THE LIBRARY 
 
 OF 
 
 THE UNIVERSITY 
 OF CALIFORNIA 
 
 PRESENTED BY 
 
 PROF. CHARLES A. KOFOID AND 
 MRS. PRUDENCE W. KOFOID 
 
tn. 
 
PLATE 1 
 
 
 
 , 
 ' 
 
 
 / 
 
 White Cells of the Blood, Leukocytes, Acting as 
 Phagocytes or Cell Eaters; Streptococci in Chains 
 Being Consumed. 
 
ELEMENTARY 
 
 BACTERIOLOGY 
 
 AND 
 
 PROTOZOOLOGY 
 
 THE MICROBIOLOGICAL CAUSES OF 
 THE INFECTIOUS DISEASES 
 
 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. 
 
 ILLUSTRATED WITH 67 ENGRAVINGS AND 
 5 COLORED PLATES 
 
 LEA & FEBIGER 
 
 PHILADELPHIA AND NEW YORK 
 1912 
 
Entered according to the Act of Congress, in the year 1912, by 
 
 LEA & FEBIGER, 
 in the Office of the Librarian of Congress. All rights reserved. 
 

 sU 
 
 PREFACE 
 
 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. 
 
 PHILADELPHIA, 1912. 
 
 M3584Q8 
 
CONTENTS 
 
 CHAPTER I 
 
 INTRODUCTION HISTORY THE PLACE OF MICROORGAN- 
 ISMS IN NATURE 17 
 
 CHAPTER II 
 
 GENERAL MORPHOLOGY REPRODUCTION CHEMICAL AND 
 
 PHYSICAL PROPERTIES 22 
 
 CHAPTER III 
 
 GENERAL BIOLOGY, INCLUDING THE CHEMICAL CHANGES 
 
 WROUGHT BY BACTERIA 33 
 
 CHAPTER IV 
 
 METHODS OF STUDYING MICROORGANISMS STERILIZATION 
 
 BY HEAT 37 
 
 CHAPTER V 
 
 DESTRUCTION OF BACTERIA BY CHEMICALS, AND THEIR 
 
 PRACTICAL USE 48 
 
 CHAPTER VI 
 THE RELATION OF BACTERIA TO DISEASE IMMUNITY . 58 
 
 CHAPTER VII 
 
 PREPARATIONS FOR AND PROCURING OF SPECIMENS FOR 
 
 BACTERIOLOGICAL EXAMINATION 71 
 
vi CONTENTS 
 
 CHAPTER VIII 
 
 THE ACUTE CHIEFLY LOCALIZED INFECTIONS OF Pus 
 
 NATURE THE PATHOGENIC Cocci 77 
 
 CHAPTER IX 
 
 THE ACUTE SELF-LIMITED INFECTIONS 98 
 
 CHAPTER X 
 THE MORE CHRONIC INFECTIOUS DISEASES .... 138 
 
 CHAPTER XI 
 
 VARIOUS PATHOGENIC BACTERIA NOT ASSOCIATED WITH 
 
 A SPECIFIC CLINICAL DISEASE 164 
 
 CHAPTER XII 
 
 YEASTS AND MOULDS 180 
 
 CHAPTER XIII 
 
 BACTERIA IN AIR, SOIL, WATER, AND MILK .... 189 
 
 CHAPTER XIV 
 DISEASES DUE TO PROTOZOA 200 
 
 CHAPTER XV 
 
 DISEASES OF UNKNOWN ETIOLOGY . 215 
 
 GLOSSARY 221 
 
BACTERIOLOGY AND PROTOZOOLOGY 
 
 CHAPTER I 
 
 INTRODUCTION HISTORY THE PLACE OF 
 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 
 or a plant. Some of these single-celled bodies have 
 2 
 
18 HISTORY 
 
 characteristics placing them without question among 
 the plants, while others 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 animalculse. The first conception of the 
 existence of such microscopic forms cannot be accred- 
 ited to these observers, 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, were 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 not a few of the present 
 have discredited the relation of bacteria to disease. 
 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 
 
HISTORY 19 
 
 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 the 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) of bacteria does not 
 occur. The results of Pasteur's work received prac- 
 tical application 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 prin- 
 ciples of modern antiseptic and aseptic surgery are due. 
 Throughout all the history of microbiological devel- 
 opment it has been possible to progress more rapidly 
 and definitely with bacteria than with protozoa. 
 Bacterial life and activity can be controlled very 
 
20 PLACE OF MICROORGANISMS IN NATURE 
 
 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, and Biitschli, and the present 
 leaders in the field Calkins, Doflein, and Prowaczek. 
 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 
 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 bacteria 
 capable of living and multiplying within the living, 
 animal body, sometimes to its detriment, while the 
 saprophytes live on dead matter and may be found in 
 nature everywhece, in air, soil, water. The body upon 
 
PLACE OF MICROORGANISMS IN NATURE 21 
 
 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, require animal juices for their nutriment. 
 Among the protozoa this obligate parasitism exists 
 quite extensively. Many forms cannot live at all if 
 their normal cycle of life within the animal body be 
 disturbed. The saprophytes include the vast number 
 of organisms having important functions among the 
 higher vegetables and the growth of these in soil. It 
 has been suggested that at one time, now long past, 
 all bacteria might 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 
 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 technique 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 advisable to introduce between the 
 object glass and the lens a drop of pure cedar oil in 
 order that light can be made pure and concentrated. 
 The microscope is also used to examine the colonies 
 of bacteria. Bacteria are studied either in the fresh 
 living condition or when stained by appropriate dyes. 
 
 Bacteria are exceedingly small single cells, in their 
 
GENERAL MORPHOLOGY 
 
 23 
 
 natural state transparent, colorless, and apparently 
 homogeneous, possessing a very low power of refracting 
 light. They consist of a wall which is probably a 
 
 FIG 1 
 
 Microscope: A, ocular or eye-piece; B, objective; C, stage; D, "iris" dia- 
 phragm; E, reflector; F, coarse adjustment; O, fine adjustment; H, sub-stage 
 condensing apparatus; /, nose-piece. 
 
24 GENERAL MORPHOLOGY 
 
 simple condensation of the interior. The ordinary 
 animal or vegetable single cell 1 contains an easily dis- 
 tinguishable 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. Into this 
 cytoplasm the nourishment of the cell passes. Of 
 bacteria, either in their natural condition or stained 
 for examination, only the nucleus and the wall can 
 be seen, the intervening layer being exceedingly thin. 
 
 FIG. 2 
 
 o 
 a 
 
 OD 
 
 a, staphylococci; b, streptococci; c, diplococci; <7, tetrads; e, sarcinse. 
 (Abbott.) 
 
 In shape, bacteria are either spherical, called cocci 
 (sing., coccus), or straight rods, called bacilli (sing., 
 bacillus), or curved rods, called spirilla (sing., spiril- 
 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 
 
 1 See frontispiece for an example of cell. Nearly all living calls are com 
 parable to these leukocytes. 
 
GENERAL MORPHOLOGY 25 
 
 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 
 in three planes. In size microorganisms vary consider- 
 ably. Perhaps a proper conception of some organisms 
 
 FIG. 3 
 
 -^ 
 
 <^>w V 
 
 a, bacilli in pairs; b, single bacilli; c and d, bacilli in threads; e and /, 
 bacilli of variable morphology. (Abbott.) 
 
 FIG. 4 
 
 o b c d 
 
 a and d, spirilla in short segments and longer threads the so-called 
 comma forms and spirals; b, the forms known as spirochsetse, c, the thick 
 spirals sometimes known as vibrios. (Abbott.) 
 
 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. Bac- 
 teria are measured in terms of microns. The metric 
 unit, a micron, equals about 2TTro^r f an inch. 
 
26 SPECIAL CHARACTERS 
 
 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 sarcinse. 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 
 medium. 
 
 SPECIAL CHARACTERS 
 
 The cell is sometimes surrounded by an envelope 
 or capsule and this is taken advantage of in identi- 
 fication. It is particularly well developed on bacteria 
 while in or lately removed from animal tissues upon 
 which they have been growing. The exact function 
 or importance of these capsules is not known. 
 
SPECIAL CHARACTERS 
 
 27 
 
 Some bacteria are able to move from place to place 
 in a fluid medium. This is due to the presence of 
 
 FIG. 5 
 
 Capsule stain by Hiss' method. Rhinoscleroma bacillus. X 1000. (Thro.) 
 
 FIG. 6 
 
 XV 
 
 A 
 
 Bacilli showing one polar flagellum. (Park.) 
 
 extremely fine filamentous extensions from the cell 
 wall, which upon microscopic examination look like 
 
28 
 
 SPECIAL CHARACTERS 
 
 wavy hairs. These are called flagella (sing., flagel- 
 lum). They are arranged either at one end, both 
 
 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.) 
 
 ends, or around the whole surface of the cell. They 
 propel the bacterium by a quick waving or lashing 
 motion. 
 
SPECIAL CHARACTERS 29 
 
 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 mav bear little or no resemblance to the parent 
 
 FIG. 9 
 
 Unstained spores in distended ends of bacilli. (Park.) 
 
 organism. These spores are not to be considered as 
 evidences of reproduction, but merely as a resting or 
 resistance stage. When conditions of life suitable to 
 the normal 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 
 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 
 
30 SPECIAL CHARACTERS 
 
 they resist the agencies quickly fatal to the adult 
 forms. Bacteria in their ordinary development are 
 said to be vegetating, and we must differentiate 
 between the vegetative stage and the spore-forming 
 stage. 
 
 Protozoa (sing., Protozoan). 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-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 mesh work. The nucleus is a com- 
 plex 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 centresome. 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 struc- 
 ture 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 phe- 
 nomenon 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 flows, 
 enlarging the false foot until it embraces all the con- 
 
CHEMICAL AND PHYSICAL PROPERTIES 31 
 
 tents of the cell. The space formerly occupied by 
 the protozoon is vacated and it has moved to a position 
 directed by the pseudopod. In some protozoa a 
 portion of the body has muscular power and drives the 
 body. Again, a portion of the cell wall may be fitted 
 with a sucking apparatus, serving both to drive or to 
 attach the protozoon to another body. They gain 
 their food by simple absorption through the wall or by 
 possessing definite vacuoles or openings for this pur- 
 pose. Excretion takes place the same way. 
 
 Reproduction may occur by simple dividing as in 
 bacteria. Protozoa may divide by simple budding 
 with breaking off of the smaller piece similar in the 
 first stages to 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 
 
 Bacteria. Chemically the bacterial body is composed 
 chiefly of water (80 to 90 per cent.), the remaining 
 part being made up of proteid (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 sub- 
 stances which form the most important foodstuff for 
 animals, the proteids. Chlorides and phosphates of 
 the lighter metals form the inorganic salts. 
 
 The wall of the bacterial cell permits the passage 
 
32 CHEMICAL AND PHYSICAL PROPERTIES 
 
 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 for their nourishment, but their cells do not 
 possess the power to put together (synthesize) the 
 elementary constituents necessary for their complex 
 cell composition. Bacteria have the power both of 
 breaking down and building up; that is, they may 
 reduce some compounds to their elements or build 
 up elements into more complex substances. 
 
 The products of their breaking down and building 
 up are utilized by plants and are presented to animals 
 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 
 3 
 
34 GENERAL BIOLOGY 
 
 bacteria in the alimentary tract, but some of those 
 present are beneficial in effect. They gain access in the 
 food and air. They assist in making fats more easily 
 assimilable, and they destroy some of the pathogenic 
 bacteria. Incidentally it might be added that their 
 activity in producing excessive putrefaction and fer- 
 mentation may be harmful to the body in general. 
 
 Bacteria require for their life moisture, some degree 
 of heat, and a variety of foodstuffs. 
 
 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 
 
CHEMICAL CHANGES WROUGHT BY BACTERIA 35 
 
 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. Advantage is taken of these bacterial ferments 
 in the industries, especially that of spirituous liquor- 
 making. In this case the bacteria and their enzymes 
 are capable of splitting 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, 
 and many form coloring matter both in nature and 
 when grown artificially. 
 
 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 auto-intoxication. Metchnikoff 's experi- 
 ments have shown that the high acid produced by 
 
36 GENERAL BIOLOGY 
 
 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. 
 
 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 pressure or by 
 taking their nutriment to the damage of their host. 
 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 TECHNIQUE 
 
 IN the study of microscopic beings, it has been 
 necessary to elaborate a special technique 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 w y as 
 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 also is due 
 credit 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 
 
38 METHODS OF STUDYING MICROORGANISMS 
 
 from which this single organism comes the bacteri- 
 ologist colors it by certain aniline or vegetable dyes, 
 of which there are a large number. It is practically 
 impossible certainly to identify any bacterium by a 
 
 FIG. 10 
 
 Showing certain macroscopic characteristics of colonies. Natural size. 
 (Abbott.) 
 
 simple examination of a stained preparation under 
 the microscope. The observer, however, does form a 
 tentative opinion as to its probable nature, and pro- 
 ceeds to introduce some of the material into a nutrient 
 medium which he considers best adapted to its develop- 
 
LABORATORY TECHNIQUE 39 
 
 ment. Among these are broth, milk, potato, coagu- 
 lated blood serum, and broth stiffened (when cool) 
 with gelatine and the Japanese moss, agar-agar. These 
 foodstuffs, called media for short (sing., medium) are 
 
 FIG. 11 
 
 Platinum needle and loop. (Park.) 
 
 kept in test-tubes or flasks. He 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 "colonies," and secondly to see that only one 
 kind of colony, therefore only one kind of germ, is 
 present. In other words, he wishes to know if his 
 culture be "pure." These tubes and plates are placed 
 
40 METHODS OF STUDYING MICROORGANISMS 
 
 at body temperature (98 F. or 37.5 C.) in the incu- 
 bator. An incubator is a doubly insulated metal box, 
 heated by gas or electricity and controlled by an 
 automatic device by which the temperature is kept 
 constantly where desired. Practically all pathogenic 
 
 FIG. 12 
 
 Method of transferring cultures from one tube to another. (Hiss and Zinsser.) 
 
 bacteria develop best at this temperature. 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 and takes note 
 of the evidences of growth. He will make stained 
 
LABORATORY TECHNIQUE 41 
 
 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 
 thin inverted glass (Fig. 13). 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 enzymes. 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 
 
 FIG. 13 
 
 Hollow slide with cover-glass. (Park.) 
 
 upon bouillon containing the sugars. This broth is 
 placed in an apparatus called fermentation tubes, 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. 
 
 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. Animal inoculation is used for keeping 
 alive certain viruses or increasing the virulence of 
 those whose strength has declined. When the presence 
 
42 METHODS OF STUDYING MICROORGANISMS 
 
 of bacteria cannot be demonstrated by stain or 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 the germs for study. 
 It is most useful in discovering the presence of the 
 tubercle bacillus, an organism not easy to find by 
 direct examination. 
 
 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 mainte- 
 nance of a definite temperature for a long time, and 
 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 technique of 
 laboratory procedure, the preparation of the food- 
 stuffs or media on which bacteria thrive will be briefly 
 considered. They are prepared 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 appa- 
 ratus and foodstuffs wholly free from microorganisms 
 
STERILIZATION 
 
 43 
 
 are necessary in bacteriological technique. In no other 
 way can one be sure of obtaining germs in pure culture, 
 
 FIG. 14 
 
 FIG. 15 
 
 FIG. 16 
 
 A B 
 
 Autoclave, pattern of Wiesnegg: A, external appearance: B, section. 
 
44 METHODS OF STUDYING MICROORGANISMS 
 
 that is, only one kind. After the glassware contains the 
 medium, which is destroyed by dry heat, steam sterili- 
 zation is used. 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 atmospheric pressure. 
 Because of the delicacy of some of the nutrient media, 
 it is, however, necessary to sterilize these at the usual 
 
 FIG. 18 
 
 Arnold steam sterilizer. 
 
 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. 
 
 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 
 
STERILIZATION 45 
 
 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 
 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, they find it 
 
 FIG. 19 
 
 Laboratory hot-air sterilizer. 
 
 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' exposure. For example, the 
 typhoid bacillus dies when heated to 56 C. or 133 F. 
 for ten minutes, 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' 
 
40 METHODS OF STUDYING MICROORGANISMS 
 
 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 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 sterili- 
 zation that method is chosen which will do the least 
 damage to any object to be conserved. Simple boiling 
 should be undertaken whenever practicable, and immer- 
 sion 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 and surgical instruments in the absence of 
 infective material known to contain spores. Steriliza- 
 tion in live steam is the most practical method of 
 killing bacteria, as it can be carried out in the kitchen. 
 In the laboratory it is done by the Arnold sterilizer 
 (Fig. 18). 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 over night. On the 
 second occasion these will then be killed. A third ex- 
 
STERILIZATION 47 
 
 posure insures sterility. The exposure of fifteen min- 
 utes is considered to begin when the steam is up and 
 the thermometer registers 100. For sterilization of 
 objects not injured by pressure the boiler or autoclave 
 is used. By this means as much as two extra atmos- 
 phere 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 particularly adapted to the sterilization of 
 dressings and infected cast-off clothing. Hot air is 
 suitable for dried glassware and articles injured by 
 moisture. It is less efficient than moist heat. This 
 is due to the fact that organic substances 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 best of all 
 methods. 
 
 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 in the Centigrade scale is equal to the 180 in the 
 Fahrenheit scale, between 32 and 212. 
 
 To change one system to the other proceed as follows : 
 
 From Fahrenheit to Centigrade: Given degree F. 32 -i-9 X5 = 
 same degree in Centigrade scale. Example: 50 F. 32 = 18 -j- 9 = 
 2X5 = 10. Therefore 50 F. = 10 C. 
 
 From Centigrade to Fahrenheit : Given degree C. -J- 5 X 9 +32 = 
 same degree in Fahrenheit scale. Example: 10 C.^5 
 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 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, 
 (l) Attenuation is when the pathogenic or vital func- 
 tions of the bacteria are temporarily diminished. (2) 
 Antiseptic action is when the bacteria are not able to 
 multiply, but are not destroyed; they will reproduce 
 when suitable conditions for life are restored. (3) In- 
 complete sterilization or disinfection is when the vege- 
 tative forms but not the spores are destroyed. (4) 
 Sterilization or disinfection is when both vegetative 
 and spore forms are destroyed; this implies also the 
 
SILVER NITRATE 49 
 
 destruction of any products of bacteria capable of 
 producing disease. 
 
 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 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, so that most of 
 the tablets now on the market are made up with an 
 acid having no effect upon the mercury salt. This is 
 particularly true when the material to be disinfected 
 is pus, blood, feces, or the like. It is wise to use a 
 strength of 1 to 500 for one-half an hour when any 
 such organic material is present. The disadvantages 
 of this substance 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. 
 4 
 
50 DESTRUCTION OF BACTERIA BY CHEMICALS 
 
 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 Dme" (chlorinated lime). This chemical 
 is also known as bleaching powder. There is a differ- 
 ence of opinion as to its composition. Its power de- 
 pends upon the liberation of free chlorine gas. It is 
 destructive to fabrics. It quickly degenerates and is 
 therefore to be used fresh. 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. 
 Cakium hydroxide, made by adding water to quick- 
 lime, 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. 
 
 Acids. The strong mineral acids are not practical 
 disinfectants, but nevertheless, 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 and formaldehyde. Chlorine 
 
FORMALDEHYDE 51 
 
 is not included here because it is seldom used in its 
 pure state since it is highly poisonous and destructive. 
 It is eminently efficient. 
 
 Sulphur Dioxide. Sulphur dioxide is used for hos- 
 pitals, apartments, and ships. 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/ 5 
 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 commerce 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. 
 
 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 fabric is 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 
 
52 DESTRUCTION OF BACTERIA BY CHEMICALS 
 
 disinfectant chiefly because it forms new insoluble 
 odorless compounds. 
 
 It is not very irritant when taken into stomach, but 
 vapors cause considerable annoyance in the eyes, nose, 
 and mouth. The lower animals resist it considerably, 
 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. 
 
 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 
 temperature. 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, 
 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. 
 
STOCK SOLUTIONS 53 
 
 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. 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 sub judice before one can accept this 
 statement. Chloroform kills vegetative bacteria and 
 restrains spores, even in small qualities. 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. 
 
 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. 
 
 Bichloride solution : 60 grains of pulverized bichlor- 
 ide and 2 tablespoonfuls of common salfc to 1 gallon 
 of hot water = 1 to 1000. Store in glass or earthen 
 vessel. 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 quick lime. The 
 lime becomes hot, crumbles, and as the slaking is 
 completed a white powder results. 
 
54 DESTRUCTION OF BACTERIA BY CHEMICALS 
 
 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 100 
 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 the authorities for disinfection. 
 After soaking infected goods in these solutions they 
 should be boiled for at least twenty minutes, preferably 
 with soap. Materials from the sick-room 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. 
 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. 
 
DISINFECTION OF ROOMS AND HOUSES 55 
 
 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 car- 
 bolic or milk of lime solution. If caught in handker- 
 chiefs they should be burned. The hands must be 
 washed in a disinfectant after catching sputum in a 
 handkerchief. 
 
 Fia. 20 
 
 Sanitary spit-cups 
 
 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 
 
56 DESTRUCTION OF BACTERIA BY CHEMICALS 
 
 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 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 
 pasting strips of paper over them. This saves much 
 of the vapor for disinfection and protects inmates of 
 other parts of the house. 
 
 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 which kills 
 the non-spore-bearing bacilli, and holding there for a 
 few minutes. It is then cooled as rapidly as possible 
 
SUNLIGHT 57 
 
 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 actually renders it more 
 likely to spoil afterward if not properly taken care of. 
 Sunlight. A most admirable disinfectant is sunlight. 
 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 circum- 
 stances can produce disease. It is often difficult, there- 
 fore, 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 
 described 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 
 
RELATION OF BACTERIA TO DISEASE 59 
 
 in their usual seats upon and within the human body, 
 in their course past the primary defenses 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 defenses 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 
 
60 THE RELATION OF BACTERIA TO DISEASE 
 
 excessive hunger and thirst, by exposure to cold and 
 wet, or by prolonged muscular or mental strains. 
 
 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. Septicemia or bacteriemia is the presence of 
 the bacteria and their products circulating in the blood, 
 with some involvement of all the organs in the body. 
 Pyemia is similar to the last but includes the pro- 
 duction 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 that are specific or individual 
 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 indi- 
 vidual 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 
 
THE RELATION OF BACTERIA TO DISEASE 61 
 
 means the peculiar expression of bacterial disease has 
 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 mouth; 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 unquali- 
 fied means extracellular toxins, while intracellular 
 poisons are specifically called endotoxins. Some bac- 
 teria (cholera, for example) develop both kinds. 
 
 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. 
 
62 THE RELATION OF BACTERIA TO DISEASE 
 
 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. 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 poisons mentioned above. 
 
 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 
 diseases' 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. 
 Scales from the skin in the acute eruptive diseases of 
 children may transmit infection. Milk and water 
 
IMMUNITY 63 
 
 have been known to transmit diphtheria, typhoid, 
 scarlatina, and other conditions. Flies are potent 
 carriers of typhoid by soiling their feet on excreta and 
 then alighting on food. Other insects such as mos- 
 quitoes transmit disease. 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 prolific source of the spread of disease. 
 
 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 
 foods may be little or none 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 transferable. 
 
 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 
 
04 THE RELATION OF BACTERIA TO DISEASE 
 
 number of bacteria overcome the primary defenses 
 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 any severe circumstances. 
 
 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 
 
IMMUNITY 65 
 
 fever. Such an acquired immunity is called active 
 acquired immunity because the economy has had to 
 work for its protection. 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 diphtheria when the 
 serum of a horse which has been rendered resistant 
 to the toxin of the diphtheria bacilli is introduced. 
 This horse is said to possess active artificial immunity 
 because it has received 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 diphtheria 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. It 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. 
 5 
 
66 THE RELATION OF BACTERIA TO DISEASE 
 
 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, details of 
 which will be taken up later. 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 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 immunization" 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 temperatures to those 
 preferred by the individual species, or they may be 
 injected into animals until they will merely live with- 
 out producing disease. This is called reducing viru- 
 lence. 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 
 
IMMUNITY 67 
 
 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 anti- 
 toxin in horses, that is, making an anti-poison, or as it 
 is called, an antibody. The method just described 
 is usually reserved for the bacteria which produce 
 intracellular or endo-toxins. The method has been 
 used in treating anthrax, typhoid, cholera, etc. 
 
 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. 
 Their presence is sought by special technique in order 
 that we may substantiate and control the principles 
 outlined in the preceding paragraph. 
 
 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, whereas in the case of the 
 
68 THE RELATION OF BACTERIA TO DISEASE 
 
 bacteria when used themselves for active immunization, 
 the germ-cell disintegrates before the poison escapes. 
 
 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. 
 
 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. 
 
IMMUNITY 69 
 
 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 the 
 white cells of the blood (leukocytes). These cells are 
 also migrating cells, as they leave the blood stream 
 and wander over the body. These leukocytes are also 
 called phagocytes (adj., phagocytic) because they can 
 consume foreign bodies. Bacteria are such, and it is 
 the task of these phagocytes to remove them. It 
 has been found that in some conditions their power of 
 consuming bacteria is below par, and, further, that if 
 small numbers of germs incapable of producing disease 
 are introduced, the power of these cells may be 
 increased. The bodies producing this increased eating 
 or phagocytosis are the antibodies, opsonins, sup- 
 posed not to act upon the white cells, but upon the 
 bacteria and make them more suitable as food for 
 the leukocytes. These phenomena have put a valuable 
 method of treatment in the physician's hand. In 
 subacute localized disorders, particularly, but also 
 in definitely acute and chronic troubles, injections 
 
70 THE RELATION OF BACTERIA TO DISEASE 
 
 of dead cultures of the bacteria, responsible for the 
 condition, are made beneath the skin. The principles 
 of this treatment were discussed on page 66. The 
 progress of treatment is followed by a long elaborate 
 technique 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 con- 
 dition is closely watched also. It is now attempted 
 to use for "vaccination" a culture made from the 
 patient's disease. 
 
 The reader 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 labor- 
 atory procedures. The present conception of their 
 action was worked out by Dr. Ehrlich, a German 
 physician, 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 experi- 
 mental 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 technique used by the physician in 
 procuring specimens, and she should know the more 
 important parts of such technique. 
 
 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. 
 
72 
 
 BACTERIOLOGICAL EXAMINATION 
 
 Collection of Sputum. Sputum to be examined 
 for the tubercle bacillus should be received in a 
 
 Showing the method of taking a culture from the pharynx. (Morrow.) 
 FIG. 22 
 
 Wide mouthed bottle for collecting sputum. 
 
 thoroughly cleansed and dried wide-mouthed bottle. 
 This is given to the patient that he may expectorate 
 
COLLECTION OF FECES 73 
 
 directly into it. When the specimen has been collected 
 by the 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. 
 
 Collection of Urine. The collection of urine for 
 bacteriological purposes must be done by catheteri- 
 zation, using all possible surgical precautions as to 
 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. 
 This is best held by an assistant during catheterization, 
 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 
 
74 
 
 BACTERIOLOGICAL EXAMINATION 
 
 jar by pouring or by a pair of forceps sterilized by 
 passing through the flame. The cleansing of the 
 receptacle should be done by soap and water, alcohol, 
 and sterile water. 
 
 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. 
 
 FIG. 23 
 
 Forms of hypodermic syringe: A, Koch's syringe; B, syringe of Strohschein; 
 C, Overlack's form. 
 
 Technique of Punctures. Perhaps the most important 
 bacteriological technique 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 
 
TECHNIQUE OF PUNCTURES 75 
 
 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, alcohol, ether, and a wet dressing of 
 1 to 5000 bichloride of mercury applied. This remains 
 for two or three hours, and when ready to do the 
 operation, a goodly quantity of sterile water, or 
 preferably, salt solution, is doused or sopped on the 
 skin. The purpose of this sterilization of the skin 
 for a long time by the wet dressing is to destroy 
 the bacteria always present in the deeper layers. 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 spotted fever (cere- 
 brospinal meningitis) the causative germs are found 
 within the pus cells as double, biscuit-shaped cocci, 
 and they have a particular staining reaction by which 
 they are recognized (see Chapter VIII). 
 
 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- 
 
76 BACTERIOLOGICAL EXAMINATION 
 
 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. 
 
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 technique of hospital work 
 hinges on the fact that organisms capable of producing 
 pus are ubiquitous, and the protection of wounds 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. 
 Again, if they fall upon a wound made for an abdomi- 
 
78 LOCALIZED INFECTIONS OF PUS NATURE 
 
 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 tissue, 
 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 
 defense or the bacterial attack. If the former exceeds 
 the latter the part assumes its normal character after 
 a brief time. As the infecting forces become greater 
 in relation to the defense, just so there are greater 
 
LOCALIZED INFECTIONS OF PUS NATURE 79 
 
 effects in the production of infection. In increasing 
 severity there are the following grades: 
 
 FIG. 24 
 
 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.) 
 
 Abscess. A local collection of pus in which the 
 resistance put up by the tissue prevents the inflamma- 
 tion from going on to the next grade, or diffuse, not 
 limited, spreading cellulitis or phlegmon, or to multiple 
 abscesses. The next grade of severity would be 
 septicemia or pyemia, defined before. They arise 
 chiefly when the active inflammation enters and 
 involves the bloodvessels. The softening of tissue 
 
SO LOCALIZED INFECTIONS OF PUS NATURE 
 
 into pus is called suppuration, which may be defined 
 as the destruction of tissues and cells by the products 
 of bacteria. Pus under the microscope is composed of 
 white blood cells, particularly the so-called polynuclear 
 leukocytes, microorganisms, and partly or wholly 
 destroyed tissue. There is also some granular 
 fluid. 
 
 While the term pus is applied to all the degenerated 
 products of inflammation, there is a special word when 
 the material collects on a surface. This is usually desig- 
 nated as an exudate. For example, the false membrane 
 of diphtheria is called an exudate as is also the fluid 
 containing shreds within the pleural or abdominal 
 cavities, or in the lungs in pneumonia. 
 
 PUS-PRODUCING MICROORGANISMS 
 
 It has been stated that there is no particular germ 
 alway responsible for pus, but there is a small group 
 of the round bacteria most commonly present. They 
 are called micrococci or staphylococci, and strepto- 
 cocci. 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, 
 pseudodiphtheria bacillus. 
 
 Staphylococcus Pyogenes Aureus. Of the micrococci 
 there is one particular species of importance which 
 by some bacteriologists has been divided into two on 
 account of its ability to produce color in laboratory 
 cultures and because the one having a golden yellow 
 
PLATE II 
 
 Cultures of Bacteria. (Besson.) 
 
 The jellies upon w^ieh 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. 
 
PUS-PRODUCING MICROORGANISMS 81 
 
 pigment is somewhat more frequently found in pus. 
 This color-producing organism is called the Staphylo- 
 coccus pyogenes aureus (the golden pus-producing 
 coccus). See Plate II for an idea of growth and color. 
 It is about 2TTRTO of an inch across and appears under 
 the microscope in single individuals, pairs, and more fre- 
 quently, in grape-like groups. It stains fairly well with 
 most dyes used. It does not form spores and does not 
 move from place to place by its own power. It grows 
 
 FIG. 25 
 
 Staphylococcus. X 1100 diameters. (Park.) 
 
 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 
 gelatine by the ferments it produces. It is killed by 
 corrosive sublimate, 1 to 1000, in ten minutes in 
 6 
 
82 LOCALIZED INFECTIONS OF PUS NATURE 
 
 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 germi- 
 cide. 
 
 This organism is very virulent for the smaller animals, 
 which may be affected even 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 
 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. 
 
 Opsonic Index. The use of killed bacteria to produce 
 an increased resistance against an existing infection 
 has already been discussed. This method of treat- 
 ment is particularly suitable for infections with these 
 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 
 
PUS-PRODUCING MICROORGANISMS 83 
 
 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 technique 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 
 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. 
 
 Vaccine Treatment. The theory and practice of this 
 so-called "vaccine treatment" or treatment with killed 
 bacteria are beset with many difficulties, and must 
 be carried out by specialists. The dead cultures are 
 called vaccines or bacterins. Today bacterins made 
 from the patients' infecting organism are chiefly used, 
 but chemical houses are putting on the market what 
 are called stock bacterins. The most suitable disease 
 for treatment of this kind is furunculosis (boils). 
 
 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 
 
84 LOCALIZED INFECTIONS OF PUS NATURE 
 
 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. It is 
 not so widespread in its distribution as the foregoing 
 coccus, but is greatly feared in surgical wards. Strepto- 
 coccus peritonitis is usually fatal. It is commonly 
 present in the mouth, and may produce tonsillitis. 
 Disinfection of materials from streptococcic infections 
 should be done by carbolic, bichloride, or hydrogen 
 peroxide. Great care is necessary in the handling of 
 dressings, clothing, and utensils from patients with 
 streptococcus infections, because, despite the low 
 resistance of the organism, transmissions take place 
 quite easily. When the particular family of germs 
 happens to be very virulent, a single coccus may 
 transmit an infection. 
 
 FIG. 26 
 if" ,- r ..-"x 
 
 Streptococcus pyogenes. (Abbott.) 
 
 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 -simFiF to 2TT07 of an 
 inch, dividing only in one plane and therefore growing 
 in chains. They are unable to move of themselves, 
 
PUS-PRODUCING MICROORGANISMS 85 
 
 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 
 milk or gelatine. 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. Attempts at 
 producing some serum to neutralize either of these 
 toxins have met with little success. The vaccine 
 treatment is likewise not successful. 
 
 To diagnosticate infections by the staphylococcus 
 or streptococcus we are obliged to make our technique 
 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. 
 
86 LOCALIZED INFECTIONS OF PUS NATURE 
 
 MICROCOCCUS GONORRHOEA 
 
 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 gonorrhoeas or gonococcus, which enters the 
 mucous membrane directly wherever there is a slight 
 chiefly 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. 
 The causative organisms penetrates 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. It 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 
 resides 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 salpingoophoritis, requir- 
 ing operative removal of the affected parts. Either 
 
MICROCOCCUS GONORRHCEM 87 
 
 during its acute or chronic stage, the latter more 
 commonly, the gonococci may enter the blood stream 
 and affect tissues other than the genital, 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 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 
 contact, schools, for example. It is supposed to be 
 
88 LOCALIZED INFECTIONS OF PUS NATURE 
 
 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 sleeping 
 with some one with gonorrhea. 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 insti- 
 tute 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 physician 
 upon admission, and if necessary, proper bacteriologi- 
 cal 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 appro- 
 priate 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 
 like two kidney beans with their concave sides together. 
 
MICROCOCCUS GONORRH(E 89 
 
 They are also said to be of biscuit shape. Each bean is 
 about -g"o1ro o f an mcn wide and yg-Jinr of an inch 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- 
 blance between these organisms and those of meningitis 
 (p. 92), but the clinical differentiation is not difficult, 
 since the diseases are easily separated. 
 
 FIG. 27 
 
 
 
 t, "* 
 
 -.** ^ , 
 
 Pus of gonorrhea, showing diplococci in the bodies of the pus cells. 
 (Abbott.) 
 
 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, 
 
90 LOCALIZED INFECTIONS OF PUS NATURE 
 
 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 G.) 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. 
 
 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. 
 
 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, 
 
MICROCOCCUS MENINGITIDIS 91 
 
 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 enters the 
 spaces between the nervous organs and their bony 
 casement by way of the nose, whence it penetrates the 
 sieve-like plate at the top into the space beneath the 
 brain, and proceeds by extension. 
 
 The other forms of meningitis, the pneumococcal for 
 instance, gains 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 may be found in the nose 
 and throat of patients, and indeed also in the nose and 
 throat of those attending them. 
 
 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 
 the spinal column and interior of the brain. The dis- 
 ease has a high mortality. It affects chiefly the young. 
 Its results or sequelae consist in blindness, deafness, 
 and paralyses of various kinds. Mentality may be 
 affected. 
 
 In taking care of meningitis patients the chief 
 
92 LOCALIZED INFECTIONS OF PUS NATURE 
 
 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. 
 
 FIG. 28 
 
 
 
 V 
 
 ;. 
 
 '* 
 
 t 
 
 : 
 
 Meningococcus in spinal fluid. (Hiss and Zinsser.) 
 
 The nose and throat of those in attendance should be 
 sprayed with an antiseptic, those containing thymol 
 being excellent for the purpose. After death the body 
 should be encased in a cloth wetted with carbolic acid 
 solution. 
 
MICROCOCCUS MENINGITIDIS 93 
 
 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 not stained by the Gram method. 
 As is the case with gonococcus, they lie within the pro- 
 toplasm, 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 labor- 
 atory media especially if they contain blood serum or 
 glucose. They grow best in the presence of oxygen, 
 at 37.5 C. or 98 R, but die rapidly if not put on 
 fresh food frequently. They will live a considerable 
 time in the ice-box, unlike the gonococcus. 
 
 They are killed by heating to 50 C. or 122 F. for 
 ten minutes, by exposure to sunlight at once, and 
 
94 LOCALIZED INFECTIONS OF PUS NATURE 
 
 by almost all disinfectants in appropriate strength in 
 five minutes. 
 
 Antimeningitis Serum. Meningitis cocci belong to 
 the bacteria which produce endotoxins. As anti- 
 bodies to this toxin, agglutinins and antibacterial 
 bodies or bacteriolysins are formed. The endocellular 
 poisons are the bodies responsible for the peculiar 
 effects of these cocci, and there have been many 
 experiments with the object of finding a serum which 
 will counteract the effect of this part of the organism. 
 Animals are not very susceptible to the meningitis 
 coccus, but at last it was found that the poison ex- 
 tracted from the bodies by letting them disintegrate in 
 water, would poison animals. Therefore, by starting 
 with minute non-poisonous doses and rising in quantity 
 and strength it was possible to procure a serum from 
 goats which was protective or neutralizing when mixed 
 with a dose of the poison sufficient alone to affect an 
 unprepared animal. This is immunizing actively to 
 procure a serum to be injected into another animal 
 (human being) to immunize it passively. The use of 
 such a serum has met with great success both here 
 and abroad, and the mortality of the disease has been 
 greatly reduced. 
 
 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 Diplococcm or Streptococcus pneu- 
 monicB or pneumococcus. This omnipresent organism 
 gains entrance to the body almost exclusively by 
 
DIPLOCOCCUS PNEUMONIA 95 
 
 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, 
 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. 
 
 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. If cloths are used to wipe the mouth, 
 they should be burned. This is the chief method for 
 protecting the well. Rinsing the throat with a mild 
 antiseptic is advisable both for patients and nurses. 
 
 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. 
 
90 LOCALIZED INFECTIONS OF PUS NATURE 
 
 This shape and envelope are quite characteristic, and 
 almost determinative. The coccus grows very slightly 
 
 FIG. 29 
 
 Pneumococcus from bouillon culture, resembling streptococcus. (Park.) 
 FIG. 30 
 
 Pneumococci in peritoneal pus. Stained with fuchsin. X 1000 diameters 
 Clear spaces indicate capsules. (Park.) 
 
 on ordinary culture media, but best when blood or 
 blood coloring matter is added. It then produces a 
 
DIPLOCOCCUS PNEUMONIA 97 
 
 faint green color and grows best at 37 C. or 98 F., but 
 does not live long, requiring repeated transference to 
 fresh food. In sputum the pneumococcus may remain 
 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. But 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. The resistance of animals to the pneumo- 
 coccus can be increased by repeated injections, but 
 the serum of such has no value in the treatment of 
 pneumonia. The use of vaccines has not been followed 
 by uniformly favorable results. The blood in pneu- 
 monia 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 clinical course. 
 
 BACTERIUM DIPHTHERIA 
 
 Diphtheria is a disease characterized by the develop- 
 ment of a so-called false membrane upon a mucous 
 membrane or abraded surface, caused by the Bacterium 
 diphtheria, or diphtheria bacillus, or Klebs-Loffler 
 bacillus, from which the soluble poisons are absorbed 
 by the circulation. This false membrane is an inflam- 
 matory 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 
 only their toxins are absorbed and are responsible 
 

 BACTERIUM DIPHTHERIA 99 
 
 for the clinical symptoms of illness. These are moder- 
 ate fever with rapid pulse, and great prostration. 
 They are also responsible for the paralyses which 
 frequently follows 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. 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- 
 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, 
 
100 THE ACUTE SELF-LIMITED INFECTIONS 
 
 5 per cent., and drying in the sun are demanded when 
 the nurse leaves the patient. The nurse should 
 receive immunizing doses of antitoxin. Since the 
 bacilli spread through the air, sheets wetted with 
 disinfectants should be hung about, particularly at 
 doors. 
 
 FIG. 31 
 
 A. 
 
 Bacterium diphtheria: A, its morphology on glycerin-agar-agar; B, its 
 morphology on Loffler's blood serum; C, its morphology on acid blood serum 
 mixture. (Abbott.) 
 
 For diagnosis of diphtheria use is made of direct 
 examination of stained smears from the site of trouble, 
 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 
 
BACTERIUM DIPHTHERIA 101 
 
 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 TOTOT to Tinnr 
 of an inch in length, and from 5~oiro"o to 2~5iroiy of 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 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 they die in twelve to 
 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 
 
102 THE ACUTE SELF-LIMITED INFECTIONS 
 
 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 
 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 
 
BACTERIUM DIPHTHERIA 103 
 
 be injected and much blood withdrawn without 
 harming the beast. The horses receive under the 
 skin gradually increasing quantities of this toxic broth 
 until they are able to withstand huge quantities, 
 many times the quantity 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 separ- 
 ated from the red blood cells. It is then 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 technique the number of 
 "units" is determined. 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 weighing 250 grams (8i 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 
 300 to 1000 units are used. In both cases a repetition 
 of the dose iis 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 
 
104 THE ACUTE SELF-LIMITED INFECTIONS 
 
 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. 
 
 Serum Sickness. Sometimes what is called serum 
 sickness occurs after antitoxin injections. This con- 
 sists in a general feeling of illness, with skin eruptions, 
 swelling of the glands, edema, and albumin in the 
 urine. It occurs in susceptible individuals, and its 
 cause is unknown. Some ascribe it to a peculiar 
 phenomenon of also unknown nature, called anaphy- 
 laxis, not necessary to describe here. Occasionally 
 sudden death has occurred. The fatal cases are 
 said to have been in individuals susceptible to the 
 presence of horses. 
 
 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 for two successive 
 days. 
 
BACILLUS TETANI 105 
 
 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 
 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 formation 
 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 their secluded place in the 
 depths of wounds favors their development and that 
 of their toxin. If other germs are introduced the tissues 
 are further devitalized by them, and favorable con- 
 ditions for tetanus increased. Either spores or vege- 
 tating germs may be introduced on rusty nails, splinters 
 of wood or glass, blank cartridge plugs, or the grinding 
 of dirt into wounds. Tetanus sometimes appears in 
 the newborn or in the puerperal mother, particularly 
 after instrumental delivery. Ordinary gelatine is said 
 to often contain spores. 
 
106 THE ACUTE SELF-LIMITED INFECTIONS 
 
 Between the time of introduction of the germs 
 and the outbreak of symptoms a period of incuba- 
 tion 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, TTSTTO to Woo" mcn 
 long by ^"oioT to "SWOT 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 gelatine and grows characteristically in it. 
 
BACILLUS TETANI 107 
 
 In discussing the resistance of this germ to deleterious 
 agents, the spores only need be considered, because 
 the vegetative rod has the power of going into this 
 resistant stage very quickly when it meets unfavorable 
 environment. The rods grow best at 38 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. 
 
 FIG. 32 
 
 Tetanus bacilli with spores in distended ends. X 1100 diameters. (Park.) 
 
 hydrochloric acid in two hours; 1 to 1000 corrosive 
 sublimate in three hours; 1 to 1000 corrosive sublimate 
 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. 
 
108 THE ACUTE SELF-LIMITED INFECTIONS 
 
 Tetanus Antitoxin. The toxin of the tetanus bacillus 
 is one of the most virulent poisons known. For ex- 
 ample, Trnmnnnr cubic centimeter or e^oVor minim 
 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 poison 
 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. 
 
BACILLUS TYPHOSUS 109 
 
 It is best to give 10,000 units by the vein and 
 repeat 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 Peyer's plaques. These bodies swell 
 toward the free lumen of the canal, 'and the centre 
 
110 THE ACUTE SELF-LIMITED INFECTIONS 
 
 finally softens from the effect of the bacilli. When 
 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. Polluted water and food 
 infected by flies that have soiled their bodies upon ex- 
 creta, 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 hill- 
 sides, 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 water supply typhoid fever ceases 
 to be prevalent among the users of the water. Ice is 
 
BACILLUS TYPHOSUS 111 
 
 said to be another 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 con- 
 traction 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 introduced somewhere in the route from her to the 
 consumer. Vegetables grown in ground upon which 
 infected manure or water has been spread may carry 
 the disease ; such are, 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 
 
112 THE ACUTE SELF-LIMITED INFECTIONS 
 
 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. 
 
 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 carbolic 
 or corrosive sublimate solution for an hour, and then 
 boiled. The same procedure should be followed 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 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" 
 
 The typhoid bacillus is an organism exerting its 
 noxious power by means of poisons contained in its 
 body and liberated upon its disintegration. These 
 endocellular poisons are capable of calling forth a 
 reaction upon the part of the body which results in 
 
BACILLUS TYPHOSUS 
 
 113 
 
 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 
 more bacteriolysin than is possessed by the blood of 
 a person who has never suffered from typhoid. 
 
 FIG. 33 
 
 Microscopic field, showing the top of a hanging drop in a normal typhoid 
 culture. (Park.) 
 
 Widal Test. Far more important antibodies are 
 the agglutinins 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- 
 pension of the living actively motile germ is prepared. 
 Some blood from the patient is obtained, the clear 
 8 
 
114 THE ACUTE SELF-LIMITED INFECTIONS 
 
 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 observed 
 
 FIG. 34 
 
 Microscopic field, showing the top of a drop with the typhoid reaction. 
 (Park.) 
 
 under the microscope after they have stood together 
 for a definite time, and the presence of clumping, 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 
 
BACILLUS TYPHOSUS 
 
 115 
 
 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 techniques have 
 been devised to hasten work on epidemics and carriers, 
 but none is as yet very good. 
 
 FIG. 35 
 
 Typhoid bacilli from nutrient gelatin. X 1100 diameters. (Park.) 
 
 Morphology. The typhoid bacillus is a motile rod 
 5-11-00- to s TO 0" inch long and 3- oi <ro to -^WiF inch wide, 
 with rounded ends, growing in long threads at times. 
 Its motility is due to flagella all around its cell wall. 
 It forms no spores. It stains easily, oftentimes more 
 densely at the rounded ends. It grows in the presence 
 or absence of oxygen, best at 37 C. or 98 F., but also 
 at room temperature. It is killed by heating at 60 C. 
 or 142 F. for five minutes, or to 52 C. or 126 F. for 
 
116 THE ACUTE SELF-LIMITED INFECTIONS 
 
 ten minutes when in water solutions. It usually dies 
 rapidly when dried, but occasionally lives for some 
 weeks. It is killed in watery suspension by 1 per cent, 
 carbolic acid or 1 to 1000 bichloride in ten minutes. Its 
 characters in laboratory culture media are not easy to 
 describe, and indeed it often puzzles the trained observer 
 to identify it. Suspected cultures are usually subjected 
 to the Widal test, using the blood of a patient with 
 typhoid fever, and known to clump a true typhoid 
 
 FIG. 36 
 
 Typhoid bacillus with faintly stained flagella. (Loffler's method.) (Park.) 
 
 bacillus. The bacillus belongs to the so-called typho- 
 colon group (see p. 164). The lower animals do not 
 develop typhoid fever when inoculated with this germ, 
 but die of septicemia, usually with peritonitis. 
 
 Immunization. An antitoxin to the typhoid bacillus 
 cannot be produced, but attempts at active immuni- 
 zation have been made with some success. These 
 attempts take the direction of injecting the bacilli 
 in such a form that they cannot produce the disease, 
 
BACILLUS TYPHOSUS 117 
 
 but yet set up some resistance to it comparable to that 
 acquired by passing through a spontaneous attack. 
 The bacilli are prepared like the vaccines or bacterins 
 described on p. 82, and injected under the skin. A 
 slight fever may result but no further bad effects have 
 been noted. All symptoms are over in twenty-four 
 hours after each injection. The bacteria are intro- 
 duced three times. The immunity resulting is sup- 
 posed to last about two years. This vaccine method 
 is well adapted for and most used by armies going into 
 camps. The results in our army and that of Great 
 Britain have been very encouraging. It should be 
 taken by nurses doing army nursing or seeing many 
 typhoid cases. 
 
 Major Russell, U. S. A., concludes his investigations 
 into the theory and practice of antityphoid vaccination 
 as a prophylactic as follows : 
 
 1. Antityphoid vaccination in healthy persons is a 
 harmless procedure. 
 
 2. It confers almost absolute immunity against 
 infection. 
 
 3. It is the principal cause of the immunity of our 
 troops against typhoid in the recent Texas maneuvers. 
 
 4. The duration of the immunity is not yet deter- 
 mined, but is assuredly two and one-half years and 
 probably longer. 
 
 5. Only in exceptional instances does its administra- 
 tion cause an appreciable degree of personal discomfort. 
 
 6. It apparently protects against the chronic bacillus 
 carrier and is at present the only means by which a 
 person can be protected against typhoid under all 
 conditions. 
 
118 THE ACUTE SELF-LIMITED INFECTIONS 
 
 7. All persons whose profession or duty involves 
 contact with the sick should be immunized. 
 
 8. The general vaccination of an entire community 
 is feasible and could be done without interfering 
 with general sanitary improvements, and should be 
 urged wherever the typhoid rate is high. 
 
 Paratyphoid Fever. There is a variety of enteric 
 fever called paratyphoid fever. This is caused by the 
 Bacillus paratyphosus, an organism closely allied to 
 the true typhoid bacillus and only separated from it by 
 its ability to ferment certain sugars and the quantity 
 of acid it produces under artificial conditions. In para- 
 typhoid fever, however, the blood will not clump 
 (agglutinate) the true typhoid bacillus but does have 
 such an action upon the paratyphoid bacillus. In 
 this form of fever the course is shorter, the attack is 
 milder, and complications are much less frequent. 
 There is usually no ulceration of Peyer's plaques and 
 therefore hemorrhage from the bowel is of extreme 
 rarity. It is nevertheless an infectious disease, entirely 
 comparable in its origin, course, transmission, and 
 epidemic character to true typhoid fever, and the same 
 precautions of disinfection must be observed. 
 
 BACTERIUM INFLUENZA 
 
 Influenza is also called la grippe or grip, and is an 
 acute catarrhal disease usually involving the mucous 
 membrane of the upper respiratory tract, but also 
 penetrating to the deeper parts. Its causative bac- 
 terium is the Bacterium influenza or the influenza 
 bacillus. The disease is one which appears in epidemic 
 
BACTERIUM INFLUENZA 119 
 
 form usually, but sporadic cases also occur. The 
 organisms are carried in the nose and throat and 
 communicated to others in the fine particles coughed 
 or spat out. They lodge on the mucous surfaces and 
 produce an inflammation through which the poisons 
 are absorbed. The rods themselves do not usually 
 enter the blood stream, and their poisons are largely 
 extracellular. They may enter the blood, as is attested 
 by the fact that there are influenzal forms of pleuritis 
 and pericarditis, diseases probably not due to an 
 extension by continuity. Influenzal pneumonia occurs 
 when the bacteria penetrate to the lung tissue proper. 
 It is comparable in development to the pneumonia 
 caused by the pneumococcus. The bacillus may at 
 times form pus. 
 
 The attack of influenza runs an acute course. It 
 leaves but a transient immunity, and one attack is said 
 actually to predispose to another when the individual 
 is exposed subsequently. As complications of influenza 
 of the upper air passages we may have pus in the 
 sinuses about the nose, or otitis media. 
 
 While influenza is an acute disease and the bacteria 
 are actively virulent during an attack, it is believed 
 that they remain in the upper air passages in abey- 
 ance and not producing disease for long periods after 
 the acute symptoms have subsided. When they are 
 received in sputum particles upon the nose or mouth 
 of another person not resistant to them, they regain 
 their activity and inflame the parts. They are said 
 to remain in the lung tissue for a long time until 
 some reduction of the person's resistance permits 
 the lighting up of a pneumonia. 
 
120 THE ACUTE SELF-LIMITED INFECTIONS 
 
 With these facts in mind it is not difficult to under- 
 stand how sporadic cases occur and how the disease 
 spreads rapidly from one patient to another. The 
 bacilli get to work on the mucous membranes rapidly, 
 and the incubation period is short, three days at the 
 longest. Epidemics have been known to spread over 
 whole continents in a season. Many observers believe 
 that other organisms, notably streptococci, help in 
 the production of these acute influenzal colds. It is 
 undoubtedly true that the influenza bacillus is seldom 
 found in pure culture, that is, in absence of some other 
 organism with pathogenic properties. The bacilli are 
 found in the excretions and secretions from the nose, 
 mouth, and lungs. All excretions should be received 
 into carbolic acid solution, and the mouth and nose fre- 
 quently douched with a mild antiseptic. The nurse and 
 members of the family should use care with the nose and 
 mouth in frequent rinsing with weak antiseptics, such as 
 hydrogen peroxide. For diagnosticating this disease 
 smears and cultures are made from some of the glaring 
 mucus at the back of the throat or a good specimen of 
 sputum coughed from the lungs. The smears on slides 
 are stained with appropriate dyes. Under the micro- 
 scope the delicate rods are found in pairs on end, lying 
 in groups or within the pus and epithelial cells. In 
 cultivating these organisms media containing whole 
 blood or blood coloring matter, hemoglobin, must be 
 used. They will not grow in the absence of the latter. 
 Their colonies upon solid media containing it are 
 rather characteristic. During an attack the bacteria 
 produce some agglutinins in the blood and the agglu- 
 tination or clumping test may be used with them. 
 This is not highly practical and seldom used. 
 
PLATE III 
 
 Bacterium Influenzse in Sputum. (Abbott.) 
 
BACTERIUM INFLUENZA 121 
 
 The influenza organism is a very minute rod with 
 pointed or round ends and commonly lying in pairs 
 with their ends together. They do not move nor 
 form spores. They measure about 5~o1ro"o mcn l n g 
 and rooVoo- to T5T151F inch wide. They require 
 oxygen for growth, which occurs on blood containing 
 media as fine dewdrop-like colonies. Their general 
 biological characters offer fine details not needed 
 here. They require body heat, 37.5 C. or 98 F., for 
 development, and are killed at 50 C. or 122 F. for 
 ten minutes; 60 C. or 142 F. kills at once. They die 
 in twelve hours if dried in sputum, but may live 
 without multiplication for several days in moist 
 sputum at ordinary temperature. Five per cent, 
 carbolic acid kills them in well mixed sputum in five 
 minutes. For animals this bacterium is not very 
 pathogenic. Rabbits and monkeys, if injected into 
 the vein with a pure culture exhibit very quickly signs 
 of an intoxication, which rapidly passes away. Mon- 
 keys may get an acute cold by the direct application 
 of the bacilli to the abraded mucous membrane of the 
 nose. No satisfactory method has as yet been devised 
 for specifically treating influenza patients with the 
 killed germs or their antitoxins, but it is perfectly 
 feasible to use bacterin treatment since the disease is 
 usually local. It is possible that no immunity exists 
 after influenza because of the confinement of the germs 
 at one place. Experiments now under way may result 
 in something helpful for this most annoying and some- 
 times serious disease. 
 
122 THE ACUTE SELF-LIMITED INFECTIONS 
 
 BACILLUS PESTIS 
 
 Bubonic plague or "the plague" or "pest" is an acute 
 infectious disease characterized by high fever, swell- 
 ings of the regional lymph glands, or pneumonia, with 
 occasional hemorrhages (black death) under the skin 
 in severe cases, caused by the Bacillus pestis. The 
 disease is fostered by unhygienic conditions, and may 
 be said to be more common in those countries where 
 the people go about scantily clothed, especially about 
 the feet. There are two forms of the plague, according 
 to the place of entrance of the bacteria. The bubonic 
 type is that in which painful swellings and abscesses 
 occur in lymph glands when germs enter through the 
 skin and the pneumonic type occurs when they are 
 inhaled. 
 
 The bacteria enter chiefly through the skin by way 
 of minute wounds, or as was shown in India, by the bite 
 of a rat flea, parasitic to man in that country. Rats and 
 mice, indeed all rodents, are susceptible to plague and 
 they contract it from biting the living, feeding on the 
 dead and soiling themselves on dressings or excreta. 
 When infected they have great numbers of bacilli in 
 their blood, thus easily passing them on to fleas that bite 
 them. The fleas then pass the disease to other rats 
 and to man. Furthermore, rats may vomit, defecate, 
 and die where they can infect objects later handled 
 by persons. The rats are said to transmit the disease 
 also by biting people. In epidemic times the ground 
 becomes infected, and persons going barefoot may be 
 infected. By any of the skin wound methods, the 
 germs enter the subcutaneous tissue, are carried to 
 
BACILLUS PEST IS 123 
 
 the nearest lymph glands, where they set up inflam- 
 mation and pus, which is frequently discharged by 
 rupture through the skin. The bacteria enter the 
 blood stream and produce a septicemia. 
 
 1ft the pneumonic form the bacteria are inhaled and 
 set up a pneumonia not unlike that produced by 
 ordinary cocci. Here again there may be suppuration 
 and septicemia. 
 
 The bacilli produce the characteristic results chiefly 
 by means of their endotoxins, little or no separable 
 poisons being formed. There is no difference in 
 the bacteria or their products in the two forms 
 which simply depend on their mode of entry. The 
 mortality of this disease is very high, due to the 
 rapid progress made after the disease gains a foothold. 
 The incubation is three to seven days. The bacteria 
 are present in the blood, pus, and sputum in enormous 
 numbers. They may be also in dejecta. Many suppose 
 them to be in the breath, but this is probably erroneous. 
 They are in the droplets of saliva expelled by cough- 
 ing, sneezing, and talking. It is customary in times 
 of epidemics, to go about with a towel over the nose 
 and mouth, with the feet and ankles well bound, 
 and all surfaces covered. Sputum, urine, and feces 
 should be received into 5 per cent, carbolic acid and 
 allowed to remain, well mixed, for two hours. Dress- 
 ings from ulcerated surfaces must be burned. Doors 
 and windows must be screened against flies and mos- 
 quitoes. The room must be rat- and mouse-free. After 
 death formaldehyde or carbolic acid solution is to be 
 injected into the body entrances and applied about the 
 body on the winding sheet. 
 
124 THE ACUTE SELF-LIMITED INFECTIONS 
 
 For diagnosticating this disease an abscess is punc- 
 tured, the pus withdrawn, and slide smears and cultures 
 are made. The bacilli are found in countless numbers. 
 Cultivation on ordinary media is simple. A blood 
 culture will also reveal their presence. At death 
 bacteria will be found in practically every organ in 
 the body. 
 
 The plague bacillus is a short plump rod, TT~O"O~O to 
 -nrfor inch long by ^imnr to -girihro inch wide. It does 
 not move nor form spores. It grows best at 35 C. 
 or 92 F. It is stained with reasonable ease, displaying 
 a peculiar picture. The bacilli are short thick rods 
 with rounded ends. The end sections stain much 
 more densely than the middle part, called bipolar 
 staining. These rods may grow longer and appear 
 in pairs or short chains. They are killed by 60 C. 
 or 142 F. in ten minutes, or by boiling water in two 
 minutes. They resist drying for two or three days 
 under natural conditions, but when drying is hastened 
 by artificial means, they live only a few hours. They 
 resist cold and freezing for a long time, perhaps a 
 month. Sunlight destroys them in five hours. In 
 pus or sputum they may live a few weeks, but in 
 cadavers they have been found after several months. 
 Chemicals kill them as follows: 5 per cent, carbolic 
 acid and 1 to 1000 bichloride in ten minutes. Animals 
 are usually susceptible to Bacillus pestis, particularly 
 guinea-pigs and rats, and it is said that simple rubbing 
 of them on the skin of these beasts will produce the 
 infection. It is similar to the human disease. 
 
 Plague Serum. The poison of Bacillus pestis is 
 largely intracellular. It has been possible, however, 
 
PLATE IV 
 
 Bacillus of Bubonic Plague. (Abbott.) 
 
 A, in pus from suppurating bubo; B, the bacillus very much 
 enlarged to show peculiar polar staining. 
 
SPIRILLUM CHOLERA ASIATICS 125 
 
 to get a serum which will destroy the bacteria and can 
 be used therapeutically. The bacteria grown in the 
 laboratory are killed by moderate heat and injected 
 into animals. The injections are continued until 
 very large doses, fatal to unprepared animals, are 
 withstood. The serum now has properties which will 
 neutralize the endotoxins of the plague bacillus, and 
 is called a bactericidal serum. It is said to have also 
 some antitoxic properties that neutralize the small 
 amount of extracellular poison of this organism. This 
 serum is used for treatment during the attack or for 
 immunizing those exposed. The results have been 
 promising. 
 
 Not only is this passive immunity made use of, but 
 for prevention of infection, plague bacilli whose patho- 
 genic properties are destroyed by heat are also injected 
 precisely as has been described for typhoid fever. This 
 "vaccine" treatment of Haffkine, and one of the first 
 of such procedures, gives an immunity for a few months. 
 Immunity against a subsequent attack always follows 
 plague. Thus there is an active immunizing therapy 
 for plague, and passive immunizing substances can 
 be added to the patient's own defenses. 
 
 SPIRILLUM CHOLERA ASIATICS 
 
 Cholera is an acute inflammatory disease of the small 
 intestines characterized by profuse watery stools, a 
 profound prostration, muscular pains, and high fever. 
 It is caused by the Spirillum cholera asiaticce or 
 cholera spirillum or vibrio. The bacteria enter the 
 body only through the mouth, and settle upon the 
 
126 THE ACUTE SELF-LIMITED INFECTIONS 
 
 mucous membrane of the lower part of the small 
 intestine. This they penetrate only as far as the 
 deeper layers of the innermost coat of the tube, and 
 by their growth cause a shedding of the coat. The 
 shreds of the desquamated mucous membrane pass off 
 with the watery discharges, and cause the characteristic 
 "rice water" stools. The bared and congested surface 
 permits absorption of the poisons of the spirillum, the 
 body of which does not itself enter the blood stream. 
 The poison quite frequently has a depressing action 
 upon the heart muscle. It is not quite certain whether 
 or not this is a wholly extracellular toxin or combined 
 closely with the bacterial bodies. It is probably mostly 
 of the latter character, an endotoxin separated upon 
 the disintegration of the germ cells. 
 
 Cholera is a disease transmitted almost exclusively 
 by polluted water, although food infected with bacteria 
 may, of course, transmit it. Water is contaminated by 
 dejecta of cholera patients, and the vibrio leaves the 
 patient in no way but with feces (or vomiting of intes- 
 tinal contents, a rare occurrence). Large numbers of 
 vibrios are present in the feces early in the attack. Later 
 they rapidly decrease, but do not disappear from the 
 gut and feces, and may continue to come away in small 
 numbers for many months. In such cases they natur- 
 ally pollute anything with which the dejecta come in 
 contact. They do not live long in nature, however, and 
 regulations can be made to kill them. Flies having 
 soiled themselves upon cholera excreta may carry the 
 germs. Vegetables may be soiled from water. Personal 
 contact and handling of clothes from patients have the 
 same value in transmission of cholera as for typhoid 
 
SPIRILLUM CHOLERA ASIATICS 127 
 
 fever. As the organisms leave the body only with the 
 feces, measures should be taken to disinfect them, and 
 anything likely to be soiled with them. The feces 
 should be received into 5 per cent, carbolic acid 
 solution. The buttocks and anus should be wiped 
 with 1 to 1000 bichloride solution. Clothes or bedding, 
 glasses, utensils, and other objects should be soaked 
 in these solutions. Boiling when possible is advisable. 
 A disinfecting hand lotion should be constantly used 
 by the attendants. It is necessary to continue disin- 
 fection of stools for varying periods after an attack, 
 since bacteria lurk in the depths of the intestinal 
 mucosa, and are excreted long after the acute symp- 
 toms have disappeared. 
 
 Cholera is diagnosticated bacteriologically by culti- 
 vation of the stools. The organisms are present in 
 almost pure culture, and can be made to grow quite 
 easily. There are several other spirilla of similar form 
 and manner of growth, and sometimes delicate bio- 
 logical tests (see below) are necessary. Agglutination 
 tests may be used in this disease, as some clumping 
 power is acquired by the blood during an attack. 
 Another antibody is formed which has the power of 
 dissolving the cholera spirilla. This is a bacteriolysin. 
 Animals injected with the cholera organisms also 
 acquire this power. If a guinea-pig be injected with 
 spirilla up to a point where it will resist large numbers, 
 its blood serum will dissolve the living organisms 
 either in the test-tube or, what is better, within the 
 abdominal cavity of another guinea-pig. In the latter 
 case the antiserum from the prepared guinea-pig and 
 living rods are injected together. The rods are devital- 
 
128 THE ACUTE SELF-LIMITED INFECTIONS 
 
 ized and the pig lives, although another animal receiving 
 the organisms in like quantity, but without serum, will 
 die. This is the method suggested which can be used 
 to identify suspected cultures, using as the protective 
 blood serum that from an animal previously treated 
 with known cholera germs. 
 
 The cholera spirillum is a curved organism something 
 the shape of a comma, and is sometimes called the 
 comma bacillus. One end is apt to be thicker than 
 the other. It sometimes appears like an S when two 
 are joined on end. Long filaments may be seen in 
 fluids. In old laboratory cultures it may appear as a 
 short, straight rod or club. It is actively motile by 
 means of a long single flagellum on the end. No spores 
 are formed. It measures from inAnr to yjnnr mcn m 
 length by TSTIJT mcn m width. It is not easy to measure 
 since spirilla are not simple curves but spirals. It does 
 not stain with great ease, but a weak watery solution 
 of fuchsin is the best. It grows best in the presence of 
 oxygen at 37.5 C. or 98 F., but may grow at ordinary 
 temperatures. It has the power of digesting gelatin 
 and solidified blood serum, but does not clot milk. It 
 resists 60 C. or 142 F. for one hour, but boiling kills 
 at once. It multiplies at the temperature of foodstuffs, 
 and freezing does not destroy it under three days. 
 Drying kills certainly in twenty-four hours in diffuse 
 light. Sunlight kills within one hour. The figures 
 indicate some resistance to heat and light, but against 
 chemicals this is not maintained; 1 to 1000 bichloride 
 is fatal in ten minutes; 1 per cent, carbolic acid a 
 little longer; lime in any form is rapidly fatal to the 
 spirillum. 
 
BACILLUS DYSENTERIC 129 
 
 Animals do not contract cholera either spontaneously 
 or artificially, but they may be killed by the germs or 
 their poisons. The active acquired immunity they get 
 by repeated injections has been described. It has not 
 been found practical to obtain any serum from animals 
 which can be injected into human beings as a treat- 
 ment. Dead spirilla, however, can be injected into 
 well persons as a protective measure, precisely as is 
 done for typhoid and plague, and with good results. 
 
 FIG. 37 
 
 Spirillum of Asiatic cholera: /, stained by ordinary method; //, stained 
 to show flagella. (Abbott.) 
 
 BACILLUS DYSENTERIC 
 
 Dysentery occurs in two forms the bacillary type 
 
 and the amebic type. The former is caused by bacteria, 
 
 while the latter is a protozoon disease (see Chapter 
 
 XIV). Bacillary dysentery is an acute infectious 
 
 9 
 
130 THE ACUTE SELF-LIMITED INFECTIONS 
 
 disease, its chief lesion being a violent inflammation 
 of the lining of the large intestines. The disease is 
 caused by the Bacillus dysenteries or dysentery bacillus. 
 It is, however, better to say that a group of organisms 
 under this name gives rise to it because there are many 
 varieties with different chemical and serum reactions, 
 producing attacks of varying severity. Their general 
 pathogenic and etiological effects may be discussed 
 together, however. 
 
 In cholera the chief lesions are in the lower small 
 intestine, but otherwise the two diseases have many 
 things in common. 
 
 The bacilli enter probably only by the mouth in 
 infected food and drink, and pass through the ali- 
 mentary tract to their organ of predilection, the 
 colon. Here they penetrate the mucous lining to its 
 deeper layers, causing violent irritation. They may 
 get deeper into the wall or even to the glands draining 
 the colon, but not into the blood. The inflammation 
 gives rise to diarrhea which passes 'from feculent to 
 mucous, to bloody mucous, and may be almost wholly 
 blood. These effects are due to the effort of the 
 colonic wall to rid itself of the poisons, and the body 
 seems to choose this method to free itself of the 
 intruder. This fact is further shown when we inject 
 susceptible small animals with the poisons, for a con- 
 gestion of the colon with diarrhea results, although no 
 living organisms are present. The poisons of the dysen- 
 tery bacilli are probably both extracellular and endo- 
 toxins, the latter being more abundant. The toxic 
 effect, therefore is exerted by the existence of the 
 germs in the mucous membrane giving off poisonous 
 
BACILLUS DYSENTERIC 131 
 
 products of their life, and to a greater degree, by the 
 poisons liberated upon their disintegration. The 
 poisons are absorbed into the blood, giving rise to an 
 irregular fever in which sudden drops are common. 
 This sudden fall of temperature may be observed in 
 animals receiving doses of the poison. 
 
 Dysentery is transmitted like other diarrheal dis- 
 orders, that is, by the pollution of food and drink by 
 discharges of patients, since the germs leave the body 
 
 , < 
 
 FIG. 38 
 
 ^ >% * % 
 
 f -^ 
 
 Dysentery bacilli. X 1000 diameters. (Park.) 
 
 only by the feces. Disinfection of excreta, clothes, 
 utensils, and hands should be done as for cholera. 
 After an attack persons may be carriers, and disinfec- 
 tion of stools should not cease upon clinical recovery. 
 
 The blood acquires some resistance to dysentery 
 bacilli during an attack, comparable closely to the 
 changes in cholera ; that is bacterioly tic substances and 
 agglutinins are to be found. Advantage of this is taken 
 
132 THE ACUTE SELF-LIMITED INFECTIONS 
 
 in immunizing the lower animals with toxins obtained 
 in laboratory cultures. As an aid in the diagnosis of 
 dysentery the stools in which the bacteria may be found 
 almost in pure culture are cultivated. The shreds of 
 membrane or mucus from the stools are selected. 
 The development in the laboratory is comparatively 
 simple, but to identify the species or variety is any- 
 thing but easy. The agglutinins in the patient's 
 blood may be tested against pure laboratory cultures 
 of known varieties, and thus a bacteriological diagnosis 
 as to the type may be made. Thus for diagnosticating 
 dysentery we have only the feces culture and agglutin- 
 ation test. Since the bacilli are not in the blood, 
 cultures of this are not made. 
 
 The dysentery bacillus is a short, straight, probably 
 non-motile rod with rounded ends. It is quite like 
 the typhoid bacillus in shape and size, but unlike this 
 germ does not move actively. It may at times show 
 degenerated forms. It is usually single, but may be 
 in pairs. It stains easily. It grows both aerobically 
 and anaerobically, but better under the former con- 
 ditions. Its growth upon laboratory media is also 
 like that of the typhoid bacillus. Best development 
 occurs at 37 C. or 98 F., and death results when 60 C. 
 or 142 F. is held for ten minutes. 
 
 It resists freezing for a long time, possibly some 
 weeks. It is killed by drying only after long periods. 
 Its resistance to chemicals is practically the same 
 as that of typhoid bacilli. Animals do not contract 
 dysentery when they take the bacilli by mouth, but 
 when germs or their toxins are introduced under the 
 skin, into the vein or peritoneum, profound intoxica- 
 
VINCENT'S ANGINA 133 
 
 tion occurs, with fall of temperature, peritonitis, diar- 
 rhea, and in some cases hemorrhage in organs or body 
 cavities. 
 
 Dysentery Antiserum. Nevertheless, animals, notably 
 rabbits and horses, have been made to withstand 
 large doses by preparation with graded amounts. 
 They develop sera containing anti-substances to both 
 the endo- and extracellular dysentery toxins. This 
 serum has been used therapeutically in the treatment 
 of dysentery. Thus passive immunity can be secured, 
 but so far no great success has met attempts to raise 
 the resistance of human beings to dysentery by 
 injecting dead or attenuated bacilli; no active immunity 
 has been achieved. It may be well to add that in 
 producing the serum from animals to inject into 
 human beings, several varieties of the bacillus are 
 used, since dysentery may be caused by several 
 varieties. Thus an antiserum potent against more 
 than one type of infection is obtained, a so-called 
 polyvalent antiserum. 
 
 VINCENT'S ANGINA 
 
 Vincent's angina is a very important inflammatory 
 disease of the tonsils and pharynx, sometimes simu- 
 lating diphtheria in that a false membrane is also 
 characteristic of the disease. The causative bacteria 
 are spirilla and fusiform rods, probably two stages of 
 development of the same organism, since it is believed 
 that the former develop from the latter. The earlier 
 stage is the time when the pseudomembrane appears, 
 but this soon gives place to punched-out ulcerations. 
 
134 THE ACUTE SELF-LIMITED INFECTIONS 
 
 The disease is mild, producing only a little local pain, 
 slight fever, and malaise. The disease may coexist 
 with diphtheria, aggravating the latter. The bacteria 
 gain admission by direct transfer from a patient to 
 the unaffected throat. The condition is not very 
 contagious. Disinfection should be observed by 
 frequent cleansing of throat and mouth by mild anti- 
 
 FIG. 39 
 
 Vincent's bacillus with accompanying spirochsetse. (Park. 
 
 septics. Rinse water and cloths used to wipe the 
 mouth may be rendered innocuous by any practical 
 disinfectant working for half an hour. Little is known 
 of the method of action of the bacteria. They probably 
 produce the condition by soluble poisons. In diag- 
 nosticating Vincent's angina a smear from the false 
 membrane stained with particular care will show 
 long fusiform rods with sharp ends taking the dye 
 
CONJUNCTIVITIS 135 
 
 more deeply at the ends and in the form of transverse 
 bands, and quite long wavy spiral organisms, usually 
 having shallow, irregular curvatures. The bacilli are 
 4 oVo to 2"oVo inch long and 47 Jo o" to -sifiro o" inch wide. 
 They probably grow best under anaerobic conditions. 
 There is no specific treatment. 
 
 CONJUNCTIVITIS 
 
 There are many bacteria capable of producing inflam- 
 mations of the conjunctival sac, but there are a few 
 that seem peculiar in being found only in this place. 
 Whether they are separate species or not remains to 
 be seen. The most important mild inflammation of 
 the conjunctiva is the "pink eye." This acute con- 
 dition is transmitted by direct or indirect passage of 
 moist infective material from one patient to another. 
 Therefore an affected eye should be kept covered and 
 dressings handled carefully. The organisms are killed 
 by very weak solutions of the ordinary disinfectants, 
 and, indeed, probably do not resist boric acid very long. 
 The causative germ is the Koch-Weeks bacillus of 
 conjunctivitis. It is similar in size, shape, and staining 
 properties to the influenza bacillus, but differs from it 
 in that it will grow in the absence of hemoglobin, and 
 with reasonable ease on ordinary culture media. It 
 is destroyed at 60 C. or 142 F.' in two minutes. It 
 does not affect animals. There is no specific therapy. 
 
 Another form of conjunctivitis chiefly affecting the 
 angles of both eyes and running a subacute course is 
 caused by the bacillus of Morax and Axenfeld. These 
 organisms as seen in smears made best from exudate 
 
136 THE ACUTE SELF-LIMITED INFECTIONS 
 
 collecting over night, appear as short end-to-end ovoid 
 rods, each about TSTTHF inch. long. They may be 
 cultivated at body temperature on media containing 
 blood or blood serum. They produce disease by their 
 presence and by some form of toxin little understood. 
 The disease does not affect animals. 
 
 FIG. 40 
 
 Koch-Weeks bacillus (pink-eye), 3d generation. X 1000 diameters 
 (Weeks.) 
 
 PERTUSSIS OR WHOOPING COUGH 
 
 Many different organisms have been held responsible 
 for this disease. The one now holding the field was 
 described by Bordet and Gengou several years ago, 
 but only cultivated artificially within the last few 
 years. Although the discoverers failed to produce the 
 disease in monkeys when using this bacillus, never- 
 theless they hold that the presence of agglutinins and 
 a refined blood reaction, called complement deviation, 
 in the blood of patients are sufficient to incriminate it 
 
BACILLUS MELITENSIS 137 
 
 as the cause of whooping cough. They assert that endo- 
 toxins are formed. The disease is transferred directly 
 from one patient to another by means of spray 
 from coughing, spitting, or talking. The rod grows 
 only at body temperature in the presence of blood or 
 its coloring matter. It is very like the Bacillus influ- 
 enza in size and shape. It is found in the sputum 
 early in the disease as a small ovoid polar staining rod, 
 arranged in pairs end to end. It is stained easily. 
 It does not produce the disease in animals. Sputum 
 should be received in 5 per cent, carbolic acid, and 
 cloths used to wipe the mouth should be soaked in 
 the same solution. 
 
 BACILLUS MELITENSIS 
 
 Malta fever is an acute infectious disease, endemic 
 along the Mediterranean, following a course similar 
 to typhoid fever, but usually of less serious nature. It 
 is caused by the Bacillus melitensis. Goats harbor the 
 organisms and pass them out through the milk, an 
 important food in Malta. Persons can be infected by 
 introduction through a wound. The disease is a septi- 
 cemia and endotoxins are probably set free. It is 
 probably not transmitted from man to man. The 
 diagnosis is made by means of blood cultures or by 
 the agglutination test. The bacilli are exceedingly 
 short, almost coccus shape. They are about TSTOT 
 inch long, single or in pairs. No motility is seen, and 
 no spores are formed. They stain easily and grow well 
 in ordinary media at 37 C. or 98 F. Monkeys are 
 the only animals infectable. Vaccines of dead cultures 
 may be used. The bacilli are killed by the same 
 methods as the typhoid bacillus. 
 
CHAPTER X 
 THE MORE CHRONIC INFECTIOUS DISEASES 
 
 THE diseases which have been discussed are the 
 most important acute infectious diseases, and now 
 those which are accustomed to follow a more prolonged 
 course must be considered. It should be emphasized, 
 however, that any one of these may assume a rapid 
 or fulminating character and run its course quite as 
 rapidly as the acute infections. These chronic infec- 
 tions, particularly tuberculosis and syphilis, are perhaps 
 the most widespread of diseases. 
 
 BACTERIUM TUBERCULOSIS 
 
 Tuberculosis is an infectious disease capable of 
 attacking any organ or structure in the body, although 
 its commonest site is the lung. The organism is the 
 Bacterium tuberculosis or tubercle bacillus. The organ- 
 ism enters the body chiefly through the mouth and 
 nose, usually by the air, but also in food and drink. 
 If it follow the air passages it may settle upon the 
 nasal, buccal, pharyngeal, laryngeal, or bronchial 
 mucous membranes. These it penetrates, and settles 
 usually where there is lymph tissue. This it follows 
 with the lymph flow, and finds lodgement at some point 
 of low resistance. It may penetrate to the true lung 
 tissue with the air current, but it probably settles in 
 
BACTERIUM TUBERCULOSIS 139 
 
 some of the smaller air tubes, and extends into adjoin- 
 ing lung tissue by continuity. It may get into the 
 lungs by following the lymph way, or as has lately 
 been proven, it may get there from the blood stream or 
 lymph when it has been taken into the intestines in food 
 or drink. These bacteria can pass through a mucous 
 membrane into the deeper tissue without leaving any 
 inflammation at their point of entry. After having 
 entered the tissues proper they may be carried any- 
 where by the lymph and probably by the blood. 
 
 Tubercles. Having settled at a point of low resist- 
 ance, they irritate the tissue rather slowly to produce a 
 localized inflammation which is called a tubercle. This 
 is usually a gray body about the size of a millet seed. 
 The cells composing this little mass are very much 
 the same as those seen in chronic local non-tuberculous 
 inflammations, but their arrangement, particularly 
 when combined with large cells having numerous 
 nuclei about their edge (giant cells), is rather character- 
 istic of the disease. Many of these tubercles spread 
 centrifugally and coalesce. The centre of the tubercles, 
 being devoid of nutriment, since the blood supply is 
 cut off, undergoes cheese-like or caseous softening. 
 The combination of many tubercles and their destroyed 
 centre produces large caseous abscesses. When these 
 are in the lungs the softened centres may be removed 
 by being coughed up after the process has ulcerated 
 into an air passage. In the kidney the same general 
 thing may occur, and the softened matter goes into 
 the urine. 
 
 Forms of Tuberculosis. When the process ulcerates 
 into the blood supply there may result a rapid dissemi- 
 
140 THE MORE CHRONIC INFECTIOUS DISEASES 
 
 nation of the bacteria throughout the body, w T ith 
 the production of innumerable miliary tubercles every- 
 where. Among the special forms of tuberculosis are 
 meningitis, hip disease, or spine disease. The first is 
 a long-standing inflammation in which the coverings 
 
 FIG. 41 
 
 Tuberculosis of the lung. (Stengel.) 
 
 of the brain and cord and the superficial layers of 
 these organs are involved in an extensive inflammation. 
 The hip and spine diseases arise when the bacteria get 
 into the soft marrow of the bones, and extend to the 
 joint and tissues about it. 
 
BACTERIUM TUBERCULOSIS 141 
 
 Toxins. The peculiar evidences of tuberculosis are 
 due to the toxins elaborated by the causative germ, 
 which are both extracellular and endotoxic. The former 
 produce the constitutional symptoms of fever and 
 general depression of health. They are also probably 
 responsible for some of the inflammation in the neigh- 
 borhood of tubercles. The endotoxins, on the other 
 hand, produce the peculiar local inflammation called 
 the tubercle, and cause its degeneration into caseous 
 material. During an infection with tuberculosis there 
 will be developed in the body fluids a very slight 
 amount of substance as antibody to these endo- and 
 extracellular poisons. It is of little importance in 
 the diagnosis, treatment, or protection of the indi- 
 vidual, and a specific resistance to tuberculosis is not 
 acquired by passing through an attack, although it 
 is said that a tuberculous person cannot be reinfected 
 with tuberculosis. Recovery ensues when the health of 
 the individual and his tissues is strong enough to 
 inhibit the multiplication of bacilli. 
 
 Predisposing Causes and Transmission. A lighting 
 up of the disease may occur when the resistance 
 weakens by reason of some acute disease, bad habits, 
 and the like. Tuberculosis spares no walk of life, but 
 is more common where the lack of body care reduces 
 resistance. It is preeminently the disease of crowded, 
 dark, illy ventilated, badly drained tenements. It comes 
 in the pulmonary form frequently, as an infection 
 on top of an acute cold. The disease is spread in by 
 far the largest percentage of cases by the direct inhala- 
 tion of germs coughed out by a tuberculous person 
 and contained in dust contaminated by tuberculous 
 
142 THE MORE CHRONIC INFECTIOUS DISEASES 
 
 sputum. The sputum must, of course, dry before it 
 is pulverized into dust by walking on it or sweeping 
 it. The dust arising from soiled handkerchiefs or 
 cloths is likewise a danger. Park says that as many as 
 5,000,000,000 tubercle bacilli may be expectorated by 
 a consumptive person in twenty-four hours. Since the 
 ordinary uneducated consumptive is very careless of 
 his expectoration, the danger is obvious. The great 
 movement against the "white plague" now active 
 throughout the world is rapidly correcting the habits 
 of careless patients. 
 
 Tuberculosis may also be transmitted by the infec- 
 tion of food in the soiled hands of patients, or flies 
 may feed upon sputum and carry the germs upon 
 their body. The study of the transmission of tuber- 
 culosis from the cow to the human being has now 
 progressed to a point near solution. Koch said that 
 the bovine form of tuberculosis is not contracted by 
 the human being. This is true for tuberculosis of the 
 lungs, but children are susceptible to the bovine form, 
 and it affects them in the glands of the neck and of 
 the abdominal cavity. Cows may give off tubercle 
 bacilli in their milk even when there is very slight 
 evidence of the disease in their body. 
 
 The tubercle bacillus may be eliminated from the 
 human body by the feces, and health authorities are 
 requiring the disinfection of sewage from sanatoria. 
 Tuberculosis is very rarely hereditary, but children born 
 of tuberculous parents are not quite as robust as chil- 
 dren born of non-tuberculous persons, and therefore 
 they more easily contract the disease from the sur- 
 roundings contaminated by ill parents. 
 
BACTERIUM TUBERCULOSIS 143 
 
 Disinfection. To disinfect material from the tubercu- 
 lous individual it is necessary to collect it in some 
 manner, permitting burning or the action of chemicals 
 over a long time. Tuberculous sputum is best received 
 in cardboard boxes inclosed in a tin cup. The boxes 
 are burned, and the tin cup washed in 5 per cent, car- 
 bolic acid at frequent intervals. If the person expec- 
 torate into cloths they should be burned or soaked in 
 5 per cent, carbolic for at least six hours. If neither 
 of these methods is used expectoration should be 
 received in a bowl or pot containing 5 per cent, carbolic 
 acid. Feces and urine should be received and well mixed 
 into the same solution. Milk, unless it is known to 
 come from a non-tuberculous cow, should not be used. 
 After death from tuberculosis the room and all con- 
 tents should be disinfected with formaldehyde gas. 
 
 Diagnosis. The most important means of diag- 
 nosis is by finding the tubercle bacillus. To do 
 this, the sputum, urine, feces, pus, exudate, or a 
 piece of tissue is taken, stained by special methods, 
 or injected into guinea-pigs. The method employed 
 for staining these bacteria consists in using a dye 
 having an affinity for the peculiar waxy character of 
 the germ and not easily removed by acids after it has 
 once penetrated it. The bacteria are called acid-fast 
 for this reason. The stain consists of carbolic acid 
 and fuchsin. The former helps the latter to penetrate 
 the germ. We make smears upon slides, stain them 
 by this solution, treat them with an acid which will 
 decolorize everything but the tubercle bacillus. This 
 will show us red bacilli. 
 
 Sometimes the germs are present, but cannot be 
 
144 THE MORE CHRONIC INFECTIOUS DISEASES 
 
 found by staining. Some of the material is then 
 introduced under the skin or into the peritoneal 
 cavity of guinea-pigs. If tubercle bacilli be present, 
 evidences of the disease will appear in these animals 
 in from two to five weeks. The bacilli can be found by 
 staining smears from the tubercles. Agglutinins are 
 formed in tuberculosis, but the clumping test is of 
 little value. 
 
 The tuberculin reaction is a very important diag- 
 nostic measure. During its growth on artificial media 
 in the laboratory, the tubercle bacillus develops its 
 endo- and extra-cellular toxins. If these poisons, 
 called "tuberculin," obtained by removing the living 
 organisms from a fluid culture, be injected under or 
 rubbed into the skin, a characteristic reaction occurs. 
 The subcutaneous injection of as small a quantity as 
 5 milligrams or about yV minim of Koch's tuberculin 
 will cause a definite rise of temperature and a feeling 
 of general malaise within twenty-four hours. The 
 inunction of a drop of this solution into the skin, com- 
 bined with a slight irritation of the surface, will cause 
 a reddened papule or even a vesicle upon a swollen 
 base to appear within twenty-four hours. There are 
 several modifications of this skin test in practice, but 
 the principle is the same in all. It is claimed by many 
 that all adults have some tuberculosis in their body, 
 acquired during childhood, but which has remained 
 quiet or has healed completely. For this reason the 
 skin test may be positive in adults who are really not 
 suffering from their slight latent infection, and it is 
 therefore not reliable. It should only be used in chil- 
 dren. The supposed cause of the tuberculin test either 
 
PLATE V 
 
 Bacterium Pneumoniae in Blood of Rabbit. (Abbott.) 
 
 Showing encapsulated cocci, red and -white blood cells. 
 
BACTERIUM TUBERCULOSIS 145 
 
 under or upon the skin is the stimulation of the tuber- 
 culous disease by the introduced toxin, and the out- 
 pouring from the tubercles of more of their own poison. 
 No reaction of any sort follows the administration of 
 tuberculin to persons free from tuberculosis. 
 
 Morphology and General Characteristics. The tubercle 
 bacillus is a true parasite, that is, it does not multiply 
 in nature outside the animal body. It is a rather 
 large organism, about TOTTOT mcn wide and from 
 YolToir to 5~oVo inch long. It may be straight or slightly 
 bent, usually single, but also in pairs. It is non- 
 motile, and produces no spores. It stains with con- 
 siderable difficulty, owing to its thick cell wall. There 
 is much fatty and waxy matter in the tubercle bacillus 
 which gives it its resistant power. It grows upon 
 laboratory culture media very slowly. For this 
 reason it must be obtained in as pure a condition as 
 possible. Cultures are best made from the lesions in 
 guinea-pigs. For its growth this organism requires 
 the addition of glycerin, blood serum, or egg to the 
 ordinary nutrient broths and jellies. It will grow only 
 at body temperature, and not at room temperature. 
 
 It is killed by an exposure to 60 C. or 142 F. in 
 thirty minutes, to 70 C. or 160 F. in ten minutes, 
 and at 95 C. or 200 F. in one minute in watery 
 suspension. Dry heat at 100 C. or 212 F. requires 
 about one hour. The organisms resist drying in the 
 dark for considerable periods. Direct sunlight kills 
 them if in thin layer or small clumps, within four 
 hours. Diffused light requires two weeks for their 
 destruction. Sputum protected from direct sunlight 
 may contain living bacilli possibly for one year. Five 
 10 
 
146 THE MORE CHRONIC INFECTIOUS DISEASES 
 
 per cent, carbolic acid should certainly kill them in 
 sputum in twelve hours; in watery suspension in 
 thirty minutes. Bichloride of mercury is not of value 
 for sputum disinfection, but in strength of 1 to 1000 
 in watery suspension is fatal in one hour. No kind 
 of animal is absolutely resistant to tuberculosis, but 
 there are some that very seldom present the spon- 
 taneous disease, notably dogs and horses. 
 
 There are four forms or varieties of the tubercle 
 bacillus: the human, bovine or cow, bird, and reptil- 
 ian. The first two only concern us, and the distin- 
 guishing features of these groups are of small importance 
 here. The infectiousness of the bovine form for 
 humans has been mentioned. The human form is of 
 very low virulence for the cow, but may infect most 
 of the smaller animals. It has been found impossible 
 to obtain from any of the lower animals a serum which 
 will have a beneficial effect upon the disease in human 
 beings. That is, no serum can be procured which will 
 give a passive immunity. 
 
 Tuberculin. The poisons made in cultures and used 
 for the tuberculin test in the form of Koch's tuber- 
 culin have already been mentioned. There are many 
 forms of tuberculin which are incidentally modelled 
 after Koch's plans. His original was a broth upon 
 which the bacteria had grown, but freed of living forms 
 and reduced by evaporation to one-tenth its original 
 volume. This contained both the endo- and extra- 
 cellular toxins. His later forms consisted of killed 
 bacteria, of a watery extract from them, and lastly, 
 living bacteria so reduced in virulence that they could 
 not produce tuberculosis. These are all tuberculins, 
 
TREPONEMA PALLIDUM 147 
 
 the last forms being called vaccines also. We inject 
 them under the skin of tuberculous patients, beginning 
 with extremely minute doses, too small to produce 
 the tuberculin reaction described above. We increase 
 the quantity gradually until the patient can endure 
 large amounts. It is maintained that this treatment 
 is very beneficial and that a slight immunity is achieved. 
 Opinions vary as to its value, but those who have had 
 longest experience usually testify to its efficacy. This 
 is in reality an active immunization during the course 
 of the disease, but it has not been found possible to 
 inject a healthy person in the same manner and 
 thereby increase his resistance to tuberculosis. 
 
 TREPONEMA PALLIDUM 
 
 Syphilis is one of the venereal diseases. It is chiefly 
 acquired by cohabitation, but may also be contracted 
 by nurses and physicians in their professional relations 
 with patients. It is a chronic infectious disease 
 characterized by three stages, the first a primary, 
 acute, active self-limited ulceration, with some regional 
 lymph gland swellings; second, a period in which 
 various eruptions appear on the skin and mucous 
 membranes, with slowly progressive changes in some 
 of the internal organs, and third, a last stage of soft 
 tumor formation (gumma), with fibrous affections of 
 the organs and degenerations of the nervous system. 
 
 It is caused by a spiral organism called the Spiro- 
 chceta pallida or Treponema pallidum This bac- 
 terium enters small cracks or wounds, penetrates to 
 the deeper layers, invades the lymph channels, and 
 
148 THE MORE CHRONIC INFECTIOUS DISEASES 
 
 produces the primary sore, the hard chancre. Even 
 before this is fully developed, the spirochsetse have 
 journeyed to the neighboring lymph glands where an 
 enlargement results. They then invade both the lymph 
 routes and the blood and rapidly infest all bodily 
 tissues. They stimulate the small round cells of blood 
 and tissue to multiply even up to fibrous tissue forma- 
 tion, and they cause degeneration of the functionating 
 structures. Just how they make the gumma is only 
 conjectured. All their effects, however, are probably 
 due to the toxins set free upon their death and dis- 
 integration. The spirochsetse remain in the body as 
 long as the patient lives, if untreated. They leave the 
 patient probably only with the moisture of ulcerated 
 surfaces, and one protects against contamination by 
 covering the ulcerated surfaces or wearing hand 
 protection. The mildest of antiseptics will destroy 
 the germs. The incubation period varies from four 
 weeks to as many months. 
 
 Forms of Syphilis. This frightful disease which 
 causes so much mental and physical suffering may be 
 hereditary, congenital, or acquired. The first and the 
 last are easy to understand. The congenital form is 
 acquired by the infant at birth from some open, 
 active lesions on the mother. The course of the three 
 types varies a little, but the ultimate effect is the 
 same in all. 
 
 Transmission. Aside from cohabitation syphilis may 
 be transmitted by kissing, or using any object that has 
 come in contact with an open sore. Wet-nurses often 
 contract it and transmit it. In protecting against infec- 
 tion a weak 1 to 2000 bichloride of mercurv solution 
 
TREPONEMA PALLIDUM 149 
 
 should always be on hand that the ulcers may be 
 wiped before examination and the hands disinfected 
 afterward. That sleeping with or using anything 
 belonging to a syphilitic must be avoided goes with- 
 out saying. 
 
 Diagnosis. In the serum of a syphilitic, and the say- 
 ing goes, "once a syphilitic, always so," certain anti- 
 bodies are formed that can be made use of in diagnosis. 
 This is the basis of the Wassermann test upon the 
 blood. This is due to antibodies like bacteriolysins. 
 Its theory and practice are too intricately technical 
 to be included here. Suffice it to say that it is 
 certainly a positive test in 95 per cent, of syphilitic 
 cases. Otherwise syphilis is diagnosticated by finding 
 the treponema in the serum which exudes from chancres, 
 skin eruptions, and mucous patches, or the venereal 
 warts on mucous membranes. This serum is taken 
 and looked at unstained upon a background of India 
 ink or by what is called dark field illumination, which 
 is a process by which the light is made to shine upon 
 the body of the spiral from the side. It can also be 
 stained by appropriate methods, but its minute size 
 and paleness make this a trying test. 
 
 Morphology and General Characteristics. The Spiro- 
 cli&ia pallida is a corkscrew-like, actively motile, 
 delicate thread. Its windings assume the form of a 
 large arc of a small circle, and vary from four to 
 twenty. It is yinnmr to y sir oo" mcn wide and from 
 -g-oVo- to TTOTF inch l n g- It moves by end flagella, 
 in a screwing and waving motion. It is killed rapidly 
 by drying, a very fortunate thing, as many people 
 are thereby protected. Against weak bichloride and 
 
150 THE MORE CHRONIC INFECTIOUS DISEASES 
 
 carbolic acid it has no resistance. Alcohol will destroy 
 it in five minutes. Up until the beginning of 1911 no 
 success had met attempts to cultivate these spirals 
 in the laboratory. Noguchi finally succeeded in 
 growing them under anaerobic conditions in a mixture 
 of serum and agar to which a piece of sterile liver or 
 
 FIG. 42 
 
 Treponema pallidum appearing as bright refractive body on a dark field, 
 as shown by India ink or ultramicroscope. (Park.) 
 
 kidney of rabbit had been added. Only rabbits and 
 monkeys among the lower animals can be made to 
 contract syphilis, but of these only the latter shows 
 any similarity to man in the course of the disease. 
 When infective crusts from eruptions or serum exuding 
 from them is kept in the test-tube for six hours, 
 infection can no longer be transferred to monkeys. 
 
BACTERIUM LEPRM 151 
 
 No serum of therapeutic value has as yet been pro- 
 duced, nor can immunity be induced by injecting 
 dead spirochetes. Lately Noguchi has made an extract 
 of spirochaete bodies which can be used as a skin test for 
 syphilis precisely as tuberculin is rubbed into the skin 
 in diagnosis of tuberculosis. He claims good results 
 during the later stages, but as a diagnostic test of 
 recent infection it has not yet proven of value. 
 
 Chancroid. There is a venereal disease known as 
 chancroid or soft chancre in contradistinction to the 
 primary hard chancre of syphilis. This is an acute 
 infectious condition due to the bacillus of Ducrey. 
 The lesion begins as a pustule, which soon breaks 
 down into a spreading ulcer. The disease is communi- 
 cated by direct contact usually. The bacilli are in the 
 discharges and therefore can be transferred through 
 the intervention of dressings. The bacilli are extremely 
 small, double rods, not motile, and form no spores. 
 These grow on laboratory media containing blood. 
 They do not possess a great viability under artificial 
 conditions, and therefore are destroyed in discharges 
 quite easily. Simple drying seems to kill them shortly, 
 and weak solutions of the ordinary disinfectants are 
 quickly efficient. We assist in the clinical diagnosis 
 of chancroid by finding the diplo-rods, mostly within 
 leukocytes, in scrapings from the depth of the 
 ulceration. 
 
 BACTERIUM LEPItffi 
 
 Leprosy is a chronic endemic infectious disease 
 characterized by the development, in the skin chiefly, 
 but also the mucous membranes, of firm nodules and 
 
152 THE MORE CHRONIC INFECTIOUS DISEASES 
 
 diffuse swellings due to the growth and irritation of 
 the Bacterium leprce or leprosy bacillus. 
 
 Forms of Leprosy. There are two forms, the nodular 
 and anesthetic. The former is usually painless through- 
 out its course, merely giving rise to the cutaneous 
 nodules. The anesthetic form is due to an involvement 
 of the sensory nerves, which are at first irritated with 
 the production of a painful early stage, followed by 
 destruction of sensation when the inflammation has 
 progressed farther. The disease gives rise to con- 
 siderable superficial destruction of tissue, which is 
 responsible for the horrible pictures of this disease 
 in the lay mind. Fingers, toes, nose, and pieces of 
 skin may be removed by ulceration. The disease is 
 an old and widespread one commonest in the tropics, 
 but by no means confined to them. Despite long 
 familiarity with leprosy, there are many points as yet 
 undecided about its nature. 
 
 Transmission. The bacteria probably enter by the 
 nose and mouth, and it requires close association with 
 a leper for a long time in order to contract the disease. 
 The low contagiousness of leprosy should be empha- 
 sized. If one should say in a crowd, "There is a 
 leper!" the people would shun him as if he were a 
 maniac with a firearm. If one were to say under 
 similar conditions, "There is a consumptive!" he 
 would be pitied and perhaps not avoided at all. Tuber- 
 culosis is vastly more easily transmitted than leprosy. 
 The inhuman treatment accorded to lepers is due to 
 this misapprehension. The disease is probably not 
 hereditary. 
 
 When the bacteria enter the mucous surfaces thev 
 
BACTERIUM LEPUM 153 
 
 are carried by the lymph or blood to the exposed skin 
 surfaces, chiefly the face and hands. Here they settle 
 in the subcutaneous tissues and nerves, producing a 
 chronic inflammation in which lepra cells are found. 
 These are large round or oval cells, crowded with 
 bacilli, lying irregularly throughout the inflammatory 
 tissues. Leprosy does not form definite tubercles 
 
 FIG. 43 
 
 Schematic representation of section through a lepra nodule: left side of 
 picture gives appearance under low magnifying power; right side, the appear- 
 ance when highly magnified. In the latter the large lepra cells are diagram- 
 matically indicated. (Abbott.) 
 
 like tuberculosis, but the process is more diffuse; nor 
 does caseation occur. Giant cells are uncommon. 
 The bacilli produce these changes largely by poison 
 in their body and by mechanical irritation. There is 
 some reason to believe, by most recent researches, 
 that a soluble or extracellular poison is formed. The 
 bacteria are discharged from the patient by the 
 
154 THE MORE CHRONIC INFECTIOUS DISEASES 
 
 sloughing of wounds, especially the ulcers in the nose 
 and throat. The dressings and cloths used to wipe 
 the nose should be burned. Intimate contact, such as 
 sleeping with or kissing lepers, should be avoided. 
 The diagnosis is made by finding the rods in their 
 peculiar cells, which is best achieved by removing a 
 piece of the skin growths. 
 
 Morphology and General Character. The leprosy 
 bacillus, like the tubercle bacillus, is stained with 
 difficulty, and belongs to what are called the acid-fast 
 bacteria. Methods similar to that described for 
 tubercle bacillus must be used, but the determination 
 is by no means simple even to the most experienced 
 bacteriologists. The similarity to the tubercle bacillus 
 is further shown by the fact that the tuberculin skin 
 test is positive in lepers. A poison similar to tuber- 
 culin, called leprin, has been made by extracting 
 leprous tissue. It is only within the last year that 
 the pure direct cultivation of Bacterium leprce has 
 been successful, and then only upon special media 
 with a very delicate technique. More about the 
 poisons will probably be learned in the near future. 
 The bacillus of leprosy is a straight rod with rounded 
 ends, a trifle smaller than the tubercle bacillus. Its 
 resistance to chemicals and heat is probably the 
 same as that organism. It grows only at body tem- 
 perature. Some attempts have been made to use 
 devitalized leprous tissue and the vaccines from the 
 tubercle bacilli as a remedy. These have met with 
 indifferent success. 
 
 Acid-fast Bacteria. The two organisms of tuber- 
 culosis and leprosy are members of the acid-fast group. 
 
BACTERIUM MALLEI 155 
 
 There are numerous other bacteria that stain and are 
 decolorized with difficulty, but these are the impor- 
 tant disease producers. Such an organism, called the 
 Bacterium smegmatis, exists in the smegma about the 
 genitals, and is often a source of confusion when 
 examining for tuberculosis of the urogenital apparatus. 
 It does not produce disease, however. It is possible 
 also to exclude it by a special staining method. Other 
 acid-fast bacteria exist in manure, hay, and butter. 
 
 BACTERIUM MALLEI 
 
 Glanders is chiefly a disease of horses, characterized 
 by nodular growths and ulcers in the upper air passages 
 or diffuse swellings under the skin. In the latter form 
 it is called farcy. The causative organism is the 
 Bacterium mallei or glanders bacillus. Human beings, 
 who are associated with horses or who work in the 
 laboratory with cultures, may contract the disease; 
 usually, however, in the acute form, whereas the lower 
 animals commonly have a protracted attack. The 
 bacteria enter by small cracks or wounds in the mucous 
 membrane of the mouth or nose, and are carried by 
 the lymph or blood to subcutaneous tissues. Whether 
 they produce glanders proper or farcy, they stimulate 
 the tissue to produce nodules not unlike the tubercle, 
 but of more rapid progression. Quite early they 
 break down into abscesses or through the skin as large 
 sloughing ulcers. The poisons are almost entirely endo- 
 toxins, and may be extracted from cultures. A slight 
 amount of resistance is gained by passing through an 
 attack. 
 
156 THE MORE CHRONIC INFECTIOUS DISEASES 
 
 Diagnosis. Agglutinins are formed in the blood and 
 the clumping test is a valuable means of diagnosis. 
 The bacteria may also be found by making smears and 
 cultures from open ulcers or by withdrawing some of 
 the pus from an abscess. This pus may be injected 
 into the peritoneal cavity of a guinea-pig, obtaining 
 as evidence of the presence of the Bacterium mallei 
 an inflammation of the testis. The most practical 
 method of diagnosticating glanders is by the use of 
 the mallein test. Mallein is the poison elaborated 
 by the Bacterium mallei in laboratory cultures. It is 
 comparable to tuberculin, and may be used like it, by 
 injecting it under or by rubbing it upon the skin. 
 Reactions of temperature or reddening of the skin indi- 
 cates the presence of glanders. The bacilli may be 
 found also in stained smears of the pus lying in pairs 
 on end within the large so-called epithelioid cells. 
 Blood cultures sometimes give a growth. The disin- 
 fection of human material should consist in burning all 
 dressings from ulcers or cloths used to wipe the nose 
 or mouth. Bacteria leave the body only with the 
 purulent discharges. Strong antiseptics such as 1 
 per cent, carbolic acid should be used for the hands 
 and objects possibly soiled by discharges. Glanders 
 is a very infectious disease, and the bacilli are per- 
 tinacious. 
 
 Morphology and General Characteristics. The 
 glanders bacilli are straight or slightly curved rods, 
 usually single, but also in pairs or short filaments, and 
 measure from 2i)1ro o~ to suVo" mcn i n length and from 
 TFoVoT to ^o"o-o"o" mc h m width. They stain with 
 reasonable ease. They grow at 37 C. or 9S F. very 
 
BACTERIUM MALLEI 157 
 
 much better in the presence of oxygen than in its 
 absence. They do not form spores nor are they motile. 
 They are killed at 55 C. or 130 F. in ten minutes; by 
 1 to 1000 bichloride or 1 to 100 carbolic acid in ten 
 minutes. After drying they may live for ten days, but 
 do not live long in nature outside the animal body. 
 They are easily grown upon most of the laboratory food- 
 stuffs. Most of the lower animals are susceptible to 
 
 FIG. 44 
 
 Glanders bacilli. Agar culture. X 1100 diameters. (Park.) 
 
 glanders and it is of some importance in menageries. 
 The disease in animals is like that described for per- 
 sons, and the beasts do not develop anything in their 
 blood which can be used to treat human beings. Vac- 
 cines are not successful probably because the disease 
 in people is too acute to be amenable to a treat- 
 ment with mallein comparable to that described for 
 tuberculin. 
 
158 THE MORE CHRONIC INFECTIOUS DISEASES 
 
 BACTERIUM ANTHRACIS 
 
 Anthrax or woolsorters' disease or splenic fever is 
 chiefly an acute infectious disease of animals caused 
 by the Bacterium anthracis or anthrax bacillus. It is 
 contracted by human beings through association with 
 infected animals, hides, wool, rags, and the like. It 
 is not uncommonly fatal to persons. It is expressed 
 as superficial abscesses, pustules, or carbuncles scat- 
 tered over the skin, or as softening of the spleen, 
 hemorrhages into the intestinal wall and some other 
 of the organs, even the brain. The woolsorters' 
 disease, or pulmonary form, occurs from inhaling 
 bacilli into the lungs. The bacteria enter by the 
 inspired air, by swallowing, or by wounds and cracks. 
 However they enter they spread by contiguity or 
 by the lymph. Their chief action is local. They 
 do not enter the blood stream except near death. 
 They do not settle in one place and remain there, 
 but may pass from one localization to another. Their 
 action is due to a soluble or extracellular toxin. This 
 attacks any tissue and causes the accumulation of 
 edema and blood. The softenings are due to the 
 killing effect of the bacillus poisons upon the tissues. 
 This solvent action also attacks the walls of blood- 
 vessels permitting the leaking of blood or a true 
 hemorrhage. The poisons are further absorbed by the 
 circulation with a resulting fever and general illness. 
 The bacteria may leave the body with pus or sloughs, 
 by the expectoration in the pulmonary form, or by the 
 feces when the infection is intestinal or has become 
 generalized. 
 
BACTERIUM ANTHRACIS 159 
 
 Protection against anthrax is secured with difficulty 
 since its organisms produce resistant spores. The 
 sputum, feces, and wound discharges should be so 
 received that immediate burning is possible. Chemical 
 disinfection is much less reliable. Five per cent, 
 carbolic acid should be allowed to remain in contact 
 with infective material for two days. Corrosive 
 sublimate, 1 to 1000, for one day is usually sufficient. 
 
 Anthrax is diagnosticated by finding the bacteria, 
 not a very difficult matter since they grow with com- 
 parative luxuriance on laboratory media. Smears 
 also assist because of the characteristic appearance 
 of the rods. During an attack a human being or an 
 animal produces no specific changes in the blood or 
 tissues having a relation to immunity. 
 
 Morphology and General Characteristics. The anthrax 
 bacillus is a large straight rod with sharply cut ends. 
 It measures -^-^ to ^Vfr inch long by YFUTFTF to 
 2"oiro"o mcn wide. It does not possess motility, but 
 does form spores. These are round, oval, or elliptical, 
 and situated near the centre of the rod. The bacilli 
 may grow in chains suggesting bamboo sticks. They 
 require oxygen. The rods but not the spores are easy to 
 stain. They show a delicate capsule about the organ- 
 isms when stained in pus. They grow best at 37 C. 
 or 98 F., but also at lower temperatures. The vegeta- 
 tive rods are killed at 54 C. or 130 F. in ten minutes; 
 the spores are killed by boiling ten minutes or in dry 
 heat at 140 C. or 285 F. for ten minutes. The 
 resistance to chemical agents has been considered on 
 page 51. It is best not to rely on any chemical killing 
 of anthrax spores, as different cultures vary in resist- 
 
160 THE MORE CHRONIC INFECTIOUS DISEASES 
 
 ance and the environment plays an important part. 
 Anthrax bacilli grow well and characteristically on 
 laboratory culture media. It is not possible to pro- 
 duce a passive immunity to anthrax. Among the 
 great achievements of Pasteur was the discovery of a 
 method of rendering sheep immune to anthrax. He 
 discovered that by growing anthrax bacilli at a tem- 
 perature of 42 C. or 106 F. instead of 37 C. or 98 F. 
 he was able to considerably reduce their virulence. 
 
 FIG. 45 
 
 Threads of Bacterium anthracis containing spores. X about 1200 diameters. 
 (Abbott.) 
 
 By varying the length of time of cultivation at this 
 temperature, two different strengths were obtained. 
 He now injected the weaker, and followed a few days 
 later with the more virulent. The resistance of the 
 animal can thus be raised to a high level for about a 
 year. The 'method is not practicable for human 
 beings. 
 
 ACTINOMYCOSIS 
 
 Actinomycosis or lumpy jaw is chiefly a disease of 
 animals, but may affect man. It is characterized by 
 the production of large semisolid tumefactions usually 
 
A CTINOM Y COS IS 161 
 
 in the upper air passages or their neighboring tissues, 
 and in the lungs. It may spread under the skin or 
 into organs. The bones of the jaw are usually involved. 
 Any bone in the path of progression of the disease 
 may be infiltrated. The organisms causing it belong 
 to the higher bacteria, and are called Streptothrix 
 actinomyces or ray fungus, because of their tendency 
 to spread out in rays. The organism enters by way 
 of the mouth or nose into cracks or wounds. Asso- 
 ciation with animals having the disease is the method 
 of infection in man. 
 
 When the germs enter they start to proliferate and 
 excite a nodule not unlike that of tuberculosis. It 
 spreads by continuity outward and involves adjoining 
 structures. The nodules soften in the centres to 
 caseous matter in which small white or gray masses of 
 the bacterial growth may be found. This is the chief 
 source of material by which the diagnosis is . made. 
 The large tumors ulcerate through the skin at times 
 and present sloughing areas. This is the manner also 
 in which the infecting germ leaves the body. In 
 diagnosticating the disease one of the small granules in 
 the pus is taken, crushed beneath a glass, and examined 
 directly under the microscope for the ray fungus. The 
 specimen may also be stained. 
 
 Infective material from abscesses or ulcers or the 
 sputum should be burned. Chemical destruction is 
 less reliable. Ordinary care of the hands will suffice 
 as a protection, but no lack of care is justifiable. It 
 is not a very infectious disease, but a serious one and 
 one of long duration. The peculiar changes in this 
 disease are due to the life and growth of the fungus as a 
 11 
 
162 THE MORE CHRONIC INFECTIOUS DISEASES 
 
 foreign body and probably not to any peculiar toxin. 
 No immunity or peculiar blood changes follow an 
 attack. The treatment is surgical and medical, the 
 latter being confined to the use of potassium iodide. 
 
 Morphology and General Characteristics. The organ- 
 ism of actinomycosis is in the form of interwoven 
 threads, radiating from a centre, having thickened 
 
 FIG. 46 
 
 Actinomyces fungus ("ray fungus"): left, as seen in tissues under low 
 magnifying power; right, a fungus mass examined fresh under higher_ mag- 
 nifying power. (Abbott.) 
 
 or bulbous ends. These ends are important as they 
 assist in species determination and possibly have some- 
 thing to do with multiplication of the germ. The 
 threads are about 75iro o" to ^oiro G- mcn wide, their 
 length being very variable. The bulbs measure from 
 6"o lro"o to -g~oVo mcn m width and vary in length. They 
 grow with reasonable freedom in the laboratory, 
 
ACTINOMYCOSIS 163 
 
 especially upon media containing animal substances such 
 as blood serum. Their optimum temperature is 40 C. 
 or 102 F. They are killed at 75 C. or 167 F. exposed 
 ten minutes. They resist drying for a long time. 
 They are extremely resistant to chemical disinfectants. 
 Not all animals are susceptible to actinomycosis, 
 but those contracting it present about the same type 
 of lesions. Nothing in their blood serum is of any 
 value in treatment of human beings. Vaccines are 
 not used. 
 
CHAPTER XI 
 
 VARIOUS PATHOGENIC BACTERIA NOT 
 
 ASSOCIATED WITH A SPECIFIC 
 
 CLINICAL DISEASE 
 
 THERE is a large class of bacteria capable of producing 
 various inflammations or infections that do not follow 
 a constant or even uniform course. Surgically speaking 
 they are probably the most important group aside 
 from the pus cocci. It is not possible to make many 
 generalizations concerning these organisms. The 
 results of infection with them vary greatly, depending 
 first upon their own virulence and second upon the 
 resistance of their host. Biologically many of these 
 non-specific germs bear a close relationship to species 
 giving a very definite clinical disease. In the first 
 example, the colon bacillus, this is well illustrated. A 
 certain group of bacteria is spoken of as the typho- 
 colon series. This means that they possess character- 
 istics relating them to one another. Certain members 
 of the series can be separated only by very careful 
 technique, yet they are capable of setting up easily 
 distinguishable affections. 
 
 THE TYPHOCOLON BACILLI 
 
 The colon bacillus is the common normal inhabitant 
 of animal intestines, particularly of the colon whence it 
 derives its name. The group of bacteria, the typho- 
 
THE TYPHOCOLON BACILLI 165 
 
 colon series, to which this organism belongs and of which 
 it and the typhoid bacillus are the most conspicuous 
 representatives, embraces many species, subspecies, and 
 varieties. A botanical and chemical classification satis- 
 factory to all authorities has not yet been made. It can 
 be said in general that all members of this group find 
 the intestinal tract a suitable place for life, some under 
 normal, others under pathological conditions. Old 
 classifications of the typhocolon group admitted only 
 organisms capable of motion, but some later observers 
 include many non-motile, and even encapsulated forms. 
 Inasmuch as a very close separation on the basis of 
 technicalities is not necessary in this work, it has 
 been deemed best to choose the principal clearly defined 
 species for description. Such descriptions permit of 
 extension in a general way to the nearest congeners, 
 and therefore we may say that we are considering 
 types. The typhoid and paratyphoid bacilli have 
 been sufficiently described in Chapter IX. 
 
 The Colon Bacillus. The colon bacillus proper, 
 called also the Bacillus coli communis, is a non-spore- 
 bearing, sluggishly motile, delicate rod, measuring 
 from 2Tlroo- to W<ro inch in length and 6"oi3~o"o to ^-Q-Q 
 inch in width. It appears when stained as a single 
 rod usually, but occasionally in pairs or short chains. 
 It takes the laboratory dyes with ease, usually more 
 deeply near its rounded ends. It moves by flagella 
 arranged all about the cell wall. It grows with ease 
 artificially, best in the presence of oxygen, but also 
 in its absence. Development will occur at any tem- 
 perature from 10 to 43 C or 50 to 108 F. It 
 produces no spores. No color or pigment is developed 
 
166 PATHOGENIC BACTERIA 
 
 when cultivated in the laboratory. It possesses the 
 power of coagulating milk and of acid fermentation, 
 with the production of gas, in most of the carbohydrates 
 (sugars and starches) used for the differentiation of 
 bacteria. It does not produce ferments capable of 
 liquefying gelatin or the milk curd. It does, however, 
 break up simpler substances and forms indol, a putre- 
 factive product. 
 
 FIG. 47 
 
 Colon bacilli. Twenty-four-hour agar culture. X 1100 diameters. (Park.) 
 
 The colon bacillus is killed at 60 C. or 140 F. in 
 ten minutes. It resists freezing for a long time, perhaps 
 several months. Drying usually kills in one day, but 
 certain individuals may remain viable for many days 
 or weeks. It is killed by carbolic acid, 1 to 1000, 
 in twenty minutes, or 5 per cent, in two minutes in 
 watery suspension. About the same time hold for 
 bichloride of mercury, 1 to 4000 and 1 to 1000. To 
 weak acids it is resistant, as is shown by its passage 
 
THE TYPHOCOLON BACILLI 167 
 
 in food through the hydrochloric acid of the stomach. 
 This is also true of the typhoid bacillus. It will 
 multiply in feebly acid or alkaline solutions. Direct 
 sunlight kills almost at once, while diffuse light is 
 withstood for a long time. 
 
 The colon bacillus is found in the intestines of 
 man and animals in health or disease. It is expelled 
 with the feces and therefore gets into water-courses. 
 Examination of water for public health purposes 
 aims at its discovery as an indication of sewage 
 pollution. Its presence in milk may be accounted 
 for by contamination of milk in cans washed with 
 polluted water. It should not be forgotten that 
 despite the greatest personal care, colon bacilli are 
 widely distributed on everything that comes in contact 
 with man and animals. The newborn baby's intestine 
 is free of them, but does not long remain so as the 
 organisms find their way in with food, from the hands 
 of attendants, or possibly through the anus and up the 
 rectum. The bacilli may be found in the superficial 
 layers of the earth. The colon contains most of the 
 bacilli and the number decreases upward in the small 
 intestine until in the stomach they are rarely found. 
 They may, however, at times enter the liver by means 
 of the bile passages or portal vein system. 
 
 The constancy with which the colon bacilli are 
 present in the intestine raises the question as to their 
 function or value there. This is probably best answered 
 today by saying that they assist in controlling the 
 growth of certain putrefactive bacteria, and that they 
 may assist somewhat in breaking up simple substances 
 so that these may be more easily absorbed. 
 
168 PATHOGENIC BACTERIA 
 
 The toxin of the colon bacillus is within its body, 
 no extracellular poison being formed. If one inject 
 the dead organisms into an animal in sufficient number, 
 mucous membrane irritation, paralyses, and convul- 
 sions may occur. Living bacilli introduced into the 
 peritoneum cause peritonitis and septicemia, the 
 organisms entering the blood stream. An abscess will 
 usually result if they are brought under the skin. In 
 man colon bacilli seldom go beyond the mucous 
 membrane of the intestine because of the resistance 
 offered by that tissue. After death the organisms 
 rapidly invade the different organs of the body. 
 Whenever the resistance of the body is reduced an 
 opportunity is presented for the spread of these 
 organisms. When sepsis occurs there is an inflammation 
 of the mucous membrane of the intestine, a swelling 
 of Peyer's plaques comparable to that seen in typhoid 
 fever. There may be inflammation of the gall-bladder, 
 the pelvis of the kidney, or abscesses in various parts 
 of the body. Cystitis may occur which may be a 
 part of a general infection, descend from the kidney, 
 or arise from introduction of the organisms through 
 the urethra. An ascending infection from the bladder 
 to the pelvis of the kidney and on into the substance 
 of the organ is not an uncommon disease process. 
 This frequently occurs in pregnancy or after labor. 
 
 The inflammations of the gall-bladder and its 
 passages and of the liver may arise either from intro- 
 duction of bacilli up the common bile duct, or as a 
 part of colon bacillus septicemia. The peritonitis 
 seen after perforation of the intestines is the result of 
 manv kinds of bacteria of which the colon bacillus 
 
THE TYPHOCOLON BACILLI 169 
 
 may be the most numerous. It is probable that this 
 organism alone is able to inflame the peritoneum, as 
 it certainly can produce localized and diffuse pus 
 collections. The colon bacillus is frequently the only 
 organism found in acute appendicitis. It has been 
 found as an important factor if not the sole cause in 
 pneumonia and pleurisy. It has been found to cause 
 meningitis and endocarditis. 
 
 No antiserum of practical value has been produced 
 by the injection of these organisms into the lower 
 animals. On the other hand, some success has been 
 attained in establishing active immunity both as a 
 preventive and as a remedial agency by injecting 
 increasing quantities of dead bacteria. 
 
 Diagnosis. Colon infections are diagnosticated chiefly 
 by finding the organism. They are present in the 
 fibrinous exudate or pus, and in the blood in septi- 
 cemia. We grow some of this in ordinary nutrient 
 broth or jelly, and isolate in pure culture. Colon 
 bacilli are, of course, easily obtained from the stools. 
 The agglutination or clumping test can also be used 
 in colon bacillus infections, since agglutinins are formed 
 during an attack. Pus or other bacteria containing 
 substances should be disinfected by mixing with 5 per 
 cent, carbolic acid and allowing it to act for at least 
 one-half hour. 
 
 Paracolon Bacilli. These organisms resemble the 
 Bacillus coli communis so closely that only the dif- 
 ferences need be noted. They are more actively 
 motile, they do not coagulate milk but probably pro- 
 duce alkalinity in it; they are capable of producing acid 
 and gas in only three of the sugars. They differ from 
 
170 PATHOGENIC BACTERIA 
 
 the paratyphoid bacilli in their action upon milk' and 
 their greater ability ' to ferment the carbohydrates. 
 These two groups, the paracolons and paratyphoids 
 (see page 118), are called the intermediates between 
 the true typhoids and colons. Their cultivation is 
 performed as outlined for the colon bacillus. The 
 typical species of this group is the Bacillus enteritidis 
 of Gartner or the meat-poisoning organism. 
 
 The disease produced by this bacterium is very 
 acute, but in some infections by members of this 
 group the disease may last as long as paratyphoid 
 fever. The bacteria are present in meat, probably 
 within the animal before slaughter. In Europe where 
 the refrigerating systems are less complete than in 
 this country, meat passes from the butcher to the 
 consumer directly, and therefore there may be epi- 
 demics when infected cattle are slaughtered. 
 
 The bacteria pass into the intestines, are absorbed 
 by their walls, and pass into the blood stream. The 
 infection gives diarrhea of the typhoid or cholera 
 type, prostration, and sometimes delirium. The 
 disease is usually transmitted only by meat in the 
 form of cuts or as sausage, and these foods are unaltered 
 in color and taste by the presence of the bacteria. 
 
 The toxin is peculiar in that it resists cooking 
 sufficient to destroy the life of the bacilli and drying 
 or smoking does not diminish its power. It is an 
 endotoxin. The bacillus may form pus and the author 
 has seen it as the cause of a diffuse pelvic inflamma- 
 tion. When injected into animals the paracolon 
 bacilli are capable of giving rise to a fatal septicemia 
 with acute inflammations, hemorrhages, and collapse. 
 
MUCOSUS CAPSULATUS GROUP 171 
 
 The bacilli are found chiefly by examination of the 
 stools or by cultivation of the circulating blood or 
 material from abscesses. Infective material should 
 be rendered innocuous by the means outlined for the 
 colon and typhoid bacilli (p. 112). 
 
 A very important means of diagnosis with all the 
 infections of the typhocolon group is the agglutination 
 test. These congeners produce agglutinins having some 
 affinity for all members of the group. The method of 
 use in this test consists in finding that member of the 
 group that will be clumped by the greatest dilution of 
 the patient's serum. This organism is then considered 
 the causative one. No practical remedy has been 
 found by the use of antitoxins or vaccines. 
 
 MUCOSUS CAPSULATUS GROUP 
 
 This group has been included with the colons by 
 many of the later authorities. Such a classification 
 is open to some objection, but it is quite proper to 
 discuss the organisms directly after the colon group, 
 since the two types have some things in common and 
 both are constantly present in the intestinal tract. 
 
 The bacteria in question are non-motile, plump, 
 straight rods without spores but surrounded by a 
 capsule, at least when in the animal body. They 
 measure from -g-g-J-o-fr "to s^Vo" mcn m length, and from 
 5~oTTTr to TGTRTO mcn m width. They may be found 
 lying singly, but when in the body are commonly 
 united in pairs or short chains about which one may 
 find the capsule. We may find the capsule in milk or 
 gelatine cultures. They are easily stained by ordinary 
 
172 PATHOGENIC BACTERIA 
 
 dyes. They grow well, best at body temperature, but 
 also as low as 12 C. or 54 F., or as high as 41 C. or 
 106 F. They are killed at 56 C. or 133 F. in ten 
 minutes. They resist drying quite well. Freezing is 
 rather rapidly fatal to them. They grow best in the 
 presence of oxygen, but may live without it. All the 
 artificial cultivations of this group are characterized 
 by luxurianqe, with a tendency to a slimy, smeary, or 
 tenacious consistency, hence the name "mucosus." 
 None of the group can soften gelatin or make indol. 
 They all produce some degree of acidity in milk, but 
 not all can curdle it. 
 
 The various members behave very differently in 
 regard to sugars and upon these reactions they are 
 classified. The poison produced by the bacteria of 
 this group is probably all endotoxic. They irritate 
 the part also mechanically by their presence. These 
 bacilli are widely distributed in animal life, but less 
 so otherwise in nature. They are transmitted directly 
 from man to man, by particles of saliva or sputum or 
 in fecal discharges, or in pus, which should be disin- 
 fected as given for the colon bacillus. Besides the 
 special conditions to be mentioned later, members of 
 this group have been known to cause pyelitis, gastro- 
 enteritis, peritonitis, pleuritis, and septicemia. 
 
 The most important member of the group is the 
 Bacterium pneumonia of Friedlander, a common cause 
 of pneumonia, next in importance for the acute lobar 
 pneumonia to the pneumococcus. The pneumonia 
 is characterized by its sticky nature. It is usually 
 short in duration and grave in prognosis. The bacilli 
 may enter the circulation and give rise to localized 
 
MUCOSUS CAPSULATUS GROUP 173 
 
 inflammations, including abscesses, elsewhere in the 
 body. It has been known to cause nasal sinus trouble, 
 otitis media, endocarditis, and meningitis. The bac- 
 teria are found by blood or sputum culture. Agglu- 
 tination tests are not of value. 
 
 FIG. 48 
 
 i 
 
 t 
 
 .:. '-v.v 
 
 * 
 
 1 % * 
 
 ' <* * * * ~H 
 % ^ 
 
 Bacillus mucosus capsulatus. (Hiss and Zinsser.) 
 
 Two other members of this group associated with 
 disease in man are Bacterium rhinoscleromatis and 
 Bacterium OZCBUOS. The former is said to cause a slow 
 granulomatous inflammation on the nose, mouth, or 
 larynx, in which hard nodular swellings are formed, 
 
174 PATHOGENIC BACTERIA 
 
 containing large typical cells loaded with bacilli. 
 Bacterium ozcence is associated with fetid atrophic 
 rhinitis or nasal catarrh. 
 
 All the mucosus group are moderately pathogenic 
 for animals, but injections into these experimentally 
 do not call forth prototypes of the diseases in man. 
 
 FIG. 49 
 
 Bacillus of rhinoscleroma. Section of tissue showing the microorganisms 
 within Mikulicz cells. (After Frankel and Pfeiffer.) 
 
 Usually a septicemia with extensive fibrin deposit 
 on serous membranes results. The thick, stringy, or 
 viscid character of the exudates is peculiar to these 
 bacteria. No antiserum has been produced to use in 
 cases of disease caused by them, but there have 
 been some favorable results after injecting dead 
 organisms during an attack. 
 
MUCOSUS CAPSULATUS GROUP 
 
 175 
 
 Bacterium Bulgaricum. Another organism not far 
 removed from the group just described, of practical 
 if not of pathogenic importance, is the milk-souring 
 bacillus. There are many varieties, but the one now 
 used most is the Bacterium bulgaricum of Massol. It 
 has the property of breaking up the fat of milk and 
 producing lactic acid. This butter milk or sour milk 
 
 FIG. 50 
 
 Bacterium bulgaricum. X 1000 diameters. (Piffard.) 
 
 is used in intestinal diseases (see p. 35) at the sug- 
 gestion of Metchnikoff. The large quantity of lactic 
 acid is inimical to many disease-producing, putrefac- 
 tive and fermenting bacteria that elaborate absorb- 
 able poisons, giving rise to auto-intoxication. The 
 
176 PATHOGENIC BACTERIA 
 
 organism, a large one, from T2~tf o"o to ^.^ inch in length * 
 grows in chains, best at 44 C. or 111 F., in milk, but 
 may be cultivated on other media. The souring 
 of milk takes place within twenty-four hours if the 
 temperature be correct (see Chapter on Milk). 
 
 Bacillus Aerogenes Capsulatus of Welch. A very 
 important putrefactive organism in the intestine is 
 the Bacillus aerogenes capsulatus of Welch. This 
 organism grows only in the absence of oxygen. It is 
 a large, straight, or slightly curved rod, from ^3iro"o 
 inch up to YIJQ" inch long by about ^oirro mcn w i^ e ' 
 non-motile, and encapsulated. It has the power of 
 fluidifying gelatin and clotting milk. It is introduced 
 to the human body by wounds, probably, or it may go 
 out from the intestinal tract through a solution of the 
 mucous membrane. When lodging in the organs it 
 forms gases, giving an appearance to the liver called 
 a foam or sponge liver. It has an importance in 
 obstetrics as gas-infection sometimes appears after 
 mechanical treatment within the uterus. It is prob- 
 ably not pathogenic to entirely healthy tissue, but 
 when an injury devitalizes a part an entrance is 
 afforded. It is responsible for the early bloating of 
 some cadavers. 
 
 Bacillus of Malignant Edema. The bacillus of 
 malignant edema is a common inhabitant of the soil 
 and may be found in dust. It grows only in the absence 
 of free oxygen, but may be cultivated with ease in 
 the laboratory particularly if sugar be added to the 
 medium. It is a long delicate rod measuring about 
 STTTfriF inch in thickness and -ginyTF to -oVo" inch in 
 length. It moves by flagella arranged along the sides. 
 
BACILLUS PYOCYANEUS 177 
 
 Spores are formed about the middle of the length. 
 These spores are responsible for the great resistance 
 presented by the germ. The pathogenic properties 
 are due to a soluble separable toxin. The bacteria 
 themselves do not enter the blood stream. At the 
 site of inoculation an edematous and bloody swelling 
 appears which in susceptible individuals spreads 
 rapidly. Death results from toxemia. This germ is 
 frequently responsible for spontaneous disease in the 
 lower animals, but in man is probably only introduced 
 by some mechanical injury. It has been known to be 
 introduced by hypodermic injections when a dirty 
 needle was used. Its most common method of intro- 
 duction is in grinding dirt into a wound such as a 
 compound fracture. One attack confers immunity 
 against a second. All discharges or dressings should 
 be so received that they can be burned. 
 
 Bacillus Proteus Vulgaris. The Bacillus proteus 
 vulgaris is a widely distributed organism of pro- 
 nounced putrefactive powers. It is very similar to the 
 colon bacillus. It has been encountered in abscesses, 
 pyelonephritis, endometritis, and peritonitis. Meat 
 poisonings have been traced to it. Its toxin is very 
 poisonous. It is frequently a harmless inhabitant of 
 the intestinal tract. It is quite resistant, and to kill 
 it requires the most approved disinfectants acting 
 over a considerable time. 
 
 Bacillus Pyocyaneus. Bacillus pyocyaneus is the 
 organism of green pus. This bacterium is widely dis- 
 tributed on the skin and mucous membranes of man 
 and animals. Its disease-producing powers are low 
 and considerable reduction of resistance on the part of 
 12 
 
178 PATHOGENIC BACTERIA 
 
 the host may be assumed when infection occurs. It 
 may enter by cracks or wounds, and not infrequently 
 is associated with other bacteria, notably the pus cocci. 
 The pyocyaneus bacillus is an actively motile straight 
 or slightly curved, non-spore-forming rod measuring 
 from 2TTOTT inch to -goVo inch long and y-g-J-g- Q inch 
 wide. Its motility is due to one flagellum placed 
 at one end. 
 
 FIG. 51 
 
 Bacillus pyocyaneus. (From Kolle and Wassermann.) 
 
 It grows readily at room or body temperature, best 
 in the presence of oxygen. On agar jelly it forms pig- 
 ments which color the growth itself and the medium 
 upon which it is living. These pigments are of two 
 kinds, a green one and a fluorescent one. They impart 
 a beautiful green fluorescence to the tube of culture 
 material. The bacillus has the power to elaborate a 
 gelatine-digesting and a milk-curdling ferment. Its 
 powers of resistance to heat and chemicals are rather 
 high. Materials to be disinfected should be exposed 
 
BACILLUS PYOCYANEUS 179 
 
 to carbolic acid or formaldehyde solutions for half an 
 hour. 
 
 The poisons of the pyocyaneus bacillus are twofold- 
 one an endotoxin, the other a soluble separable toxin. 
 These substances, more especially the latter, have the 
 power of destroying some other bacteria. The broth 
 culture, freed of bacteria and reduced to one-tenth 
 its volume, is used sometimes to rid the throat of 
 persistent diphtheria bacilli. This is called "pyocy- 
 anase." The toxins are more poisonous to animals 
 than are the living cultures. Most small laboratory 
 animals are susceptible to injections of the living 
 pyocyaneus bacillus. The bacilli may multiply within 
 the body and enter the blood stream. It is maintained 
 that some part of the toxin has the power to destroy 
 red blood cells. 
 
 The pyocyaneus bacillus may, by its presence on 
 wounds, delay their healing. It is commonest perhaps 
 in boils in the axilla and groin. It has been found 
 in otitis media and in gastro-enteritis of debilitated 
 children. There may be a general sepsis under which 
 circumstances pleurisy, pericarditis, and the like may 
 be looked for. A diagnosis is made solely by finding 
 the pigment-producing bacillus in pus or other exudate, 
 or possibly by blood culture. Active immunity may 
 be produced in the lower animals by exceedingly 
 careful technique, but it has not been found profitable 
 to use the antiserum upon human beings. We know 
 little as yet of vaccine treatment in such infections. 
 
CHAPTER XII 
 YEASTS AND MOULDS 
 
 THIS chapter is devoted to a consideration of the 
 next higher groups of the plant algae above the bacteria . 
 They are the yeasts or Blastomycetes and the moulds 
 or Hyphomycetes. That there is any sharp separation 
 of these forms from the bacteria, or even from one 
 another, cannot be maintained. There are various 
 gradations in character from the typical representa- 
 tives of the groups toward the others, so that there are 
 intermediary species incapable of classification. The 
 typical members of each family have very distinct 
 criteria and about them similar forms must be classified. 
 
 The yeasts and moulds are very widely distributed 
 in nature, but have but slight pathogenic powers. 
 The former are of importance in the making of spiritu- 
 ous liquors, bread, etc. The moulds have little use, 
 and except for their frequent appearance as contami- 
 nations, and in a few diseases, are of little interest 
 to the pathologist or bacteriologist. 
 
 YEASTS 
 
 Yeasts are spherical or ovoid bodies with a doubly 
 contoured wall and a highly granular protoplasm oft- 
 times with fat droplets in it. They measure from 
 
YEASTS 181 
 
 TSTT to T^TJ inch in length and are about two-thirds as 
 wide as long. The characteristic feature of the yeasts 
 is their method of reproduction, which takes place by 
 a swelling out of a part of the cell wall like a ball, into 
 which the protoplasm flows. This is called "budding." 
 When the daughter-cell arrives at the proper size, 
 the connection with the parent dissolves and the new 
 cell is free. Spores have been observed within the 
 yeast cells, and these develop into adult cells when the 
 old cell ruptures. Yeasts grow upon nearly any organic 
 substance providing there is moisture. The best media 
 and temperatures vary with the species. The kinds 
 pathogenic for man grow best upon foodstuffs con- 
 taining simple sugars, but may thrive also on complex 
 substances. They are grown with reasonable ease in 
 the laboratory, but care must be used to get them in 
 pure cultures as their development is slow. Their 
 peculiar effect upon carbohydrate containing stuffs is 
 due to their enzyme which has the power of making 
 ethyl alcohol. How much effect this has upon the 
 production of disease in man is not known. 
 
 Blastomycosis. The disease produced by yeasts in 
 man called Blastomycosis, and the causative agent is 
 called Saccharomyces Busse, after the man who first 
 described it. By the first, a genus name, it is seen to 
 belong to the same group as that used for bread-raising, 
 Saccharomyces cerevisice. It is not known just how 
 the disease is contracted, but the yeast probably 
 enters wounds, cracks, or hair follicles. It penetrates 
 into the deep layers of the skin and sets up abscesses 
 of slow development and spread. These may break 
 down and leave a sluggish ulcer which later shows a 
 
182 YEASTS AND MOULDS 
 
 tendency to heal. More serious phases of this infection 
 are, however, met when the lung is first affected. Then 
 a pneumonia, ending in sepsis results. In these cases 
 the outlook is hopeless. The disease is probably due 
 wholly to the mechanical presence of the yeasts. The 
 germs leave the body in pus or sputum. They are 
 not easily destroyed, and all infective matter should 
 be burned. It is, however, not a very contagious 
 disease. 
 
 FIG. 52 
 
 
 Saccharomyces Busse. X 350 diameters. (From Kolle and Wassermann.) 
 
 There is no antiserum treatment and the few cases 
 upon which vaccines were tried have not held out 
 much promise in this direction. Yeasts are held 
 responsible for some diseases in lower animals, but the 
 question is not yet settled. When injected into them 
 intentionally varying results are obtained. It can be 
 said that they settle by preference in the lungs and 
 spleen. 
 
MOULDS 
 
 183 
 
 MOULDS 
 
 This group is by no means so simple as the yeasts. 
 The genuses vary in almost every vital activity. The 
 following remarks, therefore, pertain to those forms 
 having some importance in human medicine. The 
 moulds or branching fungi consists of long, interlacing, 
 hair-like threads called mycelia (sing., mycelium), 
 
 FIG. 53 
 
 Penicillium glaucum. Gelatin culture. Spread stained with gentian-violet. 
 500 to 1. (From Itzerott and Niemann.) 
 
 from which come off end branches called hyphse, upon 
 which the reproducing parts usually develop. These 
 mycelia are made up either of one long continuous 
 cell with a cell wall, and an easily distinguishable, long 
 nucleus, or they may break up into shorter forms each 
 with a separate nucleus. Their length and width are 
 so variable that measurements would be misleading. 
 
184 
 
 YEASTS AND MOULDS 
 
 Their general naked-eye appearance and size is well 
 known to any who have observed the felt-like or cottony 
 moulds upon decaying organic matter. 
 
 FIG. 54 
 
 These two half-plates show three months' growth on peptone-maltose agar of 
 t wo megalosporon varieties of the ringworm fungus . Natural size . (Park . ) 
 
 Multiplication occurs in two ways. Upon the hyphse 
 may develop a reproductive organ, the sporangium, 
 containing spores that become free upon its rupture. Or 
 
MOULDS 185 
 
 the hyphse may split into segments giving off end pieces 
 as reproducing elements, called conidia, the whole 
 giving the appearance of the hand bones, the phalanges 
 representing the conidia (see Penicillium glaucum). 
 
 FIG. 55 
 
 Achorion Schonleinii. (Fliigge.) 
 
 These moulds enter by wounds, cracks or hair follicles, 
 and develop in the superficial layers of the skin. The 
 mechanical irritation set up by their presence is largely 
 responsible for the various diseases they occasion. To 
 be sure, they can form enzymes, but of what impor- 
 tance they are in human lesions is not known. The 
 diseases are not highly contagious, but of great ten- 
 acity when once well advanced. Infective material 
 
186 YEASTS AND MOULDS 
 
 comes away in all cases with discharges, and should 
 be burned. Their principal diseases in the human 
 being are as follows: 
 
 Ringworm. Of this there are two varieties ringworm 
 of the skin, Tinea circinata, and ringworm of the hairy 
 portions, Tinea tonsurans or Tinea sycosis. This is due 
 to the Trichophyton of various species, depending upon 
 the size of the spores. It is commonest in children 
 in schools, and appears also where uncleanliness pre- 
 vails, as evidenced by epidemics from a badly kept 
 barber shop. The fungus grows into the hair 
 sheath and inflames its base. The disease appears 
 characteristically as circular, scaly patches, which are 
 rapidly denuded of hair. This disease, as far as known, 
 is only transmitted from man to man. 
 
 Favus. This disease is caused by a mould called 
 Achorion Schonleinii, and affects chiefly the hairy 
 portions of the body. Animals as well as man are 
 affected, and while it is usually transmitted from 
 person to person, it is not uncommonly contracted by 
 fondling affected cats and dogs. Debilitated persons 
 are most susceptible. The fungus penetrates the hair 
 shaft, sets up a little inflammation which slowly spreads, 
 and is soon covered with a curious sulphur-yellow 
 concave crust called a scutulum. The place becomes 
 bald because the nutrition of the hair is cut off. Some 
 cases are on record where this fungus has spread to 
 all the tissues of the body, doing damage by the irrita- 
 tion of its presence. 
 
 Thrush. Thrush or soor is a disease caused by the 
 Oidium albicans, and is characterized by the presence 
 of small white patches on the mucous membrane, 
 
MOULDS 
 
 187 
 
 usually of the mouth, in unclean or illy nourished 
 children. It may be found in the vagina. It has been 
 known to spread throughout the body. 
 
 FIG. 56 
 
 
 
 Oidium albicans: g, conidia; e, pus cells. (From Plaut in Kolle and 
 Wassermann.) 
 
 Pityriasis Versicolor. This is a disease chiefly of 
 unclean persons produced by the development of 
 Microsporon furfur in the superficial layers of the 
 epithelium. It may appear anywhere on the body, 
 but chiefly affects the short-haired skin. It is very 
 slightly contagious. 
 
 Diagnosis. The diagnosis of these conditions depends 
 upon finding the particular fungus. Some of the pus 
 
188 YEASTS AND MOULDS 
 
 from a blastomycotic abscess or some of the scales 
 from the underside of the crusts of the skin diseases 
 produced by moulds is softened in weak caustic and 
 examined in a moist condition under the microscope. 
 The single, or budding cells of the yeasts or the branch- 
 ing mycelia of the moulds are usually found with 
 ease. In case it is desirable to cultivate the fungi a 
 long elaborate technique is necessary. 
 
CHAPTER XIII 
 BACTERIA IN AIR, SOIL, WATER, AND MILK 
 
 BACTEEIA IN AIR 
 
 THE bacteria naturally found in air are not patho- 
 genic, but consist usually of spore formers and moulds, 
 in other words, those having some resistance to dryness 
 and sunlight. There are more in the layers of the 
 atmosphere near the earth, circulating in air currents 
 after being raised in dust. When there are no currents, 
 bacteria tend to settle on surfaces, as they are heavier 
 than air. After rain storms the atmosphere may be 
 nearly free of organisms. More pathogenic forms are 
 found where people live or congregate, so that air 
 currents produced by human activities tend to increase 
 the bacteria floating about. Colon bacilli are sometimes 
 found in the air above streets. Organisms may be 
 carried in currents set up by coughing or blowing. 
 This is well shown by the fact that tubercle bacilli 
 may be found at a distance of twenty feet in front of 
 a coughing consumptive. The practical application 
 of this principle is the use of moisture in dusting or 
 sweeping. Surfaces of a sick room should be wiped 
 with a moist cloth, preferably using a disinfectant 
 that will not hurt the hands. Bacteria cannot leave a 
 moist surface. They may be freed by the bursting of 
 bubbles of sputum or other infective fluid. They do 
 
190 BACTERIA IN AIR, SOIL, WATER, AND MILK 
 
 not travel far by this means if air currents be absent, 
 and there is probably little danger from simple unpleas- 
 ant odors from drains if protected from these currents. 
 Bacteria are found in air by filtering a definite quantity 
 of air through cotton or sugar. The former is washed, 
 the latter dissolved in sterile water, and this is examined 
 as outlined under water. 
 
 BACTERIA IN SOIL 
 
 Microorganisms live in the first few feet of the earth 
 wherever moisture and a small amount of nourishment 
 are found. Pathogenic forms are nearer the surface, 
 while deeper in pure saprophytes are found. Bacteria 
 are deposited from dust, water, and the dejecta of 
 animals. Pathogenic ones are only to be found where 
 animal life exists, while in uninhabited or untilled 
 lands they probably do not exist at all. The denser 
 the population the more disease-producing kinds are 
 found. Rain will wash away soil and carry with it 
 bacteria into water-courses. This is of great impor- 
 tance where human dejecta are deposited on the 
 ground. 
 
 Typhoid fever epidemics have been known to have 
 such an origin. Typhoid germs can live in soil for many 
 months. Vegetables are easily contaminated, and if 
 eaten raw can transmit the disease. Cholera vibrios 
 have a shorter life in this place. Anthrax bacilli live 
 a long time and cattle are sometimes infected by 
 their pasture. Actinomycosis is well known to spread 
 through a herd because of infected pasture land. 
 The bacteria of soil are found by planting some of it 
 
BACTERIA IN WATER 191 
 
 in laboratory media, placing a part at ordinary tem- 
 perature and another at body temperature. By the 
 latter means the forms parasitic to animals are found. 
 Tetanus bacilli are, perhaps, the most widespread 
 of pathogenic bacteria in the soil. Their resistant 
 spores remain alive an unlimited time. Persons going 
 barefoot and subject to wounds or bruises, may con- 
 tract the disease. Tubercle bacilli, in dead persons, 
 live only a few months, but when contained in sputum 
 spat upon the earth survive for a long period. 
 
 BACTERIA IN WATER 
 
 In water there are many hundreds of species, but 
 it may be said in general that all the disease-producing 
 kinds are in water because discharges from human 
 disease have been put into it. Of course this may not 
 be direct, but through the agency of soil as mentioned 
 above. Some bacteria may be carried into streams by 
 rain which brings down the dust. Rain itself is nearly 
 free of germs. Bacteria may be present in water up 
 to the billions without altering greatly its clearness or 
 giving it an odor. Of the two water sources recognized 
 by hygienists, ground water (deep wells) and surface 
 water (ponds, lakes, and rivers), the second is by far 
 the more important and the more easily polluted. 
 Large bodies of water, either still or moving, tend to 
 rid themselves of bacteria. In still or slowly moving 
 bodies such as reservoirs, germs settle with other 
 organic and inorganic matters. For water-courses of 
 any character purification is aided by changes in 
 temperature during the day and night and the very 
 
192 BACTERIA IN AIR, SOIL, WATER, AND MILK 
 
 efficient disinfecting properties of direct sunlight. 
 Oxygen absorbed from the air also assists in destroy- 
 ing bacteria. There are certain saprophytes in water 
 and sewage capable of breaking up organic matter and 
 freeing oxygen, which, either free or in going into com- 
 bination with other elements in chemical union, is 
 inimical to pathogenic non-spore-forming bacteria. 
 
 In this book a word may be useful as to the means 
 of artificially purifying water for domestic purposes. 
 For the community water is purified by settling in 
 reservoirs, or by filtration through sand and stones, 
 sometimes aided by the addition of chemicals. For 
 household purposes bacteria in water may be removed 
 by house filters made of porcelain attached to the 
 house supply, or what is better, by boiling. The flat 
 taste of boiled water may be removed by allowing air 
 to go through by pouring from one container to another 
 several times. 
 
 Water in a shallow vessel, preferably of copper, will 
 be practically sterilized by an hour's exposure to direct 
 sunlight. This is practicable for camping parties who 
 are compelled to use water under suspicion. 
 
 Principal Water-borne Diseases. The principal dis- 
 eases transmitted by water are typhoid, cholera, and 
 dysentery. Typhoid bacilli may live in water, espe- 
 cially if surrounded by a bit of protective and nutrient 
 organic matter, for many weeks. The question is 
 often asked as to how a few germs in a glass or two 
 of water can cause typhoid fever. As a matter of 
 fact, when an epidemic of typhoid is starting there are 
 usually supposed to be many germs and not a few 
 in the water. What probably happens is that a small 
 
BACTERIA IN WATER 193 
 
 particle of organic matter, possibly feces, is swallowed. 
 This may contain many thousand organisms. 
 
 Although cholera organisms live in water a shorter 
 time than typhoid bacilli, they are said to be viable 
 for several weeks. Relatively more cholera organisms 
 are discharged with a cholera stool than is the case of 
 typhoid bacilli in enteric fever. Dysentery bacilli live 
 only a short time in water probably, and the impor- 
 tance of water in the dissemination of dysentery is ques- 
 tioned by some observers. Certain it is that some 
 epidemics appear to be water-borne. 
 
 Typhoid and colon bacilli are always present in 
 typhoid stools. It is hardly probable that the former 
 could get into water without the other. Moreover, 
 the colon bacillus is present in all alimentary tracts. 
 It is more easily detected in any mixture or solution 
 than any other of the intestinal bacteria. Therefore it 
 is taken as an indication of sewage pollution in water. 
 This may not mean that typhoid bacilli are present, but 
 merely that contamination of water by sewage from 
 animal sources has occurred. Whether from man or 
 animals, it is obvious that dejecta should not come into 
 water intended for human consumption. The methods 
 of water examination now in use all aim at the detec- 
 tion of Bacillus coll. Because of its peculiarities in the 
 fermentation of sugars, certain media are adopted as 
 standards for its isolation. Water is carefully collected 
 and kept upon ice so that no increase of bacteria will 
 occur. In the laboratory suitable measures are taken 
 to determine the whole number of bacteria and the 
 presence of the colon bacillus. The whole number is 
 estimated by growing the water in flat plates of agar 
 13 
 
194 BACTERIA IN AIR, SOIL, WATER, AND MILK 
 
 jelly and counting the number of colonies growing 
 in forty-eight hours. It is assumed that each colony 
 grows from a single bacterium. Chemical examination 
 of water aims at the determination of the quantity of 
 organic matter indicative of sewage pollution. Stand- 
 ards have been set by sanitarians, but they are not 
 necessary here. 
 
 BACTERIA IN MILK 
 
 Milk in the deeper parts of the udder of the healthy 
 cow is probably wholly free from bacteria. The ducts 
 of the teats, however, are almost never free from some 
 germs, and of course the outside skin contains many. 
 In a diseased udder there may be not only the germ 
 causing the disease, but other intruders from the 
 outside. Bacteria come into milk from the cow her- 
 self or from the outside. The latter is probably the 
 more important and the factors which must be con- 
 sidered are the dirt on the skin, swishing of the soiled 
 tail, the soiled hands of the dairyman, and the cans, 
 contaminated by manure or by polluted water. 
 
 Milk is a capital culture medium for almost all bac- 
 teria, and as it is warm when drawn, growth may begin 
 very soon. Unless the milk be cooled very soon, to a 
 temperature at which bacterial growth is retarded or 
 stopped, souring will occur. Perfectly fresh milk has a 
 very slight restraining influence upon the development 
 of some feebler bacteria, but this power is soon lost 
 and bacterial growth may be unlimited. It is best to 
 keep milk not above 40 F. or 5 C., but so low a 
 temperature is not always possible to maintain. The 
 
BACTERIA IN MILK 195 
 
 consumer should strive to keep milk at the lowest 
 temperature practicable. Cities are now controlling 
 their milk supply by various regulations as to the 
 dairy management and shipping systems. The most 
 important domestic means of having clean milk consists 
 in receiving it in perfectly clean bottles and keeping 
 it on ice. 
 
 Pasteurization. On account of the lack of perfect 
 municipal control of the milk supply, it is necessary 
 to resort to Pasteurization. This consists in heating 
 the milk to 60 or 70 C., 140 to 158 F., for ten to 
 twenty minutes, and then cooling rapidly. Various 
 methods are in use commercially, but this can be done 
 very easily in the home, using a double boiler and a 
 thermometer. Pasteurization kills all but the spores 
 of bacteria, which are of little danger if the milk be 
 kept on the ice or used shortly. Some persons object 
 to the use of this heating because the food value 
 of the milk is reduced by making certain chemical 
 constituents harder to digest. The casein curds of milk 
 become tougher after boiling. However, some German 
 pediatrists are now using boiled cows' milk for certain 
 intestinal disorders of children. If properly carried 
 out, Pasteurization does more good than harm, and 
 has proven its value by the reduction of the death 
 rate from infantile diarrhea in summer time. The 
 greatest objection anyone can raise to Pasteuriza- 
 tion is that it gives a false sense of security. It 
 cannot be too strongly emphasized that any natural 
 antibacterial power possessed by the raw milk is 
 destroyed by Pasteurization and that rigid precautions 
 should be observed that the heated milk is not allowed 
 
196 BACTERIA IN AIR, SOIL, WATER, AND MILK 
 
 to remain at a temperature permitting the growth of 
 bacteria. If kept below 60 F. and used within twenty- 
 four hours the consumer is probably safe at all times. 
 
 Spoiling of Milk. In the summer conditions for the 
 spoiling of milk are more favorable than in winter, 
 since the temperature is unfavorable for its preser- 
 vation, and more dust and flies introduce bacteria. 
 Bottles in which milk is served should be washed 
 when empty, with cold water first, and then boiled or 
 well scalded. If a small quantity of milk remain in 
 the bottom putrefactive and fermentative bacteria grow, 
 and dry on the bottle making it harder to clean 
 subsequently. Milk bottles should be considered as 
 possible carriers of disease and the user should assume 
 his part of the responsibility by cleaning them out 
 and not leave it entirely to the milkman. The author 
 knows of one instance where a milk bottle was used 
 as a spittoon. 
 
 Souring of Milk. The souring of milk is due to a 
 variety of bacteria, chief among which is Bacterium 
 lactis aerogenes, related to the Bacterium fulgaricum 
 described above. This germ is ubiquitous. It is not 
 pathogenic. It produces a fermentation of the sugar 
 of milk, lactose, into lactic acid. Moulds may help this 
 and oftentimes lactic acid and ethyl alcohol may be 
 formed side by side. The latter predominates in the 
 carbonated milks like koumys. Other bacteria cause 
 clot, or precipitation of the casein, the forerunner of 
 cheese. Streptococci from the udder or manure may 
 also help in souring. 
 
 To make buttermilk in the home is a simple matter. 
 A quantity of whole or skim milk is boiled and cooled. 
 
BACTERIA IN MILK 197 
 
 A tablet containing the lactic acid bacilli, a small 
 quantity of pure culture of the organism, or a "starter" 
 from a previous making is then added to this cooled 
 milk and set aside in a warm room (about 75 F.) over 
 night. The result is a rather agreeable sour milk. 
 Pharmaceutical chemists and laboratories are now 
 supplying tablets and cultures for this purpose. 
 
 Diseases Caused by Polluted Milk. Many diseases are 
 believed to be due to bad or polluted milk. If milk 
 merely carry the germs this is easily understood, but 
 as is the case in the diarrheas of infants, the trouble 
 may lie not with the bacteria introduced with the 
 milk, but with the disturbance of digestion caused 
 by the abnormal chemical conditions brought about 
 by souring. These strange chemical substances 
 so pervert normal digestion that really pathogenic 
 bacteria, the dysentery bacillus group, for example, 
 are able to exert their noxious effects. Streptococci 
 commonly present in the teats, identical with the 
 Streptococcus pyogenes, are said by some to take advan- 
 tage of this disturbed digestion. The examination for 
 streptococci consists in simple staining and finding of 
 them lying in or about pus cells. Health authorities 
 have rules covering this method of examination and 
 the interpretation of results. 
 
 Scarlet fever, although its cause is unknown, is 
 known to spread along milk routes and has at times 
 been traced to a case on a dairy farm. Foot and 
 mouth disease of cattle, another condition of unknown 
 etiology, has been found in children drinking milk 
 from affected cows. The bacillus of diphtheria may 
 live in milk a long time and may be carried along a 
 
198 BACTERIA IN AIR, SOIL, WATER, AND MILK 
 
 milk route. It is said that cholera may be transmitted 
 by milk contaminated with polluted water. 
 
 Typhoid Fever. Typhoid fever may be trans- 
 mitted by milk when a case exists on a dairy farm or a 
 dairyman uses polluted water to wash his cans. In 
 perfectly fresh milk the germs do not thrive, but when 
 a little older the milk offers no resistance to their 
 multiplication. If sour, the lactic acid and alcohol not 
 only inhibit their growth, but actually kill them. It is 
 frequently in the period from cooling to distribution and 
 use that contamination occurs. This is done by the 
 hands of dairymen, shippers, tasters (dipping the finger 
 into the milk), or by domestic servants. Carriers 
 of typhoid bacilli are a prolific source of epidemic 
 spread by milk. Although some sanitarians discredit 
 the milk transmission of typhoid, the following obser- 
 vations are very significant when taken together with 
 the fact that the Bacillus typhosus has been found in 
 milk. There is a relatively greater number of women 
 and children affected in milk-born epidemics, while in 
 water and general epidemics more men are affected. 
 Pasteurization easily kills the typhoid bacillus. 
 
 Tuberculosis. The question of the transmission of 
 tuberculosis by milk is one that has raised much dis- 
 cussion, since Koch said that the bovine type of 
 bacilli does not produce tuberculosis in human beings. 
 The matter seems settled now that tuberculosis in 
 the young may be caused by the bovine bacillus, and is 
 most commonly located in the cervical and abdominal 
 glands and in the meninges. If a cow have tuber- 
 culosis of the udder, tubercle bacilli are usually found 
 in great numbers in the milk. If she have lesions 
 
BACTERIA IN MILK 199 
 
 elsewhere she may still excrete the bacilli in the 
 milk, but it is impossible to determine when or in 
 what numbers. The natural corollary is not to use 
 milk from a tuberculous animal. Tuberculin tests 
 are now being required almost everywhere when 
 permission to register a milch cow is asked. No cow 
 giving a tuberculin test should be used for a milk 
 supply. Bacilli are also excreted in feces of infected 
 animals, and are easily carried into the milkings by the 
 swishing tail. Tubercle bacilli of human sources may, 
 of course, be in milk if handled by a consumptive. 
 Pasteurization does not surely kill the tubercle bacillus, 
 especially if surrounded by a bit of mucus. 
 
 Examination of Milk.- Milk is examined for the 
 presence of colon bacilli, and the whole number of bac- 
 teria just as in the case of water. For the demon- 
 stration of tubercle bacilli by stain a special technique 
 is necessary. We usually inject some of the milk, 
 cream, or sediment into guinea-pigs, and expect 
 lesions in them. The chemical examination of milk 
 usually shows its food value, which may be affected 
 by bacteria. 
 
CHAPTER XIV 
 
 DISEASES DUE TO PROTOZOA 
 
 THERE are not many recognized specific diseases in 
 man due to these lowest animal forms, but those well 
 known are of the greatest importance, because of their 
 prevalence in some parts of the world and an account 
 of the difficulties presented to medical treatment. It 
 may be said in general that the protozoan diseases of 
 man represent a phase in the life history of the causative 
 microorganism, and are in fact stages through which 
 the protozoa pass in order to fulfil their cycle of life. 
 The subject of protozoology is of enormous magnitude, 
 and it is impossible to even outline all the steps which 
 may be passed through, in a work like this. An attempt 
 will, therefore, be made to describe the important 
 diseases due to protozoa, with a general statement 
 covering the morphology and life history of the 
 organism. Of the many thousands of species in nature, 
 only a handful are pathogenic for man. The disease- 
 producing types fall into the following zoological 
 families or genera: Sarcodina (rhizopoda, amoebae), 
 Mastigophora (Flagellata, trypanosoma), Infusoria 
 Heterotricha (balantidium), Sporozoa (coccidia, hemo- 
 sporidia, plasmodium). The diseases we shall see all 
 fall into these groups. They are for the most part 
 dependent upon the animal body for the continuance 
 
AMEBIC DYSENTERY 201 
 
 of their life. Other forms live in water, earth, decaying 
 matter, or as apparently harmless commensal species 
 within the intestinal tract of animals from insects up. 
 
 SARCODINA 
 
 Amebic Dysentery. Amebic dysentery is a subacute 
 or chronic inflammatory disease of the large intestine, 
 caused by the Enlamceba histolytica or dysenteric ameba. 
 It is not definitely settled as to the means by which 
 this protozoon is transmitted, but water is probably the 
 most important method. The cells multiply in the small 
 
 FIG. 57 
 
 Entamceba histolytica (Schaudinn) from the stool of a dysentery patient. 
 The same individual showing two successive movements. The nucleus 
 contains the nucleus and three red blood cells. Enlarged 500 to 1. After 
 Jiirgens (from Kisskalt and Hartmann). 
 
 intestine, pass downward, and penetrate the mucous 
 membrane of the colon. Here in the deeper layers 
 they set up the inflammation largely by their presence, 
 but also by some soluble excretory substance. From 
 here they may be carried throughout the body, and 
 give rise to abscesses notably in the liver. These are 
 
202 DISEASES DUE TO PROTOZOA 
 
 of long standing, and may present work for surgical 
 interference. 
 
 The protozoa leave the body with the feces, which 
 to be disinfected must be well treated with carbolic 
 acid or burned. They should never be allowed to 
 dry, because the entameba may become more resistant 
 in a dry state, due to a curious spore-like stage. This 
 disease is diagnosticated by finding the parasites in 
 the feces or pus, which must be kept at a proper tem- 
 perature during the examination. Some of the material 
 is examined on a warmed plate and kept not lowerth an 
 77 F. all the time. At this degree the peculiar move- 
 ments of the amebse are noted as a pushing out of a 
 part of the cell wall like a bud. This is the pseudopod 
 or false foot. This means of progression enables the 
 organism to penetrate intact mucous surfaces and pass 
 through sand filters impermeable for bacteria. 
 
 The Entamceba histolytica is an irregularly shaped 
 mass of simple protoplasm with a primitive structure. 
 Its nucleus is usually single in contrast to other amebre. 
 It measures up to -$%-$ inch. It moves and embraces its 
 food by the pseudopods. It reproduces by division or 
 by the production of daughter-cells within its body. 
 When these are massed together and held by a cap- 
 sule, it is said to be encysted. When such cysts are 
 taken into the body the intestinal juices probably 
 dissolve the capsule and let the cells go free. Encyst- 
 ment occurs when conditions for life become unfavor- 
 able. Amebse are not killed by cold, but succumb to 
 60 C. or 140 F. in one hour. Acids are unfavorable 
 for the growth. They are cultivated artificially with 
 great difficulty, and are usually combined with bacteria, 
 
KALA-AZAR 
 
 203 
 
 in whose presence they multiply without hindrance. 
 Only monkeys and dogs are susceptible to the amebae 
 causing disease in man. No therapy depending on 
 antitoxins or vaccines is practicable. 
 
 MASTIGOPHORA 
 
 Kala-azar. In the next group of protozoa, the flagel- 
 lata, several are pathogenic for man. Kala-azar is a 
 
 
 Protozoa in a case of tropical ulcer. X 1500 approximately. (Aftei Wright.) 
 
 peculiar, slow disease, called by various names, depend- 
 ing upon its locality dumdum fever, kala-azar, etc. 
 exhibiting a large spleen, hemorrhages, anemia, and 
 
204 
 
 DISEASES DUE TO PROTOZOA 
 
 fever. The causative microorganism may be found 
 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 
 flagellum on the forward end. They are from y^T 
 
 2000 
 
 to 
 
 8000 
 
 inch long and about two-thirds as wide. 
 
 FIG. 59 
 
 Trypanosoma gambiense. (From Calkins. Preparation by F. W. Balstack.) 
 
 Trypanosomiasis. The next flagellate to cause dis- 
 ease is the Trypanosoma, two species of which are 
 pathogenic for man, causing a disease called try- 
 panosomiasis, or sleeping sickness. This affection is 
 
TRYPANOSOMIASIS 205 
 
 commonest in Africa, because of the prevalence of 
 the tsetse fly there. The protozoa are transmitted 
 by the bite of a fly within whose body the blood 
 sucked from an infected person leaves the trypano- 
 soma. The bite of these flies, the tsetse fly, becomes 
 infective for the well twenty-four hours after biting 
 the affected, and continues so for about four or five 
 days. These pests bite during the daytime, so that 
 protection and screening of houses is insufficient 
 usually to guard against the disease. Of course the 
 infected persons as well as the healthy must be pro- 
 tected 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 "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 when 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. 
 
206 DISEASES DUE TO PROTOZOA 
 
 Trypanosomas are irregular, elongated, twisted 
 bodies with a large nucleus variously placed, and a 
 thickened ribbon-like edge, the undulating membrane, 
 which starts as a minute secondary nucleus at the 
 hind end and ends in a rather long whip-like flagellum 
 at the fore end. They range from ^oW mcn 
 to giro mcn m length and they are about ysVo mcn 
 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 culture 
 has raised the resistance of certain low r er 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. 
 
 Relapsing Fever. Relapsing fever is caused by the 
 Spiroclwta Obermeieri transmitted by a mosquito, 
 
RELAPSING FEVER 207 
 
 probably of the genus Culex. The spirochseta circulates 
 in the blood during attacks and settles in the spleen 
 between them. The disease is characterized by inter- 
 mittent attacks of continued fever beginning suddenly, 
 lasting four to six days, and ending by crisis. The 
 febrile periods recur with eight to ten day intervals of 
 freedom from symptoms. Blood is examined during the 
 fever and we find under the microscope long, ^QQ~Q 
 inch, delicate, ^Q^-Q-Q inch wide, wavy spirals with 
 
 FIG. 60 
 
 Spirochaeta Obermeieri blood smear. Fuchsin. X 1000 diameters. (From 
 Itzerott and Niemann.) 
 
 corkscrew and undulatory movements. They have 
 not been successfully cultivated, but it is known that 
 they are not very resistant to deleterious agencies. 
 Some immunity is left after an attack, and use has 
 been made of the serum in treating the sick. There 
 are several species of this spirochete, differing very 
 slightly, and to make an antiserum it is necessary to 
 use many varieties. Texas and African tick fever are 
 due to this genus 
 
208 
 
 DISEASES DUE TO PROTOZOA 
 
 Trichomonas. Two protozoa of a slight medical 
 importance are the Trichomonas vaginalis, with its 
 nearly related varieties, T. intestinalis and T. pulmon- 
 alis, and the Lamblia 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 
 
 FIG. 61 
 
 FIG. G2 
 
 Trichomonas vaginalis. 
 (Blochmann.) 
 
 Lamblia intestinalis. 
 (Schewiakoff.) 
 
 of the irritation by the protozoa. However, the 
 vaginitis and cystitis caused by the T. vaginalis is a 
 serious matter in children. These are usually pear- 
 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 
 
MALARIA 
 
 209 
 
 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 
 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 malaria, the P. vivax, and 
 
 Some of the principal forms assumed by the plasmodium of tertian fever in 
 the course of its cycle of development. (After Thayer and Hewetson.) 
 
 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 
 fourth day, the quartan type; and (3) a continuous, 
 typhoid-like type, the malignant or sestivo-autumnal 
 fever. 
 
 The species vary in finer morphological details, but 
 they follow the same course in their transmission 
 14 
 
210 DISEASES DUE TO PROTOZOA 
 
 and development in regard to infectivity, except that 
 they require d'ffering 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 
 recognized by their position on a surface. Their 
 
 FIG. 64 
 
 Egg of Culex (a) laid together in "small boat;" those of Anopheles (6) 
 separate and rounded. (From Kolle and Hetsch.) 
 
 FIG. 65 
 
 a b 
 
 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.) 
 
 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 with the head 
 bent down. Furthermore, the wings of the Anopheles 
 are furred on the flat surface, while the Culex wings 
 are only fitted with widely set, fine hairs on the edges. 
 There are many other differences, but these will 
 
MALARIA 
 
 211 
 
 suffice as general guides. The female mosquito bites 
 a malarial person and receives the parasites into 
 her stomach. Here they undergo reproduction by a 
 sexual process, and appear in her venomosalivary 
 gland in a condition ready for transmission to the 
 
 FIG. G6 
 
 c d 
 
 Body of Culex (a) when resting is held parallel to wall in a curved 
 position, that of Anopheles (6) stands 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.) 
 
 next person bitten. This gland is connected with the 
 biting apparatus, and some of its secretioli 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 repro- 
 duction in the mosquito requires seven to ten days. 
 When a person is bitten the parasites, left under the 
 
212 
 
 DISEASES DUE TO PROTOZOA 
 
 skin, penetrate their cell of choice, the red blood cor- 
 puscle. In the body of this cell they have the power 
 of undergoing an asexual division (see Fig. 63). The 
 minute form swells into a large body and breaks up 
 into small spores. When this mass of young forms 
 has reached a size too great for the red cell the latter 
 
 FIG. 67 
 
 In Culex the palpse (a) of the female are very short, of the male are longer 
 than the proboscis; in Anopheles the palpse (ft) of both sexes are about equal 
 in length with the proboscis. (From Kolle and Hetsch.) 
 
 bursts, synchronously with which we have the chill. 
 By this bursting young forms are again set free in the 
 blood, 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. As a result of this, severe grades of anemia 
 result. The cycle of development from the young form 
 
MALARIA 213 
 
 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 successive 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. 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 inflam- 
 mation 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 
 
214 DISEASES DUE TO PROTOZOA 
 
 colored parasites containing quiet granules will be 
 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. 
 
 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 
 infection with cowpox 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 cowpox. Jenner in 1798 was 
 the one who first developed the principle of using 
 cowpox in the protection against human variola. The 
 exact cause of smallpox is not known. It is supposed 
 
216 DISEASES OF UNKNOWN ETIOLOGY 
 
 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 de- 
 lirium. 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. 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 
 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 
 susceptible animal will die within three weeks as a rule. 
 
 Pasteur found a method for protective inoculation 
 treatment against rabies. He found that if the spinal 
 cord of a rabbit suffering from rabies were dried in a 
 vacuum it lost its virulence for other rabbits. If he 
 dried it two weeks nearly all of the virulence was lost, 
 
YELLOW FEVER 217 
 
 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 glycerine 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 two days dried is used. The mortality 
 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 Stegomyia calopus, which takes 
 some of the infective blood from a patient and trans- 
 mits it to another person. Some cycle of development 
 of the virus takes place in the mosquito because the 
 
218 DISEASES OF UNKNOWN ETIOLOGY 
 
 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 appearance of the virus in 
 the patient's blood. Furthermore, the patient's blood 
 only remains infective for three days. The virus is 
 so small that it will pass through the unglazed porce- 
 lain filters used in the laboratory. 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. 
 
 Scarlet Fever and Measles. These two easily com- 
 municable diseases are transmitted apparently by the 
 virus cast off in scales from the skin. Nevertheless 
 the specific causative agent is unknown. It has lately 
 been shown that measles is transmissible to monkeys 
 at some particular time of the disease, which appears 
 from present knowledge to be quite early. The most 
 recent researches fail to show that measles scurf will 
 carry the disease to monkeys. Streptococci were once 
 thought to be the cause of scarlet fever. It would 
 seem from results obtained within the last year that 
 these organisms may be exonerated. 
 
 Typhus Fever. Although this condition is not under- 
 stood clearly, it now seems that body lice, flies, and 
 ticks transmit it. 
 
 Poliomyelitis. This is an acute apparently infectious 
 disease characterized by a mild constitutional illness 
 
ACUTE ARTICULAR RHEUMATISM 219 
 
 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 
 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. There is as yet no reliable 
 specific treatment. The only laboratory test consists 
 in finding an excess of clear cerebrospinal fluid in 
 which there is a slight excess of a certain organic sub- 
 stance 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. 
 
 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 
 rheumaticus 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 
 inflammations of the heart lining after this disease 
 are frequently streptococcal. 
 
220 DISEASES OF UNKNOWN ETIOLOGY 
 
 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 ulcer- 
 ation, 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- 
 cha?ta. The treatment is of a radical surgical char- 
 acter, as ordinary external applications are unavailing. 
 It is not very contagious, but discharges and sloughs 
 are best burned. 
 
 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. 
 
GLOSSAEY 
 
 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 sensivity due to idio- 
 syncrasy to or previous injection with certain organic sub- 
 stances but otherwise unexplained as yet. Symptoms: 
 shortness of breath, skin irritations, and sometimes death. 
 
 Antibodies Substances developed in the blood serum 
 which neutralize all 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. 
 
222 GLOSSARY 
 
 Bacillus (pi., Bacilli) The genus of motile rods. 
 
 Bacteriaceae 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." 
 
 Bacteriolysin An antibody that will dissolve bacteria. 
 Related words: bacteriolysis, bacteriolytic. 
 
 Bacteriology The study of bacteria. Adj., bacterio- 
 logical. 
 
 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 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 organisms. 
 
 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. 
 
 Culture The mass of bacteria grown artificially upon 
 laboratory foodstuffs. The general term applied to the way 
 bacteria grow. See colony. Adj., cultural. 
 
GLOSSARY 223 
 
 Cytoplasm The soft part of 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. 48 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. 
 
224 GLOSSARY 
 
 Immunity The resistance of the body to illness. See 
 p. 64 for kinds. Related words: to immunize, immuni- 
 zation, immune. 
 
 Infective Any material carrying disease viruses. 
 
 Inhibit Restrain, limit. 
 
 Inject To put anything within the body; in this book 
 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. 
 
 -logy A suffix meaning a " study of" the root, such as 
 morphology, which see. 
 
 Medium (pi., Media) General name given to foodstuffs 
 upon which bacteria are grown artificially. 
 
 Micrococcus The genus 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. 
 
 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 225 
 
 Organic A substance having the form, the chemistry, or 
 some characteristics of living matter; example, cane-sugar. 
 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 ameba?, 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 fer- 
 mentation, which see.) 
 
 Pyogenes. Pus-producing. Adj., pyogenic. 
 
 15 
 
226 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 family), but the 
 former belongs to the species "leo," and the latter to the 
 species " tigris. ' ' See Genus. 
 
 Spirochseta (pi., Spirochaetae) 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 cowpox 
 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, 79 
 
 Achorion Schoenleinii, 186. See 
 
 Favus. 
 
 Acid-fast bacilli, 143, 154 
 Acids, 50 
 Actinomyces, 161. See Strep- 
 
 tothrix actinomyces. 
 Actinomycosis, 160, 163 
 
 bacteriological diagnosis of, 
 
 161 
 disinfection during attack 
 
 of, 161 
 in soil, 190 
 transmission of, 161 
 "Active immunization," 66 
 Aerobe, 221 
 Aerobic bacteria, 34 
 Agglutinins, 69, 221 
 Air, bacteria in, 142, 189 
 currents, 189, 190 
 examination of, for bac- 
 teria, 190 
 transmission of disease by, 
 
 142, 190 
 
 Alcohol, 153, 196 
 Alga?, 21 
 
 AmebaB, 30, 200, 201 
 Amebic dysentery, 129, 201 
 diagnosis of, 202 
 disinfection during at- 
 tack, 202 
 Anaerobe, 221 
 Anaerobic bacteria, 34 
 Anaphylaxis, 104, 221 
 Anirnalculse, 18 
 Animal inoculation, 41 
 Anthrax, 67, 158 
 antibodies, 159 
 
 Anthrax, bacillus, 66, 158 
 
 general description of, 
 
 159 
 pathogenic powers of, 
 
 158, 160 
 poisons of, 158 
 relation of, to an- 
 thrax, 158 
 resistance to heat and 
 
 chemicals, 51, 159 
 in soil, 190 
 vaccines, 160 
 bacteriological diagnosis of, 
 
 159 
 disinfection during attack 
 
 of, 159 
 
 transmission of, 158, 159 
 vaccines, 160 
 Antibody, 67 to 69, 221 
 Anti-endptoxins, 67 
 Antimeningitis serum, 94 
 Antiseptics, 48 
 Antitoxin unit, 103, 108 
 Antitoxins, 65, 67, 103, 108, 221 
 Asexual, 221 
 Attenuation, 48, 221 
 Autoclave, 44 
 Auto-intoxication, 35, 175 
 
 B 
 
 BACILLI, 21, 24, 222 
 
 Bacillus coli communis, 165. 
 
 See Colon Bacillus, 
 of Ducrey, 151. See Chanc- 
 roid, 
 dysenteric, 129. See 
 
 Dysentery bacillus, 
 enteritidis, 170 
 
228 
 
 INDEX 
 
 Bacillus of Koch-Weeks, 135 
 melitensis, 137. See Malta 
 
 Fever, 
 of Morax and Axenfeld, 
 
 135 
 
 paratyphosus, 118 
 pestis, 122. See Plague 
 
 bacillus. 
 
 proteus vulgaris, 177 
 pyocyaneus, 177 
 
 diagnosis of infections 
 
 with, 179 
 general description of, 
 
 178 
 pathogenic powers of, 
 
 177, 179 
 poisons, 179 
 resistance to heat and 
 
 chemicals, 178 
 
 where found, 177 
 
 tetani, 105. See Tetanus 
 
 bacillus. 
 
 typhosus, 109. See Ty- 
 phoid bacillus. 
 Bacteria, 17, 21, 222 
 
 activities and nature of, 33 
 aerobic, 34 
 anaerobic, 34 
 biological classification of, 
 
 21 
 
 capsule of, 26 
 chemistry of, 31 
 colonies of, 38 
 cultivation of, 38 
 cytoplasm of, 24 
 endotoxins of, 61 
 entrance of, to body, 58 
 enzymes of, 34 
 extracellular toxins of, 61 
 in fermentations, 34 
 ferments of, 34 
 flagella of, 27 
 in hair, 99 
 
 in intestinal tract, 33 to 36 
 intracellular toxins of, 61 
 lactic acid, 36 
 motility of, 26 
 nucleus of, 24 
 nutrition of, 31, 34 
 pathogenic, 20 
 poisons of, 60, 61, 68 
 in putrefaction, 34 
 
 Bacteria, relation of, to disease, 
 
 58 
 
 reproduction of, 26 
 resistance of body to, 59, 
 
 63 to 70, 78 
 size of, 25 
 specificity of, 60 
 spores of, 29 
 staining of, 38 
 toxins of, 61, 67, 68 
 transmission of, 62 
 vegetating, 46 
 wall of, 23 
 Bacteriacese, 21, 222 
 Bactericide, 222 
 Bacteriemia, 60 
 Bacterin treatment, 66, 82 
 Bacterins, 83, 222 
 Bacteriology, 17, 222 
 Bacteriolysin, 69, 222 
 Bacterium aerogenes capsu- 
 
 latus, 176 
 anthracis, 158. See Anthrax 
 
 bacillus, 
 bulgaricum, 175, 176, 
 
 196 
 
 diphtherise, 98. See Diph- 
 theria bacillus, 
 influenza, 118. See In- 
 fluenza bacillus, 
 lactis aerogenes, 196 
 lepra), 151. See Leprosy 
 
 bacillus, 
 of malignant edema, 
 
 176 
 mallei, 155. See Glanders 
 
 bacillus, 
 ozsense, 173 
 pneumonias, 172. See 
 
 Friedlander's bacillus, 
 tuberculosis, 138. See 
 
 Tubercle bacillus. 
 Balantidium coli, 200 
 Beri-beri, 220 
 
 Bichloride of mercury, 49, 53 
 Blastomycetes, 21, 180 
 diagnosis of, 187 
 disinfection during attack, 
 
 182 
 
 transmission of, 181 
 Blood culture technique, 74 
 Boiling for sterilization, 46 
 
INDEX 
 
 229 
 
 Bordet-Gengou bacillus, 136. 
 
 See Whooping cough 
 Boric acid, 50 
 Buttermilk, 196 
 
 CALCIUM, hydroxide, 50 
 Cancrum oris, 220 
 Capsules, 26 
 Carbolic acid, 52, 53 
 Carriers, 99, 112, 127, 222 
 Caustic soda, 50 
 Cell, 24, 222 
 Cellulitis, 79 
 Centrosome, 30 
 Centigrade scale, 47 
 Cerebrospinal meningitis, 91 
 
 puncture, 74 
 Chancroid, 151 
 
 Chemical disinfectants, 49 to 53 
 practical uses of, 53 to 
 
 57 
 Chemistry of bacteria, 31 
 
 of protozoa, 32 
 Chloride of lime, 50 
 Chlorinated lime, 50 
 Chloroform, 53 
 Cholera, 67, 125 
 
 agglutination in, 127 
 bacteriological diagnosis of, 
 
 127 
 
 bacteriolytic test for, 127 
 disinfection during attack, 
 
 127 
 
 spirillum, 61, 127, 193 
 agglutinins of, 127 
 carriers of, 127 
 general description of, 
 
 128 
 
 in milk, 198 
 pathogenic powers of, 
 
 126, 129 
 poisons of, 127 
 relation of, to Asiatic 
 
 cholera, 126 
 resistance of, to heat 
 and chemicals, 128 
 in soil, 190 
 vaccines, 129 
 in water, 61, 193 
 
 Cholera, transmission of, 126 
 vaccination against, 129 
 Cilia, 30 
 Coccacese, 222 
 Cocci, 21, 24, 222 
 Coccidia, 200 
 Colon bacillus, 80, 165, 189 
 
 diagnosis of, infections 
 
 with, 169 
 general description of, 
 
 165 
 pathogenic powers of, 
 
 168 
 
 poisons of, 168 
 resistance of, to heat 
 and chemicals, 166 
 vaccines, 169 
 use in intestines, 167 
 in water, 193 
 where found, 167 
 Colonies, 38, 222 
 Commensal, 222 
 Complement, 69, 222 
 Conjunctivitis, gonorrheal, 87 
 Koch-Weeks, 135 (pink- 
 eye) 
 
 Morax-Axenfeld, 135 
 Copper sulphate, 50 
 Corrosive sublimate, 49 
 Cowpox, 215 
 Creolin, 52 
 Cresols, 52 
 Cultivation, 38, 222 
 Culture, 222 
 Cytoplasm, 24, 30, 223 
 
 DEJECTA, 223 
 
 Dengue, 220 
 
 Diarrhea, infantile, from milk, 
 
 197 
 Diphtheria, 98 
 
 administration of anti- 
 toxin in, 103 
 antitoxins, 103, 
 bacillus, 61, 65, 98 
 antitoxins, 103 
 discovery of, 100 
 general description of, 
 100 
 
230 
 
 INDEX 
 
 Diphtheria bacillus in milk, 
 
 197 
 pathogenic powers of, 
 
 99, 102 
 poisons, 103 
 relation of, to diph- 
 theria, 98, 99 
 resistance of, to heat 
 and chemicals, 101 
 bacteriological diagnosis of, 
 
 99, 100 
 disinfection during attack, 
 
 99 
 serum sickness following, 
 
 104 
 
 transmission of, 99, 197 
 Diplococci, 26 
 Diplococcus pneumonise, 94. 
 
 See Pneumococcus. 
 Disease, 58 
 
 transmission of, 62 
 water-borne, 192 
 Disinfectants, 48 
 
 uses of, 53 to 57 
 Disinfection, 48, 223 
 of dejecta, 54 
 of room and houses, 55 
 of sputum, 54 
 of water-closets and sinks, 
 
 55 
 
 Dumdum fever, 203 
 Dysentery, amebic, 129, 201 
 bacillary, 129 
 
 antibodies, 131 
 antiserum, 133 
 bacteriological diag- 
 nosis of, 132 
 disinfection during 
 
 attack, 131 
 transmission of, 130, 
 
 131 
 bacillus, 129 
 
 agglutinins, 131 
 antisera, 133 
 bacteriolysins, 131 
 general description of, 
 
 132 
 pathogenic powers of, 
 
 130, 132 
 poisons, 130 
 relation of, to dysen- 
 tery, 130 
 
 Dysentery bacillus, resistance 
 of, to heat and chemicals, 
 132 
 
 ENCYSTMENT, 223 
 Endotoxins, 61, 67 
 Entamoeba histolytica, 201, See 
 
 Amebic dysentery, 
 general description of, 
 
 202 
 pathogenic powers of, 
 
 201, 203 
 
 Enteric fever, 109. See Ty- 
 phoid fever. 
 Enzymes, 4 1,223 
 
 in industries, 36 
 Etiology, 223 
 Exudate, 80 
 
 FAHRENHEIT scale, 47 
 
 Favus, 186 
 
 Feces, collection of, 73 
 
 sterilization of, 54 
 Fermentation, 19, 34, 41, 196, 
 
 223 
 Ferments, 34, 41,223 
 
 in industries, 36 
 Fever, 60 
 Flagella, 27, 30 
 Flagellata, 200 
 
 Flies, in transmission of disease, 
 63, 110 
 
 tsetse, 205 
 
 Formaldehyde, 50, 51, 54 
 Formalin, 50, 51, 54 
 Friedlander's bacillus, 172 
 
 pathogenic powers of, 
 
 173 
 
 Fungi, 21 
 Furunrulosis, 83 
 
 G 
 
 GENERATION, spontaneous, 19 
 Genus, 223 
 
INDEX 
 
 231 
 
 Germination, 223 
 Glanders, 155 to 157 
 bacillus, 155 
 
 general description of, 
 
 156 
 pathogenic powers of, 
 
 155, 157 
 poisons, 155 
 relation of, to glanders 
 
 155 
 resistance of, to heat 
 
 and chemicals, 157 
 vaccines, 157 
 bacteriological diagnosis of, 
 
 156 
 disinfection during attack, 
 
 156 
 
 mallein in, 156, 157 
 transmission of, 155 
 vaccines in, 157 
 Glassware, 42 
 Glossary, 221 
 Gonococcus, 62, 86 
 
 in conjunctivitis, 87 
 general description of, 88 
 relation of, to gonorrhea, 
 
 86 
 resistance of, to heat and 
 
 chemicals, 88 
 Gonorrhea, 86 
 
 bacteriological diagnosis of, 
 
 90 
 disinfection during and 
 
 after attack, 90 
 Gonorrheal conjunctivitis, 87 
 
 ophthalmia, 87 
 Growth, 223 
 
 H 
 
 HAIR, bacteria in, 99 
 
 Hanging drop, 41 
 
 Heat sterilization, 42 to 47 
 
 Hemosporidia, 200, 209 
 
 Heterotricha, 200 
 
 Host, 21, 223 
 
 Hot air sterilization, 47 
 
 Hydrogen peroxide, 50, 51 
 
 Hydrophobia, 216 
 
 disinfection against, 217 
 Pasteur tretament for, 216 | 
 
 Hydrophobia, transmission of, 
 
 216 
 
 virus of, 216, 217 
 Hyphse, 183 
 Hyphomycetes, 21, 180 
 
 ICE and typhoid fever trans- 
 mission, 111 
 
 Immunity, 63 to 70, 224 
 acquired, 64 
 active, 64 
 
 acquired, 65 
 artificial, 65 
 natural, 64 
 passive, 64, 65 
 
 acquired, 65 
 racial, 64 
 
 Impetigo contagiosa, 220 
 Incubation period, 62 
 Incubator, 40 
 Infection, 60 
 
 predisposing causes to, 59 
 Infective, 224 
 Inflammation, 77 to 80 
 Influenza, 118 
 
 agglutinins, 120 
 bacillus, 62, 91, 118 
 
 general description of, 
 
 121 
 pathogenic powers of, 
 
 119, 121 
 poisons, 119 
 relation of, to in- 
 fluenza, 118 
 to other diseases, 
 
 119 
 resistance to heat and 
 
 chemicals, 121 
 vaccines, 121 
 bacteriological diagnosis of, 
 
 120 
 disinfection during attack, 
 
 120 
 
 immunity after attack, 120 
 transmission of, 119 
 Infusoria, 200 
 Inhibit, 224 
 Inject, 224 
 Inoculate, 224 
 
232 
 
 INDEX 
 
 Inorganic, 224 
 Intoxication, 60 
 Iodine, 53 
 
 alcohol, 53, 54 
 Isolate, 224 
 
 KALA-Azar, 203 
 Klebs-Lreffler bacillus, 98 
 Koch- Weeks bacillus, 135 
 
 LACTIC acid bacteria, 35, 175, 
 
 196 
 
 Lamblia intestinalis, 208 
 Leishmania Donovani, 204 
 Leprin, 154 
 Leprosy, 151 to 154 
 bacillus, 151 
 
 general description of, 
 
 154 
 pathogenic powers of, 
 
 152 
 
 poisons of, 153 
 relation of, to leprosy, 
 
 152 
 bacteriological diagnosis of, 
 
 154 
 disinfection during attack, 
 
 154 
 
 forms of, 152 
 transmission of, 152 
 Lesion, 224 
 Leukocytes, 69, 224 
 Lichens, 21 
 Lime, milk of, 53 
 Lysol, 52 
 
 M 
 
 MALARIA, 208 
 
 diagnosis of, 213 
 estivo-autumnal, 209, 212 
 malignant, 209, 213 
 prevention of, 214 
 quartan, 209, 211 
 tertian, 209, 211 
 
 Mallein, 156 
 Malta fever, 137 
 
 bacilli in, 137 
 general description of, 
 
 137 
 
 transmission of, 137 
 Mastigophora, 21, 200, 203 
 Measles, 218 
 
 Meat poisoning bacteria, 170 
 Media, 37, 39, 41, 224 
 Meningitis, 90, 91 
 antiserum to, 94 
 bacteriological diagnosis 
 
 of, 93 
 coccus, 65, 91 
 
 antiserum, 94 
 general description of, 
 
 93 
 
 relation of, to menin- 
 gitis, 91 
 
 disinfection during, 92 
 Methods of examination, 37 
 Microbiology, 17 
 Micrococcus, 80, 224 
 
 gonorrhoea, 86. See Gono- 
 
 coccus. 
 intracellularis meningitidis. 
 
 See Meningitis coccus. 
 Microscope, 22 
 
 technique of, 22, 41 
 Microsporon furfur, 187 
 Milk, bacteria in, 194 
 
 cholera spirilla in, 198 
 diphtheria bacilli, 197 
 diseases transmitted by, 62, 
 
 99, 116, 197 
 
 examination of, 197, 199 
 fermentation of, 196 
 infantile diarrhea from, 197 
 of lime, 53 
 
 pasteurization of, 195 
 scarlet fever from, 197 
 souring of, 196 
 spoiling of, 196 
 tubercle bacilli in, 198 
 typhoid fever and bacilli in 
 
 relation to, 198 
 Morax-Axenfeld bacillus, 135 
 Morphology, 224 
 of bacteria, 20 
 of protozoa, 30 
 variations of, 24 
 
INDEX 
 
 233 
 
 Mosquitoes, anopheles, 210 
 culex, 207, 210 
 in transmission of diseases, 
 63, 206, 209, 210, 214, 
 217 
 Moulds, 21, 180, 183 
 
 diseases due to, 186, 187 
 general description of, 183 
 
 to 185 
 
 pathogenic powers of, 185 
 Mucosus capsulatus group, 171 
 general descrip- 
 tion of, 171 
 pathogenic power 
 
 of, 174 
 poisons, 172 
 resistance of, to 
 heat and chem- 
 icals, 172 
 transmission of, 
 
 172 
 
 vaccines, 174 
 Mumps, 219 
 Mycelium, 183 
 
 N 
 
 NOMA, 220 
 Nucleus, 24, 30, 224 
 Nutrition of bacteria, 31, 
 of protozoa, 31 
 
 OIDIUM albicans, 186 
 Ophthalmia neonatorum, 87 
 Opsonic index, 82 
 Opsonins, 69, 224 
 Optimum, 224 
 Organic, 225 
 
 PARACOLON bacilli, 169 
 Paratyphoid bacilli, 118 
 Parasites, 20, 225 
 
 facultative, 21 
 
 obligate, 21 
 Pasteur treatment of rabies, 216 
 
 Pasteurization, 56, 195, 199 
 Pathogenic, 225 
 Pathology, 225 
 Pellagra, 220 
 Penicillium glaucum, 185 
 Phagocytes, 69, 225 
 Phagocytosis, 69, 225 
 Phenol, 52 
 Phlegmon, 79 
 Pink eye, 135 
 Pityriasis versicolor, 187 
 Plague, 122 
 
 antiserum, 124 
 bacillus, 123 
 
 antisera, 125 
 
 general description of, 
 
 124 
 pathogenic power of, 
 
 122, 124 
 poisons, 123 
 relation of, to plague, 
 
 122 
 resistance of, to heat 
 
 and chemicals, 124 
 vaccines, 125 
 bacteriological diagnosis of, 
 
 124 
 disinfection during attack, 
 
 123 
 
 immunity against, 125 
 immunization against, 124 
 rat fleas in transmission of, 
 
 122 
 
 rats in transmission of, 122 
 transmission of, 122 
 vaccines in, 125 
 Plane, 225 
 Plasma, 225 
 Plasmodium, 200 
 falciparum, 209 
 general description of, 213 
 life in mosquitoes, 211 
 malaria?, 209 
 pathogenic powers of, 211, 
 
 212, 214 
 vivax, 209 
 Pneumococcus, 90, 94 
 
 in diseases other than 
 
 pneumonia, 91, 95 
 general description of, 95 
 pathogenic powers of, 97 
 poisons, 97 
 
234 
 
 INDEX 
 
 Pneumococcus, relation of, to 
 pneumonia, 95 
 
 resistance of, to heat and 
 
 chemicals, 97 
 Pneumonia, 94, 172 
 
 bacteriological diagnosis of, 
 95 
 
 disinfection during, 95 
 Poliomyelitis, 218 
 
 virus of, 219 
 Proliferate, 225 
 Protoplasm, 224, 225 
 Protozoa, 17, 30, 200 
 
 biological classification of, 
 21, 200, 225 
 
 centresome of, 30 
 
 chemistry of, 32 
 
 cilia of, 30 
 
 cytoplasm of, 30 
 
 examination for, 42 
 
 flagella of, 30 
 
 morphology of, 30 
 
 motility of, 30 
 
 nucleus of, 30 
 
 nutrition of, 31 
 
 pseudopods of, 30 
 
 reproduction of, 31 
 
 requirements, 32 
 
 temperature for, 32 
 
 wall, 30 
 
 Protozoology, 17 
 Pseudodiphtheria bacilli, 80, 
 
 104 
 
 Pseudopods, 30, 225 
 Ptomain poisoning, 63 
 Pus, 80 
 
 bacillus of green, 177 
 
 collection of, 71 
 Putrefaction, 34, 225 
 Pyemia, 79, 160 
 Pyocyaneus bacillus, 80, 177 
 Pyogenes, 225 
 
 RABIES, 216. See Hydrophobia. 
 
 Rain, bacteria in, 191 
 
 Ray fungus, 161. See Strepto- 
 
 thrix actinomyces. 
 Relapsing fever, 205 
 Reproduction, 26 to 31 
 
 Rheumatism, acute articular, 
 
 219 
 Streptococcus 
 
 rheumaticus in, 
 
 219 
 
 Rhizopoda, 200 
 Ringworm, 186 
 Room disinfection, 51, 55 
 Russell, Major, U. S. A., anti- 
 typhoid vaccination, 117 
 
 S 
 
 Saprophytes, 20, 226 
 in intestine, 35 
 
 Sarcinae, 26 
 
 Sarcodina, 21, 200, 201 
 
 Scarlet fever, 218 
 
 from milk, 197 
 
 Schizomycetes, 21 
 
 Septicemia, 60, 79 
 
 Serum, 226 
 
 Sexual, 226 
 
 Silver nitrate, 49 
 
 Skin sterilization, 54 
 
 Sleeping sickness, 204. See 
 Try panosomiasis . 
 
 Smallpox, 66, 215 
 
 Smegma bacillus, 155 
 
 Soap, as disinfectant, 53 
 
 Sodium carbonate, 50 
 hydroxide, 50 
 
 Soil, 190 
 
 actinomycosis from, 190 
 anthrax bacillus in, 190 
 bacteria in, 190 
 cholera bacillus in, 190 
 tetanus bacillus in, 191 
 tubercle bacillus in, 191 
 typhoid bacillus in, 190 
 
 Soor, 186. See Thrush. 
 
 Species, 186 
 
 Spirilla, 21, 24 
 
 Spirillum cholerae asiaticse, 125. 
 See Cholera spirillum. 
 
 Spirochseta, 226 
 
 Obermeieri, 206 
 pallida, 147. See Trepon- 
 ema pallidum . 
 
 Spontaneous generation, 19 
 
 Spores, 29, 46, 47, 49, 51 
 
INDEX 
 
 235 
 
 Sporozoa, 21, 200, 208 
 Sputum, collection of, 72 
 
 sterilization of, 54, 143, 146 
 tuberculous, collection and 
 sterilization of, 55, 143 
 Staining, 38, 41 
 Staphylococci, 26, 80, 226 
 Staphylococcus epidermidis 
 
 albus, 75, 82 
 pyogenes albus, 82 
 aureus, 80 
 
 discovery of, 85 
 diseases produced 
 
 by, 82 
 
 general descrip- 
 tion of, 81 
 resistance of, to 
 heat and chemi- 
 cals, 81 
 Steam sterilization, 44, 46, 47 
 
 sterilizer, 44, 46, 47 
 Stegomyia calopus, 217 
 Sterilization, 42 to 47, 48 to 
 
 57, 226 
 of dejecta, 54 
 of fabrics, 54 
 of glassware, 42 
 hot air, 47 
 incomplete, 48 
 of sputum, 54, 55, 143, 146 
 of utensils, 54 
 of water-closets, 55 
 Strain, 226 
 Streptococci, 26, 61, 80, 90, 
 
 196, 226 
 
 Streptococcus pyogenes, 83 
 discovery of, 85 
 diseases due to, 84, 85 
 general description of, 
 
 84 
 
 rheumaticus, 219 
 Streptothrix actinomyces, 161. 
 
 See Actinomycosis. 
 general description of, 
 
 162 
 pathogenic powers of, 
 
 161, 163 
 poisons, 161 
 relation to actinomy- 
 
 cosis, 161 
 
 resistance of, to heat 
 and chemicals, 163 
 
 Sulphur dioxide, 50, 51 
 
 Sunlight, 57 
 
 Syphilis, 147 to 151 
 antibodies in, 149 
 diagnosis of, 149, 151 
 forms of, 148 
 skin reaction in, 151 
 transmission of, 147 
 Wassermann blood reaction 
 in, 149 
 
 TECHNIQUE, 37 
 Temperature optimum, 45 
 Tetanus, 105 
 
 antitoxin, 108 
 
 administration of, 108 
 unit of, 108 
 bacillus, 65, 105 
 antitoxin, 108 
 effect of anaerobic life, 
 
 106 
 general description of, 
 
 106 
 pathogenic powers of, 
 
 105 
 relation of, to tetanus, 
 
 105 
 
 resistance of, to heat, 
 and chemicals, 107 
 in soil, 191 
 spores of, 106 
 toxins of, 61, 108 
 bacteriological diagnosis of, 
 
 106 
 disinfection during attack, 
 
 106 
 
 Thallophyta, 21 
 Thermometer scales, 47 
 Thrush, 186 
 Tinea circinata, 186. See 
 
 Ringworm. 
 
 sycosis, 186. See Ring- 
 worm. 
 
 tonsurans, 186 See Ring- 
 worm. 
 Toxins, bacterial, 60, 61, 67, 68, 
 
 226 
 
 extracellular, 61 
 intracellular, 61, 67 
 
236 
 
 INDEX 
 
 Trachoma, 220 
 Transmission of bacteria, 62 
 
 of disease, 62 
 Treponema pallidum, 147 
 
 general description of, 
 
 149 
 pathogenic powers of, 
 
 148, 150 
 poisons, 148 
 relation of, to syphilis, 
 
 147 
 
 resistance of, to heat 
 and chemicals, 149 
 transmission of, 147 
 Trichomonas, 208 
 intestinalis, 208 
 pulmonalis, 208 
 vaginalis, 208 
 Trichophyton, 184, 186 
 Tricresol, 52 
 Trypanosoma, 200, 204 
 
 general description of, 
 
 206 
 pathogenic powers of, 
 
 205 
 Trypanosomiasis, 204 
 
 transmission of, 205 
 Tsetse fly, 205 
 Tubercle bacillus, 62, 138 
 in air, 189 
 forms of, 146 
 general description of, 
 
 145 
 
 in milk, 142, 198 
 pathogenic powers of, 
 
 138, 146 
 
 poisons, 141, 146 
 relation of, to tuber- 
 culosis, 138, 141 
 resistance of, to heat 
 and chemicals, 145 
 in soil, 191 
 transmission of, 141 
 vaccines, 146 
 Tubercles, 139 
 Tuberculin, 144, 146, 199 
 Tuberculosis, 138 to 147 
 agglutinins in, 144 
 antibodies in blood in, 141 
 bacteriological diagnosis of, 
 
 143 
 from cows, 142, 198 
 
 Tuberculosis, disinfection dur- 
 ing attack, 143 
 forms of, 139 
 from milk, 198 
 skin test in, 144 
 sputum in, disinfection of, 
 
 143, 146 
 
 transmission of, 141 
 tuberculin reaction in, 144, 
 
 199 
 
 treatment, 146 
 vaccines, 146 
 Tumefaction, 226 
 Typhocolon group of bacilli, 
 
 164 to 171 
 discovery of, 171 
 Typhoid bacillus, 61, 80, 109 
 agglutinins, 113 
 carriers, 112 
 general description of, 
 
 115 
 
 in milk, 198 
 pathogenic powers, 
 
 109, 116 
 poisons, 112 
 relation to typhoid 
 
 fever, 109 
 
 resistance to heat and 
 chemicals, 115, 116, 
 in soil, 190 
 vaccines, 117 
 in water, 110, 193 
 fever, 67, 109 
 
 antibodies after attack , 
 
 113 
 
 bacteriological . diag- 
 nosis of, 114 
 bacteriolysins in, 113 
 carriers, 112 
 disinfection during at- 
 tack, 112 
 
 immunity after, 113 
 immunization against, 
 
 116 
 
 Russell's vaccination 
 against, result of, 
 117 
 
 transmission of , 110 
 by flies, 111 
 by ice, 110 
 by milk, 111, 19S 
 by oystors, 111 
 
INDEX 
 
 237 
 
 Typhoid fever, transmission 
 of, by personal 
 contact, 111 
 by sewage, 110 
 by vegetables, 
 
 111,190 
 
 by water, 110, 193 
 Widal reaction in, 113 
 Typhus fever, 218 
 
 URINE, collection of, 73 
 sterilization of, 54 
 
 VACCINES, 83, 146, 226 
 
 Vaccination, 215 
 
 Vaccine treatment, 66, 82, 83, 
 
 117, 125, 146 
 
 Variola, 215. See Smallpox. 
 Vegetables, in typhoid fever 
 
 transmission, 111, 190 
 Vegetative bacteria, 30 
 Viable, 226 
 Vincent's angina, 133 
 
 bacteriological diag- 
 nosis of, 134 
 disinfection during 
 
 attack, 134 
 
 general description of 
 microorganisms of, 
 135 
 poisons, 134 
 
 Virulence, 41, 60, 226 
 Virus, 41, 226 
 Vulvovaginitis, 87 
 
 W 
 
 WATER, bacteria in, 191 
 -borne diseases, 192 
 cholera spirilla in, 192 
 colon bacilli in, 193 
 diseases transmitted by, 62, 
 
 192 
 
 dysentery bacillus in, 193 
 examination of, 193 
 purification of, 191, 192 
 typhoid bacilli in, 110, 192, 
 
 193 
 
 fever from, 110 
 Whooping cough, 136 
 
 Bordet-Gengou bacil- 
 lus in, 136 
 general description of, 
 
 137 
 Widal reaction, 69, 113 
 
 collection of blood for, 
 74 
 
 YEASTS, 21, 180 
 
 diseases due to, 181 
 general description of, 180 
 pathogenic powers of, 181, 
 
 182 
 relation to blastomycosis, 
 
 181 
 Yellow fever, 217 
 
 mosquitoes in, 217 
 
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