunity, it is well to consider here the basis of the present-day bacterin treatment. The ordinary vaccination against smallpox depends upon the fact that human smallpox virus passed through a calf for a number of times loses its power to produce smallpox in man. It does retain power to produce a sore, and this sore contains sufficient of the poison related to smallpox virus to stimulate in the vaccinated person a condition resistant to the virus which would 76 THE RELATION OF BACTERIA TO DISEASE cause true general smallpox. The great Pasteur found that if he heated anthrax bacilli and injected them into sheep, these animals became resistant to the disease anthrax. Since the time of Pasteur the management of the process which has been called " active immuniza- tion" has been learned. To accomplish this a virus must be treated as was the virus of smallpox, that is, it must be rendered incapable of causing general disease, but it must not be so altered that it has no relation to its original form. The living organisms can be taken and subjected to higher or lower tempera- tures than those preferred by the individual species, or they may be injected into animals until they will merely live without producing disease. This is called reducing virulence. They may be killed by heat or obtained in mass and crushed and ground into a pulp. Again, the broth or other material upon which they grow may be used after removing the bacterial bodies by filtering them off through porcelain filters. Having obtained the virus in a reduced state either dead or as active principles, it is injected beneath the skin of the individuals whom it is desired to protect, beginning in minute doses and increasing the quantity as the condition permits. By this means the resistance of the animal or person to this particular germ is increased, and the process corresponds to that of the production of antitoxin in horses, that is, making an antipoison, or, as it is called, an antibody. The method just described is usually reserved for the bacteria which produce intracellular or endotoxins. The method has been used in treating anthrax, typhoid, cholera, etc. IMMUNITY 77 Serum Treatment. Since it is possible to create in animals by the injection of bacteria, a condition of the blood serum which neutralizes the bacterial poisons, there has arisen a specific treatment of many bacterial diseases. The ones found most suitable for this therapy are diphtheria, tetanus, meningitis, dysentery, cholera, streptococcus, and pneumonia. The antiserums are administered by injection under the skin of patients, and serve the purposes first of neutralizing any poison which may be circulating, of agglutinating free germs, of stimulating the phagocytes to devour the organisms, and of keeping the poisons from destroying the cells of the organs. The various antisera will be discussed under their respective diseases. Anaphylaxis. When the principal constituent of flesh and blood, protein, is taken into the alimentary tract it is digested and absorbed because digestive ferments are there for the purpose. If it be injected in solution under the skin a ferment has to be prepared in order to remove it. If, now, it be injected a second time this ferment is ready and attacks the protein, digesting it rapidly. The products of this digestion appearing suddenly in the tissues are apt to poison them. If a guinea-pig be injected with horse serum and the dose be repeated ten days -later, the animal will have dyspnea, skin irritability, and die. This is anaphylaxis, which we shall for our purpose con- sider as a hypersusceptibility to protein matter not taken in the normal manner. Some persons exhibit great susceptibility to antiserum injection because they are anaphylactic to the horse serum, and while a few deaths have occurred, they usually react by the 78 THE RELATION OF BACTERIA TO DISEASE appearance of "serum sickness." This is a condition appearing five to twelve days after serum injection, con- sisting of skin rashes, malaise, fever, and albumin in the urine. The reaction occurs most often in persons who have asthma when in the presence of horses, and the physician should inform himself as to this contingency. No reaction will appear if the serum be given very slowly, or the first dose divided by a few hours, or if a second injection be given in two to four days. A single large, rapid injection of horse serum should never be given to a patient, because it might make him susceptible to horses or to later serum injections, against which a second dose within five days will protect him. Nurses should have a hypodermic of T i-o gr. of atropin ready for emergencies, since this drug is the only treatment for acute symptoms after antitoxin injections. The jeader must not picture that these so-called antibodies are substances that can be handled. They are invisible chemical parts of the serum of the blood, and only perceptible through extremely delicate labora- tory procedures. The present conception of their action was worked out by Dr. Ehrlich, a German chemist and physicist. His theory, broadly speaking, assumes a group of substances circulating in the blood which can be stimulated to meet and destroy invaders, and thereby protect the body. Besides the three methods above outlined, in which practical therapeutic use has been made of the known facts in the study of immunity, still others have been devised, but they are scarcely yet out of their experimental stage. CHAPTER VII. PREPARATIONS FOR AND PROCURING OF SPECIMENS FOR BACTERIOLOGICAL EXAMINATION. WHILE it may not be the duty of the nurse to obtain all specimens for bacteriological purposes, she is often requested to obtain the more common things, and it behooves her to know how this should be done. The nurse is very commonly expected to prepare the patient for technic used by the physician in procuring specimens, and she should know the more important parts of such technic. Collection of Pus. For the taking of cultures of pus from abscesses or from infected surfaces of ulcers or sinuses, an applicator, usually of wood, wound with cotton and sterilized within a glass test-tube, is used. The nurse most commonly sees this in con- nection with throat cultures. When this applicator is passed over the diseased surface, some of the bacteria present adhere to the cotton. The adhering particles are transferred by the physician to some suitable food upon which the germs will grow. In preparing an exposed infected surface for culture-taking, the nurse need have ready only sterile water or a very weak (1 per cent.) boric acid or sterile physiological salt solution. Anything stronger may destroy the bacteria. 80 BACTERIOLOGICAL EXAMINATION Collection of Sputum. Sputum to be examined for the tubercle bacillus should be received in a thoroughly FIG. 22. Showing the method of taking a culture from the pharynx. (Morrow.) FIG. 23. Widc-rnouthed bottle for collecting sputum. cleansed and dried wide-mouthed bottle. This is given to the patient that he may expectorate directly into it. When the specimen has been collected by the COLLECTION OF URINE 81 patient, the bottle, including the inside of the mouth, should be wiped off with a cloth moistened with 5 per cent, carbolic acid solution. When specimens of sputum are intended for careful bacteriological cultivation with the idea of finding out what the causative bacteria in the case may be, the procedure is different. In this case the bottle, again a wide- mouthed one, must be plugged with raw cotton and sterilized, preferably by dry heat. Someone should supervise the collection of the specimen and see that the patient spits a representative (instruction from doctor) sample directly into the bottle and does not let it touch the outside of the neck. The part of the cotton plug which extends beyond the mouth of the bottle should be held by someone and the stopper part not allowed to touch anything while out of the bottle. After the plug is replaced the outside of the bottle is cleansed, as for tuberculosis sputum. The sputum is an excretion from the trachea, bronchi, and lungs, and care should .be taken that the specimen collected is such and not saliva mixed with posterior nasal mucus. In children it is necessary to induce a cough and to collect the sputum on cotton-tipped applicators. Collection of Urine. The collection of urine for bacteriological purposes must be done by catheteri- zation, using all possible surgical precautions as- to genitalia, hands, and instruments. The urine must be allowed to fall from the end of the catheter directly into a bottle or test-tube sterilized with a raw cotton plug, the plug being removed when the collection is ready and held carefully, so that the part which fits into 6 82 BACTERIOLOGICAL EXAMINATION the tube touches nothing. This is best held by an assist- ant during catheter ization, so that it will not be contaminated. Collection of Feces. The best method of collecting feces is to have them passed directly into a sterilized Mason jar. This, however, is not always practicable, and they may be received in a thoroughly cleansed bed-pan or chamber and transferred afterward to the Mason jar by pouring or by a pair of forceps sterilized FIG. 24. Forms of hypodermic syringe: A, Koch's syringe; B, syringe of Strohschein; C, Overlack's form. by passing through a flame. The cleansing of the receptacle should be done by soap and water, alcohol, and sterile w r ater. Collection of Blood for Widal Test. In preparing for a Widal blood test (see Typhoid Fever) the finger or ear lobe is cleansed with soap and water and alcohol. It is then pricked with a needle and the blood collected on unglazed paper, glass slides, or in glass tubes. For direct examination of the blood the procedure with the patient is the same. TECHNIC OF PUNCTURES 83 Technic of Punctures. Perhaps the most important bacteriological technic with which the nurse has an important duty is the puncturing of cavities such as drawing fluid from a chest or knee, the cerebrospinal fluid from the spinal canal, or the taking of blood from a vein. For all these the skin over the site of operation is cleansed precisely as for a major operation. It is the practice of the author for vein puncture, in making a blood culture, to have the arm at the bend of the elbow inside (sometimes the leg is used) scrubbed with soap and water, using a very soft brush, washed with sterile water, and either painted with 10 per cent, iodin alcohol or a wet dressing of 1 per cent, formaldehyde applied; if the puncture is not done for some time, fresh iodin solution is used when everything is ready. These two methods have been found very successful in destroying the bacteria always present in the deeper layers of the epidermis. They are chiefly small white cocci not unlike the cocci that cause abscesses. They' will be considered later under the name Staphylococcus epidermidis albus. There is little to be done by the nurse aside from preparation and general assistance, but she should know what is being done and why. Fluids are removed from the pleural cavity or spinal canal and elsewhere, because in these locations bacteria of specific kind or in characteristic conditions are to be found. For instance, in cerebrospinal menin- gitis the causative germs are found within the pus cells of the cerebrospinal fluid, as double, biscuit- shaped cocci, and they have a particular staining reac- tion by which they are recognized (see Chapter VIII.) 84 BACTERIOLOGICAL EXAMINATION The blood is taken from the veins and grown in broth alone or broth stiffened with gelatin or agar- agar in order to find out if living bacteria are circu- lating in the blood stream, as is the case in typhoid fever and septicemia. For entering these cavities or veins a syringe, prefer- ably of glass, with a good-sized needle, larger than the medicinal hypodermic type, is used. The syringe and needle may be sterilized by boiling, with a pinch of soda, for ten minutes or by autoclave, the best means provided the operation be done immediately. Metal parts will rust if the syringe and needle are sterilized by moist heat and allowed to dry out. The hot-air oven is not suitable for sterilizing in this case. Milk. Nurses are frequently required to send sam- ples of milk for examination, especially in well-directed hospitals. Of course, when bottled milk is used an unopened quart bottle should be sent to the labora- tory. When the milk is supplied in cans it is neces- sary to have a sterilized 50 c.c. pipette and a sterilized bottle or flask. The lid of the can is carefully removed, the pipette, held only by the mouth end and protected throughout its length from touching the neck of the can, is plunged into the milk for six inches and filled by suction with the mouth. The milk is transferred to the sterile bottle or flask, again observing the pre- caution of not touching the neck of this container. The stopper or plug of the receiving vessel is best held by an assistant and the part w r hich fits into the vessel must touch nothing. As soon as the milk is collected it should be put on ice or sent to the laboratory imme- diately. CHAPTER VIII. THE ACUTE CHIEFLY LOCALIZED INFEC- TIONS OF PUS NATURE THE PATHOGENIC COCCI. So far the general conditions. under which bacteria live, grow, and exert their peculiar forces have been considered, but now a more direct study will be under- taken of individual groups and single species, with the object of learning what the various diseases due to microorganisms are, and what relations the germs bear to the clinical disease. Perhaps the most frequent condition a nurse has to meet is an abscess or local surgical infection with or without pus. All the technic of hospital work hinges on the fact that organisms capable of producing pus are ubiquitous, so that the protection of w r ounds or of patients of medical cases with their lowered vital resistance is imperative. There is no one germ that always produces local infection or pus, but many bacteria possess this power. Moreover, some bacteria may produce a simple abscess in one case and a violent inflammation of the heart lining in another. This depends in part upon the virulence of the germ and also upon its mode of entry. If pus cocci fall upon a simple cut in the skin of an otherwise healthy person, a red, dropsical swelling or an abscess may result. 86 LOCALIZED INFECTIONS OF PUS NATURE Again, if they fall upon a wound made for an abdomi- nal operation, they may penetrate to the interior and cause a peritonitis. Still, again, pus germs may make their entrance in the ways first cited, but cause no trouble at the site of entrance, being carried hence by the blood stream to cause trouble at other places. Any reaction set up by bacteria is called inflammation, and in no other conditions is this so well illustrated as in the effects of "pus cocci." Inflammation. Inflammation is the reaction on the part of the body to the presence of bacteria themselves or to their products. It is expressed by swelling, increased heat, redness, pain, and some loss of function. It is not worth while to go deeply into what may be seen under the microscope in inflammation, but to explain the physical expressions of inflammation just given a few lines seems advisable. The swelling, heat, and redness are due to an increase of the blood in the affected part, called forth by forces exerted by the bacteria. These are protective phenomena whereby the body sends an excess of its most potent protective tis- sue, the blood, to stop the onslaught of microorganisms. The forces exerted by the invaders attract the white cells of the blood, which collect about the outsiders and try to destroy them. The pain is due to the irritation of the fine nerves of the part, and loss of function can be explained by a combination of all the other features of inflammation. The further course of this reaction depends upon which force is the stronger, the body defence or the bacterial attack. If the former exceed the latter the part assumes its normal character after a brief time. As the infecting forces become greater LOCALIZED INFECTIONS OF PUS NATURE 87 in relation to the defence, just so there are greater eft'ects in the production of infection. In increasing severity there are the following grades: Abscess is a local collection of pus in which the resistance put up by the tissue prevents the inflamma- FIG. 25. Secondary infection of a glomerulus of kidney by the Staphylococcus aureus in a case of ulcerative endocarditis. The cocci (stained doubly) are seen plugging the capillaries and also lying free. X 300. (Muir and Ritchie.) tion from spreading, thus keeping it in a limited space. There is some effect on the general body by absorption of a few bacteria or their poisons, but a densely packed zone of leukocytes around the pus keeps it from gen- eral invasion. Should this barrier be broken or the resistance be too low to hold the invaders a spread of 88 LOCALIZED INFECTIONS OF PUS NATURE the pus occurs and cellulitis or phlegmon arises. The next grade of severity would be septicemia or pyemia, defined before, which arises when the active inflam- mation enters and involves the bloodvessels. The softening of tissue into pus is called suppuration, which may be defined as the destruction of tissues and cells by bacteria and their products. Pus under the micro- scope is composed of white blood cells, particularly the so-called polynuclear leukocytes, microorganisms, some of which are free, others englobed by phagocytes, partly or wholly destroyed tissue, and, at least early in inflammation, a delicate mesh work of coagulum called fibrin; the last is dissolved shortly as the sup- puration proceeds. There is also some granular fluid. The fluid and cells which appear in inflammation are collectively called an exudate. This may be of several forms; it may be true pus; it may be a thin, watery fluid in which are floating shreds of a gray, friable character, called lymph, in reality a coagulum, such as is formed in blood clotting, but without red- blood cells; it may be a tenacious covering of a surface, called a false membrane, such as is seen on a diphtheritic throat, more or less closely adherent to the surface from which it arises; it may possess special characters, such as hemorrhagic when much blood is admixed, or mucoid when it resembles mucus. PUS-PRODUCING MICROORGANISMS. It has been stated that there is no particular germ always responsible for pus, but some varieties of the round bacteria are the commonest causes. Thev are PUS-PRODUCING MICROORGANISMS 89 called micrococci or staphylococci, and streptococci. Certain members of the group of cocci may also do other things than produce simple pus or abscesses. These will be considered at the end of this chapter. Bacteria other than cocci which can produce pus are the colon bacillus, pyocyaneus bacillus, typhoid bacillus. Staphylococcus Pyogenes Aureus. Of the micrococci there is one particular species of importance which by some bacteriologists has been divided into two FIG. 26. Staphylococcus. X 1100 diameters. (Park.) varieties because members of the group differ in their ability to produce color in laboratory cultures and because the one having a golden-yellow pigment is somewhat more frequently found in pus. This color- producing organism is called the Staphylococcus pyo- genes aureus (the golden pus-producing coccus). See Plate II for an idea of growth and color. It is about 2TiiTrTr of an inch across and appears under the micro- scope as single individuals, pairs, but more frequently in grape-like groups. It stains fairly well with most 90 LOCALIZED INFECTIONS OF PUS NATURE dyes used. It does not form spores and does not move from place to place by its own power. It grows best about 85 F. It is killed about 56 C. or 130 F. at ten minutes in the moist condition, but when com- pletely dry it may require boiling to kill. When dried on cloth or paper it may live three months. This organism grows well on ordinary laboratory foodstuffs, and produces, particularly in the presence of diffuse light and oxygen, a golden yellow color. This coccus has the property of coagulating milk and liquefying gelatin by the ferments it produces. It is killed by corrosive sublimate, 1 to 1000, in ten minutes in watery solution. In pus a considerably longer time is required. 1 to 20 carbolic kills in one minute; 1 to 500 in about one-half hour. The pus in which the staphylococcus lives supplies a protective envelope, and should be well mixed and diluted with the ger- micide. This organism is very virulent for the smaller animals, which may be infected by rubbing on, or injection under, the skin. It will then produce a local abscess or septicemia. It may produce acute inflammation of the interior of the heart, or bone disease. Staphylococcus Pyogenes Albus. The Staphylococcus pyogenes albus is precisely like the foregoing except that it does not produce the golden-yellow pigment, but grows in a porcelain-white manner. There is an organism on the skin to which we give the same name, but add the word "epidermidis." It is con- stantly present on the surface, in the epidermis, and in the glands of the skin. Since its pus-forming ability is so feeble, "pyogenes" may be omitted and the PUS-PRODUCING MICROORGANISMS 91 name Staphylococcus epidermidis albus given. It does not produce disease, but is of constant annoyance in making blood cultures. Another staphylococcus pro- duces a lemon-yellow color. These staphylococci are very widely distributed and seem to be almost constantly upon the surfaces of the body, upon skin, in the sebaceous and sweat gland openings, on the mucous membranes. For this reason they are of great surgical importance and may originate, in a postoperative infection, from the patient, physician, or nurse. Their rather high resistance to disinfection demands great care in surgical technic. The com- monest conditions in which these cocci are implicated are pimples, boils, carbuncles, lymph-gland swellings, osteomyelitis and endocarditis. Vaccines and Opsonins. The use of killed bacteria to produce an increased resistance against an existing infection has already been discussed. This method of treatment is particularly suitable for infections with staphylococci. The procedure is about as follows: Cultures are made from the diseased part, grown in large quantities on laboratory media, washed off, suspended in physiological salt solution and heated to a temperature which will kill their disease-producing properties and stop their multiplication, but will not alter their peculiar chemical composition. The number of bacteria are then counted by a special technic and hypodermic injections are made of definite numbers. The size of dose and rate of increase of number injected are controlled by what is called the opsonic index. The opsonins, as will be remembered, are substances in the blood which make the bacteria suitable for ingestion by 92 LOCALIZED INFECTIONS OF PUS NATURE the white cells of the blood or phagocytes. The opsonic index is the relation of the ability of the patient's white cells to ingest bacteria as compared with a normal person's white cells. This latter is considered 1. If a person is infected with the pus cocci it means that his opsonic index is below 1, and we try to increase it up to or beyond 1. Many different conditions have been found amenable to this treatment, but furunculosis has responded better than others. Streptococcus Pyogenes. The cocci which grow in chains, streptococci, must now be considered. There are many varieties, but the Streptococcus pyogenes (the pus-producing streptococcus) is the only one that need be considered. This organism gives rise chiefly to the spreading inflammation, such as ery- sipelas, cellulitis, and septicemia. It may cause a localized abscess. It is a rapidly growing organism when conditions are suitable, and is the commonest cause of puerperal infection. It frequently attacks the blood and causes a solution of the red cells. Strep- tococcus peritonitis is usually fatal. It is commonly present in the mouth, and may produce tonsillitis. It is not so wide-spread in its distribution as the fore- going coccus, but is greatly feared in surgical and maternity wards. Streptococci are capable of pro- ducing inflammation of many sorts and no tissue of the body seems able to resist tl^em when of sufficient virulence. They most commonly affect the tonsil, heart lining, lung and subcutaneous tissue. Disinfec- tion of materials from streptococcic infections should be done by carbolic acid, bichloride, or hydrogen peroxide. Great care is necessary in the handling of dressings, PUS-PRODUCING MICROORGANISMS 93 clothing, and utensils from patients with streptococcus infections, because, despite the low resistance of the organism, transmissions take place quite easily, and it is highly probable that it always occurs by direct transference of the germs as they live a very short time exposed to light and air. This is particularly true of puerperal infections, which are commonly the result of infection with bacteria of high virulence. This germ, unlike the staphylococcus, cannot infect through the undamaged skin, demanding a wound for its entrance. Streptococci vary in virulence and FIG. 27. Streptococcus pyogenes. (Abbott.) when the particular family of germs happens to be very virulent, a single coccus may transmit an infection. In diagnosticating streptococcic infections it is necessary to make smears on glass slides and cultures in appropriate media. The germs are found to be very small single cocci varying from 5-^,7017 to ^ido of an inch, dividing only in one plane and therefore growing in chains. They are unable to move of themselves, stain well by most methods, multiply best at 37 C. (98 F.), but also at lower temperatures, and grow as very delicate gray colonies. They have no effect upon 94 LOCALIZED INFECTIONS OF PUS NATURE milk or gelatin. On media containing blood they have the property of dissolving the red coloring matter. They are killed in ten minutes when exposed to 52 C. (126 F.). When dried in blood or pus they may live for a considerable time at room temperature, but die quickly at body heat unless their food is repeatedly renewed. They are killed by corrosive sublimate, 1 to 1000; carbolic acid, 1 to 100; and hydrogen peroxide, 1 to 100, in ten minutes if exposed in water. Pus supplies a protective envelope, and the germicide must be allowed to act longer. Streptococci are very virulent for most lower animals and the same lesions may be produced by artificial injection as arise spontaneously in man. Streptococci produce a slight amount of extracellular poison, but more arises from the disintegration of the bacterial cells. The vaccine treatment is not always successful. An antistreptococcus serum has been prepared by injecting horses with a number of cultures in order to call forth antibodies to all varieties. In all cases of severe streptococcus infection this should be used and good results have been reported from some quarters. To diagnosticate infections by the staphylococcus or streptococcus we are obliged to make our technic suit the individual case. If an abscess exist it is sufficient to collect the pus. If a cellulitis or bone disease is to be examined, it is necessary to go deeply into the tissue and select the bloody material near the healthier tissue. In septicemia or heart disease, a blood culture is made. Both organisms grow with ease upon ordinary culture media. MICROCOCCUS GONORRHEA 95 MICROCOCCUS GONORRHEA. Gonorrhea is an acute inflammatory and pus-forming disease with its chief manifestations in the mucous membrane of the urethra. It is caused by the Micro- coccus gonorrhea or gonococcus, which enters the mucous membrane directly wherever there is a slight, even invisible, abrasion. This disease is one of the venereal affections, and is probably one of the most prevalent of all diseases. In the male its acute stage lasts for three to six weeks, while in the female it may be transient or pursue a very long course. In both sexes it tends to infect the other genital organs, and is probably the chief cause of salpingitis and oophoritis. In later stages when all bacteria have not been removed by a perfect cure, the germs penetrate to the deep parts of the mucous membrane of the external urinary channel, and there rest for long periods apparently undestroyed by the protective forces of the body, and without setting up any change by which their presence can be detected. They may be stimulated to renewed activity by a congestion of the part by any means. This peculiarity of hiding is the reason for the fact that a person once affected by this disease remains infective for others for a very long time. The bacteria reside in the Bartholin's glands of the female or the posterior urethra, Cowper's and prostatic glands of the male. At present there is no perfectly reliable method by which to ascertain the freedom from gono- cocci of a person once affected. Late results of this disease are urethral stricture, chronic inflammation of any other genitals, such as salpingo-oophoritis, requir- 96 LOCALIZED INFECTIONS OF PUS NATURE ing operative removal of the affected parts. Either during its acute or chronic stage, the latter more commonly, the gonococci may enter the blood stream and affect tissues other than the genitals, for which it has a predilection, the serous surfaces, joints, heart lining, or meninges. These conditions arising after such spreading are very difficult to treat, and not infrequently leave a permanent defect. The inflammations of the eyes, notably the con- junctiva, produced by the gonococcus are very com- mon, and one authority says that half the world's blindness is due to it. This complication is due to carrying of germs from the seat of primary disease, on the fingers, handkerchiefs, and the like, to the eye. The result is a frightful acute, pussy conjunctivitis, running a long, acute course and leaving opacities of the cornea or adhesions of the iris in many cases. Destruction of the eye may result. Not only does this disease affect those with gonorrhea, but it may be transferred to others by objects soiled with pus. The commonest transmission of gonorrheal ophthalmia, as it is called, is to the newborn. This is ophthalmia neonatorum. It is a common practice of obstetricians, especially in hospitals, to instil a few drops of a weak nitrate of silver solution (2 per cent.) into the eyes of newborns, whether there is or is not a history of gonorrhea in the mother. A more serious and baffling phase of gonorrhea is seen in the vulvovaginitis of little girls, which fre- quently sweeps like wildfire through a hospital ward, despite all attempts to stay its progress. It also appears in any institution where children are in close MICROCOCCUS GONORRHEA 97 contact, schools, for example. It is supposed to be transmitted by water-closet seats and directly from child to child. It may be spread by bedclothes, towels, clothing, basins, bed-pans, and in other ways. Children have been known to contract the affection by occupy- ing the same bed as an infected person. Efforts to eradicate this vulvovaginitis should be directed toward removing the source. This is sometimes impossible, since it cannot always be found. It is much better to institute a strict quarantine of every little girl admitted to a ward by using separate bed and body clothing and utensils. She should be examined by the house physi- cian upon admission, and if necessary, proper bacterio- logical examinations made. If affected, such objects that are used on her as can be burned should be so disposed of. Others should be soaked in carbolic acid solution for at least twenty-four hours. It is the practice in many places to place on all female children a T-binder, which is burned upon removal. Patients must not be allowed to go to the water-closet, but a bed-pan used, to be later disinfected by appropriate solutions. Flaming objects, such as a bed-pan, is an excellent method of disinfection. The curious part about the transmission of vulvovaginitis is that its causative agent, presumably always the gonococcus, is either in a highly resistant state, or it is protected in some manner, since agencies, such as drying, that will kill the bacterium under ordinary conditions seem to have little or no effect upon it. The gonococcus was first described by Neisser in 1879. It is classified, and correctly, among the round organisms or cocci, although it is usually seen in pairs 7 98 LOCALIZED INFECTIONS OF PUS NATURE like two kidney beans with their concave sides together. They are also said to be of biscuit shape. Each bean is about ^ oinro of an inch wide and 2~olj oir f an i ncn long. In pus or culture they are of this figure, but in the former they are characteristically lying within the pus cells between the wall and the nucleus, but not within the latter. Free pairs are also seen, but it is unwise to name them when not in the cells, because other cocci may resemble them. There is a resem- FIG. 28. Pus of gonorrhea, showing diplococci in the bodies of the pus cells. (Abbott.) blance between these organisms and those of meningitis (p. 100), but the clinical differentiation is not difficult, since the diseases are easily separated. The gonococcus does not stain by Gram's method, a quite important criterion for the bacteriologist. It is cultivated with difficulty. For purposes of growing it in the laboratory a broth or jelly must be used to which has been added some blood or blood serum or fluid from a hydrocele or the peritoneum. It grows best in the presence of free oxygen, a curious fact, MICROCOCCUS GONORRHEA 99 since it will live for long periods in places where there is no free oxygen. It grows best at 98 F. (37.5 C.) but dies out very rapidly. In the ice-chest it may live somewhat longer. Direct sunlight kills the gonococcus almost at once. 105 F. (41 C.) will kill the organism in a few minutes. Almost any good disinfectant will kill it in five minutes if directly applied to the bare germ. "If completely dried, however, and protected from light, it may live on sheets and clothing, from eighteen to twenty-four hours." This bacterium produces an intracellular or endo- toxin, which is as potent when injected into animals as a devitalized mass as the living form itself, although the gonococcus has very little effect upon laboratory experimental animals. Some observers have been able, by injecting goats with coccus poison or the germs themselves, to produce an antiserum against the gonococcus, and therewith treat human cases with some success. Vaccination with killed gonococci has been found of some value in chronic stages and, by some observers, in acute stages also. The bacteriological diagnosis is easily made by spreading some of the pus upon glass slides, staining appropriately, and examining under the microscope. In the chronic gonococcus infection the discovery of the germ is extremely difficult. For the diagnosis of obscure cases of vulvovaginitis Dr. Norris recommends a washing with 1 to 5000 bichloride solution in a pipette filled with a bulb. The chemical removes the surface epithelium and cocci hidden in the depths are drawn out. The fluid can be centrifugalized and the sediment stained. 100 LOCALIZED INFECTIONS OF PUS NATURE MICROCOCCUS INTRACELLULARIS MENINGITIDIS. Meningitis, or inflammation of the membranes covering the brain and spinal cord, may be caused by several bacteria, such as streptococci, pneumococci, and influenza bacilli, but we shall deal chiefly with epidemic cerebrospinal meningitis or spotted fever. (The latter is a common term which should be dis- carded for meningitis, and confined to typhus or jail fever.) Epidemic cerebrospinal meningitis is an acute primary inflammation due to a coccus called the Micrococcus or Diplococcus intracellularis menin- gitidis of Weichselbaum . or the meningitis coccus or meningococcus. The organism probably gains access to the meninges by way of the nose, whence it passes through the sieve-like bones through which the olfac- tory nerves emerge from the skull. By this route it penetrates to the under surface of the brain and extends along the meninges. The other agents of meningitis, the pneumococcus for instance, usually gain entrance by way of the blood or lymph, directly through the skull-base or by an extension from the middle ear, where suppuration may burrow through the bone. The meningitis coccus is found in the nose and throat of patients, and also in the nose and throat of about 10 per cent, of their attendants. The affection produces a thick, stringy, purulent exudate in the spaces between the nervous system and their coverings, the meninges, called the arachnoid space. This exudate covers the brain and cord, and fluid accompanying it distends the various cavities of MICROCOCCUS MENINGITIDIS 101 the spinal column and interior of the brain. The dis- ease has a high mortality. It affects chiefly the young. Its results or sequela? consist iivbliiicmess, deafness, and paralyses of various kinds. /.MentpiitV ;nmy,:be affected. If . FIG. 29. Meningococcus in spinal fluid. (Hiss and Zinsser.) In taking care of meningitis patients the chief concern is with discharges from the nose and mouth. These cavities should be cleansed with a mild anti- septic, say boric acid, and the cotton or what not used should be burned or soaked in carbolic acid solution. The nose and throat of those in attendance should be 102 LOCALIZED INFECTIONS OF PUS NATURE sprayed with an antiseptic, those containing thymol being excellent for the; purpose. After death the body should be entasea in- 4 cloth wetted with carbolic acid .solution.: ', ' ': In the diagnosis of this disease from a bacteriological standpoint, the most important procedure is the lumbar puncture. This is the introduction of a needle into the meningeal space by entering between the vertebrae of the lumbar region. Its purpose is the withdrawal of fluid. This fluid is usually thin, turbid pus containing flakes of fibrin. The turbidity is due to great numbers of pus cells. These cells con- tain the cocci of meningitis, which are of the same general size, shape, and arrangement as the gonococcus. They are so like this coccus that one must be well versed indeed to differentiate between the two without a knowledge of the source of the specimen. The meningitis cocci show a great variance in size and shape within the same specimen, conditions not com- mon with the gonococci. They also stain differently, although both are decolorized in the Gram method. As is the case with gonococcus, they lie within the proto- plasm, but not in the nucleus. Given a turbid fluid from a case suggestive of meningitis, it is possible to make a diagnosis by finding these cocci. The cocci may also be found in the blood. They develop agglu- tinins whereby an additional assistance in diagnosis may be given. The cocci are grown with moderate ease on labora- tory media, especially if they contain blood serum or glucose. They grow best in the presence of oxygen, at 37.5 C. or 98 F., but die rapidly if not put on fresh food frequently. PLATE III uf Diplococcus Pneumonias in Blood of Rabbit. (Abbott.) Showing encapsulated eoeci, red and white blood cells. DIPLOCOCCUS PNEUMONIA 103 They are killed by heating to 50 C. or 122 F. for ten minutes, by exposure to sunlight at once, and by almost all disinfectants in appropriate strength in five minutes. It has been possible to produce a very effective antiserum by injecting into horses suspensions of whole and disintegrated meningitis cocci. The antiserum is introduced into the space between the cord and the meninges by lumbar puncture, first withdrawing some of the spinal fluid to make room for it. By this treatment, especially when instituted early in the disease, a great deduction in the mortality, and in the deformities so frequently following meningitis, has been effected. DIPLOCOCCUS (STREPTOCOCCUS) PNEUMONIA. Pneumonia or inflammation of the lungs may be caused by a great many organisms, but by far the commonest one is the Diplococcus or Streptococcus pneu- monice or pneumococcus. This omnipresent organism gains entrance to the body almost exclusively by the nose or mouth. It enters the air passages and penetrates to the finer parts of the lungs, there setting up a rather characteristic inflammation. In certain types of pneumonia the disease may involve whole lobes; again, small patches here and there may be involved, the intervening tissue being practically normal. From the lungs the bacteria naturally pene- trate into the blood stream. This emphasizes the fact that while pneumonia expresses itself chiefly in the lungs, it is in reality a general infection. It should, 104 LOCALIZED INFECTIONS OF PUS NATURE moreover, be included among the transmissible infec- tions because it appears in epidemics, and definite instances of communication directly from the sick to the well are known. By reason of the spread of pneumococci through the blood, complications in the form of involvement of nearly every tissue in the body may result. The interior of the heart, the pleura, and the meninges are most commonly affected. These organisms may also cause conjunctivitis, tonsillitis, otitis, and arthritis. For diagnosis bacteriologically, cultures are made from the sputum, selecting the blood-streaked speci- mens, and of the blood. Sputum should be dis- infected by receiving it directly in 5 per cent, car- bolic solution. Not only must care be used to collect sputum, but the lips and checks of the patient should be kept clean, and all attendants should rinse their nose and throat frequently with hydrogen peroxide or Dobell's solution. Pneumococci do not live long on objects, but may be transferred by persons in the hair and nasopharynx, in which places the germs are pro- tected from light and drying. After pneumonia it is not common for patients to remain as carriers, but attendants may be accidental carriers. The coccus belongs properly to the streptococci, since it divides only in one plane, and its cultures may appear in chains. It has the peculiarities of growing in an oval shape in pairs, with the distal ends pointed (lance-shape), and being surrounded by a capsule. This shape and envelope are quite characteristic, and almost determinative. The coccus grows very slightly on ordinary culture media, but best when blood or DIPLOCOCCUS PNEUMONIA 105 blood coloring matter is added. It then produces a faint green color and grows best at 37 C. or 98 F., but FIG. 30. Pneumococcus from bouillon culture, resembling streptococcus. (Park.) FIG. 31. Pneumococci in peritoneal pus. Stained with fuchsin. X 1000 diameters. Clear spaces indicate capsules. (Park.) does not live long, requiring repeated transference to fresh food. In sputum the pneumococcus may remain 106 LOCALIZED INFECTIONS OF PUS NATURE alive and capable of producing disease for several months if protected from light. If the sputum be dried and powdered, so that it could be inhaled, the cocci live for a few days in diffused light. Direct sunlight kills them almost immediately. They are killed at 52 C. or 126 F. in ten minutes. It is said that the best way to disinfect sputum is by the addition of about one-third alcohol. The pneumococcus itself has a very low resistance to any of the ordinary disinfectants, being killed in a few minutes. Most of the lower animals, particularly mice and rabbits, but not birds, are susceptible to the pneumo- coccus. However, a true pneumonia as seen in man has not been produced artificially. The pneumococcus produces a small quantity of poison aside from itself, but acts chiefly by reason of substances within the germ cell. It has been found that there are four closely related varieties of pneumococci capable of causing pneumonia and that against two of them it is possible to produce in horses a powerful antiserum. In a given case of pneumonia the causative strain of cocci is isolated and studied ; if it belong to one of the two proper varieties the respective antiserum may be injected under the skin or into a vein. The death-rate of pneu- monia for these two kinds has been somewhat reduced by this treatment. The use of vaccines has not been followed by uniformly favorable results. The blood in pneumonia contains some agglutinins, but they are not of much value in diagnosis CHAPTER IX. THE ACUTE SELF-LIMITED INFECTIONS. IN this chapter are included the infectious diseases which are due to a specific microorganism and which tend to run a definite course. BACTERIUM DIPHTHERIA. Diphtheria is a disease caused by the Bacterium diphtheric?, or diphtheria bacillus, or Klebs-Loffler bacillus, characterized by the development of a so- called false membrane upon a mucous membrane or abraded surface, from which the soluble poisons are absorbed by the circulation. This false membrane is an inflammatory exudate thrown out by the body under the stimulus of the bacteria, as a means of protection against them. Myriads of bacteria are included in the meshes of this exudate. If the false membrane be removed a raw, bleeding surface is exposed. Some- times this is done for the purpose of applying remedial agents. The false membrane of diphtheria appears most commonly upon the throat and nose, but it may be found upon the eye, vagina, or skin wound. This is the disease par excellence for explaining the effect of toxins extracellular and separable from the bacteria. The organisms do not enter the body, but 108 THE ACUTE SELF-LIMITED INFECTIONS only their toxins are absorbed and are responsible for the clinical symptoms of the illness, such as mod- erate fever with rapid pulse and great prostration. They are also responsible for the paralyses which frequently follow an attack, such as heart weakness or laryngeal failure. Diphtheria is contracted by receiving, on a suscep- tible surface, some of the bacteria themselves. They usually come from an active case. However, after recovery from the attack, at a time when no symptoms exist, fully virulent bacteria may remain in the throat for many days. People with such a condition are called "carriers" and strict hygienic measures are being taken now by all health authorities to prevent spread of the disease by such means. Coughing or sneezing dislodges particles containing diphtheria bacilli, and spreads the disease. Infection has been known to travel by milk, where the dairyman had a case on his farm. The milk had become infected by those handling it. Nurses and doctors contract the disease frequently by their close association with the patient. They can protect themselves while inspect- ing a throat by placing a piece of glass before the patient's mouth so that if he cough the organisms will not get into the examiner's face. The absolute isolation of patient and nurse is now demanded by health authorities. All materials that can be so treated should be burned. Utensils and fabrics should be soaked in carbolic acid solution and then boiled. Great care must be used by the nurse with her hands, face, nose, throat, hair, and clothes. The lodgement of diph- BACTERIUM DIPHTHERIA 109 theria bacilli in the hair is of special danger, since they remain active for a long time. To prevent the settling of the bacilli in the hair it is advisable to wear a cap that will completely cover the head. Thorough wash- ing with soap and water, rinsing in hydrogen peroxide, 5 per cent., and drying in the sun are advisable when A. FIG. 32. Bacterium diphtherias: A, its morphology on glycerin- agar-agar; B, its morphology on Loffler's blood serum; C, its mor- phology on acid-blood serum mixture. (Abbott.) the nurse leaves the patient. The nurse should receive immunizing doses of antitoxin. Since the bacilli spread through the air, sheets wetted with disinfec- tants should be hung about, particularly at doors. For diagnosis of diphtheria use is made of direct examination of stained smears from the site of trouble, 110 THE ACUTE SELF-LIMITED INFECTIONS and cultures upon blood serum, the best culture medium. The bacilli are rather characteristic in their irregular shape. They are rods of unequal length and width, full of granules, which stain more deeply than the rest of the rod. Their ends are usually clubbed or the whole rod may have the shape of a wedge. They may be straight or bent. They vary from inrij o~ to Y oVo of an inch in length, and from ^Triuiy to YTFUIF f an inch in breadth. They are very apt to show peculiar, more or less characteristic forms of degeneration. A special stain called Loffler's alkaline methylene-blue solution is used to show the peculiarities of their structure. The diphtheria bacilli are non-motile, non-spore-bearing rods. They are not pronounced in their manifestations of life under artificial conditions, except for toxin production, but they grow readily on most laboratory culture media. Solidified blood serum is the preferred artificial foodstuff. Upon it they grow in such a manner as to render diagnosis easy, both by the naked-eye appearance and by their shapes under the microscope. These bacilli grow best at the body temperature, 37 C. or 98 F., but also at a lower point. They are killed at 58 C. or 140 F. for ten minutes. Boiling kills in one minute. In the dry state, protected from daylight, these organisms may live several months. With such protection, when moist or in exudate, as from the throat, life may persist for at least four months. Direct sunlight kills within half an hour. On cloth or other absorbing material their life is long, but indeterminate. On coins thev die in twelve to BACTERIUM DIPHTHERIA 111 thirty-six hours. On toys, lead- and slate-pencils and tumblers they may live several weeks. They do not live long in cultures unless frequently transferred to fresh food. They resist cold. These data concerning the viability of the Klebs-Loffler bacillus in the outer world help to explain the sudden and otherwise inex- plicable outbreaks of diphtheria, and the difficulties of their eradication. To disinfectants they present a slightly greater resistance than most non-spore- bearing bacilli. Carbolic acid, 1 to 100, kills in ten minutes; corrosive sublimate, 1 to 1000, in twenty minutes. Hydrogen peroxide kills them rather easily. These figures are for bacteria suspended in water. Diphtheria bacilli will kill most experimental animals, but the guinea-pig is the most susceptible. Here they characteristically produce a sloughing at the site of inoculation, a peritonitis, and a congestion of the adrenal gland. Sometimes organisms suggestive of diphtheria bacilli are found in the throat without a membrane. In order to prove if these be true diph- theria forms, some of a culture is injected under the skin of a guinea-pig. If the changes described are produced, and the animal dies in three days, it shows that the organism in question was a true virulent diphtheria bacillus. Diphtheria Antitoxin. The specific poison of the organisms and the means used to neutralize it must now be discussed. The poison of the diphtheria bacillus is not only made in the false membrane in the human case, but is elaborated by the organism in artificial media in a laboratory. This poison itself will kill the lower animals. The toxin is obtained by growing the 112 THE ACUTE SELF-LIMITED INFECTIONS germs on broth, made in a manner found most suitable for its development. The broth is freed of bacterial bodies and injected into horses. This animal is chosen for its size and freedom from disease affecting humans, and because large quantities of material may be injected and much blood withdrawn without harm- ing the beast. The horses receive under the skin gradually increasing amounts of this toxic broth until they are able to withstand huge quantities, many times the dose necessary to kill them if given at first. They are then considered to have some neutralizing substances for this toxin. This neutralizing property is known to be in the blood serum. The horse is then bled, and the serum separated from the red blood cells. It is tested against the original toxin used for making the injections. This is done by mixing the two in definite parts, allowing the mixture to stand a few minutes, and injecting it into guinea-pigs. By appropriate technic the number of " units" is deter- mined. A "unit" is that quantity of horse serum, or antitoxin, which will neutralize 100 times the smallest quantity of toxin necessary to kill a guinea-pig weigh- ing 250 grams (8 ounces). The horse-serum antitoxin has now a value for clinical purposes, as the quantity to be given can be controlled. Newer methods have permitted the refinement and concentration of this antitoxin, so that there is now less inconvenience in giving it. The dose for treatment varies from 1500 to 5000 units by injection under the skin. In bulk this may be less than a teaspoonful. For immunizing purposes, that is, to protect persons exposed but not yet suffering from the disease, from BACILLUS TETANI 113 300 to 1000 units are used. In both cases a repetition of the dose is frequently demanded, and in case the exudate does not fade, the injections may have to be given several times. The effect is a passive acquired immunity, as it is the addition of a toxin-neutralizing substance to aid tissues, for which they themselves have not worked. The visible effects of antitoxin administrations are a rather rapid disappearance of the false membrane, a fall of temperature, and a lessening of constitutional prostration. For the best results in the treatment of diphtheria, antitoxin should be used early. Each hour of delay in using it after the diagnosis has been made reduces the good chances of the patient. For large cities the decrease in mortality has been 50 per cent., and in the favorable cases, even 75 per cent. Pseudodiphtheria Bacilli. There is a group of organ- isms called pseudodiphtheria bacilli, because of their resemblance in morphology and growth to the true disease-producing type. They are sometimes found in jaw abscesses or otitis media. They do not produce the typical diphtheritic sore throat. The presence of such forms in the throat often leads to erroneous diagnoses, and lengthens quarantine. Quarantine is demanded by health authorities until the throat is shown to be clear of diphtheria bacilli. BACILLUS TETANI. Tetanus or lockjaw is a disease characterized by tonic and clonic spasms of the muscles due to the effect of the soluble poisons of the Bacillus tetani or tetanus 114 THE ACUTE SELF-LIMITED INFECTIONS bacillus upon the central nervous system. This poison, like that of the diphtheria germ, is separable or extracellular. It is produced by the bacteria, absorbed along the motor nerves, and carried to the brain and cord. Tetanus bacilli enter the body almost invariably by punctured or lacerated wounds. They multiply in the deep, covered position afforded by such wounds, but are not themselves taken up by the blood to be distributed throughout the body, only their poisons being absorbed. The bacteria are common in soil, manure, dust from covered places, wood, and the like. Their vitality is considerable, due to the forma- tion of resistant spores. Wounds carry the germs beneath the skin, where they lie covered and hidden in the deeper tissues. They do not grow in the presence of oxygen (anaerobic), so that a secluded place in the depths of wounds favors their development and that of their toxin. Simple uncomplicated, open wounds are probably never the site of development for tetanus bacilli. If other germs are introduced the tissues are further devitalized by them, and they absorb any available free oxygen, so that favorable conditions for tetanus are increased. Either spores or vegetating germs may be introduced on rusty nails, splinters of wood or glass, blank-cartridge plugs, or the grinding of dirt into wounds. Tetanus some- times appears in the newborn or in the puerperal mother, particularly after instrumental delivery. Ordi- nary gelatin, sometimes injected under the skin to arrest hemorrhage, is said to often contain spores. Between the time of introduction of the germs and the outbreak of symptoms a period of incubation BACILLUS TETANI 115 elapses which may be as short as three days or as long as six weeks. The muscles nearest the wound are affected first, as a rule, but the characteristic symptoms of lockjaw soon appear. After death very little is to be found by postmortem. The danger from patients with tetanus is quite inconsiderable, the only infective material being the discharges from the wound or the pieces cut away surgically. Such objects are used for injection into animals to establish a diagnosis. This, however, is seldom necessary, as tetanus is quite clear in its symp- tomatology. All dressings and pieces removed sur- gically must be burned with actual fire. Boiling and baking are unreliable. The first treatment usually undertaken is the surgical cutting away of skin and subcutaneous tissue far beyond the original wound, in order to remove all bacilli. If these are removed no more toxin can be made. The tetanus bacillus is large, T2~io~7J to 7^oVo mcn long by Troloir to 3"o o HIT inch wide; it is a motile, spore- bearing bacillus, growing only when the atmospheric oxygen is shut out. The motility is due to flagella arranged all about the cell wall. The spores develop at one end and give the rod a drumstick appearance. They are best seen in old cultures. The spores may leave the parent bacillus and lead an independent existence. In this state they are not motile, and are stained with great difficulty. The vegetative rod, however, stains with comparative ease. The organism can digest gelatin and grows characteristically in it. In discussing the resistance of this germ to deleterious agents, the spores only need be considered, because 116 THE ACUTE SELF-LIMITED INFECTIONS the vegetative rod has the power of going into this resistant stage very quickly when it meets unfavorable environment. The rods grow best at 37 C. or 98 F. The spores are killed at 105 C., 221 F., when exposed ten minutes to streaming steam. They are destroyed by chemicals as follows: 5 per cent, carbolic acid in ten hours; 5 per cent, carbolic acid plus 0.5 per cent, hydrochloric acid in two hours; 1 to 1000 corrosive sublimate in three hours; 1 to 1000 corrosive sublimate - FIG. 33. Tetanus bacilli with spores in distended ends. X 1100 diameters. (Park.) plus 0.5 per cent, hydrochloric acid in one-half hour; 1 per cent, silver nitrate in five minutes. When dried the tetanus spores will live several years. Sunlight very slowly kills them. Most animals are susceptible to the tetanus bacillus or its toxins. Rats and birds are the least, while horses and man are the most sensitive. Tetanus Antitoxin. The toxin of the tetanus bacillus is one of the most virulent poisons known. For ex- ample, TOO oV UTO cubic centimeter or ^5\T oil minim BACILLUS TETANI 117 has been known to kill a mouse. It is composed of two parts, one the major, with a primary irri- tating and secondary paralyzing effect on the cen- tral nervous system, and a minor part having a solvent action upon the red blood cells. These poisons develop both in wounds and on laboratory culture media. The methods for procuring this poison are essentially those described under Diphtheria, and similar methods are used to immunize horses against it. The antitoxin is in the immunized horse's serum, and is refined and used in the same general manner as diphtheria antitoxin. The unit in this case is the quan- tity of antitoxin necessary to neutralize 1000 times the smallest dose of toxin required to kill a guinea-pig weighing 350 grams, llf ounces. The conditions of administering antitoxin for tetanus are somewhat dif- ferent from those in diphtheria. In the latter the posion is largely circulating in the blood, while in tetanus some of it is at the point of infection, some in the muscles and nerves and central nervous system, and the least part is in the blood. To reach all of these places it is necessary to make injections into the vein and under the skin as well. The surgeon attempts to reach those parts first which have been affected the longest, to halt at once any further damage there, and therefore methods of treatment vary. Antitoxin is sometimes injected directly into the nerves in order that some may neu- tralize what toxin is remaining in them along their length or in their muscle distribution. In severe, rapidly developing cases it may be injected into the meningeal space or directly into the brain tissue. It is best to give 10,000 units by the vein and repeat 118 THE ACUTE SELF-LIMITED INFECTIONS at several-hour intervals until symptoms start to abate. The sooner after the symptoms appear that antitoxin is given the more favorable is the outlook. Antitoxin is now given freely by health authorities, to all who receive firearm wounds about July 4. BACILLUS TYPHOSUS. Typhoid fever or enteric fever is an acute infectious disease caused by the Bacillus typhosus or typhoid bacillus circulating in the blood and settling in the various organs, particularly the lymphatic structures of the small intestines. The bacteria enter the body via the mouth and are able to pass the stomach into the small intestines. Here they are taken up by the lymphatic organs, which immediately begin to swell. This reaction brings more blood to the part and the circulation soon contains the germs. The incubation period is that time elapsing between the introduction of the typhoid bacillus into the alimentary canal and the first positive signs that it has been taken up and disseminated by the blood stream. Then there are gradually increasing fever, malaise, a relatively slow pulse, distention of the abdomen, diarrhea or constipation, rose spots, and other signs of the true infection. The incubation is about two weeks. The bacteria, while not true pus- formers, do cause a breaking down of tissue. This is characteristically seen in the lymphatics of the small intestine called Fever's plaques. These bodies swell toward the free lumen of the canal, and the centre finally softens from the effect of the bacilli. When BACILLUS TYPIIOSUS 119 the softened part separates and is removed, a ragged, punched-out ulceration remains. This ulceration may be progressive and eat into bloodvessels, causing intestinal hemorrhage so common in this disease. If the ulceration be directed out toward the peritoneal surface of the intestine, perforation and peritonitis may ensue. The presence of the typhoid bacilli and their toxins in the organs, notably the spleen, causes characteristic changes which need not be dwelt upon here. Typhoid fever is more common in men between the ages of twenty and thirty-five years. Spring and autumn are the seasons of greatest prevalence. It spreads from patient to patient usually through the intervention of food and drink and accidental or chronic carriers. Water and food polluted by flies that have soiled their bodies upon excreta, form the greatest sources of indirect propagation. Water is polluted by the dumping of sewage containing typhoid germs into a water course used as a drinking supply. Typhoid bacilli can live within a particle of feces over the winter, so that the infection of a water course in the spring is not to be wondered at. When winter breaks up the spring rains wash down the hillsides, sweeping before them surface collections into streams. The greatest danger, however, exists when towns empty their sewerage systems into a stream from which other communities lower down take their domestic supply. This means of spread is proven by the fact that when known infected sewage is no longer dumped into a w r ater supply typhoid fever ceases to be prevalent among the users of the water. Ice is said to be another 120 THE ACUTE SELF-LIMITED INFECTIONS method of transmitting this disease. It is best not to inculpate the ice itself, since freezing kills whatever germs are not squeezed out in the contraction of the water when becoming solid, but rather blame the dirty methods of cutting, storing, and distributing. Ice not infrequently becomes covered with manure and earth in storing and lading for distribution. The unwashed hands of the ice-man are only too familiar. When ice is placed in the water cooler in public places it is frequently washed under a spigot and then picked up in the hands of the distributor. Typhoid bacilli do not multiply to any considerable extent in water, but merely remain viable. Milk is a prolific source of spread, since it is easy for the dairyman with a case of typhoid on his farm to infect this product. Fresh milk has a mild restraining effect upon typhoid germ growth, but does not kill many. The bacilli do not come from the cow, but are intro- duced somewhere in the route from her to the con- sumer. Vegetables grown in ground upon which infected manure or water has been spread may carry the disease; such as, for instance, water-cress, lettuce, tomatoes, or others that are eaten raw. Oysters fattened in water contaminated by sewage are said to transmit the disease. House-flies may settle upon human excreta in out- houses or toilets or in sick-rooms, and by walking on articles intended for food, leave behind some of the germs. The personal contact of nurse, physician, or a member of the family must never be underestimated as a means of direct transmission. Indeed, it is looked upon by BACILLUS TYPHOSUS 121 some authorities as the most important and fruitful method. Upon bed-pans, glasses, eating utensils, bed linen, or clothes there may be a few bacilli lurking, which can easily be conveyed to the mouth by persons handling these objects. The typhoid bacilli may lurk in the body, probably in the bile passages, for a long time after the attack. For this reason disinfection of stools and urine should be continued for at least two months after the patient is well. Such people as may spread the disease by this means are called "carriers." There are also cases on record in which persons who never suffered with typhoid fever have excreted the bacilli in their stools. It is probable that these persons have had sufficient resistance to overcome intestinal disease, but the germs have infested the bile passages and passed down them to be mixed with the excreta. Two such cases are known to the writer, one of which had a history of having nursed her husband in a fatal attack of typhoid, but whose personal history is free of any illness suggesting this disease. Measures for preventing infection should be directed toward killing all the typhoid bacilli, not such a diffi- cult task. Infective material consists of feces, urine, expectoration, and possibly perspiration. Any of these may infect bed or body linen, and the last can spread the bacilli on dishes or hands. All discharges should be received in carbolic acid solutions, well mixed and allowed to stand half an hour before emptying into a drain. Clothing of all kinds should be soaked in car- bolic or corrosive sublimate solution for an hour, and then boiled. The same procedure should be followed 122 THE ACUTE SELF-LIMITED INFECTIONS with glasses and eating utensils. The mouth should be washed or wiped with boric acid solution frequently. A dish of bichloride, 1 to 2000, should be convenient, so that the nurse or visitor may cleanse the hands frequently. The typhoid bacillus is an organism exerting its noxious power by means of poisons contained in its body and liberated upon its disintegration. These FIG. 34.- Microscopic field, showing the top of a hanging drop in a normal typhoid culture. (Park.) endocellular poisons are capable of calling forth a reaction upon the part of the body which results in some antibody formation. Second attacks of typhoid are rare and the reason is probably that a sort of active immunity is gained by one attack. As a matter of fact, it can be shown by laboratory methods that blood after typhoid fever has more power to destroy the bacilli than before the attack; that is, it has BACILLUS TYPHOSUS 123 more bacteriolysin than is possessed by the blood of a person who has never suffered from typhoid. Widal Test. Far more important antibodies are the aggliitinins used extensively in the diagnosis of the disease. These are bodies in the blood which when brought into contact with the bacilli, make them stop moving and clump together. To use this for diagnostic purposes a fluid culture or salt solution sus- FIG. 35. Microscopic field, showing the top of a drop with the typhoid reaction. (Park.) pension of the living, actively motile germ is prepared. Some blood from the patient is obtained, the clear serum collected and mixed with the bacterial suspen- sion in dilution of 1 part of the serum to 20, 50, 100 or more parts of the bacterial suspension. These dilutions are used because sera from some persons entirely free from typhoid will clump the bacilli in low dilution, 1 to 5 or 1 to 10. The mixture of serum and bacteria is 124 THE ACUTE SELF-LIMITED INFECTIONS observed under the microscope after they have stood together for a definite time, and the presence of clump- ing, with loss of movement, noted. In case this occurs typhoid is present. This agglutination reaction is called the Widal test, and is positive in about 95 per cent, of all cases (see Figs. 33 and 34.) Cultures. It is also of aid in the diagnosis of typhoid to make a blood culture. This consists in withdrawal, under sterile conditions, of blood from a vein, placing Fi(r. 36. Typhoid bacilli from nutrient gelatin. X 1100 diameters. (Park.) it into suitable culture medium, and keeping it at body heat in the incubator. If typhoid bacilli be present they will grow so that we may isolate and identify them. The bacilli may be isolated also from the feces and urine during an attack, and as mentioned above, for a long time afterward in the case of carriers. The methods for isolation are tedious and difficult, and need not be described here. Many technics have been devised to hasten work on epidemics and carriers, but none is as yet very good. BACILLUS TYPHOSUS 125 Morphology. The typhoid bacillus is a motile rod Y5 W IT to -g oV r *mfiK$ r*^ 1 " '' *^ ir '*** jl ^cV-' I ^ %4. FIG. GO. Protozoa in a case of tropical ulcer. X 1500 approxi- mately. (After Wright.) ing upon its locality dumdum fever, kala-azar, etc. exhibiting a large spleen, hemorrhages, anemia, and fever. The causative microorganism may be found 218 DISEASES DUE TO PROTOZOA almost anywhere in the body, but chiefly in the. spleen, whence it may be obtained by puncture with a needle. It is said that bed-bugs and mosquitoes transmit the disease. The protozoon responsible, Leish- mania Donovani, is an ovoid or circular or comma- like mass with two nuclei, and one moderately long FIG. 61. Trypanosoma gambiense. (From Calkins. Preparation by F. W. Balstack.) flagellum on the forward end. They are from 12 ooo to g-oVo mc h l n an ^ about two-thirds as wide. See Fig. 60. Trypanosomiasis. The next flagellate to cause dis- ease is the Trypanosoma, two species of which are pathogenic for man, causing a disease called trypano- somiasis, or sleeping sickness. This aft'ection is com- TRYPANOSOMIASIS 219 monest in Africa, because of the prevalence of the tsetse fly in whose body the protozoa are transmitted. The bite of these flies becomes infective for the well three days after biting the affected, and continues so for about four or five weeks. These pests bite during the daytime, so that protection and screening of houses is insufficient usually to guard against dis- ease. Of course the infected persons as well as the healthy must be protected from insects. Inasmuch as it is thought that some species of trypanosomas in the blood of the lower animals are infective for man, strict quarantine is placed on animals within countries where this disease exists, and upon exported specimens. When the protozoa come into the blood they are carried throughout the body and lodge chiefly in the lymph glands, an enlargement of which is an early sign of infection. When the disease is well settled we see progressive anemia, weakness, and sleepiness, whence comes the name u sleeping sickness." The end comes from profound anemia and prostration. Pains and dropsical collections are common. The disease lasts a varying time. The early stages are slow, but w T hen the great depression begins it usually progresses rapidly to a fatal end. The changes pro- duced are those of obstruction to the lymphatic system and low-grade chronic inflammations. The micro- organisms are_ present in the blood, all organs, including the lymph glands, and the cerebrospinal fluid. From all these places they may be recovered in making a diagnosis. Trypanosomas are irregular, elongated, twisted bodies with a large nucleus variously placed, and a 220 DISEASES DUE TO PROTOZOA thickened ribbon-like edge, the undulating membrane, which starts as a minute secondary nucleus at the hind extremity and ends in a rather long whip-like flagellum at the fore end. They range from ^T O inch to -3-5-5- inch in length and they are about ^o o mc ^ wide. They move by a sinuous, jerking, boring action. Division takes place by longitudinal splitting, probably beginning at the hind end and proceeding along the undulating membrane. The true nucleus shows its division late. The human trypanosoma has resisted artificial cultivation until very recently, and at the present time it is very difficult to cause development in the laboratory. Other forms of these protozoa have been grown with comparative ease. Most animals may be the hosts of trypanosoma; in some there will be disease, in others the organisms live as harmless commensals. The modern treatment consists in using an arsenic preparation called atoxyl. Numerous attempts have been made to produce a serum by injecting animals with trypanosoma. Sera thus obtained have a slight beneficial effect upon the lower animals, but have not proven of great value with human beings. The injection of attenuated cultures has raised the resistance of certain lower animals. The fact that some resistance can be attained by attempts toward the production of active and passive immunity indicates that trypanosoma exert their action by some poison. Whether it be in their bodies or elaborated in the juices about them is not known. Trichomonas. Two protozoa of a slight medical importance are the Trichomonas vaginalis, with its nearly related varieties, T. intestinalis and T. pulmo- MALARIA 221 nalis, and the Lajnblia intestinalis. These forms may infest the vagina, intestine, or lung, and cause some irritation, probably not particularly inflammatory. They are held responsible oftentimes for the inflamma- tion set up by bacteria gaining entrance at the site of the irritation by the protozoa. However, the vaginitis and cystitis caused by the T. vaginalis are serious matters in children. These are usually pear- FIG. 62. Trichomonas vaginalis. FIG. 03. Lamblia intfestinalis. (Blochmann.) (Schewiakoff.) shaped bodies, with prominent nucleus and well- marked anterior flagella. The trichomonas has a heavy undulating membrane. SPOROZOA. Malaria. The most important disease caused by protozoa is malaria. This is an infectious disease characterized by intermittent chills, fever, and sweats, with prostration and progressive anemia. It is com- mon in lowlands, where stagnant water collects, or in the vicinity of slowly moving water, permitting the 999 DISEASES DUE TO PROTOZOA propagation of mosquitoes. It is not communicable by contact of man to man. It is the infestation of the red blood cells by a parasite having three forms, belonging to the order Hemosporidia. The parasites are called the Plasmodium vivax, the P. malarioe, and the P. falciparum. Three types of attack corre- spond to the three protozoal species: (1) That which gives chills and fever every third day, the tertian malaria; (2) one where the paroxysm appears every FIG. 64. Some of the principal forms assumed by the plasmo- dium of tertian fever in the course of its cycle of development. (After Thayer and Hewetson.) fourth day, the quartan type; and (3) a continuous, typhoid-like type, the malignant or estivo-autumnal fever. The species vary in finer morphological details, but they follow the same course in their transmission and development in regard to infectivity, except that they require differing times for their full development. The female mosquitoes of the genus Anopheles carry the disease from one person to another. They fly and bite in the early evening. These mosquitoes may be MALARIA 223 recognized by their position on a surface. Their body forms a large angle with the surface, and the head is on a line with the body. The ordinary mosquito, Culex, stands parallel with the surface w r ith the head FIG. 65. Egg of Culex (a) laid together in "small boat;" those of Anopheles (6) separate and rounded. (From Kolle and Hetseh.) bent down. Furthermore, the wings of the Anopheles are furred on the flat surface, w r hile the Culex wings are only fitted with widely set, fine hairs on the edges. There are many other differences, but these will suffice as general guides. The female mosquito bites a b FIG. 66. Larva of Culex (a) hangs nearly at right angles to water surface; those of Anopheles (6) are parallel to the surface. (From Kolle and Hetsch.) a malarial person and receives the parasites into her stomach. Here they undergo reproduction by a sexual process, and appear in her salivary gland in a condi- tion ready for transmission to the next person bitten. 224 DISEASES DUE TO PROTOZOA This gland is connected with the biting apparatus, and some of its secretion is left under the skin when the mosquito bites and sucks blood. It is probably the secretion from this gland which causes the itching of the ordinary mosquito bite. This reproduction in the mosquito requires seven to ten days. When a FIG. 07. Body of Culex (a) when resting is held parallel to wall in a curved position, that of Anopheles (b) at an angle of about 45 degrees and is straight; wings of Culex (c) are generally not spotted; those of Anopheles (d) are spotted. (From Kolle and Hetsch.) person is bitten the parasites, left under the skin, penetrate their cell of choice, the red blood corpuscle. In the body of this cell they have the power of under- going an asexual division (see Fig. 64). The minute form swells into a large body and breaks up into small spores. When this mass of young forms hasjreached a size too great for the red cell the latter bursts, syn- MALARIA 225 chronously with which we have the chill. By this bursting young forms are again set free in the blood, each capable of entering other red blood cells. Of course, not all the cells are affected, but in severe cases one of every thirty red blood cells may contain the parasites, but as the disease progresses and successive FIG. 68. In Culex the palpse (a) of the female are very short, of the male arc longer than the proboscis; in Anopheles the palpaj (6) of both sexes are about equal in length with the proboscis. (From Kolle and Hetsch.) crops of corpuscles are destroyed the sum total of the damage may be great. As a result of this, severe grades of anemia result. The cycle of development from the young form to the bursting requires forty- eight hours for the tertian malaria and seventy-two hours for quartan malaria, while in estivo-autumnal malaria there is a slowly progressive attack on suc- 15 226 DISEASES DUE TO PROTOZOA cessive cells by a curious extracellular and intracellular crescent-shaped body. The anatomy of these plasmodia is of great intricacy, and undergoes so many changes that it is hardly desirable to go into detail here. Suffice it to say that it is a body when adult somewhat larger than a red blood cell, full of actively moving granules. The young forms are homogeneous, and are found with the greatest difficulty except when specially stained. They probably get all their granules from the destruc- tion of the red blood cells. Some adult forms have flagella about their wall. The power of producing disease lies partly in their destruction of the important cells of the blood and partly in a poison they produce. The internal organs, especially the spleen, are injured first by the damage to the blood, and secondarily by the extra work thrown on them in trying to destroy the parasites and to remove the pigment which is liberated by the cellular disintegration. A slight immunity remains after an attack. There is a relative racial immunity among the negroes. The cases that do not wholly recover or that have remote recurrences are said to be harboring quiescent parasites in the spleen. A chronic inflammation of this organ often results. Diagnosis. The disease is diagnosticated by making fresh or dried and stained preparations of the blood and examining them under the microscope. Should malaria organisms be present, faint, irregular shadows or larger bodies filled with dancing granules are seen in the unstained blood, while in stained smears fairly well- colored parasites containing quiet granules will be MALARIA 227 found. Animals are not susceptible to human malaria. Monkeys may be artificially infected. No antiserum or vaccine treatment is possible now. Quinine is a specific, and if properly used will cure all cases. The spread of malaria is checked by preventing the propa- gation of mosquitoes. These insects lay their eggs on the surface of quiet water. The young remain at the surface of the water when they require air. Oil is spread upon the surface of the water and all marshes are drained. No increase of the insects can go on if these two things are done. CHAPTER XV. DISEASES OF UNKNOWN ETIOLOGY. WHILE this book concerns itself with the relation of microorganisms to disease, it is fitting that men- tion be made of some communicable affections, in which the causative agent is not yet known. The clinical observations upon these infections indicate that they are due to some form of living body which present methods of investigation do not permit us to demonstrate. It is inconceivable that so specific a condition as smallpox should come from anything but a self-reproducing agent. Nevertheless the viruses of these diseases must be, at least in some part of their existence, very tiny, because they are able to pass through the pores of a porcelain filter that would hold back bacteria. For this reason the following diseases are said to be due to "filterable viruses." We may later learn to know the agents as physical entities, but those which can be cultivated now are only imperfectly understood. Smallpox or Variola. This is an acute infectious dis- ease characterized by severe constitutional symptoms and a rash which becomes pustular, leaving behind it after recovery peculiar depressed scars. It is believed today that the various affections of man, cow, horse, and sheep are practically identical. Certain it is that RABIES OR HYDROPHOBIA 229 infection with cow-pox will give resistance to human smallpox. Vaccination was formerly practised by transferring the pox from person to person, but now fresh material is used from a cow which has been artificially infected with smallpox. By passing this- virus through the calf it is so altered that it cannot produce smallpox in man yet it can, when inoculated into the skin, call forth an immunity against subsequent infection with that disease. Jenner, in 1798, was the one who first developed the principle of using cow-pox in the protection against human variola. The exact cause of smallpox is not known. It is supposed to spread by contact either directly with the sick or indirectly by objects having been in contact with them. Such objects are called fomites. Bacteria are present in the pustules caused by vaccination and in the eruption of smallpox, but they have been proven to be secondary invaders. Rabies or Hydrophobia. This is an acute infectious disease to which nearly all animals are susceptible, characterized by slowly progressive palsies and deli- rium. Hydrophobia means fear of water. Such an emotion does not exist, but animals merely avoid water because they cannot swallow it. The cause of rabies is excreted in the saliva and may be transmitted by the bite of a rabid animal, or by getting the saliva into an open wound. The virus is innocuous if swallowed. After having entered the body the virus travels to the central nervous system and remains there throughout the whole attack. The spinal cord particularly is involved. The only evidence there is of the actual causative germ is the presence of minute 230 DISEASES OF UNKNOWN ETIOLOGY stainable granules in the nerve cells of the brain. These so-called "Negri bodies'.' are demonstrated by special staining methods. When a dog is suspected he is killed and his brain removed. Bits of it are stained for microscopic examination and other pieces are made into an emulsion, which is injected into the brain of a rabbit. If rabies virus be present this sus- ceptible animal will die within three weeks as a rule. Recently attempts at the cultivation of the rabies virus have been rewarded by the development, under anaerobic conditions, of minute globoid bodies with a tiny nucleus and with such cultures animals have been infected. Pasteur found a method for protective inoculation treatment against rabies. He found that if the spinal cord of a rabbit suffering from rabies were removed and dried in a vacuum it lost its virulence for other rabbits. If he dried it two weeks nearly all of the virulence was lost, but if only two days, its strength was only slightly impaired. He found that if he inoculated animals with gradually increasing strengths or quantities of emulsions made from these dried rabbits' spinal cords, a certain degree of immunity was obtained. This principle is now used in treating persons bitten by rabid animals. The treatment is possible after the bite and the outlook is better the sooner after infection the treatment is begun. The spinal cords of rabbits are ground up in glycerin and injections are made under the skin. The patient first receives a dose from a cord dried fourteen days, then from one dried twelve or thirteen days, then ten or eleven days, and so on until one dried two days is used. The mortality RABIES OR HYDROPHOBIA 231 from rabies has been greatly reduced by this method of active immunization. At present there is no very accurate laboratory diagnostic test in rabies. The development of the symptoms must be awaited to make the diagnosis in people bitten by rabid animals. The ordinary disinfecting dressings of bichloride of mercury and carbolic acid solutions are worthless for the bites of rabid animals. It is necessary to use the actual cautery or fuming nitric acid in order to certainly remove rabies virus from a wound. Yellow Fever. This is an acute infectious disease chiefly of tropical countries, characterized by great prostration, severe pains, hemorrhages, and jaundice. The cause is not known. The disease is transmitted by the mosquito called Stcgomyia calopus, which takes some of the infective blood from a patient and trans- mits it to another person. The virus is in the patient's blood in a condition in which the mosquito can take it during only the first three days of fever. Some cycle of development of the virus takes place in the mosquito because the insect is only capable of depositing it in a bite when twelve days shall have elapsed since it bit a yellow-fever patient. More than that, five days elapses between the bite of the mosquito and the ap- pearance of the virus in the patient's blood. Because of these facts the modern conception of yellow fever supposes a protozoon as the cause. There are no laboratory diagnostic measures nor as yet any specific treatment. The spread of yellow fever is prevented by destroying the breeding places of the mosquito, a difficult thing, since this insect breeds in lowlands and bushes and in houses. It bites usually in the late afternoon. 232 DISEASES OF UNKNOWN ETIOLOGY Typhus Fever. Although this condition is not under- stood clearly, it now seems that body lice, flies, and ticks transmit it. It is a filterable virus also and can be transmitted to monkeys. A bacterium has lately been found, however, which in certain ways seems to have something to do with the disease. Typhus fever exists in America in a mild form known as Brill's disease. Scarlet Fever. This is variously ascribed to protozoa and to streptococci; neither claim is well supported. The virus is in the blood and can be transmitted to monkeys at the height of the attack; in these animals a fever occurs, but no disease typical of scarlatina. The virus may be also in the peeling skin. Measles. As in the former disease various micro- organisms have been held responsible but no certain one can be convicted. The virus in the blood of patients, in their nasal and buccal secretions, and when any of these are transferred to a monkey a fever quite like that of the human disease will develop. The viruses of both diseases are filterable. Poliomyelitis. This is an acute apparently infectious disease characterized by a mild constitutional illness followed by gradually appearing and progressing paralyses. It may be sporadic or appear in epidemics. The infective agent and its mode of transmission are not known. It probably enters by the nose and throat. The virus is present in the blood, lymph glands, and especially in the central nervous system. It is so small that it will pass through porcelain filters such as are used for water purification. The disease may be reproduced in monkeys by injecting this virus ACUTE ARTICULAR RHEUMATISM 233 by almost any route, and it is strictly comparable to that seen in human beings. It is not known how the virus leaves the body, but as the nose and throat seem the most likely places, they should be disinfected in both frank and mild ambulant cases and in atten- dants by the use of hydrogen peroxide solution. There is as yet no reliable specific treatment. The only laboratory test consists in finding in the cerebrospinal fluid an excess of a certain organic substance called globulin and a very small number of cells. Mumps. This is an acute inflammatory infectious disease of the salivary glands, the cause of which is not known. It is disseminated by direct contact, and the virus is in the saliva. Other Diseases. Other diseases which human beings may contract due to invisible viruses, are foot-and- mouth disease of cattle, dengue, trachoma, beri-beri, and pellagra. Nearly all of these viruses are small enough to go through a porcelain filter. It may be said in general that to protect one's self from the infec- tion the local lesions and skin eruptions should be disinfected. Acute Articular Rheumatism. The modern concep- tion of this disease is that it is an acute infection. Many bacteria have been described as its cause, but their defenders have not built up unanswerable argu- ments in their support. The theory now holding the stage is that a streptococcus called Streptococcus rheumaticm enters by the tonsils, penetrates to the blood stream, and settles in the joints. Certain it is that we frequently have streptococcus sore throat associated with acute rheumatism, and that the 234 DISEASES OF UNKNOWN ETIOLOGY inflammations of the heart lining after this disease are frequently streptococcal. Impetigo Contagiosa. This is an acute pustular eruption of the skin, thought, but not proven, to be due to the pus cocci. Some observers maintain that a protozoon is the cause. At all events pus cocci, both streptococci and staphylococci, are present. The lesions are at first pustules, but soon break down to flat ulcers. They occur chiefly upon the face. The disease is transmitted by direct intimate contact, such as kissing. Mild antiseptics are sufficient: 1 to 1000 carbolic acid or 1 to 3000 corrosive sublimate. A salve of mercury is usually prescribed. Its importance is greatest in surgical and children's wards and clinics and in schools. Noma or Cancrum Oris. This is a perforating ulcera- tion, usually of the cheek, on weak and debilitated children. It is said to be due to a host of different organisms, cocci, pseudodiphtheria bacilli, and many others. The one most frequently found is an anaerobic germ of double appearance, as a rod and as a spiro- chete. The treatment is of a radical surgical charac- ter, as ordinary external applications are unavailing. It is not very contagious, but discharges and sloughs are best burned. GLOSSARY. THE meaning of many words occurring several times in the text is given here that the reader may the more intelligently follow the subject matter. Certain unusual terms used seldom and sufficiently explained under special headings are not repeated here. Nearly all words in scientific language are derived from Latin or Greek roots and are to be pronounced precisely as printed. Aerobic Preferring or demanding atmospheric oxygen for life. Agglutinins Substances in the serum capable of clumping bacteria. Related words: to agglutinate, agglutination. Anaerobic Preferring or demanding the absence of atmospheric oxygen for life. Anaphylaxis A condition of high sensitivity due to idio- syncrasy to or previous injection with certain organic substances but otherwise unexplained as yet. Symptom: shortness of breath, skin irritations, and sometimes death. Antibodies Substances developed in the blood serum which neutralize the toxins of bacteria, but this word is usually used with reference to intracellular toxins. Antitoxins Antibodies developed in the blood serum which neutralize extracellular toxins of bacteria. Asexual Applied to forms that can multiply without being divided into two separate and recognizable sexual elements. Attenuate To reduce in virulence. 236 GLOSSARY Bacillus (pi., Bacilli) The genus of motile rods in the vegetable kingdom. Bacteriacese The family of rod-shaped bacteria. Bactericide A substance used to kill bacteria; also called a " germicide." Related word: bactericidal. Bacterins The dead bodies of bacteria used to treat disease by injection under the skin; also called "vaccines." Bacteriology The study of bacteria. Adj., bacterio- logical. Bacteriolysin An antibody that will dissolve bacteria. Related words: bacteriolysis, bacteriolytic. Bacterium (pi., Bacteria) From Greek word meaning little stick; the genus of non-motile rods. The words are also used to mean any of these lowest plants. Carrier A term applied to a person who carries germs capable of being transmitted to and infecting others, but himself not necessarily suffering at the time from the disease caused by the germ. Cell The smallest recognizable unit in biology. Cells are single and independent in bacteria and protozoa, but are combined and dependent upon one another in the higher plants and animals. Coccacese The family of the spherical vegetable organ- isms. . - Coccus (pi., Cocci) A spherical organism. Colony The individual group growing upon laboratory foodstuffs, and usually referring to one small group. The word is used for the growths upon flat dishes that are sup- posed to arise from a single organism. Commensal Living in harmless union either indepen- dently or for mutual benefit. Complement A constituent of all sera which helps in the union of antibodies and bacteria. Cultivation A word used to embrace all the procedures employed to make germs grow under the laboratory con- ditions. GLOSSARY 237 Culture The mass of bacteria grown artificially upon laboratory foodstuffs. The general term applied to the way bacteria grow. See Colony. Adj., cultural. Cytoplasm The soft part of a cell between the wall and the nucleus; also called protoplasm. Dejecta The feces and urine; also used to mean sputum, sweat, and morbid discharges. Disinfection The destruction of infective material. See p. 53 for various degrees. Encystment The grouping together within a resistant membrane of forms or stages in the life cycle of organisms, or a resting stage when conditions for life are unfavorable. Enzyme The products of life of organisms by which they digest their foodstuffs. A substance capable of splitting others into simpler ones without itself undergoing any change or entering into the new product. Also called ferment. Related words: enzymic, enzymatic. Etiology Study of the cause of a disease and its trans- mission; also the cause itself. Ferment (pronounced fer-ment) See Enzyme. Fermentation The breaking of sugars and starches (carbohydrates) by bacterial ferments, with the production of carbon dioxide, alcohols, and sometimes acids. Related words: to ferment, fermentative. Genus Next to the lowest division of biological classi- fication, including members of the lowest division, species, among which there are only slight differences. Members of a genus must be alike in all important characters. See Species. Germination The progressive multiplication of the active adult forms. Growth A word used to cover the appearance of a culture on laboratory media, and sometimes used interchangeably with culture. Host The body which carries a parasite. 238 GLOSSARY Immunity The resistance of the body to illness. See p. 71 for kinds. Related words: to immunize, immunization, immune. Infective Any material carrying disease viruses. Inhibit Restrain, limit. Inject To put anything within the body; in this book it usually means to put beneath the skin. Inoculate To put some infective material within the body; usually used in experimental work upon lower animals. Inorganic Of the mineral world and not necessarily associated with living matter; example, salt. See Organic. Isolate Used to indicate the procuring of germs from morbid fluids or to the obtaining of a single kind, a pure culture, usually by finding one type of colony. Related word : isolation. Lesion Used to indicate any physical change from normal. Leukocytes The colorless, so-called white cells of the blood. Medium (pi., Media) General name given to foodstuffs upon which bacteria are grown artificially. Micrococcus The germs of spherical organisms dividing in two planes. Morphology A study of the physical nature, size, and shape of any object. Adj., morphological. Nucleus (pi., Nuclei) A mass within a cell clearly out- lined from and denser than the cytoplasm or protoplasm, and in which the reproductive powers of the cell probably lie. -ology A suffix meaning a "study of" the root, such as morphology, which see. Opsonins Substances in the blood serum which prepare foreign bodies, usually bacteria, for consumption by the white cells of the blood, the phagocytes. Optimum The best, most suitable. GLOSSARY 239 Organic A substance having the form, the chemistry, or some characteristics of living matter; example, egg white. See Inorganic. Parasite An organism living on or in a host to the detri- ment of the latter. Adj., parasitic. Pathogenic Capable of producing disease. Pathology The study of disease the broad subject of the cause, production, and result of disease, and especially the changes it produces in the body. Related words: patho- logic, -al. Phagocytosis The act of consuming foreign bodies, notably bacteria, by the large white cells of the blood, called phagocytes. Adj., phagocytic. Plane The geometrical dimension. There is one plane in a line, two planes in a surface, and three planes in a body, such as a cube. Plasma The fluid part of the blood including the con- stituents capable of clotting. See Serum. Poisons Used generally to indicate any substance danger- ous to body. Has no particular significance for bacterial products when used alone. Proliferate To multiply, increase. Prophylaxis Guarding against beforehand. Measures toward preventing disease. Adj., prophylactic. Protoplasm See Cytoplasm. Protozoa (sing., Protozoon) The lowest order of animals, independent single-celled organisms. Pseudo False, resembling. Pseudopods The foot-like projections of the cell wall and cytoplasm shown by amebse, a method of progression for these protozoa. Putrefaction The decaying of proteid (the large part of meat and fish) with the production of foul odors and poisonous substances. (This is to be contrasted with fermentation, which see.) Pyogenes Pus-producing. Adj., pyogenic. 240 GLOSSARY Saprophyte An organism capable of living on dead or decaying matter. Adj., saprophytic. Serum (pi., Sera) The clear light yellow fluid part of the blood which exudes after clotting has occurred, and in which antibodies reside. Sexual Requiring two different forms for reproduction. Species The lowest biological division of living forms, varying only in unimportant characters, but possessing all the characters of the genus to which they belong. Lions and tigers belong to the genus Felis (or cat), but the former belongs to the species "leo," and the latter to the species "tigris." See Genus. Spirocheta (pi., Spirochetae) The spiral or corkscrew-like organisms; name given both to family and genus. Staphylococcus The spherical coccus which grows in grape-like masses. Sterile Bacteriologically speaking, entirely free of living organisms. A surgically sterile thing may contain organisms from the air which do not hurt the patient. Related words: sterility, sterilization, to sterilize. Strain An individual culture of a species isolated from a case. Streptococcus The spherical coccus which grows in chains. Toxins The poisonous products of bacterial life. Tumefaction Any tumor-like swelling.)/ Vaccine Originally used for the inoculation of cow-pox as a protective against smallpox; now used for that and for the injection of dead or attenuated bacteria for active immunization or treatment during disease. See Bacterins. Related words: to vaccinate, vaccination. Viable Capable of living and reproducing. Virulence The power possessed by organisms to develop poisons and produce disease. It varies in different strains, but depends also upon the resistance of the host. Virus -Any factor which produces disease, either individ- ually recognized or obscure; usually applied to poisons not specifically isolated, like rabies virus. INDEX. A ABSCESS, 87 Achorion Schoenleinii, 200. See Favus Acid-fast bacilli, 154, 168 Acids, 56 Actinomyces, 174. See Strep- tothrix actinomyces Actinomycosis, 174 bacteriological diagnosis of, 174 disinfection during attack of, 176 in soil, 203 transmission of, 174 "Active immunization," 72 Aerobe, 235 Aerobic bacteria, 36 Agglutinins, 74, 235 Air, bacteria in, 153, 202 currents, 202 examination of, for bacteria, 203 transmission of disease by, 149, 202 Alcohol, 56, 216 Algae, 21 Amebas, 22, 215, 216 Amebic dysentery, 129, 215 diagnosis of, 216 disinfection during attack, 216 Anaerobe, 235 Anaerobic bacteria, 36 Anaphylaxis, 77, 235 Animate ulae, 18 Animal inoculation, 45 Anthrax, 76, 171 16 Anthrax bacillus, 76, 171 general description of, 172 pathogenic powers of, 171, 173 poisons of, 171 relation of, to anthrax, 171 resistance to heat and chemicals, 57, 173 in soil, 203 vaccines, 173 bacteriological diagnosis of, 172 disinfection during attack of, 172 transmission of, 171, 172 vaccines, 173, 176 Antibody, 72 to 75, 235 Anti-endotoxins, 72 Antimeningitis serum, 103 Antiseptics, 52 Antiserum, 77, 106 Antitoxin unit, 111, 112, 117 Antitoxins, 72, 73, 109, 111, 116, 235 Asexual, 235 Attenuation, 52, 235 Autoclave, 46 Auto-intoxication, 37, 188 B BACILLI, 22, 26, 236 Bacillus coli communis, 178. See Colon bacillus of Ducrey, 163. See Chanc- roid dysenteriae, 140. See Dysen- tery bacillus 242 INDEX Bacillus enteritidis, 183 of Koch-Weeks, 146 rnelitensis, 128. See Malta fever of Morax and Axenfeld, 146 paratyphosus, 127 pestis, 132. See Plague ba- cillus proteus vulgaris, 190 pyocyaneus, 191 diagnosis of infections with, 193 general description of, 191 pathogenic powers of, 192 poisons, 192 resistance to heat and chemicals, 191 where found, 191 tctani, 113. See Tetanus bacillus typhosus, 118. See Typhoid bacillus Bacteria, 17, 22, 236 activities and nature of, 34 aerobic, 36 anaerobic, 36 biological classification of, 21 capsule of, 28 chemistry of, 33 colonies of, 41 cultivation of, 40 to 43 cytoplasm of, 25 endotoxins of, 66 entrance of, to body, 63 * enzymes of, 36 extracellular toxins of, 66 in fermentations, 36 ferments of, 36 flagella of, 28 in hair, 104 in intestinal tract, 35 to 38 intracellular toxins of, 66 lactic acid, 37, 188 motility of, 28 nucleus of, 25 nutrition of, 35 pathogenic, 20 poisons of, 65, 66, 73 in putrefaction, 37 relation of, to disease, 63 reproduction of, 27 1 Bacteria, resistance of body to, 64, 70 to 74, 86 size of, 27 specificity of, 64 spores of, 28 staining of, 44 toxins of, 66, 72, 73 transmission of, 67 vegetating, 50 wall of, 25 Bacteriacea3, 22, 236 Bactericide, 236 Bacteriemia, 65 ! Bacterin treatment, 75, 91 Bacterins, 75, 91, 236 Bacteriology, 17, 236 Bacteriolysin, 74, 236 , Bacterium aerogenes capsula- tus, 189 anthracis, 171. See Anthrax bacillus bulgaricum, 188, 189, 210 diphtheria?, 107. See Diph- theria bacillus influenzse, 128. See Influenza bacillus lactis aerogenes, 210 leprse, 165. See Leprosy bacillus of malignant edema, 190 mallei, 168. See Glanders bacillus ozsense, 187 pneumonia?, 185. See Fried- lander's bacillus tuberculosis, 149. See Tu- bercle bacillus Balantidium coli, 214 Beri-beri, 233 Bichloride of mercury, 53 Blastomycetes, 22, 195 diagnosis of, 201 disinfection during attack, 196 transmission of, 195 Blood culture technic, 84 Boiling for sterilization, 50 Boils, 91 Bordet-Gengou bacillus, 147. See Whooping-cough Boric acid, 56 Buttermilk, 210 INDEX 243 CALCIUM, hydroxide, 55 Cancrum oris, 234 Capsules, 28 Carbolic acid, 55 Carriers, 69, 108, 121, 137, 236 accidental, 69 chronic, 69 hidden, 69 passive, 69 Caustic soda, 54 Cell, 25, 236 Cellulitis, 88 Centigrade scale, 51 Centrosome, 31 Cerebrospinal meningitis, 100 puncture, 83 Chancroid, 163 Chemical disinfectants, 52 to 62 practical uses of, 58 to 62 Chemistry of bacteria, 33 of protozoa, 33 Chloride of lime, 54 Chlorinated lime, 54 Chloroform, 56 Cholera, 136 agglutination in, 138 antiserum, 77 bacteriological diagnosis of, 137 bacteriolytic test for, 138 disinfection during attack, 137 spirillum, 66, 136, 206 agglutinins of, 138 carriers of, 137 general description of, 138 in milk, 211 pathogenic powers of, 136, 140 poisons of, 136 relation of, to Asiatic chol- era, 136 resistance of, to heat and chemicals, 139 in soil, 203 vaccines, 140 in water, 205, 206 transmission of, 136 vaccination against, 140 Cilia, 32 Coccacese, 236 Cocci, 22, 26, 236 Coccidia, 214 | Colon bacillus, 89, 178 diagnosis of, infections with, 182 general description of, 178 pathogenic powers of, 181 poisons of, 181 resistance of, to heat and chemicals, 179 use in intestines, 180 vaccines, 182 in water, 206 where found, 180 Colonies, 41, 236 Commensal, 236 Complement, 74, 236 Conjunctivitis, gonorrheal, 96 Koch-Weeks, 145 (pink eye) Morax-Axenfeld, 146 Copper sulphate, 54 Corrosive sublimate, 53 Cow-pox, 229 Creolin, 55 Cresols, 55 Cultivation, 41, 236 Culture, 237 Cytoplasm, 25, 32, 237 DEJECTA, 223 Dengue, 220 Diarrhea, infantile, from milk, 197 Diphtheria, 107 administration of antitoxin in, 112 antitoxins, 112 bacillus, 66, 69, 107 antitoxins, 111 discovery of, 109, 111 general description of, 110 in milk, 211 pathogenic powers of, 108, 111 poisons, 66, 111 relation of, to diphtheria, 107 resistance of, to heat and chemicals, 110 244 INDEX Diphtheria, bacteriological diag- nosis of, 110, 111 disinfection during attack, j 108, 109 serum sickness following, 77, j 78 transmission of, 108, 211 Diplococci, 27 Diplococcus pneumonise, 103. I See Pneumococcus Disease, 63 transmission of, 67 water-borne, 205 Dishes, disinfection of, 50 Disinfectants, 52 uses of, 58 to 62 Disinfection, 53, 237 of dejecta, 60 practical, 53 of room and houses, 61 of sputum, 60 of water-closets and sinks, 61 Dressings, disinfection of, 50 Dumdum fever, 217 Dysentery, amebic, 140, 215 bacillary, 140 antibodies, 142 antiserum, 77, 143 bacteriological diagnosis of, I 142 disinfection during attack, i 141 transmission of, 141, 142 bacillus, 140 agglutinins, 142 antisera, 143 bacteriolysins, 142 general description of, 143 pathogenic powers of, 141, 143 poisons, 141 relation of, to dysentery, 140 resistance of, to heat and chemicals, 143 ENCYSTMENT, 237 Endotoxins, 66, 72 Entamreba histolytica, 216. See Amebic dysentery Entamocba histolytica, general description of, 216 pathogenic powers of, 216 Enteric fever, 118. See Ty- phoid fever Enzymes, 36, 44, 237 in industries, 36 Etiology, 237 Exudate, 88 FAHRENHEIT scale, 51 False membrane, 88 Favus, 200 Feces, collection of, 82 sterilization of, 60 Fermentation, 19, 36, 44, 210. 237 Ferments, 36, 44, 237 in industries, 36 Fever, 65 Filterable viruses, 228 Flagella, 28, 32 Flagellata, 214 Flies in transmission of disease, 68, 120 tsetse, 68, 219 Fomites, 68 Formaldehyde, 56, 58, 59 Formalin, 56, 58, 59 Friedlander's bacillus, 185 pathogenic powers of, 185 Fungi, 21 GENERATION, spontaneous, 19 Genus, 237 Germination, 237 Glanders, 168 to 171 bacillus, 168 general description of, 170 pathogenic powers of, 169 poisons, 169 relation of, to glanders, 168 resistance of, to heat and chemicals, 170 vaccines, 171 bacteriological diagnosis of, 169 INDEX 245 Glanders, disinfection during attack, 169 mallein in, 169 transmission of, 168 vaccines in, 171 Glassware, 46 Glossary, 235 Gonococcus, 67, 95 in conjunctivitis, 96 general description of, 97 relation of, to gonorrhea, 95 resistance of, to heat and chemicals, 99 vulvovaginitis due to, 96 Gonorrhea, 95 bacteriological diagnosis of, 99 disinfection during and after attack, 97 Gonorrheal conjunctivitis, 96 ophthalmia, 96 Gram stain, 45 Growth, 237 HAIR, bacteria in, 109 Hanging drop, 44 Heat sterilization, 46 to 51 Hemosporidia, 214, 222 Heterotricha, 214 Host, 21, 237 Hot-air sterilization, 51 Hydrogen peroxide, 54 Hydrophobia, 229 disinfection against, 231 Pasteur treatment for, 230 transmission of, 229 virus of, 229, 230 Hyphse, 197 Hyphomycetes, 22, 194 ICE and typhoid fever trans- mission, 119 Ileocolitis, 140 Immunity, 70 to 78, 238 acquired, 71 active, 71, 76 acquired, 72 artificial, 72 Immunity, natural, 71 passive, 72, 77 acquired, 77 racial, 71 Impetigo contagiosa, 234 Incubation period, 67 Incubator, 42 Infection, 65 predisposing causes to, 64 Infective, 238 Inflammation, 86 to 88 Influenza, 128, 147 agglutinins, 131 bacillus, 67, 100, 128 general description of, 131 pathogenic powers of, 129 poisons, 129 relation of, to influenza, 129 to other diseases, 129 resistance to heat and chemicals, 131 vaccines, 132 bacteriological diagnosis of, 130 disinfection during attack, 130 immunity after attack, 129 meningitis, 129, 132 transmission of, 129 Infusoria, 214 Inhibit, 238 Inject, 238 Inoculate, 238 Inorganic, 238 Insects, 68 Intoxication, 64 Iodine, 56 alcohol, 56, 59 Isolate, 238 KALA-AZAR, 217 Klebs-Loeffler bacillus, 107 Koch-Weeks bacillus, 146 Koumyss, 189 LACTIC acid bacteria, 37, 188, 210 Lamblia intestinalis, 221 246 INDEX Leishmania Donovani, 218 Leprin, 167 Leprosy, 165 to 168 bacillus, 165 general description of, 167 pathogenic powers of, 167 poisons of, 167 relation of, to leprosy, 165 bacteriological diagnosis of, 167 disinfection during attack, 167 forms of, 165 transmission of, 165 Lesion, 238 Leukocytes, 75, 87, 88, 238 Lichens, 21 Lime, milk of, 59 Lysol, 56 M MALARIA, 68, 221 diagnosis of, 226 estivo-autumnal, 222, 225 malignant, 222 prevention of, 227 quartan, 222, 225 tertian, 222, 225 Mallein, 171 Malta fever, 128 bacilli in, 128 general description of, v!28 transmission of, 128 Mastigophora, 22, 214, 217 Measles, 232 Meat poisoning bacteria, 183 Media, 40, 41, 44, 238 Meningitis, 100 ' antiserum to, 77, 103 bacteriological diagnosis of, 102 carriers, 69 coccus, 102 antiserum, 94 general description of, 102 relation of, to meningitis, 100 disinfection during, 101 influenzse, 129, 132 Methods of examination, 39 Microbiology, 17 Micrococcus, 89, 238 gonorrhoea, 95. See Gono- coccus intracellularis meningitidis, 100. See Meningitis coccus Microscope, 23 technic of, 23, 43 Microsporon furfur, 201 Milk, bacteria in, 207 cholera spirilla in, 211 collection of, 84 diphtheria bacilli, 211 diseases transmitted by, 68, 128, 210 examination of, 213 fermentation of, 209, 210 infantile diarrhea from, 210 of lime, 59 pasteurization of, 208 scarlet fever from, 211 souring of, 210 spoiling of, 209 streptococci, 207 tubercle bacilli in, 207, 212 typhoid fever and bacilli in relation to, 211 Morax-Axenfeld bacillus, 146 Morphology, 238 of bacteria, 23 of protozoa, 31 variations of, 26 Mosquitoes, anopheles, 68, 222 culex, 223 stegomyia, 68, 231 in transmission of diseases, 68, 221, 231 Moulds, 94, 197, 221 diseases due to, 197 to 201 general disposition of, 197 to 199 pathogenic powers of, 199 Mucosus capsulatus group, 184 general description of, 184 pathogenic power of, 184 poisons, 185 resistance of, to heat and chemicals, 185 transmission of, 185 vaccines, 187 Mumps, 233 Mycelium, 197 INDEX 247 N NOMA, 234 Nucleus, 25, 31, 238 Nutrition of bacteria, 35 of protozoa, 38 OIDIUM albicans, 200 Ophthalmia neonatorum, 96 Opsonic index, 91 Opsonins, 74, 91, 238 Optimum, 238 Organic, 239 PARACOLON bacilli, 182 Parasites, 20, 239 facultative, 21 obligate, 21 Paratyphoid bacilli, 127 Pasteur treatment of rabies, 230 Pasteurization, 62, 208, 213 Pathogenic, 239 Pathology, 239 Pellagra, 233 Penicillium glaucum, 198 Phagocytes, 74, 239 Phagocytosis, 75, 239 Phenol, 55 Phlegmon, 88 Pinkeye, 145 Pityriasis versicolor, 200 Plague, 132 antiserum, 135 bacillus, 132 antisera, 135 general description of, 134 pathogenic power of, 133, 135 poisons, 133 relation of, to plague, 132 resistance of, to heat and chemicals, 134 vaccines, 135 bacteriological diagnosis of, 134 disinfection during attack, 134 Plague, immunity against, 135 immunization against, 135 rat fleas in transmission of, 133 rats in transmission of, 133 transmission of, 132, 133 vaccines in, 135 Plane, 239 Plasma, 239 Plasmpdium, 214 falciparum, 222 general description of, 226 life in mosquitoes, 224 malarise, 222 pathogenic powers of, 223 to 226 vivax, 222 Pneumococcus, 100, 103 antiserum, 106 in diseases other than pneu- monia, 100, 104 general description of, 104 pathogenic powers of, 106 poisons, 106 relation of, to pneumonia, 103 resistance of, to heat and chemicals, 106 Pneumonia, 103, 185 antiserum, 77, 106 bacteriological diagnosis of, 104 disinfection during, 104 Poliomyelitis, 232 virus of, 232 Proliferate, 239 Protoplasm, 239 Protozoa, 17, 22, 31, 33, 38, 45, 214 biological classification of, 22, 214, 239 centrosome of, 31 chemistry of, 33 cilia of, 32 cytoplasm of, 31 examination for, 45 flagella of, 32 morphology of, 31 motility of, 32 nucleus of, 31 nutrition of, 32 pseudopods of, 32 reproduction of, 32 248 INDEX Protozoa requirements, 38 temperature for, 38 wall, 31 Protozoology, 17 Pseudodiphtheria bacilli, 113 Pseudopods, 32, 239 Ptomain poisoning, 69 Pus, 85, 88 bacillus of green, 191 collection of, 79 Putrefaction, 37, 239 Pyemia, 88 Pyocyanase, 192 Pyocyaneus bacillus, 89, 191 Pyogenes, 239 R RABIES, 229. See Hydrophobia Rain, bacteria in, 204 Ray fungus, 174. See Strepto- thrix actinomyces Relapsing fever, 163 Reproduction, 27, 32 Rheumatism, acute articular, 233 streptococcus rheumati- cus in, 233 Rhizopoda, 214 Ringworm, 199 Room disinfection, 53, 61 Rubber gloves, disinfection of, 50 Russell, Major, U. S. A., anti- typhoid vaccination, 126 S SAPROPHYTES, 21, 240 in intestine, 37 Sarcinse, 27 Sarcodina, 22, 214, 215 Scarlet fever, 69, 232 from milk, 211 Schizomycetes, 22 Septicemia, 65, 88 Serum, 240 sickness, 78 treatment, 77 Sexual, 240 Silver nitrate, 54 Skin sterilization, 56, 59, 83 Sleeping sickness, 68, 218. See Trypanosomiasis Smallpox, 75, 228 Smegma bacillus, 168 Soap as disinfectant, 56 Sodium carbonate, 54 hydroxide, 54 Soil', 203 actinomycosis from, 203 anthrax bacillus in, 203 bacteria in, 203 cholera bacillus in, 203 tetanus bacillus in, 204 tubercle bacillus in, 204 typhoid bacillus in, 203 Soor, 200. See Thrush Species, 240 Spirilla, 22, 26 Spirillum cholera; asiaticge, 136. See Cholera spirillum Spirocheta, 240 Obermeieri, 164 pallida, 159. See Treponema pallidum Spontaneous generation, 19 Spores, 28, 50, 51, 55, 56 Sporozoa, 22, 214, 221 Sputum, collection of, 80 sterilization of, 60, 154, 157 tuberculous, collection and sterilization of, 60, 154 Staining, 40, 44 Staphylococci, 27, 89, 240 Staphylococcus epidermidis albus, 83, 90 pyogenes albus, 90 aureus, 89 discovery of, 94 diseases produced by, 91 general description of, 89 resistance of, to heat and chemicals, 90 Steam sterilization, 46, 47, 50 sterilizer, 48, 50 Stegomyia calopus, 231 Sterilization, 46 to 51, 52 to 58, 240 of dejecta, 60 of fabrics, 59 of glassware, 46 INDEX 249 Sterilization, hot-air, 51 incomplete, 52 of sputum, 60, 154, 157 of utensils, 60 of water-closets, 61 Strain, 240 Streptococci, 27, 67, 89, 92, 211, 240 Streptococcus pyogenes, 92 antiserum, 77, 94 discovery of, 94 diseases due to, 92 general description of, 93 rheumaticus, 233 Strep tothrix actinomyces, 174. See Actinomycosis general description of, 175 pathogenic powers of, 174 poisons, 174 relation to actinomycosis, 174 resistance of, to heat and chemicals, 176 Sulphur dioxide, 57 Sunlight, 62 Syphilis, 159 to 163 antibodies in, 161 diagnosis of, 161 forms of, 160 skin reaction in, 163 transmission of, 160 Wassermann blood reaction in, 161 Syringes, disinfection of, 50 TECHNIC, 39 Temperature optimum, 45 Tetanus, 77, 113 antitoxin, 116 administration of, 117 unit of, 117 bacillus, 72, 113 antitoxin, 116 effect of anaerobic life, 114 general description of, 115 pathogenic powers of, 114 relation of, to tetanus, 114 resistance of, to heat and chemicals, 116 Tetanus bacillus in soil, 204 spores of, 115 toxins of, 66, 116 bacteriological diagnosis of, 115 disinfection during attack, 115 Thallophyta, 21 Thermometer scales, 47 Thrush, 200 Tinea circinata, 199. See Ring- worm sycosis, 200. See Ringworm tonsurans, 200. See Ring- worm Toxins, bacterial, 66, 72, 73, 240 extracellular, 66 intracellular, 66 Trachoma, 233 Transmission of bacteria, 67 of disease, 67, 68 Trays, disinfection of, 50 Treponema pallidum, 159 general description of, 161 pathogenic powers of, 159 poisons, 159 relation of, to syphilis, 159 resistance of, to heat and chemicals, 161 transmission of, 160 Trichomonas, 220 intestinalis, 221 pulmonalis, 220 vaginalis, 220 Trichophyton, 198, 200 Tricresol, 55 Trypanosoma, 214, 218 general description of, 219 pathogenic powers of, 219 Trypanosomiasis, 218 transmission of, 214 Tsetse fly, 68, 219 Tubercle bacillus, 68, 149 in air, 202 forms of, 153 general description of, 156 in milk, 153, 212 pathogenic powers of, 150 poisons, 155, 158 relation of, to tuberculosis, 151, 153 resistance of, to heat and chemicals, 157 250 INDEX Tubercle bacillus in soil, 204 transmission of, 152 vaccines, 158 Tubercles, 150 Tuberculin, 152, 155, 158, 212 Tuberculosis, 149 to 158 agglutinins in, 155 antibodies in blood in, 152 bacteriological diagnosis of, 154 from cows, 157, 212 disinfection during attack, 154 forms of, 150 from milk, 212 skin test in, 155 sputum in, disinfection of, 154, 157 transmission of, 152 tuberculin reaction in 155 treatment, 157, 158 vaccines, 158 Tumefaction, 240 Typhocolon group of bacilli, 177 to 184 discovery of, 184 Typhoid bacillus, 69, 89, 118 agglutinins, 123 carriers, 69, 121 general description of, 125 in milk, 211 pathogenic powers of, 118, 126 poisons, 122 relation to typhoid fever, 118 resistance to heat and chemicals, 125 in soil, 203 vaccines, 126 in water, 119, 206 fever, 118 antibodies after attack, 122 bacteriological diagnosis of, 123 bacteriolysins in, 123 carriers, 121 disinfection during attack, 121 immunity after, 122 immunization against, 126 Typhoid fever, Russell's vac- cination against, result of, 126 transmission of, 119 by flies, 120 by ice, 120 by milk, 120, 211 by oysters, 120 by personal contact, 120 by sewage, 120 by vegetables, 120, 203 by water, 119, 205, 206 Widal reaction in, 123 Typhus fever, 232 URINE, collection of, 81 sterilization of, 60 VACCINATION, 229 Vaccine treatment, 75, 91, 127, 132, 158 Vaccines, 75, 91, 229, 240 Variola, 228. See Smallpox Vegetables in typhoid fever transmission, 120, 203 Vegetative bacteria, 31 Viable, 240 Vincent's angina, 144 bacteriological diagnosis of, 144 disinfection during attack, 144 general description of micro- organisms of, 145 poisons, 144 Virulence, 45, 65, 240 Virus, 240 filterable, 228 Vulvovaginitis, 96, 99 W WATER, bacteria in, 204 -borne diseases, 205 cholera spirilla in, 206 INDEX 251 Water, colon bacilli in, 206 diseases transmitted by, 68, 205 dysentery bacillus in, 206 examination of, 207 purification of, 205 typhoid bacilli in, 119, 205, 206 fever from, 119 Whooping-cough, 147 Bordet-Gengou bacillus in, 147 general description of, 147 Widal reaction, 74, 123 collection of blood for, 82 YEASTS, 22, 194 diseases due to, 195 general description of, 194 pathogenic powers of, 195, 196 relation to blastomycosis, 195 Yellow fever, 68, 231 mosquitoes in, 68, 231 RETURN TO the circulation desk of any University of California Library or to the NORTHERN REGIONAL LIBRARY FACILITY Bldg. 400, Richmond Field Station University of California Richmond, CA 94804-4698 ALL BOOKS MAY BE RECALLED AFTER 7 DAYS 2-month loans may be renewed by calling (415)642-6233 1-year loans may be recharged by bringing books to NRLF Renewals and recharges may be made 4 days prior to due date DUE AS STAMPED BELOW LIBRARY USE JAN 15 '87 THE PACIFIC GuAST JOURNAL OF NURSING