INFECTION, IMMUNITY 
AND 
INFLAMMATION INFECTION, IMMUNITY 
AND 
INFLAMMATION' 
A Study of the Phenomena of Hypersensitiveness and 
Tolerance, and Their Relationship to the 
Clinical Study, Prophylaxis, and 
Treatment of Disease 
/ 
BY 
FRASER B. GURD, B.A., M.D., C.M., F.A.C.S. 
Montreal 
Lecturer in Applied Immunology and in Surgery, McGill University. Asso- 
ciate Surgeon, Montreal General Hospital. Surgeon, Western Pavilion, 
Montreal General Hospital. Consultant in Surgery and Surgeon 
in Charge St. Anne's Hospital, Department of Soldier's Civil 
Reestablishment. 
ST. LOUIS 
THE C. V. MOSBY COMPANY 
1924 Copyright, 1924, By The C. V. Mosby Company 
(All rights reserved) 
Printed in U. S. A. 
Press of 
The C. V. Mosby Company 
St. Louis TO 
MY FATHER 
DAVID F. GURD, M.D. 
THIS BOOK IS AFFECTIONATELY 
DEDICATED PREFACE 
Since the discovery of the phenomenon of anaphylaxis in 
1906, the attention of immunologists throughout the world has 
been directed in large measure to the study of hypersensitive- 
ness and its relationship to other immunologic processes. Al- 
though this chapter in our investigation of disease is not yet 
fully written, I am of the opinion that there has now ac- 
cumulated a sufficient amount of data regarding the phenom- 
enon of tissue hypersensitiveness to the presence of foreign 
albuminous substances, and the companion state, in conse- 
quence of which the tissues are rendered insusceptible to 
symptoms of tissue irritation, to which the name "tolerance" 
is applied in this volume, to justify a more general knowledge 
of these facts by the practicing physician and surgeon. 
Although I believe that the immunologic process, at least 
as it applies to the tissue reaction against colloidal proteins, 
is, in fact, an exhibition of digestive activity on the part of 
the tissue cells, I do not wish to obscure, by the discussion of 
the nature of the reaction which occurs between antigen and 
antibody, the importance of the truth that hypersensitiveness 
and tolerance are phenomena which are readily demonstrated 
both in animals and in man. An appreciation of the fact that 
the two states may, and often do, exist in the same individual 
is of the utmost importance, both in the study of clinical phe- 
nomena and in the treatment and prophylaxis of infectious 
disease. 
Anaphylaxis constitutes the first stage in the immunologic 
reaction, and, although, under very exceptional circumstances, 
it may constitute a danger to the life of the animal or indi- 
vidual, it serves a useful purpose in that, in consequence of 
hypersensitiveness of the tissues to the complex protein mol- 
ecules which constitute bacteria, the bacterial cell bodies are 
immediately recognized by the tissue, as irritants. The nor- 
7 8 
PREFACE 
mal response of the tissues to the presence of small particles 
of irritant substances is focal hyperemia, accumulation of 
leucocytes, and phagocytosis of the irritant particles. 
A proper appreciation of the allergic phenomenon, as de- 
scribed by von Pirquet, and its relationship to anaphylaxis 
and tolerance, places the prevention and treatment of infec- 
tion by means of bacterial or other protein preparations upon 
a rational basis. In the absence of a working hypothesis, the 
production and control of alterations in the immunologic state 
of the human individual become, not only difficult, but 
dangerous. 
Since 1914, when I first brought forward the point of view 
expressed in this volume, the clinical study of infectious proc- 
esses and the control and guidance of inflammation, whether 
by means of mechanical (operative) or specific immunologic 
methods, has confirmed, in my opinion, the accuracy of the 
hypothesis which is elaborated in this contribution. 
No attempt has been made to include in this volume a com- 
plete bibliography. Specific references have been made only 
to such publications as have been employed to illustrate a 
definite phenomenon, or support an hypothesis. My own views 
have been indicated, and. where it was thought necessary, the 
contrary opinions have been presented, although I have made 
it my aim to eliminate unnecessary argument. 
Although the general subjects of infection and immunity 
are considered in a broad way, I have endeavored to limit 
the discussion to such facts and theories as are of importance 
to the clinical practitioner. Bacteriology is not discussed 
from the viewpoint of differentiation of strains of micro- 
organisms, but a study is made of those characteristics of 
bacteria which determine their pathogenicity and their power 
to stimulate reactive phenomena on the part of the host. 
In the chapters upon the application of immunity principles 
to the treatment of disease, and in the explanation of disease 
phenomena, the importance of immunology is indicated, al- 
though no attempt has been made to make the presentation 
of these aspects of the subject exhaustive. Serology, insofar PREFACE 
9 
as it refers to technical methods for the identification of im- 
mune bodies, has been excluded. There are at the present 
time a number of very excellent volumes written in English, 
in which technical methods of serology are described and 
the relative importance of in vitro reactions discussed. For 
the presentation of the subject for the laboratory worker, 
the reader is referred to contributions of this nature. The 
author has made use of the following works with consider- 
able freedom: Kolmer: Infection Immunity and Specific Ther- 
apy. Zinsser: Infection and Resistance. Wells: Chemical 
Pathology, and Physiological Reviews, 1921, Vol. 1, No. 1: The 
Present Status of Anaphylaxis. Karsner and Ecker: Princi- 
ples of Immunology. Vaughan: Protein Split Products. 
Besredka (Gloyne) : Anaphylaxis and Antianaphylaxis. 
If this small volume, which has been written by a practicing 
surgeon who, for many years, has made the study of infec- 
tion and the reaction of the tissues to irritants his special 
interest and hobby, be of value in stimulating other clinical 
observers to further inquiry into this fascinating and prac- 
tical branch of biology, the effort entailed in its preparation 
shall have been adequately rewarded. CONTENTS 
CHAPTER I 
PAGE 
Defensive and Offensive Reaction of the Body Against Irritants 17 
General Introduction, 17; Serum Reactions, 20; Cellular Reaction, 
22. 
CHAPTER II 
Infection and Infectious Agents 24 
Introduction, 24; Historical, 26; Morphologic and Chemical Char- 
acteristics of Bacteria, 28; Characteristics of Bacteria Deter- 
mining Their Pathogenicity, 31; Factors which Determine Relative 
Virulence of Bacteria, 46; Factors Influencing Infection, 53. 
CHAPTER III 
Immunity and Immunization 55 
Introduction, 55; Elementary Facts Regarding Immunity, 63. 
CHAPTER IV 
General Principles of Acquired Immunity as Exemplified by 
Toxin-Antitoxin Reaction 65 
Toxin-Antitoxin Immunity, 67; Passive Immunization, 68. 
CHAPTER V 
Anaphylaxis-Hypersensitiveness 73 
Introduction, 73; Definitions, 75. 
CHAPTER VI 
Fundamental Phenomena Characterizing Hypersensitiveness, De- 
sensitization and Tolerance in the Guinea Pig ... 79 
CHAPTER VII 
More Detailed Description of the Phenomena of Anaphylaxis in 
the Guinea Pig and Other Animals 84 
Clinical Phenomena of Shock in the Guinea Pig, 84; Postmortem 
Findings in Guinea Pigs Dying in Anaphylactic Shock, 86; Ana- 
11 12 
CONTENTS 
PAGE 
phylaxis in the Rabbit, 87; Anaphylaxis in the Dog, 88; Post- 
mortem Findings in Dogs Dying of Anaphylactic Shock, 89; 
Anaphylaxis in the Cat, 90; Anaphylaxis in the Goat, 90; Ana- 
phylaxis in Man, 90. 
CHAPTER VIII 
Physiology of Anaphylactic Shock 97 
Tissues Affected in Anaphylaxis, 98; The Role of the Liver in 
Anaphylaxis, 101; Effect of Anaphylactic Shock upon Coagula- 
tion of Blood, 103; Effect of Anaphylactic Shock upon Tempera- 
ture, 104; Effect of Anaphylactic Shock upon Leucocytes, 104; 
Depletion of Complement in Anaphylaxis, 105; Increase in Blood 
Nitrogen in Anaphylaxis, 105; Lymphagogue Reactions in Dogs, 
105; Nonstriated Muscle Reaction in Vitro, Schultz-Dale Reaction, 
106. 
CHAPTER IX 
Transferred Anaphylaxis 109 
Protocol, 112; Transferred Anaphylaxis from Mother to Off- 
spring, 112. 
CHAPTER X 
Desensitization 113 
CHAPTER XI 
Tolerance 116 
Antisensitization, 120. 
CHAPTER XII 
Nature of Anaphylactic Antigen (Anaphylactogen) 121 
Specificity of the Anaphylactic Reaction, 125. 
CHAPTER XIII 
Anaphylactoid Phenomena 129 
Endotoxins, 129; Anaphylatoxin (Friedberger), 130; Protein 
Split Products (Vaughan), 133; Peptone Poisoning, 136; His- 
tamine, 137; Taraxy (Novy), 139; "Nonspecific Anaphylaxis," 
139; Anaphylactoid Phenomena Due to Flocculation of Colloids, 
140. 13 
CONTENTS 
CHAPTER XIV 
PAGE 
Site of the Reaction Between Antigen and Anaphylactic Antibody 142 
CHAPTER XV 
Nature of the Reaction Between Anaphylactic (First Order) 
Antibody and Antigen 154 
The Theory of Parenteral Digestion, 157; Objections to the Theory 
of Parenteral Digestion, 161; Explanation of the Phenomenon of 
Tolerance, 166. 
CHAPTER XVI 
Allergic Reaction 174 
Von Pirquet's Studies upon Vaccinia, 177; Factors Determining 
Specific Types of Allergic Reaction, 182. 
CHAPTER XVII 
The Function of the Leucocytes in Immunologic Processes . . 185 
Opsonin, 189; Relationship of Hypersensitiveness and Tolerance 
to the Phagocytic Reaction, 193. 
CHAPTER XVIII 
Protein-lysin Immunity. Alexin (Complement) and Sensitizing 
Substance (Amboceptor) 198 
Alexin or Complement, 199; Origin of Alexin, 200; Relationship 
of Complement to Leucoprotease, 201; Multiplicity of Alexins, 
203; Sensitizing Substance (Amboceptor), 203; Resistance of 
Amboceptor to Heat and Desiccation, 204; Sensitizing Experi- 
ments, 204; Reciprocal Activity of Complement and Amboceptor, 
205; Multiplicity of Amboceptors, 205; Complement Fixation or 
Binding, 206; Complement Binding Reactions, 206. 
CHAPTER XIX 
Agglutinins and Precipitins 210 
Agglutinins, 210; Group Agglutinins, 211; Nature of Agglutinin 
Reaction, 212; Precipitins, 213. 
CHAPTER XX 
Relationship of Anaphylacttn to Other Immune Bodies . . . 215 
Identity of all First Order Antibodies, 215. 14 
CONTENTS 
CHAPTER XXI 
PAGE 
IlEMOCELLULAR REACTION. THE LEUCOCYTE COUNT IN DIAGNOSIS AND 
Prognosis 220 
Physiologic Variations in Circulating Leucocytes, 221. 
CHAPTER XXII 
Focal Vascular and Cellular Reaction to Irritants. Inflamma- 
tion 223 
Nature and Qualities of Serum, 225; Phenomena of Inflammation, 
226; Nature and Origin of Cells Which Take Part in the In- 
flammatory Process, 227. 
CHAPTER XXIII 
Classification of Inflammatory Reactions 230 
Acute Inflammation, 231; Chronic Inflammation, 233; Granu- 
lomata, 236; Tuberculosis, 236; Syphilis, 237; Leprosy, 238; 
Other Granulomata, 241; Protective Effect of Macrophages upon 
Certain Microorganisms, 241. 
CHAPTER XXIV 
Anaphylaxis in Man 243 
Reactions to the Parenteral Introduction of Horse Serum in Man 
-Serum Sickness, 243; Determination of Hypersensitiveness and 
Method of Desensitization, 247; Treatment of Anaphylactic Re- 
action in Man, 249; Clinical Examples of Hypersensitiveness to 
Nonbacterial Proteins, 250; Constitutional Manifestations of In- 
fection and Reaction, 258; The Role of Anaphylaxis in Resistance 
to Infection (Vaughan's Conception), 262; Factors Determining 
Relative Susceptibility to Infection, 266. 
CHAPTER XXV 
Application of Immunity Principles to the Prevention and 
Treatment of Disease 270 
Serum Therapy, 270; Production and Preparation of Antitoxic 
Sera, 276; Antitoxic Serum-Treatment of Diphtheria, 277; The 
Prophylactic and Therapeutic Employment of Tetanus Antitoxin, 
278; Antipneumococcus Serum, 283; Bacillary Dysentery, 284; 
Prophylactic and Therapeutic Employment of Bacterio-proteins 
(Vaccines) and Pollen Extracts, 287; Prophylactic Employment 
of Vaccines, 290; Rabies, 291; Prophylactic Immunization Against 
Diphtheria, 293; The Therapeutic Employment of Vaccines, 296; CONTENTS 
15 
„ • m PAGE 
Vaccine Treatment of Furunculosis, 298; The Treatment of 
Gonorrheal Infection by Means of Vaccines, 300; Tuberculin 
Therapy, 302; Dosage and Interval T. R. and B. E., 307; The 
Treatment of Hay Fever by Means of Pollen Extracts, 309; 
Nonspecific Protein Therapy, 312. 
CHAPTER XXVI 
Therapeutic Guidance of the Acute Inflammatory Reaction . . 315 
Clinical Inhibition of Inflammatory Reaction, 316; Clinical Stimu- 
lation of Inflammatory Reaction, 319; Surgical Removal of Ir- 
ritants, 320. INFECTION, IMMUNITY, AND 
INFLAMMATION 
CHAPTER I 
DEFENSIVE AND OFFENSIVE REACTION OF THE 
BODY AGAINST IRRITANTS 
General Introduction 
Throughout the lifetime of the individual, the animal or 
human body is periodically exposed to the entrance of foreign 
irritant substances. It is only as a result of constant pre- 
paredness on the part of the tissues, that the latter are able 
to maintain their capacity for functioning and the body to 
prolong its existence. 
Broadly speaking, there are two methods by which the 
offensive and defensive functions of the tissues are accom- 
plished: (1) by the elaboration, on the part of the tissue cells, 
of soluble substances which are capable of neutralizing or 
destroying injurious agents; (2) by the phagocytic and lytic 
activity of certain of the body cells. 
Since the study of these two processes requires special tech- 
nical methods, and hence special training, they have been 
divided into two groups, both of which are worthy of, and 
have received by numerous investigators, most careful ob- 
servation and research. The science which treats of the con- 
stitutional reaction of the body to irritants, as evidenced by 
the elaboration of certain soluble substances and their dis- 
charge into the blood, lymph, and other body fluids, is known 
as immunology. 
The reactive processes, as manifested by morphologic (vis- 
ible) changes at the site of the introduction of, or invasion 
by, irritating substances are termed inflammation. Inflamma- 
17 18 
INFECTION, IMMUNITY, AND INFLAMMATION 
tion consists, therefore, of the focal reaction of the tissues 
against irritants. 
The larger proportion of the cells which take part in local 
inflammatory reactions are derived from the blood stream, 
into which they are discharged from the myelogenous and 
lymphogenous tissues, in increasing numbers, during the course 
of reactive phenomena. There occur during the course of 
infectious diseases changes in the productive activity of the 
tissues, more particularly of the bone marrow, as well as 
deviations from the normal cell content of the blood. This 
readjustment of blood cell precentages may be conveniently 
called the hemo cellular reaction. 
All forms of reaction, with the exception of rare instances 
of reflex reaction, are stimulated by the presence in the tis- 
sues, in which the reaction occurs, of some form of irritant. 
If we attempt to divide the causative factors which provoke 
inflammatory reactions according to their physical nature, we 
find that in so doing, we understand, to a considerable degree, 
the usefulness of the individual elements taking part in the 
reactionary process, and, thus, are enabled to appreciate the 
rationale of the reaction itself. 
Three main types of irritant are met with, viz.: 
(a) Diffusible substances, such as toxins, alkaloids, crys- 
talloids. 
(b) Colloidal substances, proteids. These may be either 
(1) soluble, as egg albumen and serum protein, or (2) partic- 
ulate, as bacterial cells. 
(c) Insoluble and nonfermentable substances, such as car- 
bon and the metallic elements. 
As might be expected the manifold substances belonging 
to any group vary much in toxicity or irritant qualities; it 
may be noted however, that no matter what may be the rela- 
tive toxicity of the foreign substance, an attempt is usually 
made by the tissues of the host to combat this effect and to 
remove the source of irritation. It will be observed, more- 
over, that the physical as well as the chemical nature of the REACTION OF BODY AGAINST IRRITANTS 
19 
foreign substance determines the type of reactionary process 
exhibited. 
The pathogenic effect of irritants upon the body tissue is 
due to a variety of injurious actions: 
1. By their simple mechanical presence foreign substances, 
even though not in themselves irritating to the tissues, may 
destroy cells in their immediate vicinity and interfere with 
the function of the part in which they are situated, e.g., 
drainage tubes, projectiles, anthracite pigment, and air and 
other gases (such as are produced by B. aerogenes capsulatus 
during its growth). 
2. If the irritant substance be soluble, it is carried to dis- 
tant parts of the body and may cause injury to cells far re- 
moved from its point of entrance, e.g., bacterial and other 
toxins, and alkaloidal poisons. 
3. Insoluble toxic substances may injure tissue cells in jux- 
taposition to them. 
4. Living, growing bacteria and animalculae may, in addi- 
tion, destroy tissue as the result of their metabolic activity, 
e.g., muscle tissue by the B. aerogenes capsulatus, and red 
blood cells by the plasmodium of malaria. 
Irritants not only differ in physical and biological type, but 
the extent of their injurious action varies to a very consider- 
able degree, some being almost inert, e.g., catgut and most of 
the metallic elements; whereas others (hydrocyanic acid, 
tetanus toxin) are so potent that extremely small amounts 
lead to rapid and violent death of the individual. 
As we study the reactive changes which occur in the animal 
body, we find, as might well be expected, that different types 
and degrees of irritants are met by the exhibition, on the part 
of the body tissues, of different methods of defense. We note, 
moreover, that certain substances are not antagonized in their 
action in any way and that the fate of the individual into 
whose tissues the irritant gains entrance will depend largely, 
or entirely, upon the amount of the substance introduced. 
Such we find to be the case with the alkaloidal poisons, as well 
as the majority of toxic mineral substances, such as arsenic, 20 
INFECTION, IMMUNITY, AND INFLAMMATION 
lead, and mercury. Experiments prove that repeated intro- 
duction into the animal body of certain drugs, such as the 
aldehydes and alcohols, as well as a number of alkaloids, is 
followed by the exhibition of a certain degree of tolerance 
to such drugs. Drug tolerance of this sort is not looked upon 
as an immunity reaction; nor is there any suggestion that 
this form of tolerance is related to tolerance to the presence 
of protein derivatives in the tissues. 
It is pointed out later in this volume that the most impor- 
tant type of irritant and the one which is met by specific anti- 
body production is that composed of protein complexes in 
colloidal form. Although all colloids are not antigenic,1 it 
is a fact that, so far as we know at present, all antigens are 
colloids. The chief obstacle to a more adequate understanding 
of the defensive reactions of the tissues is due to the fact that 
the chemistry of the colloids is as yet obscure. 
Since bacteria and their derivatives constitute by far the 
most important group of irritant substances, they have been 
made the object of special consideration in this volume. The 
action of microorganisms as causative factors in disease is 
complicated by the fact that, in studying them, we are dealing 
with a type of irritant, the concentration of which fluctuates, 
and the chemical constitution of which is very insufficiently 
known. 
During the earlier studies of immunity processes, bacteria 
were employed almost exclusively as antigens. Later the data 
obtained as a result of such experiments were generalized so 
as to be applicable to all antigens. Since the discovery of the 
anaphylactic reaction, the fundamental observations have been 
made with nonbacterial antigens. 
Serum Reactions 
There are present in the body fluids, blood, lymph, etc., 
substances which are capable of combining with, digesting, 
or absorbing, specific chemical bodies, and which are known 
'Any substance which stimulates the tissue cells to produce antibodies is 
called an antigen. REACTION OF BODY AGAINST IRRITANTS 
21 
as antibodies. The study of the nature, method of production, 
and manner of action of such antibodies, is known as immu- 
nology. Substances against which specific antibodies are pro- 
duced are called antigens. 
The science of immunology is recognized today as one of 
the most important of all biologic branches of medicine, since 
it attempts to discover and explain the basic principles under- 
lying protection from, and cure of, infectious diseases.2 
In this chapter, it is not my intention to discuss in detail, 
the nature of such antibodies, nor their method of production, 
but rather to draw attention, in a broad way, to the impor- 
tant part which they play in disease conditions. At present 
it is sufficient to state that the body fluids of man and animals 
normally contain bodies which are able to act as antidotes to 
many forms of toxins, and also substances which are able to 
alter certain solid (particulate) organic materials, notably 
proteins, in a manner which leads to their inactivation as 
harmful agencies and their subsequent destruction. It must 
be noted also, that, to a very considerable extent, the toxin 
or foreign material is neutralized by a specific substance pres- 
ent in the blood, and, furthermore, that under certain circum- 
stances of stimulation there is exhibited by the body, the 
ability to manufacture an enormous increase in the number 
of such specific antibodies. 
An individual, or animal, whose tissues contain substances 
which lead to the immediate overwhelming of the invader, is 
protected against infection. The state of the body, by virtue 
of which it is able adequately to defend itself, is termed 
prophylaxis. 
There is a natural prophylactic state against certain types 
of bacteria, which is known as nahtral immunity. In general, 
however, the immune state is developed only after the stimu- 
lation of the tissue cells, by previous successful encounter with 
like germs, active immunity, or by the introduction of specific 
2In addition, immunologic contributions of recent years have shown that 
a number of previously obscure clinical entities, e. g„ asthma, hay fever, 
and eczema, are the result of the reaction of the tissues to the presence 
of nonviable protein antigens. 22 
INFECTION, IMMUNITY, AND INFLAMMATION 
antibodies contained in the serum of some other individual 
or animal, in which active immunization has previously been 
stimulated. The gift of antibodies in this manner, is known 
as passive immunity. 
For the most part, the production of antibodies under stimu- 
lation is specific; that is to say, the activity of the anti- 
substances elaborated by the tissues, and discharged into the 
body fluids, is directed chiefly against the antigen, whether 
bacterial toxin, heterologous protein, or cell body, which has 
stimulated their production. 
Cellular Reaction 
In the defense of the tissues against invasion by bacteria, 
not only are there chemical substances produced, the action 
of which is inimical to the life of the microorganisms, but cer- 
tain cellular and tissue constituents of the body take part in 
the destruction of the bacterial cell by a process of ingestion 
and subsequent intracellular dissolution of the bacterium. 
Such a process is known as phagocytosis. 
In a general way, we note that certain foreign substances 
stimulate phagocytosis on the part of special types of cells. 
Exactly what the attributes of the foreign substances must 
be, in order that the cells may be induced to attempt their 
destruction, is insufficiently understood. It is evident, how- 
ever, that it is because the foreign material is irritating, and 
hence injurious, to the tissues that this means is adopted for 
its destruction. The type of cell, which takes part in protec- 
tive reactions, is determined largely by the nature of the irri- 
tant substances. As a general rule, markedly irritant foreign 
substances are the object of attack by the neutrophile poly- 
morphonuclear leucocyte. 
It may be stated that it would appear that the endolysins 
of certain body cells, notably the leucocytes (leucoprotease), 
are considerably more potent than the serum lysins.3 The 
exhibition of phagocytic activity on the part of the cells is 
'Lysins-Substances potent to cause solution of proteins in particulate 
form. REACTION OF BODY AGAINST IRRITANTS 
23 
thus the more effective, as well as the more economical, means 
of combating infection. 
If microorganisms which gain entrance to the body tissues 
are able to adapt themselves to the conditions as regard 
oxygen supply, moisture, and foodstuffs-qualities which all 
parasitic, and many saprophytic, bacteria possess-their con- 
tinued growth will depend upon the adequacy of the defensive 
properties at the disposal of the body. 
If the combined antibody and phagocytic properties of the 
tissues be sufficiently potent, the invader is forthwith de- 
stroyed; no infection occurs; and no visible pathologic lesion 
is manifest. This phenomenon, which may be termed sub- 
infection (Adami), is in itself harmless, and is in reality use- 
ful, as it stimulates the production of larger numbers of anti- 
substances. 
If the number of microorganisms introduced, considered as 
units, be larger than the number of available units of anti- 
bacterial properties, not all of the former are destroyed, and 
the survivors which maintain their vitality continue to pro- 
liferate. If the capacity for antibody production be well 
developed, the body at once commences the manufacture of 
new antibodies, with the result that, although the number of 
units of bacteria is being rapidly multiplied and hence large 
numbers of antibody units are exhausted or inactivated, there 
eventually comes a time when the rate of production of anti- 
bacterial properties surpasses that of the multiplication of 
bacteria. From this instant the number of bacteria present 
in the tissues commences to diminish, with the result that 
ultimately the invaders, or at least those brought in contact 
with the blood stream and body fluids, are completely 
destroyed. CHAPTER II 
INFECTION AND INFECTIOUS AGENTS 
Introduction 
Infection consists in the entrance into, and. growth within, 
the animal (or plant) tissues of minute living bodies of veg- 
etable or animal origin. The process or state of infection has 
been differently defined by various writers. Adami, and oth- 
ers, consider infection to comprise the succession of changes 
induced in the organism, generally, by the growth within it 
of microbes. Such a definition embodies not only the phe- 
nomenon of infection but also the reaction on the part of the 
tissue against invasion by the morbific agent; for, although 
it is true that, as a rule, unusual cell accumulations and im- 
mune body production follow the entrance of bacteria, pro- 
tozoa, etc., into the tissues, these changes represent reactions 
on the part of the host, and are better studied under the 
headings of immunity and inflammation. 
Infective agents may be divided into four main groups, as 
follows: 
I. Bacteria. 
II. Yeasts, moulds and fungi. 
III. Protozoa and metazoa. 
IV. Filterable viruses. 
Bacteria, as a class, are commonly considered to belong to 
the lowest type of plant life and are closely related to, and 
are indeed in many instances only with difficulty differenti- 
ated from, the more simple moulds and fungi. 
The protozoa represent the simplest form of animalculse. 
Among the higher animal forms (metazoa} the helminthes 
(worms) are the most important. Their activity is usually 
confined to the intestinal tract. 
24 INFECTION AND INFECTIOUS AGENTS 
25 
The vegetable and animal types mentioned are readily dem- 
onstrated visually and, with few exceptions, have been studied 
by means of animal experiment, or under conditions of cul- 
tivation in vitro. There remain a number of infective bodies 
whose potency in the production of disease and the induction 
of immunity are well established, but which, owing to their 
minute size, are invisible under the microscope. Since these 
bodies are capable of filtration through the finest porcelain 
filters they have been termed filterable viruses. 
Practically all local pathologic lesions which are classified 
as inflammations, as well as many constitutional diseases, are 
caused by the presence, and growth, in the body of one or the 
other of these microscopic vegetable forms (bacteria, yeast, 
and moulds) or of those animalcuhe known as protozoa. No 
aspect of the study of disease is of so great importance to 
the practicing physician or surgeon, as an appreciation of 
the mode of action of bacteria in producing pathologic changes 
in the body, and the various means at the disposal of the 
body, by which it may overcome such invaders. 
The different manifestations of infection, as recognized and 
classified clinically, represent chiefly the evidences of the re- 
action of the tissues of the host under stimulation by the 
invader. It has been found, moreover, that infection by dif- 
ferent types and species of microorganisms, is, in many in- 
stances, followed by reactions of a specific type, and, since 
many pathogenic infective agents demonstrate a predilection 
for certain particular tissues, it is possible to recognize from 
the clinical manifestations alone the nature of many infecting 
microorganisms. Thus are diagnosed infection by the typhoid 
bacillus, and by the streptococcus in erysipelas, as well as 
invasion by the viruses of smallpox, measles, and other 
exanthemata. 
There is a comparatively large number of affections the 
specific etiologic agents of which cannot be thus recognized 
and for whose diagnosis bacteriologic methods must be em- 
ployed. The more precise methods of the laboratory permit, 
moreover, an earlier, as well as a more exact diagnosis than 26 
INFECTION, IMMUNITY, AND INFLAMMATION 
those of the clinician. In certain diseases, as in syphilis, the 
identification of the specific infective agent permits the em- 
ployment of proper treatment, at an earlier period in the 
course of the disease, than would otherwise be possible. 
Historical 
The history of the development of the biologic science of 
bacteriology, as applied to the observation and treatment of 
disease, is of comparatively recent growth; for, although, 
even as far back as 1683, Leouwenhoek, a lens maker of Hol- 
land, described minute moving forms in material collected 
from the mouth, and, although, from time to time, observa- 
tions were recorded in which more exact details of the struc- 
ture of such forms were mentioned (Muller, 1786, Ehrenberg, 
1838), it was not until the early part of the latter half of the 
last century that Pasteur, although investigating as a chem- 
ist the cause of deterioration of certain wines, recognized and 
described the all-important part played by bacteria in bring- 
ing about changes in the chemical nature of their environment. 
Coincidently with the acquirement of this new knowledge 
Pasteur applied it to the study of pathologic conditions, and 
to the production of immunity. 
Up to the time of Koch's employment of solid culture media 
in the isolation of single pure strains of microorganisms, the 
study of the nature and properties of bacteria was accom- 
plished only with the most tedious labor, and was rewarded 
with relatively meager results. From this time, 1876-1881, 
however, the possibilities of more precise methods of study by 
means of the employment of pure cultures were appreciated. 
Gradually, but with steady progress, a constantly increasing 
number of pathogenic processes have been proved to be due 
to bacterial activity, or to the presence of fungi or protozoa. 
It is to Koch, moreover, that we owe the promulgation of a 
series of postulates which have been accepted as being useful 
and necessary in associating a given microorganism with a 
specific disease. According to Koch's postulates the chain 
of evidence upon which this connection may be based, is: INFECTION AND INFECTIOUS AGENTS 
27 
(1) The demonstration of the microorganism in all cases of 
the disease, in such a relationship to the pathologic process 
that its causative nature seems probable: (2) the artificial 
cultivation of the organism in pure growth: and (3) the repro- 
duction of disease by inoculation of the microorganism so 
isolated. 
Although, previous to 1860, the subject of bacteriology, as 
such, was practically unknown to all but a very occasional 
worker, the fact that there was some substance, or virus, 
which was responsible for the development of disease proc- 
esses in man, was appreciated, as is evidenced by the employ- 
ment by Jenner of the exudate from cases of vaccinia to 
inoculate the healthy individual. In obstetrics also, White, 
Semmelweis, and Holmes recognized that as the result of 
uncleanliness, contact with infected patients, etc., cases of 
puerperal fever developed. Basing their actions upon these 
observations, they adopted methods which were strikingly 
modern in their nature, and which were successful in con- 
trolling markedly the incidence of this disease. 
Following the appreciation of bacteria as the cause of 
wound infection, Lord Lister (1865) applied his knowledge 
of the germicidal action of certain substances, especially car- 
bolic acid, to surgery. From this time dates the advance in 
surgical technic with which we are all familiar; for, al- 
though a more comprehensive recognition of the biology of 
bacteria has led to the discarding of some of the practices 
thought by Lord Lister to be necessary, the value of his work 
cannot be overestimated. 
There are several aspects of the biology on life history of 
bacteria, which it is of the greatest importance that the prac- 
ticing physician rightly appreciate. For instance, an adequate 
idea of the various factors which influence favorably, or the 
opposite, the life and multiplication of microorganisms, is of 
the greatest value, not only in the proper handling of infec- 
tious processes, but also in prophylaxis. Again the chemical 
constitution of bacteria is of paramount importance, since 
their activity as pathogenic agents, as well as their protection 28 
INFECTION, IMMUNITY, AND INFLAMMATION 
from the defensive properties at the disposal of the body, 
depend, in large measure, upon their more intricate chemical 
peculiarities. An attempt will be made to prove in considera- 
tion of immunology in a later chapter, that it is largely upon 
the relative amount and exact nature of the protein constitu- 
ents of the bacterial cell body, that the various clinical man- 
ifestations of bacterial invasion (infection) depend. 
One of the most important contributions to our knowledge 
of the method of action of chemical germicides, as also of 
immune processes, is that of Ehrlich in his recognition, and 
elaboration, of the principle of chemotaxis or receptor affinity. 
According to Ehrlich's hypothesis, the ability of any living 
cell to incorporate into its protoplasm chemical substances, 
present in its vicinity, depends upon the presence of receptors, 
or special unsatisfied molecules, which are capable of attract- 
ing and combining with specific substances. The normal 
metabolism of the cell depends upon the presence of such re- 
ceptors for useful and essential food particles. Ehrlich proved 
that not only do cells possess affinities for useful and helpful 
foreign molecules, but that they also possess receptors capable 
of attracting and combining with injurious substances which 
may ultimately lead to the death of the cell. 
Morphologic and Chemical Characteristics of Bacteria 
Structure.-Bacteria consist of unicellular organisms which 
exhibit an extremely simple structure. In contrast to the 
more complicated morphology of higher vegetable, as well as 
animal, cells, bacterial cells show no differentiation into a 
distinct nucleus and cytoplasm; although it is probable that 
infinitely small masses of nucleo-protein (chromatin) material 
which are scattered throughout the cell body, and which con- 
stitute a large part of the total protein content of the bacte- 
rial cell, influence the life processes of the bacterium in a 
manner similar to that exerted by the nucleus of higher types 
of cells. It must be regarded as possible, however, that there 
may be a specially differentiated portion of the cell represent- INFECTION AND INFECTIOUS AGENTS 
29 
ing the nucleus which, so far, has not been demonstrated by 
the technical means at present at our disposal. 
The majority of bacteria consists simply of a homogenous 
material surrounded by a cell membrane1 and in which are 
scattered the chromatin granules or network just mentioned; 
others contain other substances which can be tinctorially dif- 
ferentiated and which are known as metachromatic granules. 
The function of the latter is, at present, not understood. 
Other bacteria, notably the tubercle bacillus and allied 
groups (B. leprae, B. smegma, etc.), are enveloped in a layer 
of fatty or waxy material which gives to them their so-called 
acid-fast properties. The protective effect of the capsule 
makes it difficult to stain the cell protoplasm, and on 
the other hand if powerful stains be employed, permits the 
body to resist the decolorizing action of dilute acids and alco- 
hol.2 Certain bacteria (e.g., B. aerogenes capsulatus, B. muco- 
sus capsulatus, pneumococcus and streptococcus mucosus) pro- 
duce, and surround themselves with, a colloidal material sim- 
ilar to mucin, which is known as a capsule and which by the 
employment of special tinctorial methods can be readily dem- 
onstrated. 
Size.-Bacteria, as a class, consist individually of extremely 
small masses of protoplasmic material in which appear chro- 
matic granules or networks; they are rendered visible only 
by the use of high power objectives. The individual cells 
vary somewhat in size, measuring from 0.1 to 0.6 microns in 
diameter, and from 0.8 to 10.0 microns, or greater, in length. 
If these measurements be compared with that of the human 
red blood cell, 7.5 microns, the diminutiveness of these trou- 
blesome parasites is more easily appreciated. Since different 
types of bacteria vary much in size, it is impossible to accu- 
rately determine the weight of the individual cell, dried bac- 
teria3 of the size of the tubercle bacillus (2.0 to 4.0 microns, 
1The exact nature of the cell membrane has so far not been demon- 
strated. Vaughan has apparently proved that it is not cellulose, since it 
gives no carbohydrate reaction. 
2It is probable that the majority of bacteria possess in the cell covering 
a small quantity of waxy material, but that this substance is not sufficient 
in amount to confer "acid-fast" properties upon the bacterium. 
'Hammerschlag (Centralbl. f. klin. Med., 1891, xii, p. 9) observed that 
the average water content of the tubercle bacillus is 85.9 per cent. 30 
INFECTION, IMMUNITY, AND INFLAMMATION 
by 0.3' to 0.5 microns) weight each, upon the average, about 
1/12,000,000,000 mg. 
Since the potency of bacterial vaccines in the production 
or guidance of immunologic processes is dependent, almost 
exclusively, on the amount of antigenic protein in the bacte- 
rial cell body, it is obvious that the fact that bacteria vary 
greatly in size and weight is of great importance in gauging 
the probable dose (in number of microorganisms) which must 
be employed. 
Spore Formation.-Certain bacteria have the property of pro- 
tecting themselves from extinction under unfavorable circum- 
stances, by means of the development of resting, nonvegeta- 
tive, highly resistant forms, known as ''spores." The patho- 
genic bacteria which possess this means of perpetuation are 
the B. anthracis, B. aerogenes capsulatus, the B. tetani. There 
is also a large group of spore-bearing saprophytes and facul- 
tative parasites included in the subtilis-mesentericus-proteus 
groups. 
Since bacterial forms possess such very different properties 
of resistance to outside influences, it is customary to speak 
of actively growing spore-forming bacteria, as well as all 
those which do not form spores, as vegetative forms. It is 
noteworthy in this connection that bacteria, capable of spore 
formation, do not usually produce such forms if conditions be 
favorable for their growth. This fact is of the utmost impor- 
tance in the employment of intermittent methods of steril- 
ization.4 
For the surgeon the formation of spores, upon the part of 
certain bacteria, is of special interest. The ordinary means 
adopted for the destruction of vegetative bacteria are useless 
in destroying the vitality of spores. Thus boiling does not 
injure them, nor does prolonged drying result in devitalization. 
4Spore-bearing bacteria are destroyed by temperature of about 100° C. 
only if they be in a vegetative state. If circumstances (e.g., temperature, 
foodstuffs, oxygen supply) are suitable during the interval between ex- 
posure to heat, all spores are so influenced that they are replaced by actively 
growing forms, nor are fresh spores formed. Under these conditions, steril- 
ization of infected media and solutions for intravenous or subcutaneous 
medication, may be accomplished. INFECTION AND INFECTIOUS AGENTS 
31 
Tinctorial Differentiation.-One of the most important means 
for differentiating microorganisms is by their staining reac- 
tions, or affinity, for certain aniline dyes. By far the most 
important of such methods is that of Gram. The principle of 
this staining method is based upon the fact that certain bac- 
teria when stained by aniline-methyl or aniline-gentian-violet, 
and subsequently treated with a watery iodine solution,- 
Lugol's solution-do not decolorize when treated with 95 per 
cent absolute alcohol. Such bacteria are termed Gram-positive, 
whereas those which are not resistant to alcohol in this man- 
ner are classified as Gram-negative. 
The resistance of a bacterium to decolorization by Gram's 
method is, in a general way, comparable to its resistance to 
lysis or destruction by antibodies produced by the tissues.5 
Those bacilli which decolorize by Gram's technic are subject 
to dissolution when acted upon by fresh immune serum, 
whereas the Gram-positive cocci are but little injured, either 
morphologically or biologically, by soluble antibodies. 
Among pathogenic bacteria all cocci, with the exception of 
the gonococcus (Micrococcus gonorrheae), meningococcus 
(Micrococcus intracellular is meningitidis), Micrococcus mili- 
tensis, and the Micrococcus catarrhalis, are Gram-positive; 
whereas all pathologic bacilli, with the exception of the 
B. diphtheriaef B. aerogenes capsulatus, B. anthracis, and 
the acid-fast bacilli (tuberculosis, leprae), are Gram-negative. 
B. tetani, and B. mucosus capsulatus (Friedlander's pneumo- 
bacillus) are variable, sometimes retaining and sometimes giv- 
ing up the primary stain. 
Characteristics of Bacteria Determining Their Pathogenicity 
In order to understand the results of infection of the tis- 
sues by bacteria, it is necessary that the manner of vicious 
action on the part of bacteria be appreciated. "Bacteria are 
important on account of the changes which they bring about 
5It may be assumed that the resistance of Gram-positive bacteria to 
staining, to decolorization and to lysis is dependent upon relative im- 
permeability of the ectoplasm or covering of the cell body. 
'Also B xerosis and B. Hoffmani, the so-called pseudodiphtheria group or 
diphtheroids. 32 
INFECTION, IMMUNITY, AND INFLAMMATION 
in the chemical nature of their environment" (Jordan). Bac- 
teria lead to local death of tissues and to constitutional tox- 
emia and induce reactive processes (inflammation) in four 
separate ways, which depend upon (1) the production of spe- 
cific and diffusible toxins; these act both when bacteria are 
extracellular and when they are within the tissue cells them- 
selves (true toxins or exotoxins); (2) the presence as part of 
the bacterial cell, of protein bodies which, under the influence 
of substances present in the body fluid of infected animals, 
are altered with the liberation of toxic end products (second- 
ary toxins, endotoxins, anaphylatoxins); (3) the production 
of toxic alkaloidal substances known as ptomains,-cholin, 
cadaverin, etc.,-through the breaking down of tissue cells as 
the result of the metabolic activity of the bacteria; (4) mechan- 
ically, also, bacteria may impair tissue nutrition through occlu- 
sion of terminal arterioles by bacterial cell masses. 
From a biologic standpoint these substances, toxins, endo- 
toxins, ptomains, as pointed out by Jordan, consist of (1) 
secretions, that is, those substances which subserve some pur- 
poseful end in the cell economy; these may be retained within 
the cell or may pass into the surrounding medium; (2) excre- 
tions-those substances which are expelled because useless to 
the organism; (3) disintegration products, which result from 
the breaking down, fermentation and decomposition of food 
substances. These substances, which are among the most im- 
portant, depend upon the enzyme activity of certain of the 
secretions; (4) the true cell substances (endotoxin, anaphyla- 
toxin-See "Immunity"). 
As is readily appreciated, the manner of production and 
relationship of the various substances to the physiologic proc- 
esses of the bacterial cell are of comparatively little impor- 
tance as compared with the physical and chemical character- 
istics of the substances themselves. 
As is the case with the higher vegetable and animal cells, 
the changes in the chemical nature of their environment, on 
account of which both the useful and certain of the injurious 
activities of bacteria depend, are due to the elaboration of INFECTION AND INFECTIOUS AGENTS 
33 
soluble ferments or enzymes. Certain of these, as, for in- 
stance, the gelatin-liquefying enzyme of most saprophytes and 
a certain number of parasitic bacteria, diffuse out of the cell, 
whereas others act only upon assimilated simple or complex 
foodstuffs. 
Certain bacteria such as the tetanus and diphtheria bacilli, 
which possess to a very limited extent the capacity for prolif- 
erating in normal tissues, secrete an extremely powerful poi- 
son. It is clear, says Zinsser, that unless these bacteria pro- 
duced very powerful poisons, they would not be pathogenic 
at all, and would not be brought to our attention in connection 
with human disease. 
It is indeed, he says, quite conceivable that there may be 
a great many bacteria as little invasive, and which may pro- 
duce true toxins of less potency; these would never functionate 
as pathogens, simply because the weakness of their poisons, 
and their lack of invasive power, taken together, render them 
entirely incapable of establishing a foothold in, or upon, the 
living body. On the other hand, it is quite conceivable that 
bacteria which possess the property of invasiveness to a high 
degree, need not produce poison of any great potency, in 
order to cause symptoms of toxemia in the invaded animal 
body. 
Toxins.-But few types of bacteria depend for their patho- 
genicity upon toxins of the first class, namely, soluble and 
diffusible toxins which are readily isolated from the bacteria 
themselves, although a large number do develop toxic sub- 
stances of mild potency. Of those whose action depends 
chiefly upon soluble toxin elaboration, the B. diphtheriae, 
B. tetani, and B. botulinus, are by far the most important. 
Streptococci and pneumococci produce leucocyte poisons (leu- 
cocidin) as well as hemolysin; these properties are, however, 
of relatively little importance when compared with the ex- 
treme virulence of these bacteria. In addition to the bacteria 
mentioned above, the dysentery, plague, and pyocyaneus bac- 
illi and the cholera vibrios all produce moderately active 
toxins. 34 
INFECTION, IMMUNITY, AND INFLAMMATION 
Bacterial toxins manifest a selective action upon certain 
tissue cells. Tetanus toxin, diphtheria toxin, and the pyo- 
cyaneus toxin, as well as the filtrable virus of rabies, attack 
the central nervous system. The vagus is affected by the 
toxins of the diphtheria bacillus, the influenza bacillus and the 
B. pyocyaneus. Rainy7 found distinct biologic changes in the 
motor cells in patients dying from diphtheria intoxication. 
The majority of soluble toxins produce a peripheral vascu- 
lar dilatation and thus induce lowering of blood pressure. 
The special affinity of toxins for certain tissues is well 
exemplified by the tetanus toxin which produces its effect 
through its action upon the central nervous system. If an 
animal be injected intravenously with tetanus toxin, and the 
blood examined at the end of three or four minutes, no toxin 
can be demonstrated in the blood; it can, however, be recov- 
ered by a process of extraction from all tissues but the central 
nervous system, and this, notwithstanding the fact that it 
acts obviously through its effect upon the central nervous 
system. 
If one gram of guinea pig brain is triturated with 10 cubic 
centimeters of normal salt solution an emulsion is made 
which is capable of neutralizing 100 fatal doses of the toxin 
(for white mice). On the other hand emulsions of other tis- 
sues, blood, spleen, muscles, etc., do not possess this property 
(Ransom). It is, then, evident that as a result of its affinity 
for the toxic body the central nervous system renders itself 
susceptible to its poisonous action. 
Although these facts are true of most animals, white mice, 
guinea pigs, etc., it is found that in the rabbit both liver and 
spleen have the property of fixing tetanus toxin and thus mit- 
igating the effects of its injection. Again, in the tortoise no 
fixation of the toxin in the central nervous system or in other 
tissues occurs, neither is this reptile subject to tetanic intoxi- 
cation. 
True toxins are recognized to be catabolic products of cell 
metabolism,-bacterial or higher vegetable; they act in ex- 
'Rainy: Jour. Path., 1900, vi, 444. INFECTION AND INFECTIOUS AGENTS 
35 
tremely minute doses; 0.0002 milligram of diphtheria toxin is 
sufficient to kill a guinea pig weighing 250 grams, in three 
days. Specimens of tetanus toxin have been prepared that 
are fatal to white mice in doses as small as 0.0005 milligrams. 
When toxins are injected into animals in sublethal doses, anti- 
toxin is produced by the tissues of the animal. 
Although toxins have not been isolated in a pure state, 
they are believed to be proteins. They diffuse with difficulty, 
thus indicating their colloidal nature. Amino-acids are not 
derived by hydrolysis. They give a positive biuret and a 
negative Millon's test, thus showing their protein constitution 
and the absence of aromatic radicles. 
Diphtheria toxin is precipitated by alcohol and by full satu- 
ration with ammonium sulphate. It is destroyed promptly 
by boiling and by exposure to a temperature of 73° C. for 
five minutes. It is injured by freezing and by the action of 
light. 
The amount of toxin produced by one and the same strain 
of microorganism is tremendously influenced by the culture 
medium in which its multiplication takes place. Kendall has 
drawn attention to the fact that in the presence of a liberal 
supply of carbohydrate foodstuffs, the majority of bacteria 
will not attack protein substances, except to the limited extent 
necessary for their vital processes. Theobald Smith has shown 
that the diphtheria bacillus produces toxin, only when forced, 
as the result of an absence of carbohydrates, to subsist more 
or less exclusively upon nitrogenous material. The same holds 
true of the tetanus bacillus, with regard to toxin production 
by that bacterium. 
Ptomains.-Although all pathogenic bacteria live upon, and 
utilize, body tissue to supply nutrition for their metabolic 
activities, a small percentage only, liberate or synthesize from 
the tissue proteins poisonous substances of any special toxicity. 
A certain number, however, more especially the anaerobic pu- 
trefactive bacteria,-B. aerogenes capsulatus, and numerous 
saprophytes, as well as many of the facultative parasites 
including the colon bacillus,-decompose the body tissues with 36 
INFECTION, IMMUNITY, AND INFLAMMATION 
the formation of highly toxic substances which can be isolated 
in crystalline form. These substances, known as ptomains 
(Brieger), are alkaloidal in nature and are represented by 
cadaverin and cholin. The action of many of these poisons is 
very powerful and, since no immunity is established against 
them, individuals infected by such microorganisms soon suf- 
fer from an intense toxemia, designated by the term sapremia, 
which, characteristically, unless the focal proliferation of 
bacteria be controlled, soon results in death of the host. 
Although ptomains occasionally cause disease and some- 
times even death, these substances are gradually being rele- 
gated to a much less important place in our appreciation of 
pathologic processes, than they have hitherto held. Especially 
is this the case, since it has been recognized that the majority, 
at least, of cases of so-called food poisoning, are the result of 
the activity of bacillus botulinus, or microorganisms of the 
paratyphoid group. 
Effects of Environment upon Toxicity.-In addition to the 
properties, mentioned in the foregoing section, which are ex- 
hibited by bacteria in order that they may be able to gain, and 
maintain, a foothold in the tissues, other qualities deserve our 
attention. It has been previously stated that in addition to 
catabolic and anabolic toxic substances such as the true toxins, 
ptomains, etc., the bacterial cell body is, under certain con- 
ditions of the tissues of the host, of very actively toxic potency. 
In a subsequent chapter it is shown that this secondary or 
anaphylactic toxicity of microorganisms is dependent directly 
upon the protein content of the bacterial cell. It has, further- 
more, been proved that certain bacteria liberate varying quan- 
tities and qualities of soluble bodies-indol, skatol, aromatic 
oxyacids, lactic acid, and acetic and succinic acids, etc., cer- 
tain of which are injurious to the tissues. The bacterial cell 
itself is found to possess a different chemical constitution under 
variable conditions of environment. 
"Lyons and Cramer8 have analyzed bacteria grown upon 
'Lyons and Cramer: Quoted by Kendall, Jour. Med. Research, 1911-12, 
xxv, 117. INFECTION AND INFECTIOUS AGENTS 
37 
media with and without carbohydrate, and, have made the 
very interesting and important observation that the actual 
chemical composition varies, the nitrogen content being 
greater in those organisms grown in media containing no car- 
bohydrate, less in media containing carbohydrate. They have 
furnished definite figures showing in a striking manner just 
what these differences are. Their figures are fairly in accord, 
and, inasmuch as the observed differences between the selected 
media are greatly in excess of the probable source of error, 
it may be assumed that the difference in composition of the 
bacteria is proved." (Kendall). 
Lyons used three bacilli for his experiments. The accom- 
panying table contains his results. 
ORGANISMS 
DEXTROSE IN PER CENT 
1 
5 
10 
(Nitrogen-substance 
62.75 
58.88 
45.88 
Pfeiffer B. 
(Ether extract 
1.68 
3.50 
2.67 
(Alcoholic extract 
12.17 
17.30 
29.60 
(Ash 
7.16 
2.97 
3.09 
(Nitrogen-substance 
71.81 
51.12 
46.25 
Bacillus No. 28 
(Ether extract 
3.32 
3.84 
2.84 
(Alcoholic extract 
11.39 
15.19 
22.78 
(Ash 
6.51 
3.66 
4.18 
(Nitrogen-substance 
61.05 
44.31 
33.25 
Thread Bacillus 
(Ether extract 
1.74 
2.24 
1.87 
(Alcoholic extract 
18.40 
21.80 
27.50 
(Ash 
8.09 
4.50 
3.02 
Cramer used four bacilli; his experiments are more extensive 
than those reported above. His organisms include the follow- 
ing: Pfeiffer's bacillus (1), No. 28 (2), Pneumonia bacillus 
(3), and the Rhinoscleroma bacillus (4). 
The importance of such alteration in the protein content of 
bacterial cell bodies, under different conditions of environment, 
may be of great importance in determining the clinical evi- 
dence of toxicity of infecting microorganisms. 
Brown9 has published observations upon the B. welchii (B. 
'Brown: Ann. Report Mass. State Board of Health, 1909 38 
INFECTION, IMMUNITY, AND INFLAMMATION 
NITROGENOUS 
SUBSTANCE 
EXTRA CT-ETHER 
ALCOHOL 
ASH 
Bacillus 
Peptone 
Dextrose 
Peptone Dextrose 
Peptone 
Dextrose 
Per Cent 
Per Cent 
Per Cent Per Cent 
Per Cent 
Per Cent 
Medium No. 1 
5 
5 
1 
5 
5 
1 
5 
5 
1 
2 
3 
1 
2 
3 
1 
2 
3 
No. 
1 
66.6 
70.0 
53.7 
17.7 
14.63 
24.0 
12.56 
9.10 
9.13 
No. 
2 
73.1 
79.6 
59.0 
16.9 
17.83 
18.4 
11.42 
7.79 
9.20 
No. 
3 
71.7 
79.8 
63.6 
16.3 
11.28 
22.7 
13.94 10.36 
7.88 
No. 
4 
68.4 
76.2 
62.1 
11.1 
9.06 
20.0 
13.45 
9.33 
9.44 
aerogenes capsulatus) which are of great import in indicating 
the importance of foodstuffs in this respect. "When grown 
in ordinary broth plus tissue and inoculated into grown pigs, 
this anaerobe produced no lesion beyond a small subcutaneous 
nodule that was transitory, but if grown in bouillon plus 
tissue that had been rendered sugar-free by fermentation with 
B. coli, it was pathogenic for guinea pigs, producing the char- 
acteristic lesions of B. aerogenes capsulatus infection." 
Bacterial Proteins-Endotoxins-Anaphylatoxins.-Although 
a certain number of bacteria, notably the diphtheria and tet- 
anus bacilli, produce soluble highly poisonous substances, it 
can be proved that the manifestations of intoxication which 
accompany the majority of infectious diseases are not due to 
such toxic products, but that the injurious substance is derived 
from the body of the bacterium. Furthermore, it appears that 
unless partial dissolution, or protein cleavage of the bacterial 
cell be accomplished, the irritant property of the bacterium is 
not exhibited. 
Two views have been held with reference to the nature of 
this poisonous moiety. Pfeiffer, who was the first to recognize 
the presence of such a toxic principle (See Immunity; Endo- 
toxins), considers that the toxin exists, preformed, in the bac- 
terial cytoplasm and that by partial lysis of the cell body it is 
set free. 
The second view, and the one which receives greater sup- 
port from recent experiments, is that which supposes that as INFECTION AND INFECTIOUS AGENTS 
39 
a result of the interaction of certain specific substances in the 
body fluids, the albumin molecule of the bacterial cytoplasm 
is altered so that it becomes an irritant to tissue cells. By 
a large group of observers it is believed that the alteration of 
the protein molecule is a partial cleavage or degradation ap- 
parently to the stage of peptone formation. This view had 
received its greatest support from the work of Vaughan and 
his associates. These observers have been successful in produc- 
ing in vitro, by simple hydrolysis, substances which appear to 
possess all the properties of Pfeiffer's endotoxins. 
In contradistinction to the primary or essential toxins pro- 
duced by microorganisms, such as B. diphtheriae, this potential 
toxicity of the protein constituents of the bacterial cell in the 
manner described, is known as secondary or anaphylactic 
toxicity. Depending upon the point of view of the author, 
this irritant has been designated by various names, including 
toxalbumin, anaphylatoxin (Friedberger), and apotoxin 
(Richet). This secondary toxicity of bacterial proteins has 
recently been the subject of much investigation and study, and 
has proved to be of paramount importance in the appreciation 
of disease phenomena. In a later chapter (Immunology), is 
discussed the means whereby this apparently protein-splitting 
process is accomplished and the conditions under which the 
splitting property on the part of body fluids is increased or 
diminished; also the manner of action of the so-called "an- 
aphylatoxins. " Suffice to state, at the present time, that the 
protein content of bacterial cells, although they are inherently 
nontoxic, may be so acted upon by specific substances in the 
serum, probably of the nature of ferments, that soluble highly 
irritant albuminoids are set free. 
Zinsser believes that "endotoxins" do not form the matrix 
of toxic-split products produced in the circulation by the 
sensitizer-alexin complex, as conceived by Friedberger and 
others; but injury by their reaction with the fixed tissue cells, 
as conceived by Vaughan, he says, cannot be excluded. 
Zinsser sums up the evidence regarding the endotoxin as 
follows: "The body substances of most Gram-negative bacteria 40 
INFECTION, IMMUNITY, AND INFLAMMATION 
are toxic for the ordinary laboratory animals. These toxic 
properties are common to many nonpathogenic, as well as path- 
ogenic bacteria of this class. It is uncertain, but unlikely, 
that they are pharmacologically specific. In a large majority 
of cases these substances have been found to be relatively re- 
sistant to heat, and do not deteriorate readily on standing. 
Such 'endotoxins' do not induce neutralizing antibodies of 
any marked degree of potency, but they do induce specific 
protein sensitizers by means of which partial specific neutrali- 
zation of their efforts may be accomplished. Similar endotoxic 
substances have not been consistently produced with Gram- 
positive bacteria." 
The simplest explanation of these facts, in the author's opin- 
ion, is that autolysis of the Gram-negative bacteria readily 
occurs in vitro, as well as lysis (digestion) in vivo. The irri- 
tant properties exhibited by the body substance is due to par- 
tial cleavage of the protein molecules with exaltation of chem- 
ism of the split products. Since the body substance of the 
Gram-positive bacteria is more resistant to the effects of pro- 
tein-splitting substances, in their environment, irritant prop- 
erties are less easily proved for the cytoplasm of this group of 
microorganisms. 
Peptotoxins.-Attention has recently been drawn by several 
different investigators to the fact that, in addition to the simple 
or primary toxins, such as characterize the diphtheria and 
tetanus bacillus and the intracellular protein content of bac- 
teria, which in common with other heterologous proteins, is 
potent to induce anaphylactic symptoms, there is produced in 
the medium in which certain bacteria are grown a soluble 
protein substance which is capable of precipitation, but not 
of coagulation by absolute alcohol and which is extremely 
toxic when introduced into sensitized animals, i.e., animals 
which have previously received injections of the same or a 
similar preparation. Since this toxic body is produced only 
when the various bacteria which are capable of producing it 
are grown upon media containing peptone, it has been termed INFECTION AND INFECTIOUS AGENTS 
41 
by Besredka and Strobel "peptotoxin."10 These observers as- 
sume tentatively that peptotoxin and anaphylatoxin are prob- 
ably identical. 
Whatever the nature of this poison, it is probably identical 
with that studied by Zinsser and Parker. It appears to be 
a fact, in view of the observations of these investigators, that 
many bacteria, such as the B. influenza, streptococcus, typhoid 
and dysentery bacilli, produce a substance which may be ex- 
tracted with ease from the culture medium, either liquid or 
solid, in or on which they have grown. These toxic substances 
resemble one another in many ways, qualitatively, no matter 
what their source. They produce paralytic symptoms in rab- 
bits, after but a short incubation period. They are harmless 
for guinea pigs; they are not stable, and are destroyed by 
temperatures of about 80° C. Serologic work has been done 
to prove the true toxin nature, and specificity of such poison. 
In general, the sera produced have neutralized the toxic sub- 
stance to a limited extent only. It is noteworthy, moreover, 
that such neutralization has been more regularly proved when 
the poison substance, and the antibody containing serum has 
been incubated prior to injection, than when both are injected 
simultaneously. 
Zinsser discusses the possibility of this poison being derived 
from the medium in which the bacteria are grown. He rules 
out from consideration peptone and histamin, but indicates 
that in his opinion, the matter is not as yet finally settled. 
Zinsser and his associates have found that many different 
bacteria will induce the formation of heat unstable toxic sub- 
stances in young cultures. The formation of this substance is 
roughly proportioned to the growth energy. The toxic prod- 
ucts are essentially similar in the symptoms they elicit in rab- 
bits, and in their harmlessness for guinea pigs. They differ in 
some essential properties from the classical endotoxins of the 
same organisms, and they seem distinct from most of the usual 
toxic substances produced by the cleavage of culture ingredi- 
"Besredka and Strobel: Soc. de Biol., 1911, Ixiii, 691. Centralbl. f. 
Bakt., Abt. 1. Ref., 1921, liii, No. 10. 42 
INFECTION, IMMUNITY, AND INFLAMMATION 
ents. The difficulty of performing serologic work, he states, 
is increased by the fact that repeated small doses often lead 
to marasmus, loss of hair, and eventual death of the animal 
treated. 
Certain results suggest an aggressive action of these poison- 
ous products. Sublethal doses of streptococci contained in 
supernatant fluid from centrifuged specimens have died in two 
or three days. 
Conditions Necessary for Bacterial Growth.-For the general 
bacteriologist, the number of bacteria submitted to study is 
tremendously large. Only a comparatively small number are, 
however, capable of maintaining their existence in the living 
tissues, either of plants or animals. Those organisms, whose 
life history is best carried out, in the presence of inert, non- 
viable substances, are known as saprophytes: those which 
multiply and grow luxuriantly in living tissues are termed 
parasites. Bacteria which are unable to thrive in living tissues 
are obligate saprophytes, while, on the other hand, those to 
whose existence living tissues are necessary as a foodstuff are 
obligate parasites. 
Saprophytic bacteria are unable to thrive in the animal body, 
partly because they are unable to procure the proper con- 
stituents for their metabolic activity and because the tempera- 
ture is not suitable, but also because there are present in the 
normal body, substances, whose presence is positively inimical 
to their growth. As will be noted later in this volume, it is 
possible for the body cells to acquire the property of producing 
such antisubstances which render impossible the growth of even 
obligate parasites. Parasitic bacteria, although they are able, 
for the most part, to remain viable outside the body, do not 
thrive, since they depend for their nutriment upon the presence 
in their immediate vicinity of certain of the intermediate prod- 
ucts of cellular metabolism. Parasitic bacteria are, apparently, 
unable by themselves to bring about the splitting of the more 
complex molecule, with the liberation of the amino-acids which 
are necessary for their nutrition. INFECTION AND INFECTIOUS AGENTS 
43 
Bacteria, as a class, are living forms which show a very- 
pronounced daintiness in their choice of foodstuffs. For the 
growth of different types to take place it is necessary that a 
sufficient supply of oxygen, water, and of nitrogen, hydrogen, 
carbon, and other elements such as sulphur, iron, etc., be pres- 
ent in an assimilable form. 
Moisture.-All microorganisms, in common with other 
species of living matter, require for their growth a sufficient 
supply of water, although for the most part moderate desic- 
cation, unless very prolonged, does not result in death of the 
cell body. 
Oxygen.-The majority of pathogenic microorganisms re- 
quire free oxygen for their growth, and are known as obligate 
aerobes. Upon the other hand there are a certain number, 
notably the tetanus bacillus and the bacillus aerogenes cap- 
sulatus, which can multiply only in the absence of free oxygen; 
these are obligate anaerobes. Still others are able to adapt 
themselves to the presence of oxygen and are likewise able to 
utilize the oxygen present, in combination in the substances 
upon which they live. Such are called facultative anaerobes 
or aerobes. 
Since the living body tissues normally contain a certain 
amount of free oxygen, infection by obligate anaerobic micro- 
organisms is unlikely to occur, unless the tissues have been 
injured, and a certain number of cells have become devitalized 
as the result of trauma or ischemia. Thus, it is a well-known 
clinical fact, exemplified in so many tragic cases during the 
war, that infection by bacillus aerogenes capsulatus (B. 
welchii), rarely takes place unless there be extensive bruising 
of the tissues. 
The great majority of pyogenic and other pathogenic bac- 
teria are aerobes; the most important anaerobic bacteria are 
the Bacillus welchii just mentioned, the tetanus bacillus, and 
the various spirochetae-Treponema pallidum (Noguchi), Spiro- 
chete pertenuis (Nichols), and the Bacillus fusiformis-the 
cause of Vincent 's angina, noma, and phagedenic ulcer (Tun- 
nicliffe). 44 
INFECTION, IMMUNITY, AND INFLAMMATION 
Temperature.-The majority of pathogenic bacteria grow 
best at a temperature which approximates that of the human 
body, 37° C.,11 98%° F., although between the range of from 
20°-42° C. most bacteria demonstrate fairly active growth. 
The highest temperature at which active growth is exhibited 
is called the maximum temperature of growth, the lowest is 
known as the minimum. The degree of heat at which cultiva- 
tion is most luxuriant represents the optimum temperature for 
that particular species. 
Factors Determining Death of Bacteria.-We have briefly 
noted the factors which tend to develop the most active growth 
on the part of pathogenic bacteria. It has been shown that, 
although it is possible to induce most bacteria to grow outside 
the body, a combination of favorable circumstances as regards 
food, oxygen supply, moisture and temperature, is, under nor- 
mal conditions, very infrequently met with. With the excep- 
tion, therefore, of certain of the anaerobic bacteria, notably 
the Bacillus tetani and Bacillus aerogenes capsulatus, which 
perhaps proliferate in the excreta of the horse, and other ani- 
mals, we find that very few pathogenic microorganisms mul- 
tiply outside the animal body. In other words, it is necessary 
for the propagation of the great majority of pathogenic bac- 
teria that they find entrance into the tissue of man, or some 
other animal body. 
Although, as just stated, the parasitic nature of pathogenic 
bacteria necessitates their entrance into animal bodies, in 
order that they may multiply, such an environment, is by no 
means essential for the maintenance of their vitality, or capac- 
ity for growth. 
Oxygen.-Although the presence of oxygen, in the immediate 
environment of bacteria, in such a state that the anabolic proc- 
esses of the bacterium may be able to utilize it in the physi- 
ology of the cell, is essential to the continued vitality of 
aerobic bacteria, nascent oxygen, such as is liberated from 
"Although the subject has been hitherto insufficiently investigated there 
is much which suggests that the determining factor in infections of the 
superficial tissues of the body is the fact that the causative agents grow 
best at a temperature below that of the internal organs. INFECTION AND INFECTIOUS AGENTS 
45 
H202 or represented by ozone, is capable of rapidly destroying 
most bacteria, if they are in a vegetative state. In fact the 
activity of many germicides is due to the liberation of nascent 
oxygen, and the consequent oxidizing property of the sub- 
stance. 
Desiccation.-Exposure of bacteria to desiccation, or drying, 
is followed in the course of a comparatively short time (1-24 
hours) by death through the removal of water from the cell 
body. As might be expected, the encapsulated bacteria and 
those surrounded by the fatty, or waxy covering, which char- 
acterize the tubercle and leprosy bacilli, prove more resistant 
to this factor, than do others not so protected. It is for this 
reason that there is such grave danger of "house infection" 
occurring with tuberculosis. 
Heat and Cold.-Although a certain degree of warmth is 
necessary in order that growth of bacteria may take place, and 
above and below the maximum and minimum limits, respec- 
tively, proliferation does not occur, the vitality of the micro- 
organism is by no means destroyed, unless the degree of heat 
bo considerably increased. It is found, also, that even extreme 
conditions of cold, such as repeated or continuous freezing 
injure bacteria only after long periods. 
Most vegetative forms are unable to resist a temperature of 
from 56-60° C. for ten minutes, if the microorganism be exposed 
to such heat in the presence of moisture. Certain bacteria, 
notably tubercle and leprosy bacilli, are not killed (in ten 
minutes) by a temperature of 70° C. Moist heat at a tempera- 
ture of 100° C. such as is obtained by boiling or the steam 
sterilizer without pressure (Arnold), kills all vegetative bac- 
teria almost instantly. 
The destruction of bacteria by means of heat, is apparently 
brought about by coagulation of the albumin of the bacterial 
cell, and, since this takes place more readily in the presence of 
moisture, it is found that higher temperatures are necessary 
if dry heat be employed. For purposes of sterilization tem- 
peratures of 120° C. or more, for several minutes, must be 
employed; if spores be present, and they must always be as- 46 
INFECTION, IMMUNITY, AND INFLAMMATION 
sumed to be present in dressings, and similar materials, for the 
sterilization of which dry heat is commonly employed, an ex- 
posure to a temperature of 140° C. for twenty minutes is neces- 
sary. 
For the complete sterilization of spore-bearing organisms 
either dry heat may be used, or steam under pressure, in an 
autoclave, may be employed. For this purpose, a temperature 
of 125° for a few minutes is sufficient. Red heat, as in a flame, 
results in instant death of all bacteria and is a method to be 
strongly recommended whenever possible. 
Factors Which Determine Relative Virulence of Bacteria 
It is a well-known fact that different strains of the same 
type of bacterium, or the same strain when exposed to a dif- 
ferent cultural environment, possess varying powers of infec- 
tivity, and relatively, greater or less, capacity for producing 
morbid and lethal changes in their host. The sum total of 
these properties of pathogenicity, constitute virulence. Viru- 
lence refers, therefore, to the relative offensive and defensive 
properties of bacteria and depends upon: (1) the adaptability 
of the microorganism as regards foodstuffs, oxygen content, 
etc., found in the tissues of the host, (2) its capacity of re- 
sisting the action of proteolytic substances in the body fluids, 
both natural and immune, of the host, and (3) its capacity 
for injuring both constitutionally and locally the tissues of the 
infected individual. 
All nonpathogenic bacteria or saprophytes are such, pre- 
sumably because they are unable to adapt themselves to con- 
ditions which maintain in the animal tissues, particularly in- 
sofar as these conditions refer to temperature, oxygen content, 
and foodstuffs, or because the normal proteolytic animal fer- 
ments are potent to destroy the bacterial cell bodies. 
Highly pathogenic bacteria are such, primarily, because they 
are able to grow and multiply in the tissues owing, in the first 
place, to the fact that they find conditions favorable as regards 
foodstuffs, oxygen, temperature, etc., and secondly, to the fact INFECTION AND INFECTIOUS AGENTS 
47 
that they protect themselves against the activity of the body 
fluids and cells by various means. 
Capsule Formation.-One of the chief protective properties 
of bacteria is an elaboration, or special modification, of the 
cell membrane, or enveloping capsule. As a means of pro- 
tecting itself against the proteotropic antisubstances in the 
serum, not only is the usefulness of the protective envelope 
most obvious, but also most efficacious. 
Certain pathogenic bacteria, when grown in the animal body, 
or in media rich in uncoagulated albumins, such as serum, 
hydrocele fluid or milk, surround themselves with a definite 
capsule or mucoid material. When such bacteria are cultivated 
upon ordinary media they lose, largely or altogether, the 
property of producing a capsule, and can be induced to return 
to their capsule-producing stage only by means of reinocula- 
tion, into suitable animals, or, less readily, by transplantation 
into albuminous media. The bacteria which belong to this 
group are, the Bacillus pneumoniae of Friedlander, the Bacillus 
of rhinoscleroma, Bacillus anthracis, Bacillus aerogenes cap- 
sulatus, the plague bacillus, Bacillus cholerae gallinarum and 
pneumococcus, certain of the streptococci, Micrococcus tet- 
ragenus, and certain yeasts, e.g., blastomyces. 
It can be readily proved that, coincident with the loss of the 
capsule forming property of such a microorganism as the 
pneumococcus, its power of infecting mice, is lessened and 
that phagocytosis of the bacterial cell in vitro is more readily 
accomplished. 
Horiuchi12 described an experiment in which he employed 
a micrococcus tetragenus having a dense capsule which re- 
sisted phagocytosis almost entirely and killed guinea pigs in 
a dose of 100 organisms. When this microorganism was grown 
for a number of days, on rather dry agar, it lost its capsule- 
forming power permanently, became subject to phagocytosis, 
and did not affect guinea pigs, even in doses of one thousand 
million. Rosenow has made similar observations upon bacteria 
of the streptococcus-pneumococcus group. 
13Horiuchl quoted from Simon: Infection and Immunity. 48 
INFECTION, IMMUNITY, AND INFLAMMATION 
In a large number of microorganisms, although true capsule 
formation has not been demonstrated, an analogous alteration 
in their physical structure occurs. Under certain conditions 
of growth in suitable animal tissues, a thickening of the ecto- 
plasm or cell membrane occurs, so that the individual members 
appear to be much larger than when grown upon simple media. 
This thickening is more marked in the more virulently path- 
ogenic strains. "This is true especially of the colon and ty- 
phoid bacilli and the streptococcus, and leads to appearances 
which often contrast strongly with the tiny attenuated forms 
which one is accustomed to see, in old cultures, on the ordinary 
media" (Simon). 
It is readily understood, upon the basis of the protective 
property of the capsule, why animal inoculation may fre- 
quently lead to an exaltation in virulence of a bacterial strain. 
Still another group of bacteria are normally, and even under 
saprophytic conditions of life, enclosed by a protective mem- 
brane, which renders them almost impervious to the action of 
harmful influences in the body fluids of the host. These are 
the microorganisms of the acid-fast group, i.e., the tubercle and 
leprosy bacilli. These bacilli are surrounded by a fatty or 
waxy envelope. That the entrance of bacteria of this type is 
not followed by a clinically fulminant and acute infection, is 
due, not so much to the fact that antisubstances are produced, 
as that their rate of growth is extremely slow and that they 
produce no toxins. Other members of this group, e.g., the 
timothy hay bacillus of Mueller, do not produce spontaneous 
morbid changes in human beings, not so much because the anti- 
substances of the serum destroy them, but because the environ- 
ment, particularly as regards temperature, is unfavorable. 
Although there is apparently no doubt but that the capacity 
of a bacterium for producing about itself a more or less im- 
permeable enveloping capsule or membrane determines its 
potential pathogenicity or infectivity, this property is not the 
only one which is altered during the process of increasing 
virulence. Thus, in certain instances, it is found that the 
passage through one animal not only does not increase its INFECTION AND INFECTIOUS AGENTS 
49 
virulence for other species, but may even have the opposite 
effect. In this way, it may be shown that the virulence of the 
bacillus of chicken cholera is increased for the fowl by passage 
through chickens, but is not affected in its action upon the 
guinea pig. 
Obviously, therefore, other devices are at the command of 
the bacterium for increasing its resistance against the delete- 
rious influences present in the host. The exact nature of these 
changes is but very imperfectly understood, but they are doubt- 
less due to the acquisition of altered biologic affinities, whereby 
the organism is able to employ different materials as food- 
stuffs, and possibly to neutralize the action of injurious sub- 
stances. That such should be the case seems very natural, 
and that direct proof of this hypothesis should be difficult is 
equally easily understood. 
It must be realized that the process of exaltation of viru- 
lence of bacteria by animal passage, or other attenuation by 
means of cultivation under more or less unfavorable condi- 
tions, does not, necessarily, depend upon the acquisition of 
new, or the marked development of latent properties, in all 
the individual members of the strain under observation, but 
represents, in all likelihood, a survival of the fittest. Thus it 
may be assumed, that in every collection of bacteria of the 
same species, certain members will be found in whom the 
capacity for growth in living tissues, the ability to form cap- 
sules, and other properties which may help them to maintain 
their vitality in the tissues, is more highly developed than 
among their fellows; many of the latter may, in turn, adapt 
themselves more readily to the saprophytic life. 
When cultures containing representatives of both these 
groups, are inoculated into animals, only those individuals in 
whom the defensive attributes are highly developed survive. 
It is their descendants that persist and multiply, and may sub- 
sequently be recovered from the tissues. Thus by means of a 
process of elimination of the less fit, combined with, in all 
probability, an educative development, there is produced a 
strain of increased virulence. If, on the other hand, subcul- 50 
INFECTION, IMMUNITY, AND INFLAMMATION 
tures to a less favorable medium be made, only the less para- 
sitic or more saprophytic members survive and the strain is 
said to have been attenuated. In this way is explained the 
fact that certain bacteria, such as the tetragen of Horiuchi 
referred to above, may, upon cultivation upon simple media 
lose, for all time, their pathogenic capacity; also the observa- 
tion, first made by Pasteur, that although it is possible to exalt 
the virulence of a species up to a certain point, there is 
ultimately reached a point beyond which no amount of animal 
inoculation will increase the virulence of a strain-the virus 
fixe of Pasteur. 
The majority of pathogenic bacteria, although by means of 
variations in cultural environment their virulence may be re- 
duced, maintain, albeit in a more or less latent state, their 
capacity for protective property formation. Bacteria of this 
class may well be termed, as has been done by Simon, poten- 
tial parasites. It is on account of this persistence of potential 
pathogenicity that such great care must be exercised in the 
employment of " nonvirulent " strains in artificial immuniza- 
tion, more particularly of human individuals. 
Whether bacteria possess the capacity for secreting sub- 
stances which directly neutralize the antibacterial substances 
in the body fluids, as is believed to be the case by Bail, Welch 
and others, and to which the name aggressins has been given, 
is decidedly problematic. That certain well-defined properties 
of bacteria, in addition to morphologic changes, capsules, fatty 
envelopes, etc., are of value to the bacterium in protecting it 
from the activity of inimical serum bodies, or in so affecting 
the tissues in which they grow that the defensive function of 
the tissue cells is, more or less, paralyzed, is easily possible of 
proof. Certain of these potentialities are liable to modification 
and are thus of importance in determining the virulence of 
different strains of the same bacterial species, or the same 
strain under altered conditions of environment. 
Many of the bacteria which are commonly classified as patho- 
gens possess but few, if any, qualities of the true parasite 
since they are almost incapable of multiplication within living INFECTION AND INFECTIOUS AGENTS 
51 
tissues, but demand in their immediate neighborhood necrosis 
or devitalized tissue which acts as a pabulum for their 
growth. Chief among these are the tetanus bacillus and the 
Bacillus aerogenes capsulatus. In addition there is a large 
group, which, though possessing much more marked infective- 
ness, require, for their active proliferation the presence in 
their immediate vicinity of devitalized tissue. Many bacteria 
possess the capacity of secreting toxins, which are capable of 
devitalizing tissues in their immediate environment, and thus 
supply for themselves the requisite supply of pabulum. 
The human tissues quickly destroy the cell body of the diph- 
theria bacillus as is evidenced by the fact that the adminis- 
tration of antitoxic serum, although this has little bacteriolytic 
power, not only mitigates the symptoms, but leads to the 
eradication of the bacilli from the focus of accumulation. The 
pyogenic cocci, streptococci and staphylococci, manufacture a 
toxic substance-leucocidin-which inactivates and destroys 
the most potent means of defense at the disposal of the host. 
Other bacteria, notably, the Bacillus welchii (Bacillus aero- 
genes capsulatus) liberate, from the broken-down tissue conse- 
quent upon their growth therein, substances (gas accumulation 
and toxins) which are potent to destroy the tissue in their 
vicinity en masse, and to lead to thrombosis of the vessels. 
Thus, it is noted, that although traumatic necrosis is almost 
invariably necessary, in order that this bacterium may be able 
to gain a foothold in the tissues, although a generalized in- 
fection occurs, only sub finen vitae, the extension of the local 
disease process is often extremely rapid. 
The capacity for toxin production varies greatly under dif- 
ferent cultural conditions and is greatest, as has been demon- 
strated by Kendall, when organisms are grown in a medium 
rich in uncoagulated albumins and practically disappears, or 
becomes latent, if an excess of carbohydrate foodstuffs be 
supplied. 
Danysz suggests a very interesting point of view with refer- 
ence to the exaltation of virulence on the part of bacteria. 52 
INFECTION, IMMUNITY, AND INFLAMMATION 
This suggestion is similar to that brought forward by Welch 
a number of years ago. The essential feature of this hypoth- 
esis is that the animal body may be considered as an antigen 
for the infecting microorganism and that this antigen provokes 
the formation of an antibody in exactly the same way, and by 
the same mechanism, as the fixing substance of the bacterium 
is antigenic for the animal body. 
He refers to experiments in which paratyphoid bacilli, which 
are virulent for field mice but not for the common rat, may 
be induced to demonstrate pathogenicity for the latter animal. 
He says, "In the last analysis the substance of the bacteria ac- 
quires a specific affinity for the rat substance and it is thanks 
to this acquired affinity that the bacteria, or more exactly its 
own specific substance, can fix and digest the rat substance and 
render it assimilable." 
A series of studies by Savtchenko show that although an- 
thrax bacilli are very rapidly destroyed in rat serum, if a 
small quantity of serum be added to a large quantity of ordi- 
nary bouillon, growth of the anthrax bacillus can be obtained. 
By continuing passages through mixtures containing relatively 
larger quantities of serum, we finally obtain a fairly luxurious 
culture in pure rat serum. These properties of serum resist- 
ance are maintained for a period after transplantation into the 
ordinary bouillon. Again, if the bacteria are removed from 
the culture by filtration and a small amount of the filtrate is 
added to rat serum, and this mixture is added to broth, 
a growth of even a nonserum resistant strain of the bacil- 
lus is obtained. It is thus seen that the excess of fixing 
substance which the bacterium has learned to produce is 
thrown off into medium in which it is growing, and that 
this substance can neutralize in vitro the bactericidal proper- 
ties of the serum and render it more assimilable for a non- 
serum resistant race. It is interesting in this connection to 
note that contrary to supposition a culture of anthrax-viru- 
lent for rats-does not become virulent when rendered serum- 
resistant (Danysz). INFECTION AND INFECTIOUS AGENTS 
53 
Factors Influencing Infection 
The normal epithelial covered surface of the body is suffi- 
ciently resistant to prevent the entrance of the great majority 
of microorganisms into the tissues. On the other hand the 
numerous glandular structures, sebaceous and sudoriferous, 
and mucous, are often the site of bacterial growth. From such 
foci invasion of the parenteral tissues by bacteria frequently 
occurs. Thus develop acne and folliculitis. A like protective 
power on the part of the epithelium of the lining of cavities 
and glandular structures is by no means so well developed, 
especially if there be an adjacent collection of lymphatic tissue. 
Numerous experiments have proved (Hess), for instance, that 
bacteria pass through the mucosa of the intestine and enter 
the lymphatic and blood streams, in the absence of any dis- 
cernible lesion of the epithelium; there is no doubt that thus 
occur many infections with the B. tuberculosis, as well as 
typhoid fever. 
The most susceptible portion of the body to infection is, 
apparently, the lymphatic tissue of the nasopharynx, espe- 
cially the tonsils, and the appendix vermiformis. Here, as 
the result chiefly of the deep indentations (crypts) or follicles 
and the macerating effect of the moisture which covers the 
surface, as well as the changes brought about by bacterial 
growth, the protective property of the epithelium is overcome 
and microorganisms find entrance into the lymphatic tissue. 
Thus in addition to the well-recognized and readily appreciated 
affections such as acute tonsillitis (streptococcus and pneumo- 
coccus infections), diphtheria and Vincent's angina, entrance 
to the tissues by this route is probably exemplified in many 
instances of scarlet fever and other acute infections, e.g., cere- 
brospinal meningitis, acute anterior poliomyelitis, influenza, 
leprosy and tuberculosis. Since many of the microorganisms 
producing these pathologic conditions are normally present in 
the mouth, their parenteral invasion is known as autoinfection. 
Similarly, bacteria which gain entrance through the appendix 
may be carried to the duodenum and gall bladder. 54 
INFECTION, IMMUNITY, AND INFLAMMATION 
In order that infection may take place, it is necessary that 
not only must pathogenic bacteria invade the tissues, but in 
addition they must be capable of multiplication. Actual in- 
fection, therefore, depends upon the focal presence of viable 
parasitic bacteria in tissues in which reactive processes are not 
stimulated, or being stimulated prove inadequate. It must be 
recognized that there occurs normally, in such situations as 
the tonsils, a constant adaptation of the cells to changes in- 
duced by the entrance of bacteria into the tissues. So long 
as this adaptation is adequate and sufficient protective activity 
is demonstrated by the tissues, no infection occurs. If, on the 
other hand, there be local loss of resistance, owing to trauma, 
vascular constriction (cold and exposure), or constitutional 
depletion of reactive forces, bacteria which gain entrance may 
obtain a foothold even though under normal conditions of the 
host their proliferation would be impossible. 
It is evident that the bactericidal properties of the serum and 
tissues can be directed against bacterial cells only insofar as 
they can be brought in contact. Unfortunately, however, it 
is not necessary for the multiplication of bacteria that they 
be in localities supplied by actively resistant powers. It is 
thus possible for pathogenic bacteria to remain viable and 
to grow upon the surface of the body, and of the nasopharynx, 
or within such tubes as the alimentary and genitourinary 
tracts, without being subjected to adequate resistance on the 
part of the tissues. Such bacteria are a constant source of 
danger to the individual host, in the event of his resistance 
being lowered from any local or constitutional cause, and, 
also, to those with whom he comes in contact, through the 
medium of droplet infection, water contamination, etc. Indi- 
viduals who harbor pathogenic bacteria, although not them- 
selves suffering from disease' in any noticeable way, are known 
technically as "carriers." CHAPTER III 
IMMUNITY AND IMMUNIZATION 
Introduction 
Purpose of Immunological Study.-"The fundamental task 
of immunology is to investigate the reaction of the living 
organism to the invasion of foreign material. In the higher 
organisms this reaction, so far as we know at present, takes 
two forms; it manifests itself both in the phagocytic activity 
of certain special cells and in the production of certain sub- 
stances known as antibodies" (Weil1). 
As has been already indicated, an appreciation of the chem- 
ical nature and biologic habits of bacteria and other patho- 
genic microorganisms is essential if the physician or surgeon 
is to understand the role played by them in the production of 
disease. The complementary science to the bacteriology of 
disease is that which deals with the means at the disposal of 
the body, through the exhibition of which the latter guards 
its tissues against infection, and overcomes and eliminates 
invading organisms once these have become established. In 
addition, the experimental investigations of more recent years 
have proved that the tissues may employ the same means to 
protect themselves against the harmful effects of certain non- 
viable foreign colloidal substances, more particularly proteins. 
The science which attempts to identify such processes, to 
analyze their nature and manner of action, and to apply for 
therapeutic and diagnostic purposes the data thus obtained, 
is known as immunology. The state of the animal body, by 
virtue of which it is protected against injurious agencies, is 
termed immunity. The process as the result of which the 
body becomes immune is termed immunization. 
1Well: Jour. Immunol., 1916-17, ii, 399. 
55 56 
INFECTION, IMMUNITY, AND INFLAMMATION 
For many years the science of immunology dealt exclusively 
with the means at the disposal of the body for guarding its 
tissues against infection and for the elimination of invading 
microorganisms. With the discovery of the phenomenon of 
anaphylaxis, it became evident that, to a considerable extent, 
the fact that bacteria and protozoa are viable proliferating 
microorganisms is, from the immunologist's point of view, 
incidental. 
Gradually it has become more and more apparent that the 
science of immunology deals with the reaction of the tissues 
to the parenteral presence of protein substances, particulate 
or in solution. The viewpoint of the immunologist at the 
present time, therefore, embraces not only the reaction of the 
tissues (either by the elaboration of soluble intra- or extra- 
cellular substances-antibodies-or by cellular and vascular 
inflammatory reactions) to invasion or infection by living 
microorganisms, but also such phenomena as serum sickness, 
asthma, eczema, pollenosis (hay fever), and perhaps such con- 
ditions as traumatic fever, and many degenerative lesions. 
More recent observations suggest that traumatic shock and 
acute intestinal obstruction are closely related to certain im- 
munologic phenomena. 
It is at once apparent that, under our definition of immu- 
nity, we include those means at the disposal of the body, by 
virtue of which it is protected against:-(1) the harmful ef- 
fects of nonviable foreign substances, and-(2) infection by 
living proliferating microorganisms. 
The science of immunology seeks to determine: 
(a) The nature of the properties at the disposal of the 
body by virtue of which it guards itself against infection, and, 
conversely, the nature of the state of the body as the result 
of which the individual is susceptible to infection. 
(b) The manner in which these properties are exalted in the 
natural cure of infection. 
(c) Artificial means whereby the natural development of 
protective properties may be augmented, whether for the pur- IMMUNITY AND IMMUNIZATION 
57 
pose of protection against infection, or in order that bacteria 
already established in the tissues may be eradicated. 
(d) Methods for the identification of specific properties of 
the body tissues, more particularly of the serum, in the diag- 
nosis of present or past infection, or for the purposes of 
prognosis. 
As the result of the study of the above questions, the atten- 
tion of the immunologist has been directed to: 
(e) The effects upon the host of the parenteral entry into 
its tissues of heterologous proteins and their derivatives, e.g., 
horse serum, plant pollen, etc. 
(f) The alterations which take place in the constitution of 
such heterologous proteins following their introduction into 
the tissues. 
(g) Attempts to determine the nature and manner of action 
of the deleterious agents, which are responsible for clinical 
manifestations of tissue irritation and injury, in such obscure 
phenomena as traumatic shock, acute (and chronic) intestinal 
obstruction, and certain types of tissue degeneration. 
The first two subdivisions of the subject apply to the phe- 
nomena which accompany infection and the subsequent course 
of infectious disease, and, as such, form the basis of all rational 
and scientific study of such affections. The second two sub- 
divisions attempt to apply such knowledge in a practical 
manner in the diagnosis of disease and the treatment of in- 
fected individuals. Sections E and F are the result of the 
natural progress of the science in the direction of an apprecia- 
tion of basic principles. Section G serves to indicate an en- 
tirely new function of the immunologist, which has been 
assumed in recent years. Previously employing known irri- 
tant substances, he has attempted to determine their effects 
upon the tissues. He has now undertaken to attempt to 
prove the nature of unknown agencies, the activity of which 
has hitherto been recognized only through their effects upon 
the tissues. 
Historical.-Several outstanding phenomena of disease are 
appreciated by all observers and are being constantly exem- 58 
INFECTION, IMMUNITY, AND INFLAMMATION 
plified in clinical experience. For instance, it is a matter of 
daily experience to note that the majority of infections run a 
definite and, usually, self-limited clinical course, and that, fol- 
lowing a state during which the infecting microorganisms 
gradually increase in number, there ensues some change in the 
relationship of host and invader, as the result of which the 
latter is eventually exterminated. Furthermore, the occur- 
rence of one infection and the consequent reaction thereto is 
followed, in the majority of instances, by a protection from, 
or at least an altered reaction to, subsequent invasion by the 
same bacterium. 
The recognition of such facts as the natural cure of dis- 
ease, and the relative protection of the individual against 
subsequent infection which is conferred by previous attacks 
of infectious disease, is not recent. For many centuries it 
has been the custom among certain of the Oriental peoples 
purposely to infect young and healthy individuals, in order 
that they might be rendered insusceptible to such diseases 
during after years. Such a method was at one time (1718) 
introduced into England from the East by Lady Montague, 
as a means of combating the spread of smallpox. The inher- 
ent danger of such a method both to the individual and to 
those about him, was sufficient to prevent this method of im- 
munization from becoming generally adopted. 
The principle of such immunization methods was, however, 
before long put to a safe and practical use by Edward Jenner 
(1796) in his employment of the virus from cases of cowpox 
for the immunization of human beings. It is of interest to 
note that Jenner established his procedure after a study of 
the subject by the method of observation followed by experi- 
ment. From the time of Jenner almost a century passed with- 
out further notable investigation into the principles of immu- 
nology. It remained for Pasteur (1880), who started the work 
as a chemist, to open up the field for the tremendous amount 
of work which has been undertaken in all parts of the world 
during the past four decades. 
Pasteur engaged himself in the investigation of the broad IMMUNITY AND IMMUNIZATION 
59 
principles of acquired immunity. He was successful in prov- 
ing that, by means of the inoculation of microorganisms, at- 
tenuated by means of aging (chicken cholera), cultivation at 
high temperatures (anthrax), and by desiccation (rabies virus), 
it was possible to induce changes in the tissues of animals as 
the result of which the latter are able to withstand inocula- 
tion by virulent strains. 
The next step in the development of the science was due to 
the recognition of the fact that it is possible to transfer, by 
means of the serum of immunized animals, protective sub- 
stances to other normal animals. The names of those who did 
pioneer work in this direction include Salmon and Theobald 
Smith (hog cholera), Brieger and Kitasato (tetanus), and 
Roux and Yersin (diphtheria). 
In Germany, Paul Ehrlich commenced work upon the phe- 
nomena of immunization. His experiments led him to formu- 
late the first series of hypotheses which attempted to indicate 
the underlying principles. Inasmuch as Ehrlich's terminology 
has impressed itself well-nigh indelibly upon the literature of 
immunology, and since part at least of his hypothesis has been 
very generally accepted, a short review of his opinions, inso- 
far as these refer to the mode of development of antibodies, 
is included. 
Ehrlich postulated in this regard that the living cell, whether 
of animal or vegetable origin, is enabled to anchor and assim- 
ilate nutritive foodstuffs only by virtue of its possessing an 
affinity for certain specific molecules present in its environ- 
ment. To such affinities the name receptor was given. Not 
only are such receptors capable of combining with and anchor- 
ing useful nutritive substances, but also of fixing noxious or 
harmful bodies, such as bacterial toxins. According to this 
hypothesis, it is only such tissue cells as have specific recep- 
tors for specific toxins that are susceptible to injury therefrom. 
Ehrlich's next step was to assume that the power of producing 
such receptors is practically unlimited, and that, once the cell 
has been stimulated to produce them, it continues to do so for 
a very considerable length of time. Stimulation is accom- 60 
INFECTION, IMMUNITY, AND INFLAMMATION 
plished by the simple effect of exhausting those receptors nor- 
mally present. Furthermore, Ehrlich assumed that, when in- 
creased production of receptors is stimulated, large numbers 
of the latter are discharged out of the cell and find their way 
into the general circulation. Receptors thus circulating have 
the same affinity as those attached to the cells, and, since 
it is believed that the junction of receptor and toxic prin- 
ciple results in detoxication of the latter, the circulating re- 
ceptors protect the fixed receptors from the injurious effects 
of injected irritants. 
For a number of years it appeared as if each new record of 
experiment rendered an understanding of the subject more 
complex, and suggested an ever-increasing number of factors. 
The last few years, however, have given evidence of a ten- 
dency towards simplification and simplicity. The theories of 
Ehrlich have been productive of an enormous amount of work, 
and have directly and indirectly stimulated most valuable 
experiment and observation. The attempt, however, of ob- 
servers to harmonize their actual findings with the demands 
of Ehrlich's hypotheses have occasionally led to an apparently 
unnecessarily complicated and, at times, false conception of 
the fundamental principles of immunologic reactions. 
The multiplication of terms to describe substances identi- 
fied in the serum of immune persons and animals, and the em- 
ployment of diagrammatic representation which has sug- 
gested the conception of synthesis rather than cleavage as the 
predominating principle in immunity reactions, have made it 
unnecessarily difficult for the student and practicing physician 
to gain a proper grasp of the subject. 
In 1883 Metchnikoff commenced the publication of a series 
of articles which had for their chief purpose a more adequate 
appreciation of the importance, in the elimination of tissue 
irritants, of phagocytic activities on the part of blood and tis- 
sue cells. Metchnikoff, who had studied and attained eminence 
as a zoologist, was prepared to find in the migratory cells of 
the human and higher animal tissues an exhibition of those 
properties which characterize the life activity of the unicel- IMMUNITY AND IMMUNIZATION 
61 
lulae. With such a preparation for the study of reactions of 
the tissues to irritants, it is easy to understand why Metchni- 
koff believed the phagocytic properties of the cells to be al- 
most exclusively important. Since Ehrlich's postulates indi- 
cated that the immune state was due almost exclusively to the 
presence in the body fluids of soluble circulating substances 
(antibodies), and since Metchnikoff claimed greater impor- 
tance for direct cell activities, there arose two schools of 
workers known as exponents of the humoral and cellular2 
theories, respectively. That both cellular phagocytosis and 
antibody production are necessary for the practical preven- 
tion of, or cure of, infectious diseases, is obvious, so that, to 
a great extent, the division of workers into so-called humoral- 
ists and cellularists has largely ceased. It seems to have been 
proved that, provided the body cells, more particularly the 
polymorphonuclear leucocytes, can be induced to take part 
in protective reactions, their functioning is more effective and 
economical of body effort than is the simple exhibition of 
antibody activity. 
In 1905, and the following year, experiments were described 
by Richet (France), Rosenau and Anderson (United States), 
Otto (Germany), and von Pirquet (Austria), which dealt with 
a phenomenon which, though previously noted,3 had not at- 
tracted the attention it deserved, and its importance had not 
been appreciated. The essential feature of this phenomenon, 
to which the name of anaphylaxis was given by Richet,4 is 
the fact that normal animal tissues are so altered by the 
parenteral5 introduction of a foreign protein that, although 
the majority of such proteins are harmless (in moderate doses) 
to normal animals, the injection of even minute doses of the 
same protein after the lapse of twelve or more days is followed 
'It should be noted that the humoral and cellular theories here con- 
sidered are in no way related to the modern humoral and cellular theories 
regarding' the site of the anaphylactic reaction which are discussed at length 
in a later chapter. 
'Theobald Smith, Flexner, etc. 
'Richet's first observations were published in 1902. 
'Parenteral by routes other than the digestive tract. 62 
INFECTION, IMMUNITY, AND INFLAMMATION 
by the immediate manifestation of symptoms of severe (com- 
monly fatal) intoxication. 
The discovery of the phenomena of anaphylaxis and allergy 
has had such a vital influence upon the science of immunology 
that a proper conception of their nature is essential, if we 
are to be able to follow the recent, and future, advances in 
the knowledge of immunity processes. At the present time 
no subject is interesting immunologists more than that which 
has to do with the relationship of anaphylaxis or hypersensi- 
tiveness to immunity. That these phenomena must be related 
to one another has been accepted by practically all observers, 
and much time and effort have been expended and many ex- 
periments performed by numerous investigators in the hope 
of proving this relationship. 
For many years immunologic experiments were carried out 
almost exclusively in vitro. Bacteria and sera were placed 
together in test tubes, and on the results observed were based 
inferences as to the processes which take place in the living 
body. 
Gradually more and more experiments have been under- 
taken upon living animals. Von Pirquet pointed out the 
necessity for such form of investigation and devised the 
method of introducing the irritant into the superficial layers 
of the skin and noting the nature, and extent, of the reac- 
tion exhibited. In association with Schick he studied inocu- 
lation with the causative agents of vaccinia, smallpox, measles 
and recurrent fever, and the effect of injections of serum, 
streptococcus suspensions, tuberculin and mallein. Upon the 
results of these experiments they based their hypothesis that 
substances, of the nature of antibodies, react with the foreign 
materials and that the products of such reaction function as 
poisons to the tissues, and consequently provoke hyperemia 
and cellular accumulation. The period of incubation is the 
time necessary for the formation of antibodies. 
Other important experiments of recent years bearing upon 
our understanding of immunity principles, are those which 
have studied the physiology of cell digestion and utilization IMMUNITY AND IMMUNIZATION 
63 
of protein foodstuffs, and the appreciation of the fact that 
digestion may, under certain circumstances, be accomplished 
parenterally (i.e., within the tissues as opposed to enteral or 
intestinal digestion). With the development of our knowledge 
of biologic chemistry, along the lines indicated above, the 
names of Fischer and Abderhalden are associated. 
Elementary Facts Regarding Immunity 
Immunity: A Relative Term.-Immunity is usually but a 
relative term. When the statement is made that a certain 
animal or person is immune, it does not necessarily follow that 
it is impossible to induce infection of such individuals, but 
that, under normal conditions of health, they are not injured 
by doses of microorganisms which are potent to produce grave 
injury, or even death, in other individuals. Thus it is found 
that, although the hen is not susceptible to infection by even 
large doses of pneumococci, so long as the hen be otherwise 
in normal health, if the hen be exposed to the injurious action 
of prolonged cooling in cold water, infection may be produced. 
Similar phenomena indicating the effect of exhaustion as 
the result of loss of sleep, insufficient food and overwork, as 
well as the deleterious action of chilling of the body, are com- 
mon in clinical experience. How frequently is the alcoholic 
debauch, with its accompanying improper feeding and expo- 
sure to cold and wet, followed by the onset of a pneumococcal 
or streptococcal infection, even though these two micro- 
organisms are among those against which the adult members 
of our urban communities are immune to a considerable 
degree. 
Natural Immunity.-If a mouse and a hen be inoculated 
with cultures of the same virulent pneumococcus, it will be 
noted that, whereas the mouse rapidly dies with symptoms of 
grave intoxication, the hen is unharmed by the inoculation. 
Such experiments prove that certain animals are not suscep- 
tible to the injurious action of bacteria which are pathogenic 
for members of another species. Such animals are said to 
possess natural immunity to infection. Examples of such 64 
INFECTION, IMMUNITY, AND INFLAMMATION 
natural immunity are not uncommon in man, as for instance 
against hog cholera, chicken cholera, coccidiosis, leueoplasmo- 
dia, and other blood parasites. 
Although such phenomena are commonly grouped under 
the heading of natural immunity, it is probable that the insus- 
ceptibility of the individual to infection is due, not so much 
to the presence of "immune bodies" in the body fluids, as to 
inability of the infecting agent to proliferate under the con- 
ditions which exist in the tissues of the host. 
Acquired Immunity: Active and Passive.-Clinical experi- 
ence proves that an attack of measles, or typhoid fever, usu- 
ally protects the individual from subsequent infection with 
the same virus or bacillus. Such an insusceptibility to, or 
protection from, infection is acquired through the active stim- 
ulation of the body's resisting properties, and is therefore 
called active acquired immunity. A similar active immuniza- 
tion may be induced by means of the injection of nonvirulent 
or dead microorganisms, as in the prophylactic immunization 
against rabies by Pasteur's method, or the employment of dead 
typhoid bacilli after the manner of Wright. To such methods 
of immunization the qualifying term artificial may well be 
applied. 
By means of the employment of the blood fluid (serum) 
obtained from animals, or human beings, which have been 
themselves actively immunized, either as the result of the 
natural cure of disease, or through artificial inoculation, nor- 
mal individuals may be rendered immune for a longer or 
shorter length of time (seven to twenty days). The resistance 
to infectious agents obtained in this way is known as passive 
or transferred immunity. CHAPTER IV 
GENERAL PRINCIPLES OF ACQUIRED IMMUNITY AS 
EXEMPLIFIED BY TOXIN-ANTITOXIN REACTION 
Soluble antibodies, which may be demonstrated in the serum 
of immune animals, may be divided into two fundamental 
groups, namely, (1) simple antitoxin formation, and (2) those 
responsible for the more complicated phenomena of proteolysis. 
In addition, there is exhibited by the tissues the property of 
development of tolerance to the irritant products of the pro- 
teolytic reaction. Since the means whereby toxins are inac- 
tivated is a simple one, and is readily studied experimentally, 
and since many of the basic immunologic principles are ex- 
emplified by this phenomenon, it is the first to receive our 
attention, and is employed to illustrate certain broad prin- 
ciples which characterize all immunity reactions. 
In Chapter II, it was noted that certain bacteria, notably 
B. diphtheriae, B. tetani, and B. botulinus, produce soluble 
poisonous substances which are known as toxins. Similar 
toxins may also be derived from a number of vegetable sub- 
stances, e.g., abrin and ricin, and are contained in the poison 
of snake venom. One of the qualifying characteristics of the 
poisons, which are called true toxins, is that they give rise to 
the production of specific antisubstances known as antitoxins, 
when injected in sublethal doses into suitable animals. 
Toxins bring about the death of certain cells in consequence 
of their ability to combine with these cells. This fact is of 
basic importance, especially since it indicates the reason 
specific diseases are characterized by the involvement of dif- 
ferent organs or groups of cells. By means of the employment 
of known chemical poisons, e.g., strychnine, atropine, mor- 
phine, phenol, arsenic, etc., it is possible to injure various tis- 
sues in a specific manner and, thus, to imitate the pathologic 
states encountered in clinical experience. 
65 66 
INFECTION, IMMUNITY, AND INFLAMMATION 
Again, the symptomatology of serum sickness, which is 
caused by an absolutely nontoxic and innocuous foreign pro- 
tein, such as horse serum, can in many respects not be differ- 
entiated from that of an acute infectious disease. This fact 
indicates the great importance of the processes that are in- 
volved in the reaction of the cell to foreign protein, and is 
essential to the comprehension of some of the most common 
phenomena of clinical medicine, as well as of cellular physi- 
ology in a general sense. 
Briefly, the theory underlying such facts is that certain 
cells are composed in part of specific unsatisfied or unstable 
molecules, which have an affinity for certain substances, which 
may be essential to the life of the cell and therefore beneficent, 
as for instance the amino-acids and other foodstuffs, or may 
be noxious and lead to degenerative phenomena or even death 
in the cells and thus to incomplete or deranged function on 
the part of the organ to which they belong. It is to these un- 
satisfied molecules that Ehrlich has given the name receptor. 
At the first stage in the elimination of foreign protein, the 
cells must first anchor it; such fixation of the antigen stimu- 
lates the production of new receptors (antibodies), and finally 
the foreign protein disappears from the body. In the absence 
of antibodies, it may remain in the body indefinitely. The 
absence of affinities on the part of any of the tissue cells ap- 
pears to govern the resistance of white mice and rats to 
diphtheria toxin. "Thus we may conclude that antibody for- 
mation or the immune response is the necessary condition 
for the elimination of certain proteins from the body, and that 
the prime requisite for antibody formation is the anchoring 
of the foreign protein by the cells" (Weil). 
There are instances of foreign proteins which the cells of 
the body do not appropriate out of the circulation. This has 
been shown to be true especially of certain toxins. Thus, 
green lizards, the marsh turtle, and some other animals, are 
not susceptible to intoxication by tetanospasmin. It is char- 
acteristic of these animals that the toxins remain in their 
circulation for a long period of time, even months. Thus ACQUIRED IMMUNITY 
67 
Metchnikoff found that a lizard, kept at a temperature of 
20° C., and injected with an amount of toxin sufficient to kill 
500 mice, at the end of two months still retained in its blood 
such an amount of the poison that 0.1 c.c. caused fatal tetanus 
in a mouse. 
Such animals are insusceptible to the effects of the poison 
for the reason that their cells do not anchor it. They retain 
the foreign substance in their blood for an indefinite period, 
simply because their excretory organs are not adapted to 
eliminate it. "But there is still a third, and most important, 
corollary of this inability of the cells to fix the poison, namely, 
the complete absence of antibodies from their blood at any 
time whatever subsequent to the injection of the poison" 
(Weil).6 
Only such cells as have the property of combining with 
heterologous protein molecules are injured by them. Simi- 
larly, only such cells as normally possess affinities (receptors 
or normal antibodies) are concerned in the elaboration of free 
antibodies. 
Toxin-Antitoxin Immunity.-If we inject a guinea pig with 
less than the minimal lethal dose7 of bacillus tetani or its tox- 
ins, allow seven to ten days to elapse, and repeat the inocula- 
tion, employing one and one-half times the M.L.D. of mate- 
rial, the guinea pig may, perhaps, show symptoms of tetanus, 
but is not destroyed by the injection. 
Similarly, we may inject a guinea pig, intraperitoneally or 
otherwise, at intervals of one week or ten days, with six grad- 
ually increasing doses of tetanus toxin, commencing with one- 
half or one-quarter the M.L.D., and eventually employing 
four or five times that amount. In such an experiment it is 
found that, ten days after the last dose, it is possible to inject 
the animal with several times the M.L.D. without provoking 
fatal intoxication. 
We have thus proven that the repeated introduction of 
"Weil: Jr. of Imm., Vol. 11, 1916-17, p. 408. 
'The smallest dose of a toxin which is sufficient to bring: about the death 
of the animal within a certain definite time (twenty-four hours) is termed 
the minimal lethal dose (M.L.D.). 68 
INFECTION, IMMUNITY, AND INFLAMMATION 
toxins into the body of a guinea pig is followed by the devel- 
opment, on the part of the animal, of an insusceptibility to 
its injurious action. Such an insusceptibility is known as 
acquired, in contradistinction to natural immunity. As will 
be presently seen, acquired immunity develops not only against 
toxins but against protein substances and against bacterial 
cell bodies. 
It is evident that there may be two explanations of the 
development of this insusceptibility of the animal to the harm- 
ful effects of a specific toxin. Either the receptors, owing to 
whose presence the cells absorb the toxic substance and thus 
bring about their own injury, have been used up, or ex- 
hausted, in absorbing, or neutralizing, the original sublethal 
dose; or substances may have been produced which render 
the toxin inert and incapable of injuriously affecting the cells. 
It is possible to prove that, usually at least, this form of im- 
munity is due to the development of an increased number of 
receptors or antibodies, which possess an affinity for the spe- 
cific toxin, whose presence in the tissues has stimulated their 
production, and, also, that these bodies are present in the 
body fluids. In consequence they neutralize, or detoxicate, 
the injected, or focally developed, toxin, and so protect the 
tissue cells. 
Passive Immunization.-If the guinea pig, employed in the 
last experiment, be bled, and the serum obtained be injected 
intraperitoneally into a normal guinea pig, the latter animal 
will be protected against the effects of a subsequent injection 
of toxin. This may be proved by injecting the animal which 
received the dose of serum from the immune8 pig with one 
and one-half times the M.L.D. of tetanus toxins. We find that 
the animal may sicken, but does not die. 
By such an experiment we demonstrate that it is possible 
to transfer protection against the action of tetanus toxin to 
a normal animal, by means of the introduction into its tissues 
of the serum of an immune animal. Such immunity as is thus 
8An animal which is protected as the result of the presence of specific 
antibodies present in its body fluid is said to be immune. ACQUIRED IMMUNITY 
69 
produced is termed 4'passive" or "transferred" immunity, 
and is clinically exemplified by the employment of antidiph- 
theritic, or antitetanic, serum for prophylactic, or therapeutic, 
purposes. 
The protection of the immune animal against the pathogenic 
action of bacterial toxin is evidently due to the presence in 
its serum of substances capable of rendering inactive the toxic 
material. This can be further demonstrated by an experiment 
such as the following, in which the toxin and the serum, which 
contains the inactivating substance (antibody), are mixed in 
vitro. 
If three cubic centimeters of the serum from an immune 
animal be added to twice the M.L.D. of diphtheria toxin in a 
test tube and the whole be placed at a temperature of 37° C. 
for one hour, the subsequent injection of the mixture into a 
normal animal is followed by no manifestations of toxemia. 
Toxin and antitoxin mixtures, if suitably graded quantita- 
tively, are thus shown to be capable of neutralizing one an- 
other in the test tube. Furthermore, it can be proved that 
the introduction parenterally into the animal body of toxin- 
antitoxin mixtures is followed by an immune body produc- 
tion on the part of the tissues of the animal inoculated.9 
A further fact is demonstrated by these experiments, namely, 
that, as the result of stimulation of the antibody-producing 
centers through the medium of a specific irritant, e.g., tetanus 
toxin, there is induced an increased production of immune 
bodies. That the production of antitoxins is of a specific na- 
ture is proved by the fact that, if snake venom or ricin be 
employed in the immunization of an animal, antitoxins will 
be produced which possess the property of neutralizing the 
poison, for instance cobra venom, by the injection of which 
the animal had been immunized, but which are not potent to 
protect the animal from poisoning by diphtheria toxin. 
This characteristic of specificity of immune substances is 
common to all types of antibodies; it must be noted, however, 
9This fact is made use of clinically in that it is now recommended that 
children that prove themselves by the Schick reaction to be susceptible to 
diphtheria toxin be immunized in this way. 70 
INFECTION, IMMUNITY, AND INFLAMMATION 
that against irritants, which are closely related to one an- 
other biologically, there are produced to a greater or less ex- 
tent common (group) antibodies. Thus antitoxic serum against 
cobra venom is found to be active, though less potent, against 
the venoms of other snakes. 
So far as has been discovered, the antitoxins present in 
immune animals are identical in nature with those present in 
normal individuals, and vary only in their marked increase 
in concentration. The same rule applies, moreover, to all 
antibodies about to be described. 
More important is the observation that, following the ces- 
sation of the stimulus, the elaboration of antibodies continues, 
so that eventually, at the end of one or two weeks, there accu- 
mulates in the serum of the animal a very considerable excess 
of antibody over the probable needs of the individual. 
If an animal which has received an injection of less than 
one M.L.D. of toxin be inoculated, or its serum tested, in 
vitro or by transferred immunity experiments, within two or 
three days after the first injection with toxins, it is found that 
no protective property of the serum can be demonstrated. 
After the third day, the presence of antibodies may be proved. 
An increase in antibody content continues gradually, and 
reaches its maximum from twelve to twenty days after injec- 
tion. According to Knorr10 one diphtheria toxin unit injected 
into the horse may lead to the production of 100,000 antitoxic 
units. 
From the time of greatest production of antibodies, there 
occurs a gradual decrease in the amount of recognizable anti- 
body. The length of time during which immune bodies remain 
in the tissues, in excess of the normal, is apparently by no 
means a constant one; the sera of many animals apparently 
remain potent up to 10 years or longer, whereas others appear 
to lose their antibody content after a lapse of but a few weeks. 
From this brief study of antitoxic bodies several outstanding 
facts are recognized, which, it may be remarked, are charac- 
teristic of other immune bodies as well: 
"Knorr: MUnchen. med. Wchnschr., 1898, p. 321, 362. ACQUIRED IMMUNITY 
71 
1. The animal body is capable of producing, if properly 
stimulated, antitoxic substances which are potent to destroy or 
neutralize certain types of poisons (toxins), especially those 
produced by bacterial activity. 
2. The proper stimulation to elicit such a response consists 
in the parenteral introduction, in sublethal amounts, of the 
specific toxin against which antitoxins are desired. 
3. Once such antitoxin production has been induced, it con- 
tinues, so that eventually the serum of an animal may possess 
many million antitoxic units as compared with the normal. 
4. The permanence of the antitoxic substance in the serum 
of immunized animals is a more or less variable one, in many 
instances persisting for a term of years. 
In the foregoing experiments we have dealt with the produc- 
tion of antibodies (antitoxins) against certain nonviable poison- 
ous substances known as toxins. The interaction of these 
substances is a perfectly simple one and can be carried out 
equally well in the test tube as in the animal body, nor is it 
necessary that the serum used be fresh. 
Certain of the physical characteristics of antitoxins are in- 
dicated as follows: 
(1) They are soluble substances. 
(2) They withstand desiccation. 
(3) When in the dry state, the antitoxic properties of sera 
are maintained for years unaltered. 
(4) The antitoxin substances are contained almost exclu- 
sively in the globulin portion of the serum. 
(5) The antitoxic property of serum is not altered by trypsin 
digestion. 
The changes in the constitution of the blood serum as the 
result of immune body development must be extremely subtle 
in character. They cannot be noted by physical or chemical 
means, such as alteration in the index of refraction, specific 
gravity, or reaction. 
That the combination of toxin and antitoxin, as of other 
immune bodies, is not a chemical binding but rather a physical 72 
INFECTION, IMMUNITY, AND INFLAMMATION 
absorption (colloidal reaction) seems probable from the fact 
that it is possible to inactivate completely the antitoxic prop- 
erty of a serum by treatment with a quantity of toxin con- 
siderably less than the amount which might be neutralized by 
the same quantity of antitoxin. This is shown by the following 
type of experiment. Suppose the potency of an antitoxic 
serum be such that 2 c.c. are sufficient to prevent death 
following the introduction of two M.L.D. of toxin; it is found 
that, if 2 c.c. of this serum be treated with a quantity of toxin 
equal to one-quarter the above amount the subsequent addi- 
tion of one M.L.D. will not be neutralized. In consequence 
death of the animal follows injection of the mixture. To this 
characteristic of antibodies the term absorption (Bordet) has 
been applied. 
Bordet has likened the relation of toxin and antitoxin, or 
the affinity of antitoxin for toxin, to that which occurs when 
blotting paper is placed in a dye such as methylene blue. For 
instance, it is found that, if a dyestuff be prepared of such 
a strength that 100 pieces of paper will be tinted a given blue, 
if all are introduced at once, this does not take place if the 
papers are added seriatim. The first pieces, in this event, take 
up from the concentrated solution more than their share of 
the dyestuff, so that by the time the last pieces are added, 
practically no tinctorial property will remain to the solution. CHAPTER V 
ANAPHYLAXIS-HYPERSENSITIVENESS 
Introduction 
In 1839 Magendie noted that rabbits which had been in- 
jected with egg albumen died after a repetition of the injec- 
tion. A typical anaphylactic experiment was performed and 
described in 1894 by Flexner. "Animals," he wrote, "that 
had withstood one dose of dog serum would succumb to a 
second dose after a lapse of some days or weeks, even when 
this dose was sublethal for a control animal." 
In 1896 Theobald Smith observed that occasionally guinea 
pigs appeared to lose their natural resistance to certain for- 
eign substances, notably serum, when reinjected with small 
quantities of a like material. 
It was not, however, until 1906 that the results of investiga- 
tions were published almost simultaneously by Rosenau and 
Anderson, by Richet, and by Otto, which served to establish 
the essential principles which underlie such protein hyper- 
sensitiveness. These observers proved that, after the lapse 
of a period of two weeks following the parenteral introduction 
of numerous substances of a protein nature, which are harmless 
to untreated animals, subsequent injection of the same material 
is followed by striking manifestations of intoxication or death. 
It appeared at first, that this phenomenon was to invalidate 
many of the observations which had previously been made upon 
immune processes, since the essential characteristic of the im- 
munity reactions, which had been studied, consisted in an in- 
susceptibility to, or resistance against, infection of the tissues. 
More extensive experiments and observations have, however, 
harmonized many of the apparent discrepancies between the 
two reactions, and gradually the importance of the phenomenon 
73 74 
INFECTION, IMMUNITY, AND INFLAMMATION 
of anaphylaxis or hypersensitiveness, and its relationship to 
immunity has been recognized. 
Certain facts concerning the phenomenon of anaphylaxis are 
of the utmost importance if the practicing physician, or sur- 
geon, is to be able to analyze the clinical manifestations of 
disease, and to intelligently guide, and assist, the tissues to 
prevent infection, or to eliminate invading microorganisms. 
The important features of the phenomenon of hypersensitive- 
ness, are that certain tissue cells, stimulated by the presence 
in the tissues of .foreign proteins, elaborate an antibody, through 
the activity of which subsequent introduction into the tissues 
of the same protein, is followed by symptoms of marked irri- 
tation, or intoxication. Although the manifestations of tissue 
irritation differ in different animals, it is a fact that in each 
species of animal the same clinical phenomena and autopsy 
findings are uniformly exhibited, no matter what the source 
or nature of the protein.1 
Gradually it has been more and more appreciated, so that 
now it is universally recognized that anaphylaxis is an im- 
munologic phenomenon. This being the case, it must be pre- 
sumed, that the process serves a useful purpose in the physi- 
ology of the body. 
The observations of Rosenau and Anderson permitted them, 
as early as 1908, to summarize the fundamental characteristics 
of the anaphylactic reaction in the following way. Horse 
serum, which is harmless in moderate doses to normal guinea 
pigs, if injected into these animals, in even minute doses, 
renders them after a definite interval of time, hypersensitive 
to subsequent injections of the same material. The interval 
necessary for the development of the hypersensitive state with 
doses of 1 to 2 c.c. is about ten days. The reaction is specific: 
injections of horse serum sensitize to horse serum only. The 
sensitive condition is transmissible from mother to offspring. 
The young of sensitized mothers are susceptible to anaphy- 
lactic shock at the first injection of horse serum. 
The anaphylactic state can be induced by injections of 
1This subject is dealt with in greater detail in the Chapter on Nature of 
the Antigen. ANAPHYLAXIS-HYPERSENSITIVENESS 
75 
various animal and vegetable proteins, and also by extracts 
of various bacteria. The bacteria used by Rosenau and Ander- 
son in their experiments included colon, anthrax, typhoid, and 
tubercle bacilli. 
Richet, some years previously, had given the name "ana- 
phylaxis," in contradistinction to "prophylaxis"-or protec- 
tion from-to any evidence of hypersensitiveness exhibited 
by an animal. Rosenau and Anderson2 accepted the term 
"anaphylaxis" to designate the phenomenon investigated by 
them. Since this time the reaction has been commonly known 
by this name. 
In 1905 von Pirquet and Schick3 published the first of their 
classic studies upon serum disease and vaccinia4 reactions. 
They recommended the use of the term "allergie" (alios- 
altered, ergia-reaction), to indicate the phenomenon studied 
by them, which it will be seen is apparently identical in 
principle with that studied by Rosenau and Anderson. Since, 
for the most part, the phenomena noted by these observers 
consisted of visible vascular and cellular reactions, the author 
has reserved the term allergy to indicate the focal morphologic 
reaction which occurs when hypersensitive animals, or men, 
are injected into the soft tissues of the body with an antigenic 
protein. 
Definitions 
In order that the subsequent experiments and discussions 
may be rendered more comprehensible, the terms employed by 
the author are defined. This is particularly necessary since 
2Rosenau and Anderson : U. S. Pub. Health & M. H. S. Hyg. Lab. Bull., 
29, 1906; 30, 1906; 36. 1907: 45, 1908. Jour. Med. Res., 1906, xv, 1907, 
xvi; also Jour. Infect. Dis., 1907, iv; 1908, v, quoted by Zinsser). 
3Vpn Pirquet and Schick: Die Serum Krankheit, Deutlcke, Leipzig, 
1905. Also Miinch. med. Wchnschr., 1906, liii, 67. 
'In 1798 Jenner in his "Inquiry into the Causes and Effects of Variolae 
Vaccinae" described the phenomena which characterize the allergic reaction 
as noted by von Pirquet. He wrote: "It is remarkable that variolous 
matter, when the system is disposed to reject it, should excite inflammation 
on the part to which it is applied more speedily than when it produces the 
smallpox. Indeed it becomes almost a criterion by which we can determine 
whether the infection will be received or not. It seems as though a change 
which endures through life had been produced in the action or disposition 
to action in the vessels of the skin ; and it is remarkable, too, that whether 
this change has been effected by the smallpox or the cowpox, the disposition 
to sudden cuticular change is the same on the application of variolous 
matter." 76 
INFECTION, IMMUNITY, AND INFLAMMATION 
the concepts designated by the same term differ somewhat 
when applied by different writers. 
Anaphylaxis5 is a phenomenon in animals which have re- 
ceived parenterally6 small doses of7 heterologous proteins (al- 
buminous substances) as a result of which they become ab- 
normally sensitive to the subsequent introduction of the same 
antigen. This abnormal sensitiveness is manifested by the on- 
set of marked symptoms of tissue irritation following the in- 
jection of foreign protein, in amounts which are harmless to 
the normal animal. 
The animal subject to anaphylaxis is said to be sensitized, or 
hypersensitive; sensitization is induced by means of a primary 
or sensitizing parenteral injection. 
The fulminant or explosive anaphylactic reaction noted in 
animals, particularly guinea pigs, is known as anaphylactic 
shock, or immediate anaphylaxis (Auer and Lewis), and occurs 
when the sensitized animal is injected after a definite period of 
time, known as the incubation period, with a second dose of 
the same protein. The protein which is injected, in order to 
prove the existence of the anaphylactic state, is known as the 
massive, exciting or toxic dose. 
Delayed anaphylaxis signifies the late development, that is, 
one or more hours after injection, of symptoms which may or 
may not lead to death of the animal. 
•In Wells' opinion the following criteria must be met if the phenomenon 
following parenteral injection is to be considered as anaphylaxis: 
1. The observed toxicity of the injected material must depend upon the 
sensitization of the animal; i. e., the substance must not produce similar 
symptoms in nonsensitized animals. 
2. The symptoms produced must be those characteristic of anaphylactic 
intoxication as observed in the usual reaction with typical soluble proteins, 
being, therefore, the same for all antigens with the same test animal, but 
differing characteristically with each species of animal. 
3. It should be possible to demonstrate passive sensitization with the 
serum of sensitized animals. 
4. It should be possible to demonstrate typical reactions in the virgin 
guinea pig uterus strip. 
5. It should be possible to demonstrate amelioration or prevention of the 
bronchial spasm in guinea pigs by proper use of atropin and epinephrin. 
6. The possibility that the observed symptoms are caused by capillary 
thrombosis or embolism must be excluded. 
7. After recovery from anaphylactic shock there should be exhibited 
a condition of desensitization under proper conditions. 
•Parenteral, 1. e., by routes other than the digestive tract In practice 
the expression indicates introduction of a substance into the tissues, as in 
intravenous, subcutaneous, intraperitoneal, or intrathecal injections. 
'Foreign substances derived from sources other than the animal's own 
tissues. ANAPHYLAXIS-HYPERSENSITIVENESS 
77 
Allergy3 (von Pirquet and Schick), as the name implies, is 
an altered reaction (inflammatory in nature) in the hypersen- 
sitive animal which is noted at the site of injection, following 
the focal introduction of antigen. 
Anaphylactin9 or allergin is the substance (antibody) assumed 
to be present in the tissues of sensitized animals which acting 
upon, or reacting with, its specific protein antigen is respon- 
sible for the manifestation of the anaphylactic phenomenon. 
It is to this substance that I have applied the term Immune 
Body of the First Order (1st Order Body). 
The term anaphylatoxin (Friedberger), or split product, is 
applied to the toxic substance which is believed by many 
observers to be developed in the tissues as the result of the 
interaction of antigen (foreign protein), first order body (an- 
aphylactin), and alexin (complement). It is worthy of note 
that the terms "endotoxin" (Pfeiffer) and "apotoxin" 
(Richet), signify in all probability the identical substance. 
Anaphylactic or hypersensitive animals which have received 
sublethal doses of the specific protein so that they do not react 
to immediate further injections with the same protein are said 
to be desensitized. 
In the literature regarding anaphylaxis much confusion has 
arisen regarding the use of the terms antianaphylactic, desen- 
sitization, and the condition referred to as refractory, and im- 
munity. The author believes that it is wise to dispense with 
the use of the terms "refractory" in speaking of the anaphy- 
lactic reaction. As a general rule the animal is said to be in a 
refractory condition, when in consequence of the administration 
of a sublethal dose of protein antigen the hypersensitive animal 
has been desensitized. 
Desensitization is due to exhaustion of the antibodies present 
in the tissues, which through their reaction with the protein 
8Wells employs the term allergy to cover all those manifestations of 
altered reactivity which cannot be included under the heading anaphylaxis. 
Anaphylaxis is looked upon by him as forming one particular form of 
allergy. 
'Southard and Gay, It must be noted, have employed the term anaphylactin 
to designate the remnant of foreign protein circulating in the blood follow- 
ing a sublethal shock. Southard and Gay: Jour. Med. Research, 1907, xvi; 
1908, xviii; 1908, xix. 78 
INFECTION, IMMUNITY, AND INFLAMMATION 
antigen are responsible for the manifestations of the symptoms 
of tissue irritation which characterize anaphylactic shock. 
The term "antianaphylaxis" has been used to indicate both 
the phenomenon of desensitization, and also the tolerant state 
induced in animals in consequence of repeated parenteral in- 
jections of a protein antigen. 
If the term "antianaphylaxis" is to be employed at all, 
it should, in my opinion, be reserved to designate the latter 
condition (tolerance). 
In general the author believes that an understanding of the 
subject is more easily acquired if the terms (a) "anaphylaxis" 
or "hypersensitiveness," (b) "desensitization" and (c) "toler- 
ance" be employed to designate, respectively, the following: 
(a) Hypersensitiveness, the state of the animal tissues in 
consequence of which it is hypersensitive to the introduction 
of small doses of specific protein antigen. 
(b) Desensitization, a condition in which, in consequence of 
a sublethal injection of the specific protein antigen which 
exhausts the bodies responsible for the anaphylactic reaction, 
the animal, for the time being, is comparable to the normal 
animal; and is not susceptible to anaphylactic shock. 
(c) Tolerance, that state of the tissues, acquired in conse- 
quence of repeated sublethal injections of protein antigen, in 
which the animal, even after a lapse of two or more weeks, is 
tolerant or immune to the introduction of doses of the protein 
antigen which suffice to induce fatal anaphylactic shock in 
hypersensitive animals. CHAPTER VI 
FUNDAMENTAL PHENOMENA CHARACTERIZING 
HYPERSENSITIVENESS, DESENSITIZATION 
AND TOLERANCE IN THE GUINEA PIG 
In this introductory chapter an attempt is made to briefly 
review the established characteristics of the phenomena of 
anaphylaxis and tolerance, and, also, to indicate an hypothesis, 
regarding their relationship to one another and to immunity 
processes in general, which, in my opinion, is sufficiently well 
supported by experimental data and clinical observations to 
deserve adoption as a working theory. 
When the animal tissues are injected with a foreign protein, 
at first there is no apparent effect. After an incubation period 
(eight to fourteen days) the further introduction of the same 
protein, (or the presence of a residual quantity of material 
from a previous introduction) is followed by manifestations of 
irritation or intoxication of the tissues. 
If the route of administration be suitable, and the size of 
the intoxicating dose sufficient, explosive symptoms, respira- 
tory or circulatory in character, or both, ensue. Such fulmi- 
nant symptoms occur more particularly if the route of ad- 
ministration be intravenous. If the protein be injected into 
the soft tissues, or into serous cavities, focal inflammatory 
reactions occur. With suitable dosage febrile reactions of 
varying intensity may be provoked. 
Striking and interesting phenomena are exhibited when 
half-grown guinea pigs are subjected to repetition of injections 
of the same antigen at varying periods. Guinea Pig A may be 
given within five days of the first injection from 0.2 to 2.0 
c.c. of sheep serum without the manifestation of untoward 
symptoms. 
Guinea Pig B fourteen days after a preliminary (sensitizing) 
79 80 
INFECTION, IMMUNITY, AND INFLAMMATION 
injection of 0.5 c.c. of sheep serum receives an intravenous 
injection of 0.5 c.c. of sheep serum. Within a period of one 
or two minutes the animal exhibits symptoms of grave irrita- 
tion and dies within from three to eight minutes in a state of 
asphyxia. 
The above constitutes the typical anaphylactic experiment 
in the guinea pig, and is known as anaphylactic shock. 
Guinea Pig C is injected upon the same day as B with an 
intraperitoneal dose of 0.2 c.c. of sheep serum. There follows 
no immediate onset of symptoms, but within a period of one- 
half to one hour the animal is found to be suffering from 
malaise; the animal's hair stands on end and the pig huddles 
itself in a corner; it may shiver, and is obviously unhappy. 
The temperature at first drops slightly, and then shows an 
elevation above the normal; a transient leucopenia occurs, 
which is followed by leucocytosis. A scant purulent exudate 
may be recovered from the peritoneal cavity. The animal com- 
pletely recovers within twenty-four hours or less. 
We have thus discovered that if an animal which is sus- 
ceptible to anaphylactic shock be given a small dose of protein, 
by a route which permits of but slow absorption into the cir- 
culating blood stream, a simple febrile reaction accompanied 
by malaise may be elicited. 
Upon the following day Guinea Pig C is injected in a man- 
ner (intravenous), and with an amount of serum, similar to 
Guinea Pig B. No symptoms of intoxication are exhibited. 
This and other experiments prove that this animal has been 
desensitized by the injection of a sublethal dose of the specific 
antigen; while in this state the animal is said to be refractory. 
Guinea Pig D receives, upon the fourth day after the original 
injection of 0.2 c.c., an intraperitoneal injection of 2.0 c.c. of 
sheep serum, and, thereafter, a like amount on three or more 
successive occasions at intervals of five or six days. 
After a lapse of from twelve to sixty days after the last 
injection, a dose, similar to that introduced into Guinea Pig 
B, is injected intravenously. No reaction takes place. 
This experiment proves that repeated sublethal doses of an 
antigenic protein render the recipient animal tolerant (or 81 
HYPERSENSITIVENESS, DESENSITIZATION AND TOLERANCE 
immune) to doses of the antigen, which are fatal to animals 
rendered hypersensitive by the injection of but one moderate 
dose of the antigen. 
Another animal prepared in the same way as Guinea Pig 
D is injected intravenously with a larger dose, 3.0 c.c. of 
sheep serum. Typical anaphylactic shock with death super- 
venes. 
Thus it is demonstrated that an animal which receives re- 
peated doses of protein, although tolerant to doses of antigen 
which are fatal to hypersensitive animals, remains hypersensi- 
tive to this protein, but that larger exciting injections must 
be employed in order to provoke anaphylactic shock. 
Another pig, Guinea Pig E, fourteen days after a sensitizing 
injection of 0.2 c.c. of sheep serum, is bled to death and its 
serum recovered. The serum thus obtained is injected into 
a normal pig with the result that the latter becomes highly 
hypersensitive. In order that such a transference of the an- 
aphylactic state may be brought about, it is necessary to inject 
from two-thirds to the total amount of serum recovered. 
Similarly, it is found that if the serum of a tolerant animal 
treated in the manner of Guinea Pig D be injected into a 
normal pig, the latter becomes passively hypersensitive. It 
is found, moreover, that but a very small amount of serum, 
e.g., 0.1 c.c., is necessary. 
The paradoxical phenomena are thus noted, that the serum 
of an animal whose hypersensitiveness is easily demonstrated, 
contains but a small number of units of the anaphylactic anti- 
body, whereas the serum of a tolerant animal contains a very 
large number of units of the same antisubstance. 
Obviously the animal D is not desensitized as was C, but 
has developed a state which may be described as tolerance 
or immunity to the protein antigen. At the same time it is 
noted that the more tolerant (immune) an animal may be, the 
greater is its potential hypersensitiveness. 
In a later chapter it is shown that it is possible to transfer 
passive tolerance to a normal animal by the employment of 
large doses of the serum from the repeatedly injected animal 
and also to confer passive tolerance upon an actively sensitized 82 
INFECTION, IMMUNITY, AND INFLAMMATION 
animal such as Guinea Pig B. How, then, can the relationship 
of these two conditions of hypersensitiveness and tolerance 
(immunity) be explained? 
In answer to this question the author suggests the follow- 
ing hypothesis. The parenteral introduction of heterologous 
proteins into the animal body is followed by the elaboration, 
by certain tissue cells, of specific antibodies, which so react 
with the protein antigen that an irritant1 substance is devel- 
oped. In consequence of the presence in the tissues of this 
anaphylactic antibody, the animal is hypersensitive to the 
reinjection of the specific protein as the result of whose pri- 
mary injection the production of the antibody was stimulated. 
Subsequent parenteral introduction of the same antigen in 
sublethal doses results in the stimulation of the production of a 
second order of antibody2 which is potent so to alter the irri- 
tant which arises from the reaction between the antigen and 
the first order body as to render it innocuous to the body cells. 
For purposes of description I have called the anaphylactic 
antibody the "immune body of the first order." The substance 
capable of so altering the product of the reaction between 
antigen and first order antibody that it no longer acts as an 
irritant is termed the "immune body of the second order." 
The immune bodies of the first order, which are responsible 
for the exhibition of the hypersensitive state, conform to the 
characteristics of other antibodies, such as antitoxins, ambo- 
ceptors, agglutinins, and precipitins. 
(a) They are produced as a result of stimulation. 
(b) They are specific for the antigen employed. 
(c) They are produced in excess of the immediate require- 
ments of the organism. 
1This irritant substance may be identical with the poisonous split product 
of Vaughan, or the "anaphylatoxin" of Friedberger. 
it remains to be definitely proved that the toxic split protein 
prepared by Vaughan is the same as the product of the antigen first order 
antibody reaction, there is much to indicate their identity. If such be the 
case, it has been proved that it is possible to induce the production of the 
antibody of the second order without the elaboration of those of the first 
order. Vaughan has performed experiments in which he shows that re- 
peated injection of the poison prepared according to his method is followed 
by a state (tolerance) as the result of which the animal is able to "bear 
three or four times the minimum lethal dose," and that, furthermore, such 
an animal is not sensitive to the whole protein from which the poison was 
recovered; nor is it possible to sensitize the animal with the split product 
alone. HYPERSENSITIVENESS, DESENSITIZATION AND TOLERANCE 
83 
(d) They are present in the body fluids, as proved by in 
vivo and in vitro experiments. 
(e) They may be transferred passively from hypersensitive 
to normal animals. 
(f) They are relatively permanent. 
By the repeated introduction parenterally into the tissues 
of protein antigen, the animal becomes "immune" or tolerant 
to further injections. The second order antibodies, which are 
responsible for tolerance, do not conform to the characteristics 
of the other antibodies. They are apparently less specific than 
antitoxins or first order antibodies; they are not produced in 
great excess; they do not persist as long as the first order 
bodies. 
The relationship of the first and second order antibodies to 
one another is as follows: The anaphylactic or hypersensitive 
first order body always appears first. The first order body 
is always present in excess of the amount of second order 
body, and always persists longer. Tolerant animals are, there- 
fore, always potentially hypersensitive. This is shown by 
allergic reactions and passive anaphylaxis as well as by means 
of direct experiments. The tolerant animal, also, ultimately 
becomes anaphylactic. The second order or tolerant anti- 
bodies may be exhausted by the introduction of a suitable 
dose of the protein, and the animal remains hypersensitive. 
Although the author does not personally believe that the 
objections to the hypothesis of toxic protein split products 
(anaphylatoxin), arising out of the reaction between anaphy- 
lactin and antigen, as brought forward by Weil, Schultz, 
Zinsser and others, are sufficiently direct to invalidate the 
hypothesis, he is anxious that the argument regarding the 
nature, source, and site of production (intra or extracellular) 
of the toxic substance, which is responsible for the manifesta- 
tions of tissue irritation which characterize the phenomenon of 
anaphylaxis, should not obscure the important facts, that, 
whereas a single small parenteral introduction of protein 
renders the recipient animal anaphylactic, repeated doses of 
the same protein are followed by the development of a state 
of tolerance. CHAPTER VII 
MORE DETAILED DESCRIPTION OF THE PHENOMENA 
OF ANAPHYLAXIS IN THE GUINEA PIG 
AND OTHER ANIMALS 
If a guinea pig weighing 250 grams be injected, intra- 
venously, or intracardially, with 4 c.c. of normal horse or 
goat serum, the animal, although it may exhibit symptoms of 
irritation for a short time, does not die and rapidly returns to 
normal. 
A second guinea pig of a similar weight to the one employed 
for the above experiment, is injected by a parenteral route 
with a small quantity, 0.1 c.c. or even less, of heterologous 
serum, and after the lapse of a period of two weeks receives 
a reinjection of 2 c.c. of the same serum directly into the 
blood stream; within from thirty to ninety seconds the onset 
of anaphylactic symptoms is exhibited. 
Clinical Phenomena of Shock in the Guinea Pig.-The ani- 
mal at first appears excited, then commences to twitch, 
scratches its nose and may cry out; there rapidly follow 
symptoms of respiratory difficulty. The animal commences 
to "buck"; within one or two minutes there is evidence of 
weakness or paralysis of certain muscles, especially of the 
hind legs. There is, commonly, also, an involuntary discharge 
of urine and feces. The animal falls upon its side, and suffers 
from marked expiratory dyspnea. This is accompanied by a 
gradually increasing cyanosis. Death supervenes in from 
ninety seconds to six or seven minutes from the time of injec- 
tion. The heart frequently continues to beat for several min- 
utes longer. 
Other characteristic phenomena consist of a very marked 
fall in blood pressure and drop in temperature. The comple- 
ment content of the blood is decreased, according to Fukuhara, 
and others, to from one-half to one-third the normal quantity. 
84 ANAPHYLAXIS 
85 
The leucocytes in the peripheral blood are diminished and 
the coagulation time of the blood is much increased. 
Similar acute reactions may be induced in the guinea pig 
by the intracerebral or postorbital route of injection of the 
toxic dose.1 
If, instead of the intravenous route, the injection be made 
into the peritoneum, the sequence of events is somewhat less 
striking. Larger doses of protein antigen must be employed 
and death rarely takes place in a shorter time than five or 
six minutes. If small doses be employed in this way, the 
animal, after the exhibition of mild symptoms of tissue irri- 
tation, appears to be fairly normal. If the dose be sufficiently 
large, the pig dies in a comatose condition, from five minutes 
to two hours after injection. It may be noted that guinea 
pigs, which recover from the intravenous injection of protein 
antigen, rapidly return to their normal state of health and 
rarely succumb to the late onset of symptoms. 
Anderson2 has described the ordinary type of reaction which 
occurs when the antigen is injected into the peritoneal cavity 
as follows: "Within five or ten minutes the guinea pig be- 
comes restless and agitated; it runs about the cage and some- 
times utters sounds of distress; then there appear manifesta- 
tions of peripheral irritation and respiratory embarrassment. 
This is shown by scratching at the mouth, coughing, sneezing, 
rapid and irregular respiration. An exceedingly characteris- 
tic feature of the respiratory involvement is that, at intervals, 
the animal makes an unusually deep inspiratory effort with 
the diaphragm, resulting in a marked sinking at the lower 
end of the sternum. The stage of excitement is soon followed 
by one of paresis, or in some cases complete paralysis. The 
animal is unable to stand and, if it attempts to do so, it 
falls upon its side." 
Guinea pigs in a condition of complete paralysis may fully 
recover, but within a short time convulsions usually begin and 
'The postorbital route of injection has been employed extensively by 
Baldwin and Krause and in their hands has proved a most successful and 
reliable technic. It is used as the method of choice by Besredka. 
2Anderson: Bull. Johns Hopkins Hosp., 1910, xxxi, 218. 86 
INFECTION, IMMUNITY, AND INFLAMMATION 
are almost invariably the forerunner of a fatal termination. 
Occasionally in guinea pigs, which are not very sensitive, 
the onset of the symptoms, following an intraperitoneal injec- 
tion, may be delayed thirty or forty minutes, but in only a few 
instances has Anderson noted the onset of symptoms delayed 
as long as an hour. 
Postmortem Findings in Guinea Pigs Dying in Anaphylactic 
Shock.-Autopsy upon guinea pigs which die as a result of 
anaphylactic shock demonstrates, almost invariably, the fol- 
lowing characteristic lesions: The whole body is cyanotic, 
the lungs are distended and collapse but little when the thorax 
is opened; they are pale, somewhat grayish pink in color, and 
usually show beneath the pleura numerous irregular ecchymotic 
patches varying in size from 0.5 to 4.0 millimeters in diam- 
eter. Occasionally, also, there is a more extensive hemorrhage, 
and the pleural cavity is found filled with fluid blood. Sub- 
epicardial hemorrhages are also frequently seen as well as, in 
one case noted by the author, diffuse hemorrhage into the 
liver substance. The longer the animal survives the injection, 
the greater is the evidence of venous congestion of the ab- 
dominal organs. 
In the guinea pig, subcutaneous injection of lethal doses of 
foreign sera are usually followed by an absence of symptoms 
for a period of one hour. If death takes place, it occurs, as a 
rule, at the end of from four to six hours. If the animal sur- 
vives, recovery is evident between the sixth and the twelfth 
hour. The symptoms manifested under such circumstances 
are : an unwillingness on the part of the animal to move about; 
it lies down, shivers, respiration becomes more and more feeble, 
and gradually in a fatal case ceases entirely. At autopsy upon 
animals which have died as the result of this delayed reaction, 
fatty degeneration of the parenchymatous organs and multiple 
hemorrhages throughout the body are characteristically found 
(Longcope, Boughton). 
Accompanying nonfatal shock, following intraperitoneal and 
subcutaneous injection of the protein antigen, there occurs a ANAPHYLAXIS 
87 
febrile reaction and the blood exhibits an increase in the num- 
ber of circulating leucocytes-leucocytosis. 
In the guinea pig sensitiveness may, as has been stated, be 
induced by way of the intravenous, intraperitoneal or sub- 
cutaneous routes, and also as in man, by the digestive and res- 
piratory tracts. No other laboratory animal has shown itself 
to be so readily affected as the guinea pig, although, as stated 
above, the rabbit, dog and man, as well as goats, sheep, horses, 
mice, chickens and pigeons, are susceptible. In other words, 
the reaction constitutes a phenomenon of general biologic 
significance. 
Anaphylaxis in the Rabbit.-Rabbits are less susceptible to 
the fulminant rapidly fatal shock which has been just described 
in the case of the guinea pig. Relatively larger doses of serum 
must be employed in order to bring about a fatal termination 
in these animals. Death is, moreover, gradual and is not char- 
acterized by dypsnea but by gradual collapse as evidenced by 
fall in blood pressure and lowering of body temperature. 
Subcutaneous injections of foreign serum into hypersensitive 
animals are followed by the development of an urticarial erup- 
tion similar to that which characterizes serum sickness in man. 
Under suitable conditions of hypersensitiveness on the part of 
the animal and size of protein dose, local edema, necrosis, and 
abscess formation may occur at the site of injection-Arthus' 
phenomenon. The maximum reaction is exhibited at the end 
of twenty-four hours. 
Arthus3 also studied anaphylactic shock in the rabbit; the 
following is taken from his description of the reaction. 
A rabbit which has been previously treated with antigen 
three times, received 2 c.c. of horse serum in the auricular 
vein. After one minute the animal began to sneeze, became 
anxious and restless. It lay on the abdomen, the respiration 
became frequent, loose passages of the bowels occurred, then 
the rabbit rolled onto its side, threw its head back and kicked 
its extremities. It then became quiet and ceased breathing. 
'Arthus: Comp. Rend, de la Soc. Biol., Iv, 817; loc. cit., Iv, 1478. Re- 
union biol., Marseille, June, 1903. 88 
INFECTION, IMMUNITY, AND INFLAMMATION 
After a short pause a few respirations occurred, and the animal 
finally died about four minutes after the injection. 
Anaphylaxis in the Dog.-The dog is more difficult to sensi- 
tize than is the guinea pig. Repeated parenteral injections of 
the antigenic protein are usually necessary. In the dog the 
symptoms of anaphylaxis are, as a rule, less violent than those 
which take place in the guinea pig, and death occurs less 
frequently. Following intravenous injection there is evidenced 
great restlessness, the animals frequently scream, and pro- 
nounced evidence of weakness rapidly supervenes. In those 
cases which succumb the animal falls over on its side, and 
may remain motionless for hours. Defecation and urination 
take place, apparently involuntarily. Dyspnea is not marked 
but there is a rapid and marked fall in blood pressure. 
This fall usually begins about forty seconds after the be- 
ginning of the intravenous injection of the antigen. The pres- 
sure usually reaches a minimum of about 25 mm. of mercury 
by the end of ninety seconds. In shocks of moderate severity, 
the pressure remains at this low level for about twenty min- 
utes, and then gradually increases, reaching normal in from 
one to two hours, depending on the severity of the reaction. 
With highly sensitized dogs, injected with relatively large 
doses of the specific protein, little or no recovery takes place, 
the pressure remaining at a low level until the death of the 
animal, which usually occurs in about forty minutes. (Man- 
waring.4) 
This phenomenon has been found to be due to a peripheral 
action on the part of the poison upon the splanchnics. (Biedl 
and Krause.5) 
In those animals which recover, once the blood pressure 
begins to rise, the other symptoms rapidly disappear. In most 
cases blood is discharged from the intestines and there may be 
developed a condition of hemorrhagic inflammation in both the 
large and small gut, which Schittenhelm and Weichdardt6 have 
4Manwaring, Chilcote, and Hosepian: Jour. Am. Med. Assn., Feb. 3, 1923, 
Ixxx, 303. 
5Biedl and Krause: Wien. Klin. Wchnschr., 1910, No. 11; also "Kraus 
u. Levaditi Handbuch," Erganzungsband 1. 
'Schittenhelm and Weichdardt: Deutsch, med. Wchnschr., 1911. 19. ANAPHYLAXIS 
89 
termed "enteritis anaphylactia.'' Leukopenia is constantly 
present, due chiefly to a loss of mononuclears. There is, too, 
a marked lengthening of the coagulation time of the blood. 
In the dog, the onset of symptoms, even though the intra- 
venous route of administration be employed, is usually delayed, 
although, as shown by Weil,7 this is not necessarily the case. 
Weil prepared dogs by two injections with 5 c.c. of horse 
serum. After an interval of two or three weeks an intravenous 
injection of 20 c.c. of the antigenic serum was employed as 
the toxic dose. "The symptoms following upon this second 
injection are characteristic and almost constant. The dog 
immediately vomits or retches, and generally has a number 
of evacuations of the bowels. Within five minutes it begins 
to stagger and to drag its hind legs. Following this prelim- 
inary state comes a period of severe collapse, which, as a rule, 
appears within ten minutes of the injection. The animal lies 
on its side and does not respond to any stimulation. Some 
animals show at first, either a fine tremor of the muscles of 
the extremities, or a coarse clonus composed of short excur- 
sions. These soon cease, and the animal is practically immo- 
bile, except for the respiratory movements. Respiration is 
either shallow or rapid, or labored, and gives the impression 
of marked dyspnea. During this stage, which terminates, 
usually within thirty minutes, with the death of the animal, 
the other characteristic features of anaphylaxis make their 
appearance. The blood pressure sinks so low that the carotid 
pulse can scarcely be detected. If blood is aspirated from 
the veins it is found to have lost its coagulability to such an 
extent that it remains fluid for several days." 
Postmortem Findings in Dogs Dying of Anaphylactic Shock. 
-At necropsy, extreme dilatation of the vessels draining the 
upper abdominal viscera is noted. 
The liver, spleen, and kidney are congested, and the veins 
of the upper intestinal tract are distended. The bowel wall, 
in rapidly fatal reactions, is deep purple in color. 
'Weil: Jour. Immunol., 1916-17, ii, p. 527, 528, 538. 90 
INFECTION, IMMUNITY, AND INFLAMMATION 
Anaphylaxis in the Cat.-The cat is relatively insusceptible 
to anaphylactic shock. Anderson and Frost,8 however, were 
successful in passively sensitizing guinea pigs with the serum 
from a cat. 
Anaphylaxis in the Goat.-Zinsser9 has experimented with 
goats and observed both serum and bacterial anaphylaxis. In 
these animals the symptoms consist of general trembling, 
weakness, labored respiration, and involuntary evacuation of 
urine. 
Anaphylaxis in Man 
Severe Immediate General Reactions-Anaphylactic Shock 
Two cases of anaphylactic shock in man that terminated 
fatally I have observed, personally, and the notes of one case, 
hitherto unpublished, have been placed at my disposal. 
In those cases in which the splanchnic type of reaction pre- 
dominates, there occur collapse, pallor, tachycardia, thready 
pulse, pain in the epigastrium and over the heart, increased 
intestinal peristalsis, rectal tenesmus, vomiting and blood con- 
centration. 
The respiratory type of reaction is characterized by chok- 
ing sensations, cyanosis, asthmatic dyspnea and arrest of 
respiration. 
The cutaneous phenomena consist of erythema, urticaria 
and "angioneurotic" edema. 
There follows an abstract of a case, report10 of a healthy 
man who collapsed following the hypodermic administration 
of a relatively small dose, 5 c.c. of horse serum, and who died 
with symptoms during life identical with those which occur 
in anaphylactic shock in the dog. Necropsy findings were 
identical with those which are found in the guinea pig. 
Case 1.-Sgt. E., aged thirty, was given 5 c.c. of serum subcutaneously 
over the right pectoralis major at 11:15 a. m., Sept. 1, 1916. He was in 
good general condition, the wounds from which he was suffering being 
trivial. 
"Anderson and Frost: Tran. Cong. Am. Phy. and Surg., 1910, p. 431. 
"Zinsser: Infection and Resistance, p. 370. 
10Gurd, F. B„ and Emrys-Roberts, E.: Fatal Anaphylaxis, Lancet, April 
3, 1920, 1, 763. ANAPHYLAXIS 
91 
At 1:30 p. M., he commenced to vomit and a bloody diarrhea developed. 
This gastrointestinal disturbance was accompanied by a moderate degree 
of collapse. At 5 P. m. his pulse was 104 and his temperature 102.8° F. 
He complained of moderate headache and thirst; there was slight general- 
ized abdominal tenderness, but no rigidity. He made no complaint of 
respiratory distress, despite the fact that he was cyanosed and restless. 
The skin was "goose-fleshed" and covered with a mild erythema. 
Until 11 p. M. his condition remained somewhat relieved. No treatment 
was instituted as his condition was not considered alarming. 
At 11 P. m., after a slight vomiting attack, the collapse became very 
severe. He became pulseless at the radials; the heart beat rose to from 
160 to 170 per minute. He became extremely cyanosed, and restlessness 
increased. During the night, stimulation was pressed to the utmost. Pitu- 
itary extract, 1 c.c. to the dose, was given every three hours. One-thirtieth 
grain of strychnine was given at 11 P. M. and its administration was con- 
tinued in doses of one-fortieth grain every three hours. He received three 
pints of saline subcutaneously during the night, and oxygen was given 
almost continuously up to the time of death. Except for the fact that he 
became quieter and more comfortable while receiving oxygen, there was no 
response to stimulation. 
At 6 A. M., September 2nd, these notes were made: "Pulse is absent 
at the wrist, heart rate 180 and feeble. There is a very marked purplish 
discoloration (cyanotic erythema) of the whole body. This discoloration 
disappears on pressure and returns very slowly. The extremities are cold. 
There has been no return of vomiting or diarrhea." 
Death ensued at 10:30 a. m., apparently due to cardiac failure second- 
ary to drop in blood pressure. Respiration during the last three hours 
of life was at the rate of from 48 to 54 per minute. 
Necropsy was performed four hours after death. Owing to the presence 
of pleural adhesions, the lungs were squeezed considerably in the process 
of removal, nevertheless, they were voluminous and downy, except over the 
posterior parts which were boggy and dark in color. The lungs were red- 
dish gray and were covered over the whole surface with innumerable sub- 
pleural collections of deep purple colored blood. Those patches11 varied 
in size from 1.5 to 5 mm. 
Beneath the parietal pleura there was a small number of similar hem- 
orrhagic spots. 
The cut surface of the posterior parts exuded a considerable amount 
of bloody, frothy fluid; the anterior portions showed a dilatation of the 
alveoli and numerous small purplish red spots. 
The upper intestinal tract showed slight capillary dilatation. 
Insofar as we were able to discover, the patient had not 
been previously wounded nor had he received, at any other 
MThese hemorrhagic patches were typical of those found in anaphylaxis 
in the guinea pig. 92 
INFECTION, IMMUNITY, AND INFLAMMATION 
time, injections of horse serum. That he was an individual 
presenting a natural hypersensitiveness to horse serum is, 
therefore, a fair assumption. 
Inasmuch as the patient in Case 2 was not under observa- 
tion by any one medical officer during the period intervening 
between the time of serum injection and his death, there is 
perhaps some slight doubt regarding the nature of the col- 
lapse that resulted. Correspondence was, however, carried 
on with those officers who had seen the patient prior to admis- 
sion to the Casualty Clearing Station, and the note made by 
the officer in charge of the patient at the main dressing sta- 
tion of the Field Ambulance stated that " while in the field 
ambulance, he appeared to be suffering slightly from shock, 
but in other respects was in good condition when he left the 
main dressing station." 
Case 2.-S. M. was admitted to the Casualty Clearing Station, six hours 
after being wounded and three hours after receiving serum injection at the 
field ambulance. 
His injury consisted of a perforating wTound of the upper third of the 
left thigh behind the bone. No large vessel was injured; there was no 
evidence of hemorrhage; the sciatic nerve was intact and there was no 
important laceration of muscle. Briefly, the wound w-as of such nature 
as was considered trivial, infection excluded. 
He was admitted at 8:30 A. M. On admission his condition was seen to 
be extremely grave; he was pale, slaty in color, and mentally stuporous; 
The mucous membranes were not blanched. The pulse was barely per- 
ceptible at the radials; the rate was over 140 per minute. There was no 
respiratory difficulty, no urticaria; the extremities were cold. 
The patient was placed under an incandescent heater with the foot of 
the bed raised, but no improvement occurred. On the contrary, he ap- 
peared to become worse. An operation was, therefore, performed at 2 p. M., 
as it was feared that despite negative findings he might be suffering 
from a deep-seated gas gangrene. 
Examination of the wound was made under gas and oxygen anesthesia. 
An intravenous saline solution containing 7.5 per cent glucose, to which 
was added 8 mm. of epinephrin, was given. Fifteen hundred c.c. was thus 
injected. During the induction of anesthesia (nitrous oxide and oxygen) 
collapse of the patient became almost complete. Respiration ceased and 
the heart sounds became almost inaudible. The rate of flow of the intra- 
venous solution was increased, and artificial respiration was employed. 
This resulted in return of signs of life. After 500 c.c. of the solution 
had been injected, there was marked improvement in the patient's con- ANAPHYLAXIS 
93 
dition, and at the time of the completion of the injection of the total 
quantity of 1,500 c.c. the patient's pulse rate was 86, of good pressure, 
and his color was good. He became mentally alert and remarked that he 
had felt ''all in," but that he was now fit. The operation itself con- 
sisted simply in an incision of the affected part for purposes of examina- 
tion. Carrel tubes were inserted. The whole procedure occupied but three 
or four minutes. Examination revealed no evidence whatever of gas gan- 
grene. 
He returned to the ward in good condition, "practically normal in ap- 
pearance, ' ' and remained fit for approximately thirty minutes, when he 
rapidly collapsed, and died at 4:30 p. m. Unfortunately, owing to pres- 
sure of work in the operating room, it was not possible to see him during 
this second period of collapse. 
Necropsy was performed thirty minutes after death. There were no 
positive findings other than enlargement of all the great and smaller veins 
in the splanchnic area. After removal of the heart, the right thorax filled 
immediately with fluid blood up to two-thirds of its capacity. Examina- 
tion of the leg confirmed the absence of gas gangrene. 
There is no doubt, in my opinion, that this was a case of 
fatal anaphylaxis following the subcutaneous administration 
of a small dose (presumably about 5 c.c.) of antitetanic serum. 
This belief is based upon the absence of any other cause of 
shock or infection, and upon the very prompt response to the 
glucose injection with its epinephrin content. At necropsy, 
as mentioned above, the only abnormality was the extreme 
content of blood in the veins and capillaries of the splanchnic 
area and the absence of clotting one-half hour after death. 
Boughton12 has reported a case (Case 3) of anaphylactic 
death, occurring in an asthmatic, following an intravenous 
injection of 1 minim of normal horse serum undiluted. 
Case 3.-"Within two minutes a typical attack of asthma supervened. 
He was given 10 minims of epinephrin intravenously with definite relief 
for about ten minutes." Four other similar doses were given, each gave 
relief for several minutes, but the patient died at forty-five minutes after 
the injection of serum. 
Necropsy was performed within half an hour after death. The face was 
cyanotic and the lips swollen. "The abdominal cavity showed intense 
injection of the vessels everywhere, being especially marked in the veins 
of the stomach, mesentery, gall bladder and appendix. The entire small 
intestine was bright red and dilated submucous vessels showed distinctly 
"Boughton, T. H.: Anaphylactic Death in Asthmatics, Jour. Am. Med. 
Assn., Dec. 27, 1919, Ixxiii, 1912. 94 
INFECTION, IMMUNITY, AND INFLAMMATION 
through the intestinal wall. The parietal peritoneum was markedly in- 
jected; no exudate was visible in the peritoneal cavity. 
"Both lungs were enormously distended and emphysematous. The left 
lung showed small areas of hemorrhage at the lateral portion of the lower 
lobe, about 4 cm. in diameter, with a gelatinous organizing exudate at 
this point. On section the lungs were found to be dry. Microscopically, 
the lungs showed passive hyperemia but no edema; there were a few small 
interstitial hemorrhages. ' ' Microscopic examination of the kidneys re- 
vealed the most marked changes: "The epithelium of the convoluted 
tubules was distinctly edematous and there was considerable degeneration 
and some necrosis; there was intense passive hyperemia. Interstitial 
hemorrhages were numerous but not extensive." 
McCallum.13 reports a case (Case 4) of fatal anaphylaxis 
following the prophylactic injection of diphtheria antitoxin, 
subcutaneously. 
Case 4.-The patient was a boy, aged eight, apparently healthy. Fol- 
lowing the injection of 2,000 units (amount of serum not stated), death 
occurred in five minutes. Two minutes after the injection was made, the 
boy made the complaint that "it had gone to his stomach." He ran out 
of the house to the privy in the back yard. One minute later he was 
heard calling, "Daddy, Daddy." His father immediately ran to his as- 
sistance and found him completely collapsed and apparently choking. His 
whole body was deeply cyanosed; he was pulseless. Artificial respiration 
was employed without avail. 
Necropsy was performed. No note regarding the condition of the lungs 
or splanchnic region is published. 
Patrick14 has reported three cases of anaphylaxis occurring 
in patients who received intravenous injections of horse serum 
in the treatment of bacillary dysentery. 
The following case well exemplifies nonfatal shock of the 
respiratory type in man following the subcutaneous introduc- 
tion of antigen. In addition it proves the possibility of 
desensitization by means of repeated small subcutaneous 
injections. 
Case 5.-Lieut. H. was admitted to the Casualty Clearing Station on 
account of asthmatic attacks, which the patient himself believed to follow 
proximity to horses. An effort was made to confirm his sensitiveness to 
horse protein, and to determine the degree of sensitiveness to horse serum. 
"McCallum, D.: Fatal Anaphylaxis Following Prophylactic Injection of 
Diphtheria Antitoxin Subcutaneously, Brit. Med. Jour., Nov. 8, 1919, ii, 596. 
"Patrick, C. A.: Anaphylactic Shock After Injections of Serum Intraven- 
ously, Brit. Med. Jour., July 28, 1917, ii, 114. ANAPHYLAXIS 
95 
At 11:30 A. m. Nov. 12, 1912, 0.25 c.c. of horse serum was injected 
intradermically into the skin on the outer border of the left upper arm. 
Fifteen minutes later there was an onset of coryza and an asthmatic at- 
tack occurred which increased for about twenty minutes. At its maximum, 
it was slightly to moderately severe. A marked swelling of the face and 
ears, more particularly of the eyelids, occurred to such a degree that he 
was unable to see. The lobes of both ears filled with fluid and hung well 
down on his neck. At the site of injection there was an edematous enlarge- 
ment, about the size and shape of a hen's egg, which hung down, having 
the appearance of a supernumerary breast. This reaction persisted, 
though gradually subsiding, for from four to six hours. 
The effect of this reaction to the injection was more marked than was 
anticipated and suggests that the dose used (0.25 c.c.) was unnecessarily 
large for the purpose of confirmation or diagnosis. 
The following day, November 13, at 11 a. it he was injected with) 0.15 
c.c. of horse serum subcutaneously; no reaction occurred. At 12:30 the 
same day he received 0.25 c.c. intramuscularly; no reaction either local or 
general took place. At 2 p. m. of the same day, he received 0.5 c.c. sub- 
cutaneously, again without reaction. 
The patient was unwilling to remain in the hospital longer, 
and seemed satisfied to have the cause of the asthma definitely 
established, hence it was impossible to attempt immunization. 
The experiment does prove a very great hypersensitiveness to 
horse protein in a patient who thought himself to be subject 
to asthma when in the presence of horses, and also the possi- 
bility of desensitizing by means of a dose of 0.25 c.c. of horse 
serum. 
The patient was discharged from the hospital with a note 
to the effect that prophylactic or therapeutic injections of 
horse serum should not be employed unless such a procedure 
was preceded by a desensitizing dose. 
For the following notes, of a similar case, I am indebted to 
Major John Fraser, M.C. 
Case 6.-The patient was wounded June 29, 1917. His injury con- 
sisted of a small perforating wound of the right upper arm. Five hundred 
units of antitetanus serum were administered at the field ambulance. Upon 
admission to the Casualty Clearing Station, three or four hours later, the 
patient was pulseless, his body was covered by a hyperemic rash, there 
was a generalized edema of the whole body and he was vomiting frequently. 
Blood count demonstrated; hemoglobin, 110 per cent; erythrocytes, 8,240,- 
000, and leucocytes, 25,000. 96 
INFECTION, IMMUNITY, AND INFLAMMATION 
Calcium lactate was given in doses of 15 grains, three times a day. 
Improvement in the patient's general condition followed after the third 
dose. 
The following day the patient's condition was satisfactory. Blood 
count showed: hemoglobin, 82 per cent; erythrocytes, 6,100,000, and leu- 
cocytes, 13,000. 
An important case of severe anaphylaxis following the ad- 
ministration of horse serum with recovery, is reported by 
Munro.15 This case is of interest on account of the adequate 
description of symptoms, and also on account of the satisfac- 
tory result which followed the treatment as instituted by 
Munro. 
Case 7.-The patient, who had received prophylactic antitetanus serum 
subcutaneously when wounded, came under Munro's care suffering from 
erysipelas of the leg. In the treatment of the latter, he was given 30 
c.c. of antistreptococcic serum intravenously. The serum was diluted. 
The extent of dilution is not stated in the article. No effort was made 
to desensitize the patient. Within one minute after the injection, the 
patient complained of choking; he grasped his larynx, breathed jerkily 
and spasmodically. Extreme cyanosis developed and the pulse became 
flickering. Breathing ceased in full respiration. Treatment was insti- 
tuted at once; the head of the bed was lowered and artificial respiration 
was commenced. Epinephrin, 30 minims; and atropin, 1/100 grain were 
given subcutaneously, and chloroform placed on a mask through which all 
air which entered the lungs during artificial respiration had to pass. 
Within five minutes, the patient's condition improved; normal breath- 
ing commenced; the pulse returned at the wrist, and was counted at 150 
per minute. The patient later made an excellent recovery. 
Iii this case the reaction was almost exclusively respiratory, 
in nature, and in this respect should be compared with 
Case 4 in which the manifestations of splanchnic dilatation 
predominated. 
"Munro, W. T.: A Case of Anaphylaxis, Brit. Med. Jour., Nov. 22, 1919, 
ii, 668. CHAPTER VIII 
PHYSIOLOGY OF ANAPHYLACTIC SHOCK 
The phenomena of immediate anaphylaxis in the guinea pig, 
described above, are those noted when the animal is allowed 
to run about. If it be fixed to the holder, other symptoms 
are more marked. There is noted a sinking of the chest at 
each inspiration which gradually becomes more marked and, 
finally, breathing ceases for about one minute. Respiration 
then commences again, and the mouth is opened at each in- 
spiratory effort. After thirty to ninety seconds, respiration 
ceases permanently, although the heart continues to beat for 
a considerable length of time. 
Basing their opinions upon the pathologic conditions found 
at autopsy, especially as regards the lungs, and the clinical 
symptoms as manifested with the animal attached to the 
holder, Auer and Lewis1 were the first to appreciate that 
asphyxia is the cause of death in anaphylactic shock in the 
guinea pig. They proved, moreover, by means of experiments, 
in which animals were kept alive after pithing, that the phe- 
nomenon occurred independently of the action of the central 
nervous system. Biedl and Krause2 have also proved that 
the fall of blood pressure, which is the most characteristic 
phenomenon in dogs, is also due to a peripheral action. 
Believing asphyxia in the guinea pig to be due to spasm of 
the muscles of the bronchioles, Auer and Lewis attempted to 
inhibit, or prevent, the development of the reaction by means 
of the hypodermic injection of atropin. In this they were 
successful. Their results have been repeatedly confirmed. 
Anderson and Schultz3 and others have also been successful 
in modifying the severity of the shock by means of the admin- 
'Auer and Lewis: Jour. Am. Med. Assn., 1909, liii, 458 ; also Jour. Exper. 
Med., 1910, xii, 151. 
2Biedl and Krause: Wien. kiln. Wchnschr., 1909, xxii, 363. 
'Anderson and Schultz: Proc. Soc. Exp. Biol, and Med., 1909, vii, 32. 
97 98 
INFECTION, IMMUNITY, AND INFLAMMATION 
istration of chloral hydrate, or of oxygen by the lungs, and 
by means of adrenalin. 
Pearce and Eisenbrey4 showed by means of experiments in 
which they employed decapitated animals, which were kept 
alive by transfusion, that the essential phenomena of ana- 
phylaxis may be brought about independently of the cerebro- 
medullary and spinal centers. 
Tissues Affected in Anaphylaxis 
The functional disturbances and anatomical results which 
are exhibited in anaphylaxis differ, as has been seen, with the 
species of animal employed for experiment, and are dependent 
upon the route adopted for the introduction of the foreign 
protein into the body tissues. That the usual absence of the 
acute symptoms, referable to the lungs in the rabbit, is not 
due to the nonformation of an antibody, such as that which is 
responsible for the phenomenon in the guinea pig, is proved 
by the fact that if the serum from a rabbit which has been 
sensitized, be injected into a guinea pig, it confers upon the 
latter a most pronounced hypersensitiveness. It would ap- 
pear, therefore, that the different manifestations of tissue ir- 
ritation, in different animals, are due to a varying susceptibil- 
ity, of their respective tissue cells, to the action of a common 
irritant responsible for the phenomenon. 
Histologic studies of guinea pigs' lungs have shown that 
the bronchi in this animal have an exceptionally developed 
musculature. The mucous membrane, moreover, is thick and 
folded. The finer bronchioles are practically nothing but 
muscular tubes surrounding a thick folded mucous membrane. 
Perfusion fluids pass through the distended anaphylactic 
guinea pig lung without obstruction; spasm of the bronchioles 
in this animal is not accompanied by spasm of the blood 
vessels. 
In the rabbit lung inflation is of much less importance than 
in the guinea pig; the symptoms are chiefly circulatory. 
4Pearce and Eisenbrey: Proc. Soc. Exp. Biol, and Med., 1909, vii, 30. PHYSIOLOGY OF ANAPHYLACTIC SHOCK 
99 
There is a marked fall in arterial blood pressure; the heart 
rate is at first slow. Distention of the right side of the heart 
is found at autopsy. Auer believes that these changes result 
from a direct effect upon the muscle of the right ventricle. 
Coca has found that during anaphylactic shock, an increased 
resistance to the perfusion of fluid through the rabbit's lung 
occurs. Histologically, the pulmonary arteries of the rabbit 
present a remarkable degree of muscular development, which 
is analogous to that of the bronchioles in the guinea pig. 
In the dog the liver and splanchnic circulations become 
tremendously engorged with blood; the systemic blood pres- 
sure falls, because of an insufficient supply of circulating blood. 
Simonds5 has shown that the walls of the hepatic veins of the 
dog differ from those of other animals, and that they show 
greater development of their musculature. He infers that 
hepatic and splanchnic congestion are the result of spasm of 
the hepatic veins. It is thus seen that there is reason for 
tentatively assuming that the characteristic features of acute 
anaphylactic shock in different animals depend upon differ- 
ence in the distribution of nonstriated muscle (Wells). 
Longcope,6 Boughton,7 and others have reported parenchy- 
matous degeneration with secondary fibrosis in the kidneys, 
hearts, and livers of rabbits and guinea pigs which have been 
subjected to repeated sublethal injections during the hyper- 
sensitive stage. The focal inflammatory reactions, which are 
considered in this volume under the heading of allergy, are 
obviously due to the presence of an irritant but not primarily 
to reactions on the part of unstriped muscle. 
The investigations of Manwaring and Crowe,8 show that 
three types of anaphylactic or anaphylactoid reactions occur 
in the guinea pig's lung. 
(a) Spasmodic contracture of the bronchial musculature 
unassociated with evident change in the pulmonary blood 
vessels. 
"Simonds: Jour. Am. Med. Assn., Nov. 8, 1919, Ixxili, 1437. 
•Longcope: Jour. Exper. Med., 1913, xviii, 678; 1915, xxii, 793. 
'Boughton: Jour. Immunol., 1919, iv, 213. 
'Manwaring and Crowe: Proc. Soc. Exper. Biol. Med., 1916, xiv, 173. 100 
INFECTION, IMMUNITY, AND INFLAMMATION 
(b) Spasmodic contracture of the pulmonary blood vessels. 
This reaction is usually accompanied by edema, and is com- 
monly followed by a mild bronchial reaction. 
(c) A condition which is referred to as pseudoanaphylactic, 
and which is described in this volume under the heading of 
anaphylactoid phenomena; namely, plugging of the pulmo- 
nary blood vessels with thrombi with consequent irritative 
contracture of the bronchial musculature. 
An important experiment has been recently carried out by 
Manwaring and his associates.9 This is described by them in 
the following words: 
''If the lungs of a normal dog are perfused for about three 
minutes with Locke's solution, followed by Locke's solution 
containing from 0.25 to 1 per cent of horse serum, no recog- 
nizable pulmonary reaction takes place. The rate of perfusion 
flow.remains constant on change from the Locke's solution 
to the dilute serum. When the tracheal clamp is released, the 
lungs collapse promptly and normally. No frothy fluid es- 
capes from the trachea. If, however, the lungs of a sensitized 
dog are similarly perfused, very marked pulmonary reactions 
occur. For example, the rate of perfusion flow, which usually 
varies from 1,200 to 1,500 c.c. a minute in medium-sized dogs, 
is rapidly reduced to about 300 c.c. a minute. With smaller 
serum doses, a slight tendency to recovery is occasionally 
noted after the third minute. 
"During this reaction, the lungs increase in size and take 
on a rubber-like consistency. When the tracheal clamp is 
released, practically no pulmonary collapse takes place. A 
large amount of clear, frothy fluid escapes from the trachea. 
If the perfusion is now continued, fluid continues to pour out 
of the trachea almost as rapidly as it escapes from the effer- 
ent cannula." 
As Manwaring points out, the most striking feature of these 
reactions is the marked increase in capillary permeability thus 
demonstrated. They believe that increased specific capillary 
'Manwaring, Chilcote, and Hosepian: Jour. Am. Med. Assn., Feb. 3, 
1923, Ixxx, p. 303. PHYSIOLOGY OF ANAPHYLACTIC SHOCK 
101 
permeability will ultimately be shown to be the dominant 
fundamental physiologic change in protein sensitization, to 
which all other anaphylactic reactions are secondary. This 
view, they believe, is in accord with clinical evidence. 
According to Manwaring9a and his associates, when the par- 
tially inflated lungs of dogs sensitized to horse serum are per- 
fused with Locke's solution containing from 0.25 to 2 per 
cent of horse serum, the following anaphylactic phenomena 
are noted, (a) A 75 per cent reduction in the rate of perfu- 
sion flow, (b) Complete immobilization of the lungs, the lungs 
showing no tendency to collapse when the tracheal clamp is 
released, (c) Marked perivascular edema, (d) The escape of 
large amounts of perfusion fluid from the trachea. The tra- 
cheal flow usually begins during the fourth minute, and reaches 
a maximum by the seventh minute. With medium sized dogs, 
about 1,000 c.c. of perfusion fluid escapes from the trachea by 
the end of the seventh minute. 
In an attempt to determine the nature of the anaphylac- 
tically increased capillary permeability thus demonstrated, 
these observers added to the perfusion fluid various substances, 
and then made quantitative determinations of the substances in 
the fluid recovered from the trachea. They found that during 
the anaphylactic reaction the capillary endothelium offers no 
demonstrable resistance to the outward passage of hemoglobin 
and serum proteins. During the first seven minutes the pas- 
sage of gelatin is retarded about 60 per cent, and that of gum 
arabic about 93' per cent. Starch and carbon particles are held 
back. There is also a reduction in the amount of fluid recov- 
ered from the trachea when gelatin, gum arabic or starch are 
added to the perfusion fluid. 
The Role of the Liver in Anaphylaxis 
In its passage through the intestinal villi, the portal blood 
comes in contact with many cells, whose function is to absorb 
and throw into the blood the various products of tryptic di- 
»a Manwaring', W. H. ; Hosepian, V. M. ; and Thompson, W. L. ; Quantita- 
tive Study of Anaphylactic Capillary Permeability, Jour. Am. Med. Assn., 
xxcii, p. 542, Feb., 1924. 102 
INFECTION, IMMUNITY, AND INFLAMMATION 
gestion. Probably, also, proteolytic ferments are absorbed 
and carried to the liver. As pointed out by Falls,10 it is also 
probable that, in consequence of decreased pressure and 
slower circulation, the carbon dioxide tension is greater in 
the portal than in the peripheral blood. Such a condition 
would tend to increase the rate of proteolysis. The rapid 
postmortem autolysis which takes place indicates that the 
liver is rich in ferments. These facts may explain the atyp- 
ical reactions of anaphylaxis which are exhibited when anti- 
gen is introduced into the portal, rather than the peripheral, 
circulation. It is assumed by Abderhalden, as quoted by Falls, 
that the liver is a buffer, between the intestinal and general 
circulation, which protects the latter from the entrance of 
foreign protein which, when incompletely digested, would 
have poisonous potentialities. 
Falls11 has found that guinea pigs may be sensitized by 
intraportal as by other routes of injection of human serum. 
Anaphylactic shock may be obtained after subsequent injec- 
tion by either intraportal or peripheral routes, but if the 
antigenic serum is injected into the portal circulation, larger 
doses are necessary to induce fatal shock. 
An interesting series of experiments carried out by Man- 
waring12 showed that exclusion of the spleen, stomach, kid- 
neys, suprarenals, and ovaries from the circulation, had no 
effect upon the occurrence of anaphylactic shock. When, how- 
ever, the liver was excluded from the circulation, none of 
the animals (dogs) reacted with anaphylactic shock to the 
injection of the serum antigen. 
Manwaring and Crowe,13 during the course of a series of 
experiments in which isolated organs were perfused with di- 
lute solutions of foreign proteins, and the perfusion fluid sub- 
sequently tested for changes in toxicity by passage through 
isolated anaphylactic lungs, found that, although the perfu- 
sion of an antigenic protein through the liver of a normal 
"Falls: Jour. Infect., Dis., 1917, xxii, 83. 
"Falls: Jour. Am. Med. Assn., 1915, Ixv, 524. 
"Manwaring: Ztschr. f. Immunol., 18, 1911 (quoted by Zinsser). 
"Manwaring and Crowe: Jour, of Immunol., 1917, ii, 511. PHYSIOLOGY OF ANAPHYLACTIC SHOCK 
103 
guinea pig did not alter the antigenic properties of the fluid, 
repeated perfusion of the liver from an anaphylactic animal 
invariably resulted in reduction in anaphylactic toxicity of 
the perfusing fluid. If the foreign protein is carried in ana- 
phylactic blood and perfused through an anaphylactic liver, 
the fluid employed usually loses, almost completely, its power 
to produce an anaphylactic response when tested with the 
anaphylactic lung. "Furthermore, on repeated passages 
through the anaphylactic liver, the perfusion fluid also acquires 
a new power, that of causing an unusual relaxation in the 
pulmonary tissues. There is also a loss of the occasional 
power of the perfusion fluid to cause vasoconstriction. The 
detoxicating effect of the anaphylactic liver is, therefore, ac- 
companied by, and is possibly due to, the explosive formation 
and liberation of vasodilator and bronchodilator substances. 
Similar findings were obtained by Simonds.14 (Cunningham.15) 
The characteristic fall in arterial blood pressure, when hy- 
persensitive dogs are injected with their specific antibody, 
does not take place in dogs which have been subjected to an 
Eck fistula, and are consequently dehepatized. From this 
fact, Manwaring and his coworkers,16 have concluded that 
the characteristic fall in arterial pressure is in some way de- 
pendent on liver function. 
"The theory we have proposed to account for this relation- 
ship assumes that the characteristic fall in arterial pressure 
is due to an explosive hepatic autointoxication, the formation 
or liberation of hepatic products having a histamin-like reac- 
tion on the extrahepatic vessels." 
Effect of Anaphylactic Shock upon Coagulation of Blood 
Coagulation of the blood in anaphylactic shock in dogs may 
be only delayed, or may be completely abolished (Weil). A 
similar change characterizes the blood of rabbits in anaphy- 
laxis and of guinea pigs, if the shock be protracted. Weil 
"Simonds: Jour. Infect. Dis., 1916, xix, 753. 
"Cunningham: Jour. Dis. Children, 1920, xix, 400. 
"Manwaring, Chilcote and Hosepian: Intestinal and Hepatic Reactions 
in Anaphylaxis, Jour. Am. Med. Assn., Sept. 10, 1921, Ixxvii, 847. 104 
INFECTION, IMMUNITY, AND INFLAMMATION 
believes that changes in the liver are chiefly concerned in the 
production of this alteration in the coagulability of the blood. 
He described experiments carried out according to a procedure 
introduced by Doyon, in which perfusion during life of the 
liver of a sensitized dog, with blood from a normal dog, showed 
that the coagulation time of the normal blood is prolonged to 
a remarkable degree when the specific antigen is added. The 
following experiment is quoted from Weil's contribution:17 
October 5. 5 c.c. horse serum subcutaneously. 
October 8. 5 c.c. horse serum intravenously. 
October 29. Doyon method. 
12.20 Carotid-portal circulation established. 
12.23 Cava blood, clotting time two minutes. 
12.25 3 c.c. of horse serum into tubing. 
12.34 3 c.c. of horse serum into tubing. 
12.53 Cava blood remains unclotted after 
twenty-four hours. 
Effect of Anaphylactic Shock upon Temperature 
Immediate anaphylaxis is characterized by a pronounced 
lowering of body temperature gradually falling to 20° cen- 
tigrade and ending in death. If, however, the onset of symp- 
toms be more gradual, an elevation in temperature occurs. 
Not infrequently in man the onset of hyperpyrexia is accom- 
panied by chills. 
Effect of Anaphylactic Shock upon Leucocytes 
In rapidly fatal cases a leucopenia is noted; in those which 
progress more slowly, there occurs a primary depression of 
the number of white cells which is followed by an increase and 
is accompanied by increased activity of the myelogenous tis- 
sues. This is evidenced by the appearance in the circulating 
blood of immature forms of the polymorphonuclear leucocyte. 
17Weil: Studies in Anaphylaxis: Anaphylaxis in Dogs. A Study of the 
Liver in Shock and in Peptone Poisoning, Jour. Immunol., 1916-17, ii, 525. PHYSIOLOGY OF ANAPHYLACTIC SHOCK 
105 
Depletion of Complement in Anaphylaxis 
Decrease in the complement-content of the blood during ana- 
phylactic shock has been noted by Michaelis and Fleischmann,18 
Sleeswijk,19 Friedmann,20 Friedberger and Hartoch,21 and 
Scott.22 
Francioni23 states that a lack of complement is found in 
serum sickness in man. This corresponds to the findings of 
Ehrlich and Morgenroth and Moreschi, who, after the first in- 
jections of rabbits with serum, found the complement dimin- 
ished between the eighth and tenth days. Sleewijk24 made an 
exact examination of the alexin content after anaphylactic 
shock. Thirty minutes after injection, the amount of alexin 
falls to a minimum. After two hours it is, again, normal in 
amount. 
Increase in Blood Nitrogen in Anaphylaxis 
In anaphylaxis in guinea pigs, as well as after peptone 
poisoning, there is a considerable increase in noncoagulable 
urea nitrogen in the blood, as well as a slight increase in 
amino-nitrogen, although it is not known whether this comes 
from the tissues or from the antigen-antibody reaction in the 
blood. The former seems more probable (Hisanobu25). 
Lymphagogue Reactions in Dogs 
Quantitative measurements by Calvary26 have shown that 
anaphylaxis in dogs is accompanied by a marked increase of 
the lymph flow (seven times the amount observed in normal 
dogs in the same time). He was able to show by controlling 
the blood pressure with barium chlorid that this lymphagogue 
action is not directly dependent upon the low pressure. 
"Michaelis and Fleischmann: Med. Klin., 1906, No. 1. 
"Sleeswijk: MUnch. med. Wchnschr., 1907, No. 34. 
zopriedmann: Ztschr. f. Immunitatsf., Orig., 1909, li, 591. 
21Friedberger and Hartoch: Ztschr. f. Immun. Orig., 1909, iii, p. 581. 
"Scott: Jour. Path, and Bact., 1909, iv, 147. 
"Francioni: Riv. di clin. Pediat., 1908, vi, 321: Sperimentals, 1904, 
p. 767 ; Riv. di clin. Pediat., 1907, v, 606. 
"Sleewijk: Ztschr. f. Immun. u. exper. Therap., 1909, ix, 133. 
"Hisanobu: Am. Jour. Physiol., 1920, 1, 357. 
"Calvary: MUnch. med. Wchnschr., 1911, No. 13. (Quoted Zinsser p. 
369.) 106 
INFECTION, IMMUNITY, AND INFLAMMATION 
Nonstriated Muscle Reaction in Vitro, Schultz-Dale Reaction 
An important form of the anaphylactic reaction has been 
extensively studied, by means of a technic known as the 
Schultz-Dale method. This method consists in suspending the 
uterus (or strip of intestine) from a sensitized guinea pig in 
a bath of Locke's fluid, and of tracing the muscular contrac- 
tions on a revolving drum. Prior to suspension of the uterus 
in Locke's solution the uterus, along with the viscera in the 
hind part of the animal, is perfused for one hour with Locke's 
solution. At the end of this period, Dale states that the muscle 
has lost its pink color, and believes that it contains no more 
serum than is contained in washed red blood cells, such as are 
used in ordinary hemoglobin experiments. 
Schultz27 has shown that horse serum induces contraction in 
excised portion of guinea pigs' unstriped muscle, also that if 
the muscle employed be from a sensitized animal, the reaction 
which occurs is more marked. Dale28 confirmed Schultz' ex- 
periments, and has shown that the virgin guinea pig uterus 
from a sensitized animal reacts by powerful contractions to 
dilutions of protein antigen of one to 100,000 or even one to 
500,000. In such dilutions sera do not induce contractions in 
nonsensitized muscle. 
Dale29 considers that the response on the part of the uterus 
from a sensitized guinea pig, when the organ is brought in con- 
tact, outside the body, with its specific antigen, is not merely 
an exaggeration of a normal reaction which plain muscle gives 
to fresh sera in general. When purified protein, such as pre- 
cipitated sera, globulin, or crystallized egg albumen, is em- 
ployed, as antigen, no reaction is obtained when the normal 
plain muscle is employed; but a typical reaction is obtained if 
the muscle be from an anaphylactic animal. One dose of the 
specific antigen, in sufficient concentration to produce maximal 
response to the anaphylactic uterus, completely desensitized the 
"Schultz: Jour. Pharmacol and Exper. Therap., 1912, iii. 
"Dale: Jour. Pharmacol, and Exper. Therap.,-1912-1913, iv, 167. 
"Dale: Jour. Pharmacol, and Exper. Therap., 1912-13, iv, 167. 107 
PHYSIOLOGY OF ANAPHYLACTIC SHOCK 
latter. Either normal or anaphylactic plain muscle gives re- 
peated response to successive large doses of a normally toxic 
serum, but this phenomena is not an anaphylactic response. 
Sensitiveness of washed unstriped muscle is seen in passive, 
as in active, anaphylaxis, and is obtained whether the serum 
producing passive sensitization is obtained from a sensitive or 
from an immune guinea pig. After sensitized muscle has been 
desensitized, mere contact with a not too great dilution of 
sensitive serum for some hours results in its again becoming 
anaphylactic. Dale was unable to sensitize normal plain mus- 
cle in this way. He found that perfusion of a normal uterus 
for five hours with diluted serum from immune guinea pigs 
produced a decided passive sensitization. 
Dale has also noted that bronchial spasm of the anaphy- 
lactic guinea pig lung is produced with apparently undimin- 
ished vigor when isolated lungs are perfused with Ringer's 
solution, which contains the antigen. 
Dale30 is of the opinion that the anaphylactic response of 
isolated plain muscle strips differ fundamentally from that 
which occurs in the uterus from normal animals, when it is 
treated with foreign serum. His experiments indicate that this 
is the case, although it must be pointed out that it is quite 
conceivable that the reaction which occurs is due to irritation 
or disturbance with metabolic activity in consequence of a 
substance which is alike present in toxic sera and produced as 
the result of the interaction of anaphylactic antibody and an- 
tigen. 
With reference to the rapid rise of tonus when the plain 
muscle strip from an anaphylactic animal is treated with its 
specific antigen, Dale remarks: "The effect can probably be 
accounted for by the mere initiation of those changes in the 
state of aggregation of the colloidal particles, which, when 
antibody and antigen are present in appropriate proportion, 
and sufficient time is allowed, result in the formation of a 
visible precipitate. It is not, however, necessary to assume the 
30Dale: Jour. Pharmacol, and Exper. Therap., 1912-13, iv, 167. 108 
INFECTION, IMMUNITY, AND INFLAMMATION 
identity of precipitin and anaphylactic antibody; if they be 
identical, as seems very probable, it is not necessary that the 
antibody should be present in such proportion as to give with 
the antigen a visible precipitate. All that is needed is that the 
antibody should have such a specific physical relation to the 
antigen that, when the two meet, a disturbance of the condi- 
tions of colloidal solution is set up in the muscle fiber." CHAPTER IX 
TRANSFERRED ANAPHYLAXIS 
That the anaphylactic (first order) antibody is present in 
the serum of sensitized animals is proved by means of experi- 
ments of transferred sensitization. If 3 c.c. of serum be col- 
lected from a sensitized guinea pig, and injected into a normal 
pig, the latter animal may be proved to have been passively 
rendered hypersensitive. Subsequent injection of antigenic 
protein, into the passively sensitized pig, is followed by charac- 
teristic manifestations of anaphylaxis. 
This phenomenon is known as transferred anaphylaxis, and 
is of the utmost importance since, in addition to proving that 
the anaphylactic antibody is present free in the serum of sen- 
sitized animals, it has rendered quantitative experiments pos- 
sible. Passive sensitization may be accomplished with any 
serum that contains antibodies. The quantitative power of 
such a serum to convey passive sensitization is in direct pro- 
portion to its antibody concentration (Zinsser). 
Anderson and Frost1 found that 3 c.c. of the serum of a 
guinea pig sensitized with a single injection of horse serum, is 
approximately the minimum amount that will constantly pas- 
sively sensitize 250 gram guinea pigs, so that they will react 
definitely to an intraperitoneal injection of 5 c.c. of horse serum 
twenty-four hours later. They also noted that serum of toler- 
ant guinea pig contains three or four times as much of the 
anaphylactic antibody as does the serum of the guinea pig 
rendered hypersensitive by a single dose of antigen. They fur- 
ther discovered that the serum of a rabbit, treated with fre- 
quent large injections of horse serum, contains more free 
sensitizing antibody than does the serum of highly sensitive 
guinea pigs. 
1Anderson and Frost: Trans. Cong. Am. Phys, and Surgs., 1910, viii, 414, 
109 110 
INFECTION, IMMUNITY, AND INFLAMMATION 
These experiments have been repeatedly confirmed. It has 
thus been shown that an animal of a species, such as the rab- 
bit, which is comparatively insusceptible to immediate anaphy- 
laxis, may yet carry in its blood even more first order antibody 
than an animal of another species, such as the guinea pig, 
which is highly susceptible. 
It has been found difficult by all observers to induce passive 
anaphylaxis if the transferred serum and the antigenic protein 
are injected simultaneously, or immediately, following one an- 
other. The most dependable results are obtained if an interval 
of twenty-four hours, more or less, be allowed to elapse, be- 
tween the introduction of the sensitizing serum and the antigen. 
It is still maintained by many observers that this period, which 
is known as the incubation period must elapse between the in- 
jection of the sensitizing serum and the introduction of the 
toxic dose, in order that anaphylactic shock may be exhibited. 
On the other hand, experiments appear to have proved that 
the incubation period is not always necessary.2 
Doerr and Russ,3 Friedberger,4 Richet,5 Biedl and Kraus,6 
Weill-Halle and Lamaire,7 have been successful in producing 
immediate shock by the injection of suitable mixtures of an- 
tigen and antibody. Their results have been confirmed by the 
author. 
The author,8 in 1911, published the results of experiments 
which proved the possibility of immediate symptoms of intoxi- 
cation following the introduction of transferred serum and 
antigenic protein without an intervening period of time. The 
fact that it has been possible to induce fatal reactions in this 
manner indicates that the fixation of receptors is not an essen- 
tial step in the phenomena of transferred anaphylaxis. 
2It is proper to point out at this point that these experiments have not 
found general acceptance among immunologists. The subject is discussed 
more argumentatively later in this volume. 
3Doerr and Russ: Studien Uber Anaphylaxie, II. Ztschr. f. Immunol., 1909, 
iii, No. 2, p. 181. 
4Friedberger: Weit. Mitteilung Uber Eiweissanaphylaxie, IV, Ztschr. f. 
Immunol., Orig., V. 4, Heft 5- 636. 
sRichet: Compt. Rend, de la Soc. Biol., 1909, Ixvi, No. 18. 
®Biedl and Kraus: Ztschr. f. Immunol., 1910, iv, No. 1 and 2. 
'Weill-Halle and Lamaire: Compt. Rend, de la Soc. de Biol., 1908, Ixv, 
141. 
8Gurd: Jour. Med. Research., 1914, xxxi, 205. TRANSFERRED ANAPHYLAXIS 
111 
For the strain of guinea pigs used in these experiments 
the minimal lethal toxic dose of sheep serum, fourteen days 
after a sensitizing dose of 0.01 c.c. of sheep serum, was 0.25 
c.c. If a sensitizing dose of 0.05 c.c. was used the minimal 
lethal toxic dose was 0.20 c.c. As an arbitrary lethal toxic 
dose, 0.20 c.c. was adopted as one unit. 
The sensitizing serum which was employed was derived from 
rabbits which had received repeated doses of sheep serum over 
several months. It was established that 0.6 c.c. of this serum 
several 
of this serum 
GUINEA 
PlG NO. 
WEIGHT 
PASSIVE SEN- 
SITIZATION 
TOXIC 
INJECTION 
RESULT 
AUTOPSY 
135 
290 gm. 
1.0 c.c. 
.5 c.c. 
Immediate on- 
set of marked 
symptoms ; 
scratching; irri- 
tability ; dysp- 
noea ; partial 
recovery; dead 
in A. M. 
Lungs moder- 
ately distended, 
with haemor- 
rhagic patches. 
119 
225 gm. 
.8 c.c. 
.6 c.c. 
Immediate on- 
set of very 
marked symp- 
toms ; convul- 
sions ; recovery. 
113 
200 gm. 
.5 c.c. 
.5 c.c. 
Immediate on- 
set of very 
marked symp- 
toms ; complete 
paralysis and 
convulsions. Ap- 
parently dying 
but recovered. 
143 
325 gm. 
1.6 c.c. 
.5 c.c. 
After five min- 
utes onset of 
marked symp- 
toms; culminat- 
ing in death 1 
hr. after injec- 
tion. 
Marked disten- 
tion of lungs, 
with numerous 
subpleural hem- 
orrhages. 112 
INFECTION, IMMUNITY, AND INFLAMMATION 
was the smallest amount that regularly conferred passive sen- 
sitiveness upon normal guinea pigs, when given forty-eight 
hours prior to a dose of one and one-half units of sheep serum. 
In the actual performance of the experiments two and one- 
half to three units of the antigen sheep serum (viz., 0.5 to 0.6 
c.c.) were employed as intoxicating doses. 
Control experiments which were published at that time show 
that it is obvious that relatively large doses of sheep serum do 
produce slight evidence of irritation in normal pigs. These 
manifestations are not comparable to those tabulated below. 
Protocol.-Guinea pigs were injected, with immune rabbit 
serum, into one jugular vein and immediately thereafter with 
sheep serum into the same or the opposite jugular vein. 
Transferred Anaphylaxis from Mother to Offspring.-The 
young born of mothers who possess a marked degree of hyper- 
sensitiveness may be proved to present the same anaphylactic 
state upon subsequent injections with a toxic dose of the spe- 
cific protein against which the mother had been sensitized. 
As with other immune bodies the anaphylactic substance is 
secreted in the milk so that nursing offspring develop passively 
a mild degree of hypersensitiveness if the mother be treated 
immediately after their birth (Wells). CHAPTER X 
DESENSITIZATION 
The injection of a sublethal dose of foreign protein, intra- 
venously, results in the immediate onset of symptoms of an- 
aphylaxis. The animal, however, rapidly recovers, and after 
a lapse of ten or fifteen minutes is apparently well. It is 
further noted that subsequent injections, during a period of 
two to five days, of lethal doses of antigen prove the animal to 
be nonsensitive to the foreign protein, nor is the serum of such 
an animal capable of transferring hypersensitiveness to an- 
other animal. The animal that has been thus rendered non- 
sensitive is said to have been desensitized.1 This refractory 
condition lasts for a period of several days. It is followed by 
a gradual return of hypersensitiveness, or by the development 
of the tolerant state. Not only may an animal be desensitized 
by the sublethal intravenous introduction of the foreign pro- 
tein, but also by means of injections made intraperitoneally or 
subcutaneously, even though no frank anaphylactic symptoms 
are manifest. It is noteworthy, moreover, that the dose of 
foreign protein need not be so large as the minimum lethal 
dose; a relatively small quantity of the antigenic material is 
sufficient to render the animal refractory. 
It is possible by means of the intravenous introduction of 
0.002 centimeters of sheep's serum, into an animal which has 
been so sensitized that a dose of 0.02 cubic centimeter of 
serum administered intravenously is followed by fatal 
' ' shock, ' ' to absorb or exhaust the available anaphylactic anti- 
bodies so that subsequently the lethal dose may be administered 
*The foregoing phenomenon of desensitization has been designated by 
the term antianaphylaxis (Besredka, Rosenau and Anderson, and others). 
The author, along with others, believes that such an employment of this 
expression is not the most suitable. In the author's opinion the term anti- 
anaphylaxis, if used at all, should be reserved to designate the condition 
of tolerance or "immunity" which is developed, by the tissues following 
repeated injections of antigenic proteins. 
113 114 
INFECTION, IMMUNITY, AND INFLAMMATION 
without the exhibition of any reaction whatever. In a similar 
way, the hypersensitive animal may be subjected to the ad- 
ministration of 0.01 c.c. of sheep's serum into the subcutaneous 
tissues with the development simply of a mild reaction. After 
recovery from such a reaction the animal is often found to 
be not sensitive to the intravenous injection of one or more 
lethal doses. 
In experiments of passive anaphylaxis the addition of even 
very minute quantities of the specific protein are sufficient to 
inactivate the sensitizing serum, so that subsequent attempts 
to induce shock became failures. 
The phenomenon of desensitization is evidently due to the 
fact that the anaphylactic bodies are satisfied, exhausted, or 
neutralized by the preliminary admixture of the protein an- 
tigen either in vivo or in vitro. The presence of quantitative 
relationships between the antigen and anaphylactin (first order 
antibody), in this reaction, proves that the latter is subject 
to the same laws of absorption as are other immune bodies. 
Isolated muscle strips exhibit the same phenomenon of de- 
sensitization immediately after exposure to the specific antigen 
as does the living animal. 
The same quantity of specificity characterizes desensitization 
as anaphylactic shock. If the guinea pig has been sensitized 
to two different protein antigens and recovers from the shock 
induced by the injection of one of them it becomes desensitized 
to this antigen, but will still react to the second protein. Wells 
has taken advantage of this phenomenon, and has found it 
reliable in determining the property of protein preparations. 
He has noted, however, that the second reaction has seldom 
been so severe as it would have been if it had been a primary 
reaction. This is due, he believes, at least in part, to exhaus- 
tion of the reacting mechanism. 
The dog, the rabbit, and man are subject to desensitization 
as the result of an injection of a sublethal dose of the antigen 
in the same way as is the guinea pig. As data is gradually 
accumulated, it is evident that the phenomenon of desensitiza- DESENSITIZATION 
115 
tion, or exhaustion of antibodies (first order bodies), is char- 
acteristic of anaphylaxis in all animals. 
Much of the pioneer work regarding desensitization has been 
carried out by Besredka. He sums up his opinion in the fol- 
lowing way: "We can prevent anaphylaxis from occurring by 
the following different methods of injection,-oral, rectal, 
subcutaneous, intraperitoneal, intracerebral, intrathecal and 
intravenous. The oral method is the least practical of all, 
because it requires at least one or two days before antiana- 
phylactic immunity (desensitization) is established. The rec- 
tal method is more prompt in action, but it is subject to some 
risks, the reabsorption of the antigen by the mucosa being 
delayed according to individual idiosyncrasy and the nature 
of the antigen. The intraperitoneal and intracerebral meth- 
ods-above all, the latter-confer immunity (desensitization) 
in a very short time, varying from a few minutes to an hour 
at the most. This immunity is the most effective and reli- 
able; but it is to be understood that these methods may be 
impracticable in the case of man. There remains vaccination 
by the subcutaneous, intrathecal, and intravenous routes. 
From these routes the physician will have to make his choice."2 
2Besredka-Gloyne: Anaphylaxis and Antianaphylaxis, 1919, C. V. Mosby 
Co. CHAPTER XI 
TOLERANCE 
An animal may be insusceptible to anaphylactic shock fol- 
lowing the injection of a foreign protein for one or other of 
three reasons. 
1. A normal animal because there are no antibodies present 
in the tissues to react with the antigen. 
2. A desensitized animal because of exhaustion of the anti- 
bodies. 
3'. A tolerant animal; that the tolerant animal differs from 
both the normal animal and the desensitized animal is evident. 
In the following pages the author attempts to indicate the na- 
ture of the protective mechanism. 
If an animal, which has received several sublethal doses of 
protein antigen, be tested by means of a dose of antigen, which 
has proved to be fatal to animals which have been rendered 
anaphylactic by means of a single small dose of antigen, no 
symptoms of tissue irritation are exhibited. If such an animal 
be bled and a small quantity of its serum, 1 to 3 c.c. be intro- 
duced into the peritoneal cavity, or by any other route, of a 
normal animal, it is found that the normal animal has been 
passively sensitized. If such a guinea pig be given an ordi- 
nary lethal dose of protein antigen intravenously it dies in 
typical anaphylactic shock. 
Obviously, therefore, the serum of the animal which has 
received in addition to a sensitizing dose, repeated sublethal 
injections of protein antigen, is not in the same state as is the 
normal animal, nor the desensitized animal. This is proved 
since, although the repeatedly injected animal is itself toler- 
ant to normal lethal doses of antigen, its serum confers passive 
hypersensitiveness upon the normal animal. 
Certain facts have been established which have, at least, an 
116 TOLERANCE 
117 
indirect bearing upon this subject. It will be of value to 
review these at this time. Normal guinea pigs, if injected 
with small quantities, e.g., 0.05 c.c. of heterologous serum pro- 
tein, become markedly hypersensitive to reinjection with the 
same antigen after a lapse of fourteen days. If a second in- 
jection of the foreign serum be made, either before complete 
hypersensitiveness has developed or in a quantity too small to 
cause death of the animal, the anaphylactic state does not de- 
velop in a manner exactly similar to that which occurs in the 
normal animal which has received but one injection. The 
difference noted consists in the ability of the second type of 
animal to withstand larger doses of foreign serum. Such an 
animal can, however, be proved to be highly anaphylactic if 
larger doses of antigenic protein be employed. It is thus 
possible to prove that animals treated in the same manner 
(by repeated sublethal injections of antigen) are relatively 
tolerant, and, at the same time, markedly hypersensitive. The 
more frequently the animal has been treated with sublethal 
doses, and the larger the doses which have been introduced, 
the more marked is the animal's insusceptibility to intoxica- 
tion (tolerance), and the more difficult is it to prove hyper- 
sensitiveness. It must be noted, however, that it is not pos- 
sible to render an animal sufficiently tolerant that it is able 
to withstand more than three to five times the usual toxic dose 
of antigen. 
In a series of experiments performed by the author1 it was 
was found that, whereas the injection of 0.5 c.c. of serum from 
a rabbit, which had received repeated doses of sheep serum, 
served to passively sensitize normal guinea pigs so that ana- 
phylactic shock developed when the guinea pig was injected 
with 0.45 c.c. of antigenic serum, the injection of 2.75 c.c. of 
the same rabbit serum rendered the recipient guinea pig tol- 
erant to a like dose of antigen. 
These experiments show the protective effect of large, as 
compared with the sensitizing effect of small, doses of immune 
rabbit serum upon guinea pigs when an interval of time elapses 
KJurd: Jour. Med. Research, 1914, xxxi, 205-222. 118 
INFECTION, IMMUNITY, AND INFLAMMATION 
Protocol 
GUINEA 
PIG NO. 
WEIGHT 
FIRST 
INJECTION 
INTERVAL 
SECOND 
INJECTION 
RESULT 
109 
225 gm. 
.6 c.c. I.R.S., 
24 hr. 
.35 c.c. S.S., i.v. 
Marked 
i.p. 
symptoms. 
Recovery. 
110 
225 gm. 
.6 c.c. I.R.S., 
24 hr. 
.34 c.c. S.S., i.v. 
Typical 
i.p. 
anaphylactic. 
Death 6 
minutes. 
103 
225 gm. 
4 c.c. I.R.S., 
.5 c.c. S.S., i.v. 
Slight 
i.p. 12 hr. 
later, 4.5 c.c. 
24 hr. 
Malaise. 
I.R.S., i.p. 
99 
210 gm. 
1 c.c. I.R.S., 
7 days 
.3 c.c. S.S., i.v. 
Very severe 
i.p. 
symptoms. 
100 
200 gm. 
1 c.c. I.R.S. 
7 days 
3.5 c.c. I.R.S., i.v. 
Very slight 
symptoms. 
.4 c.c. S.S., i.v. 
147 
210 gm. 
5 c.c. I.R.S. 
24 hr. 
.5 c.c. S.S., i.v. 
Typical 
death 4 
minutes. 
148 
215 gm. 
.75 c.c. I.R.S. 
24 hr. 
.5 c.c. S.S., i.v. 
Typical 
death 3 
minutes. 
149 
205 gm. 
2.5 c.c. I.R.S., 
24 hr. 
.5 c.c. S.S., i.v. 
Marked 
i.p. 
symptoms. 
Recovery. 
I.R.S.-Immune rabbit serum. 
i.p.- 
-Intraperitoneal injection. 
i.v.- 
-Intravenous injection. 
S.S.- 
-Sheep serum. 
between injection of the transferred serum and the intro- 
duction of the toxic dose. 
Protocol. Experiment No. 138 
Guinea pigs of 200 gm. weight were employed. These re- 
ceived intravenous injections of immune rabbit scrum and 
antigenic protein (sheep serum) within two to four minutes 
of one another. TOLERANCE 
119 
GUINEA 
PIG NO. 
RABBIT 
SERUM 
SHEEP 
SERUM 
RESULT 
113 
.5 c.c., i.v. 
.5 c.c., i.v. 
Four minutes onset of very severe symp- 
toms. Scratching of nose; dyspnea; 
convulsions, paralysis. Thought to be 
dead, but recovered. 
111 
.9 e.c., i.v. 
.5 c.c., i.v. 
Four minutes onset of moderate symp- 
toms. Dyspnea; mild convulsive seiz- 
ures. 
112 
2.75 c.c., i.v. 
.5 c.c., i.v. 
No symptoms. 
These experiments are interpreted by the author as proving 
the presence, in the circulating blood of immune animals, of 
bodies which are potent to induce the hypersensitive state 
when introduced into normal animals and, also, of bodies 
which if injected in sufficient quantities are able to render 
normal animals passively tolerant (immune). 
Thomsen2 states that a sensitizing dose of 0.004 cubic cen- 
timeters of serum produced a maximum sensitization more 
quickly than 0.1 cubic centimeter, although the maximum 
degree of sensitization is the same with each dose. 
The explanation of this fact is apparently a simple one, 
namely, that as long as there remains in the tissue of the 
injected animal a remnant of the introduced antigen, the ana- 
phylactic antibodies are exhausted as soon as they are pro- 
duced. The animal thus remains desensitized, even though its 
tissues are actively producing the anaphylactic antibodies. 
When very large doses of antigen are given tolerance may be 
engendered. Under these conditions anaphylaxis is not ex- 
hibited when minimal toxic injections of protein antigen are 
employed, until a sufficient period has elapsed for the second 
order antibody to diminish in quantity. 
Certain experiments reported by Vaughan (loc. cit., page 173) 
prove that it is possible to develop, to a limited degree, at 
least, the production of the protective or immunity conferring 
substance without rendering the animal sensitive. According 
to Vaughan it is possible to so treat an animal by the repeated 
injections of the poisonous protein split product, prepared 
'Thomsen: Ztschr. Immunitat., 1917, xxvi, 213. 120 
INFECTION, IMMUNITY, AND INFLAMMATION 
according to his method,3 that a state of tolerance is developed 
as the result of which the animal is able to "bear three or 
four times the minimum lethal dose," and that furthermore, 
such an animal is not sensitive to the whole protein from which 
the poison is recovered. 
Zinsser and Dwyer have reported experiments regarding 
tolerance to typhoid anaphylatoxin. Working with typhoid 
anaphylatoxin they found that guinea pigs, treated with sub- 
lethal doses of anaphylatoxin, developed a tolerance which 
enabled them to resist ll/2 to 2 units of poison. Such tolerance 
is exhibited within three days and lasts to a slight degree, 
for as long as two months. The tolerant state did not seem 
to be strictly specific, in that typhoid anaphylatoxin seemed 
to produce a moderate tolerance to prodigiosus anaphylatoxin. 
A certain degree of tolerance may also be induced by the 
primary administration of large doses of antigen. Rosenau 
and Anderson4 and others have published experiments in which 
it is shown that, whereas animals become hypersensitive within 
eight or twelve days after the administration of small doses of 
serum (0.01 c.c. or less), if the primary injection consists of 
3 or 4 c.c. of an antigen serum it takes several weeks before 
the animals become markedly anaphylactic. 
Antisensitization 
Antisensitization is a phenomenon somewhat similar to toler- 
ance, described by Weil.5 If a guinea pig be given a single 
dose of serum, several days before a sensitizing dose of serum 
from a rabbit immune to a foreign protein, the usual passive 
sensitization does not take place. This is explained by the de- 
velopment in the guinea pig of antibodies to the rabbit serum, 
which protect the guinea pig's tissues from the antibodies of 
the immune rabbit serum. In proof of this conclusion is the 
fact that such preliminary injection with rabbit serum does 
not prevent passive sensitization with the serum of a guinea 
pig immunized to foreign protein. 
'See p. 133. 
4Rosenau and Anderson: U. S. Pub. Health and Marine Hosp. Ser. Lab. 
Bull., 1908, xlv, quoted by Zinsser. 
BWeil: Ztschr. Immunitat., 1913, xx, 199. CHAPTER XII 
NATURE OF ANAPHYLACTIC ANTIGEN1 
(ANAPHYLACTOGEN) 
"There is no doubt that any soluble protein which can act 
as an antigen in other immunologic reactions can act as an 
anaphylactogen, and the only soluble proteins as yet found not 
to be antigenic are those which are, from the chemical sense, 
incomplete proteins." (Wells.) Those that are not antigenic 
include such proteins as have a very small variety of amino 
acids, notably the protamines and histones; also the complexes 
of these with nonprotein radicals, notably, the nucleo-proteins 
and hemoglobins. Gelatin, on the other hand, although a very 
complex and soluble protein, has no antigenic power, whether 
tested by anaphylaxis or by more sensitive immunologic meth- 
ods. The chief difference between gelatin and the ordinary 
proteins that do exhibit antigenic properties is a deficiency 
in aromatic amino acids. It is, therefore, assumed by Wells 
that aromatic amino acids must be present. 
In discussing the amino acid constituent of antigenic pro- 
teins, Wells says: "There exist proteins which lack one or 
more of the amino acids which are commonly present in 
typical proteins, yet which are strongly antigenic (e.g., zein 
from corn, which lacks glycine and tryptophane, gliadine of 
wheat and rye, or hordein of barley, which contain no glycerin 
or lysin and very little arginine or histidine). The fact that 
these last three proteins, which are so extremely poor in di- 
amino acids, are potent, while the protamines which consist 
chiefly of diamino acids, are inert, suggests that these three 
diamino acids are not of importance in the anaphylactic activ- 
ity of proteins, but since no protein is known which does not 
'The facts presented in this chapter upon the anaphylactic antigen are 
equally applicable to other antigens. 
121 122 
INFECTION, IMMUNITY, AND INFLAMMATION 
contain either histidine or arginine, we cannot prove this point 
as it seems to be proved for lysin. " (Wells.2) 
Solubility of the protein is essential, in Well's opinion, since, 
although insoluble protein may eventually be brought into 
solution in the animal body, the process is too slow to bring 
about reactions, and also it is probably accompanied by dis- 
integration of the protein molecule. Heat, of degrees that do 
not disintegrate the proteins, affects them only to the extent 
that it makes them insoluble. There are, however, only a few 
known proteins that are not made insoluble by heat, and these, 
except gelatin, are antigenic despite boiling. In this group 
are casein, ovomucoid, the so-called proteoses of plant seeds, 
beta-nucleo proteins, and perhaps the capsular substance of 
pneumococci. 
As Besredka has pointed out, if soluble antigens be diluted 
they are rendered much less susceptible to coagulation. When 
diluted the antigenic properties of the protein are not de- 
stroyed by moderate degrees of heat. 
Trypsin digestion, as might well be expected, gradually, 
though slowly, destroys the sensitizing power which latter runs 
parallel to the remnants of coagulable protein. 
Compound proteins produce anaphylaxis if they are solu- 
ble, and if the protein constituents are themselves antigenic, 
but apparently not when the protein radical is a nonantigenic 
histone or protamine. Thus, alpha-nucleoproteins and hemo- 
globin are nonantigenic, while nucleins, beta-nucleoproteins 
and hemocyanin are antigenic (Wells). 
In order that acute anaphylactic shock may be readily pro- 
duced, it is essential that the protein be soluble. On the other 
hand, in order that symptoms and signs of tissue irritation may 
be induced, solubility of the antigen is not necessary. The 
author has attempted elsewhere to point out that, whereas, if 
a soluble protein be introduced into the blood stream, or into 
*Wells and his associates have performed many experiments and have 
recorded their observations regarding- the nature of anaphylactic antigens 
(anaphylactogens). For the most part the material presented in this section 
is abstracted from the publications of these authors. For a more complete 
consideration of the subject, the reader is referred to Well's Chemical 
Pathology (Saunders, Philadelphia), or The Present Status of the Problems 
of Anaphylaxis, Physio logical Reviews, 1921, i, 44. NATURE OF ANAPHYLACTIC ANTIGEN 
123 
other tissues in which its absorption into the blood stream is 
readily accomplished, general manifestations of irritation or 
intoxication take place in an explosive fashion; the injection 
of either a less soluble antigenic protein, or by a route by 
which its absorption is less rapidly brought about is followed 
to a less marked degree by constitutional symptoms, but by 
more marked evidence of focal irritation. It is to this focal 
reaction to the introduction of proteins that the term "al- 
lergy," in the author's opinion, should be restricted. Anaphy- 
laxis then, from this point of view, described the explosive 
generalized symptoms of constitutional intoxication when the 
sensitized animal is subjected to an injection by the same pro- 
tein to which its tissues have previously been exposed, whereas 
allergy designates the phenomena which occur focally in the 
tissues at the site of injection of a less rapidly absorbable 
protein. 
The racemized proteins3 of Dakin are substances which in 
every way resemble simple proteins, except for their dimin- 
ished optical activity. They also exhibit the property of being 
resistant to proteolytic enzymes, and are not metabolized when 
fed to, or injected under the skin of, experimental animals. 
Likewise, they do not act as antigens. Presumably, as pointed 
out by Wells, these characteristics are due to changes in struc- 
tural configuration. Observations by Ten Broeck4 with the 
racemized protein of egg albumin supports the theory that 
it is the breaking down in the tissues of an injected protein 
that causes the production of antibodies. 
'A 20 per cent solution of Merck's soluble egg albumin in N/2 sodium 
hydroxide was incubated at 37° C. for three weeks. During this time the 
optical rotation gradually fell until it reached a constant value. The race- 
mized protein, after neutralization with sulphuric acid was then salted out 
by saturating the solution with ammonia sulphate. The precipitate was 
filtered off, suspended in a little water and dialyzed in the presence of a 
little toluene to free it from salts. The racemized egg albumin went into 
solution in the dialysis tube and was precipitated from this solution by 
the addition of alcohol. 
The racemized egg albumin so obtained was filtered off and dried, and 
formed a white powder resembling the original protein. . It gives the typical 
protein reactions (biuret, etc.) and differs chemically from the original 
substance only in its optical properties. Its aqueous solution coagulates on 
heating, as in the case of ordinary egg white. The reactions for tyrosine, 
tryptophane and cystine are all positive. Like racemized casein and csseose, 
it is unaffected by the proteolytic enzymes of the digestive tract. (Dakin: 
Quoted Ten Broeck.4 ) 
4Ten Broeck: Jour. Biol. Chem., 1914, xvii, 369. 124 
INFECTION, IMMUNITY, AND INFLAMMATION 
In discussing the question whether anything but an entire 
protein molecule can act as an anaphylactogen, Wells, after 
discussing the uncritical nature of much of the work which 
has been done upon this subject, concludes that "there still 
remains no satisfactory proof that anything except protein can 
act as an anaphylactogen." 
Regarding the question as to whether lipoids have antigenic 
activity the matter must, at the present time, be considered 
unproved, although the fact that lipoid substances bind alexin 
is very suggestive. 
Anaphylactoid reactions take place following the administra- 
tion parenterally of certain drugs and chemicals. Practically 
all observers, who have employed salvarsan in any consider- 
able number of cases, have noted such reactions. Wolff-Eisner 
suggests the theory that such reactions are due to an altera- 
tion of the recipients own tissue protein in such a way that 
they act as foreign proteins, and as such, are antigenic. Of 
the hypotheses brought forward to identify these drug reac- 
tions as anaphylaxis, this is the most suggestive. Up to the 
present time no direct positive evidence has been forthcoming. 
It has been, hitherto, impossible to produce passive anaphy- 
laxis with the serum of persons hypersensitive to drugs, nor 
in Wells' opinion, have convincing experiments, proving active 
sensitization in guinea pigs, been published. The author is of 
the opinion that although no direct proof is available identify- 
ing the anaphylactoid reactions to the parenteral introduction 
of drugs as true anaphylaxis, the experimental difficulties in 
procuring such proof are such that failure must not be ac- 
cepted as final. 
Abderhalden has calculated that the 20 amino acids that are 
present in proteins could form at least 2,432,902,008,176,640,- 
000 different compounds. 
The biological importance of the data obtained by the use 
of the anaphylactic reaction has been summed up by Osborne,5 
as follows: "From these facts it is evident that structural 
differences exist between very similar proteins of different 
BOsborne: Harvey Lectures, 1910-11. NATURE OF ANAPHYLACTIC ANTIGEN 
125 
origin, and it is interesting to note that chemically identical 
proteins, apparently, do not occur in animals and plants of 
different species, unless the latter are very closely related bio- 
logically. In this respect the proteins are in marked contrast 
to the other constituents of plants and animals, for not only 
do the same sugars and fats occur in many species of plants 
and animals, but many of these are common to both forms of 
life. The morphologic difference between species find their 
counterpart in the protein constituent of these tissues." 
Since gelatin, which is relatively poor in aromatic radicles, 
does not sensitize, and since it does not yield any toxic sub- 
stance when injected into animals, it has been suggested that 
the anaphylactic reaction to proteins may depend upon the 
aromatic radicles, possibly through their separation from the 
remainder of the protein molecule. 
The proteins definitely recognized as being capable of in- 
ducing anaphylaxis are, the albumins, globulins, nucleopro- 
teins, and the albumoses. Among these substances are in- 
cluded a large number of bacterial derivatives. The greater 
amount of work upon bacterial proteins has been carried out 
with tuberculoprotein, particularly by Baldwin, Kraus, and 
their coworkers at the Saranac Lake Laboratories. 
Specificity of the Anaphylactic Reaction 
The phenomenon of anaphylaxis is characterized by the ex- 
hibition of the same specificity as that which exists between 
antibody and antigen in other immunity reactions. Inciden- 
tally, it may be stated that the reaction has been made use of, 
on account of its specificity, to differentiate various types of 
proteins which have not been subjected to. identification by 
methods of chemical analysis. Doerr and Russ6 found that 
guinea pigs of the same weight, passively sensitized in the 
same way to sheep serum, reacted to reinjection of sera from 
other sources in the following minimal doses: (Hektoen.) 
'Doerr and Russ: Ztschr. f. Immunol., 1909, ill, pp. 181 and 706. 126 
INFECTION, IMMUNITY, AND INFLAMMATION 
Sheep Serum 0.004 
Goat " 0.004 
Beef " 0.01 
Swine " 0.6 
Human " 1.0 
Horse " 2.0 
Chick " no reaction 
These experiments demonstrate species specificity in anaphy- 
lactic shock, as in other immunity reactions. This specificity 
is equally well marked in the case of bacterial derivatives. 
An interesting point to which attention has been drawn by 
Uhlenhuth,7 and confirmed by Wells and others, is that not 
only does species specificity exist in the manner suggested 
above, but that there is, also, an important organ specificity. 
These observers found that, if an animal be sensitized to lens 
protein, not only will it react to the homologous lens protein 
but, also, to the lens substance derived from the same species 
or even its own lens. Recent experiments by Hektoen8 have 
confirmed in a striking fashion this organ specificity or lens 
protein. Hektoen has made the suggestion that this may be 
an explanation of the phenomenon of sympathetic ophthalmia. 
Another observation in this respect which may be of great 
significance in the study of eclampsia and other abnormal 
physiologic states characterizing pregnancy, is that the fetal 
tissue, placenta and amniotic fluid may cause anaphylaxis in 
members of the animal's own species. Heide, whose experi- 
ments have been repeated by Rongy,9 has found that injections 
of fetal serum may bring on labor, if injected into pregnant 
women shortly before term. In addition to uterine contrac- 
tions there frequently occur chills, nausea and vomiting, and 
precordial oppression or pain. 
The chief obstacle, heretofore, met with in determining ac- 
curately the specificity of the reaction, has been the difficulty 
of obtaining pure material. Wells and Osborne have carried 
out pioneer experiments in this direction. They separated from 
'Uhlenhuth: Ztschr. f. Immunol., 1910, iv. 
8Hektoen: Jour. Am. Med. Assn., July 2, 1921. 
9Rongy: Am. Jour. Obst., 1912, Ixvi, p. 1. NATURE OF ANAPHYLACTIC ANTIGEN 
127 
egg white substances of definite chemical characteristics, 
namely, ovomucoid, ovoglobulin, ovalbumin, ovovitellin (from 
yoke), and nucleoalbumin, and found that animals sensitized 
to these different components reacted much more constantly 
and readily to the pure material, by means of which they were 
sensitized, than to either the total egg white, or to the other 
constituents. Wells found that ovoglobulin prepared by the 
treatment of egg white with (NH2)SO4 to half saturation sen- 
sitized in doses as small as 0.00001 gram, and that guinea pigs 
reacted to a toxic dose of 0.001 gram. Employing the re- 
crystallized ovalbumin they found that one-twentieth of a 
milligram sensitized, while 1/1,000,000 gram prepared for a 
second lethal dose of one-twentieth of a milligram. It may be 
mentioned that these experiments of Wells, in addition to 
numerous others along other lines, prove that the same mate- 
rial is active in sensitizing and in provoking toxic symptoms. 
Well's experiments have led him to the conclusion that, 
"the entire protein molecule is not necessarily involved in the 
specific character of the anaphylactic reaction, but this is 
developed by certain groups contained therein, and that one 
and the same protein molecule may contain two or more such 
groups. It may well be that the intact protein molecule is 
involved in the reaction (for there is but little evidence that 
anything less than an intact protein molecule is capable of 
producing the typical reaction), but that certain groups de- 
termine the specificity." (Wells and Osborne.10) 
Also, "since chemically similar proteins from seeds of dif- 
ferent genera react anaphylactic ally with one another, while 
chemically dissimilar proteins from the same seed in many 
cases fail to do so, we must conclude that the specificity of 
the anaphylactic reaction depends upon the chemical struc- 
ture of the protein molecule. Corroborative evidence has been 
furnished with precipitin reactions by Landsteiner and 
Lampl."11 (Wells.) 
Although the anaphylactic reaction is a less delicate means 
10Wells and Osborne: Jour. Infect. Dis., 1913, xii, 341. 
"Landsteiner and Lampi: Jour. Biochem., 1918, lxxxvi, 343. 128 
INFECTION, IMMUNITY, AND INFLAMMATION 
of determining specificity than is the precipitin reaction, or the 
complement fixation method, the more general employment of 
the reaction in the isolated uterus strip has proved it to be 
equally sensitive. Thus Dale has been successful in differen- 
tiating crystallized albumins from hen's eggs and from duck's 
eggs. "In other words, a close relationship by immunological 
tests is here associated with chemical similarity, and a slight 
difference in chemical structure is found which presumably 
accounts for a slight immunologic difference that can be 
detected only by the most sensitive methods." (Wells.) CHAPTER XIII 
ANAPHYLACTOID PHENOMENA 
The final explanation of anaphylaxis is still unsolved. Much 
work has already been carried out by numerous observers in 
an effort to throw light upon the subject. Since the primary 
parenteral introduction of certain protein substances is fol- 
lowed by manifestations of symptoms which simulate those 
which characterize the typical anaphylactic experiment, the 
question naturally arises as to the relationship of these sub- 
stances to the anaphylactic antigen. In this chapter the 
salient features of the more important anaphylactoid phenom- 
ena are recorded and, in part, analyzed. 
Endotoxins 
Pfeiffer (1892) discovered that a given dose of cholera 
vibrios, which was harmless to a normal animal, sufficed to 
bring about rapid death of an animal which had previously 
been injected with a sublethal dose of vibrios. He used the 
intraperitoneal route of administration, and found that in the 
material removed from the peritoneal cavity, the microor- 
ganisms could no longer be identified as such. Lysis of the 
bacteria had taken place. 
It was upon this experiment that Pfeiffer built his hypoth- 
esis of endotoxins. He believed that, as a result of the lytic 
activity of the body fluids in immune animals, the bacterial 
cell bodies were dissolved, and that a preformed toxic sub- 
stance situated in the cell cytoplasm was liberated. This 
hypothetical poison he named endotoxin. 
Experiments since that time tend to show that no such pre- 
formed toxic substance does, in fact, exist in bacterial cell 
bodies, but that, as the result of the interaction of the anaphy- 
lactic antibody (first order body) with the bacterial cell pro- 
tein, there is produced an irritant substance. The exact na- 
129 130 
INFECTION, IMMUNITY, AND INFLAMMATION 
ture of the reaction which takes place between antibody and 
protein antigen is not, as is elsewhere shown, finally proved. 
In 1902 Weichdardt1 subjected rabbit's syncytial protein to 
the action of specific antisera and obtained substances which 
were toxic to normal rabbits. It is to be noted that this 
experiment was carried out before the discovery of the ana- 
phylactic phenomenon. In 1904 Wolff-Eisner2 formulated a 
theory which was essentially to the effect that specific cytoly- 
sis of bacterial and tissue cells resulted in the production of 
toxic substances. Wolff-Eisner3 as a direct result of his ex- 
periments upon this subject proposed the employment of the 
conjunctival reactions to tuberculosis which was simultane- 
ously described by Calmette4 in France. 
Anaphylatoxin (Friedberger) 
Friedemann5 found that if 3 c.c. of beef corpuscles were in- 
jected into rabbits, and the injection repeated after three weeks, 
anaphylaxis regularly occurred. Friedemann then treated sen- 
sitized red blood cells in vitro with alexin, and incubated the 
mixture He found that when the supernatant fluid was in- 
jected into normal rabbits, symptoms identical with those 
which characterize anaphylaxis supervened. In order to ex- 
clude any possible toxic action of hemoglobin the action of 
the alexin was arrested by cooling at a time just preceding the 
occurrence of hemolysis. Upon the basis of these experiments 
Friedemann expressed the opinion that anaphylaxis is due to 
the action of alexin upon sensitized protein antigen. 
Friedberger6 (1910) confirmed Friedemann's findings, and 
proved that the treatment of specific precipitates with fresh 
normal serum alexin was followed by the production of a 
toxic product. The following Friedberger experiment is 
quoted from Zinsser: "One cubic centimeter of a rabbit 
'Weichdardt: Deutsch, med. Wchnschr., 1902, p. 624 (quoted by Zinsser). 
2Wolff-Eisner: Centralbl. f. Bakteriol., 1904, xxxvli. 
'Wolff-Eisner: Berl. klin. Wchnschr., 1907, p. 1052. 
4Calmette: Compt. Rend, de 1'Acad. des Sci., June, 1907. 
'Friedemann: Ztschr. f. Immunol., 1909, iii. 
'Friedberger: Berl. klin. Wchnschr., 32 and 42, 1910; also Ztschr. f. 
Immunol., 1910, iv. ANAPHYLACTOID PHENOMENA 
131 
serum which precipitated sheep serum in a dilution of 1 to 
10,000 was mixed with 30 c.c. of a 1 to 50 sheep serum dilu- 
tion. This was kept one hour at 37.5° C. and overnight in the 
night chest, when a heavy flocculent precipitate had formed. 
This precipitate was washed to remove all traces of serum, 
and to it was added 2 c.c. of fresh normal guinea pig serum- 
as complement. This was again allowed to stand for twelve 
hours and, then, the supernatant fluid was injected into a 
guinea pig intravenously. In most cases the pigs so treated 
showed marked symptoms soon after the injection and died 
within a few hours." 
It is evident that a specific substance is present in the serum 
of sensitized (and tolerant) animals which combines with or 
so acts upon certain specific foreign proteins that the product 
of the reaction is no longer soluble in an inactive serum 
mixture. 
It is possible to dissolve out from the precipitate, by means 
of the addition of alexin, a substance which is soluble in a 
mixture of serum and salt solution, and which produces, upon 
intravenous injection into animals, symptoms of anaphylaxis. 
If inactivated guinea pig serum or sodium chloride be used 
in the experiment, the fluid is not rendered toxic. 
As the result of these experiments, Friedberger formulated 
the "anaphylatoxin" theory of anaphylaxis. The essential 
characteristic of Friedberger's theory is that anaphylaxis is 
a true intoxication by a poison which results from the action 
of alexin upon the products of a precipitin-precipitinogen 
reaction. The poison so formed he designates by the term 
' ' anaphylatoxin. ' ' 
One of the essential premises of Friedberger's hypothesis 
is that the anaphylatoxin is formed from the matrix of the 
protein antigen. This aspect of Friedberger's conception has 
been attacked by numerous writers (e.g., Weil and Zinsser). 
Doerr and Russ proved that the precipitate which results 
from the mixture of immune serum and antigen may be dis- 
solved in weak soda solution and that anaphylactic shock 
follows its intravenous injection. 132 
INFECTION, IMMUNITY, AND INFLAMMATION 
Doerr and Russ have also demonstrated that the passive 
sensitizing property of serum is proportionate to its precipi- 
tating strength. This has been confirmed by Anderson and 
Frost, who further proved that the precipitate formed by the 
action of precipitating serum upon its antigen will cause ana- 
phylactic shock in normal animals. They, therefore, assume 
that the anaphylactic antibody is identical with precipitin. 
Similar results were obtained by Anderson and Frost.7 
Washed precipitate was treated with 1.8 c.c. of normal guinea 
pig serum and injected intravenously. Marked dyspnea ap- 
peared at once, the animal was quite sick for more than an 
hour. Anderson and Frost in 1910 remarked "immediate 
anaphylactic shock in normal guinea pigs, following the injec- 
tion of mixtures of horse serum with specific antiserum, seems 
capable of explanation only by the assumption of an anaphy- 
lactic antibody. Whether the anaphylactic antibody acts as 
an intermediate link between antigen and body cells, or 
whether it serves to split up the serum into derivatives capa- 
ble of direct combination, remains an open question." 
Following experiments such as those just mentioned, the 
observations of Rosenow on the production of an anaphylac- 
tic substance by autolysis of bacteria, are of considerable 
interest. Rosenow found that injections of virulent pneumo- 
cocci, at one stage of autolysis in salt solution, produced 
symptoms and pathologic changes characteristic of immediate 
anaphylaxis. In a subsequent paper he reports the repetition 
of experiments in which he employed streptococci, staphylo- 
coccus aureus, meningococci, gonococci, the colon bacillus, the 
bacillus pyocyaneous, the bacillus dysenteriae of Shiga, and 
the spirillum of Metchnikoff. Partially autolyzed suspensions 
of these bacteria yielded similar results. These results, states 
Rosenow, speak strongly in favor of the view that the symp- 
toms in sensitized animals following a second injection of 
pneumococcus extract are due to the rapid splitting of the 
protein material, and that a similar splitting occurs at a much 
slower rate in vitro by autolysis. 
'Anderson and Frost: Trans. Cong. Am. Phy. and Surg., 1910, viii, 429. ANAPHYLACTOID PHENOMENA 
133 
It is worthy of note that staphylococci were not subject to 
proteolysis unless treated with leucocytes or serum, although 
it is not necessary that either leucocytes or serum should be 
from an immune animal. 
Protein Split Products (Vaughan) 
One of the most valuable contributions to the subject of 
protein intoxication, and its relationship to immunity, is that 
of Vaughan8 and his associates. Their chief conception, and 
the one upon which most of their experimental work has been 
brought to bear, is that every complex proteid-protein- 
consists of one common nitrogenous archon, or keystone, to 
which are attached a larger, or smaller, number of side chains. 
Each of the latter has a characteristic structure. It is to the 
variation in nature, and distributions of these side chains that 
proteins from different sources owe their differentiation from 
one another. 
In accordance with Vaughan's conception, the keystone of 
the protein molecule is common to all proteins, and forms the 
primary group. Proteins differ from one another in their 
secondary and tertiary groups. Albumins and other complex 
proteins are not poisonous, because, in them, the chemism of 
the primary group is satisfied by combination with secondary 
groups. When the secondary groups are stripped off, the 
primary becomes poisonous on account of the avidity with 
which it combines with the secondary groups of other mole- 
cules. 
By means of hydrolysis of the protein molecule, Vaughan 
believes that he has isolated, more or less crudely, the pri- 
mary group. For this purpose he employed hot (78° C.) 
alkaline (2 per cent NaOH) alcohol. This primary group is 
referred to by Vaughan as the poison or poisonous protein 
split product. One milligram of protein suffices for the pro- 
duction of enough poison to kill a guinea pig. 
When cleavage of the molecule is obtained by means of 
8Vaughan: Protein Split Products and Their Relationship to Immunity 
and Disease, Lea & Febiger, 1918. 134 
INFECTION, IMMUNITY, AND INFLAMMATION 
peptic digestion, the poison is formed about the stage of the 
formation of peptone. A similar poison was also obtained 
by Vaughan as a result of the action of blood serum, and 
organ extracts, from sensitized animals upon their specific 
antigens. 
From all true proteins examined by Vaughan, a poisonous 
moiety has been isolated having identical properties, biolog- 
ically considered, although in the form so far isolated, they 
are not chemically identical. This fact, in view of the observa- 
tions of Wells and his associates, is, in all probability, due 
simply to difficulties in purification. The poisonous group 
in the molecule is not removed from its attachments to other 
groups by purely physical solvents. The molecule must be 
disrupted by high temperature, chemical agents, or enzymes, 
before this can be done. 
When proteins are subjected to splitting in the manner de- 
scribed, there is obtained a soluble substance, which is the 
poison, and, also, an insoluble residue. When animals are 
injected with the soluble poison, symptoms identical with those 
which occur in typical anaphylactic shock are produced. 
Repeated injection with the poison does not result in in- 
creased sensitiveness: nor does injection with the soluble poi- 
son, render the animal hypersensitive to the whole protein. 
The insoluble residue is not toxic: it does, however, sensitize 
the animal against the unaltered protein. It is probable that 
this latter effect is due to the presence in the residue of a 
certain amount of protein, which thus induces hypersensitive- 
ness to itself. 
Vaughan believes that the splitting of the protein in the 
animal body is due to a proteolytic ferment, which is the 
product of certain cells. This ferment is specific for the pro- 
tein, which calls it into existence. This in Vaughan's opinion 
is the explanation of the anaphylactic phenomenon. 
Cleavage products can be produced, not only by hydrolysis 
by alcohol hydroxide solution, as employed by Vaughan, but 
also by means of a more prolonged treatment with acids or 
by exposure of the protein to high degrees of moist heat in ANAPHYLACTOID PHENOMENA 
135 
the autoclave. The substances procured by these methods 
differ, moreover, quantitatively only, from those produced 
by the ferment action of trypsin. 
Animals which have been subjected to repeated sublethal 
injections of the poison (split product) are able to withstand 
from two to four times the amount of poison which is fatal in 
controls. Vaughan speaks of this protection as being due to 
tolerance, and not immunity. He makes no effort to explain 
the nature of tolerance, and states that more work is necessary 
upon the subject. 
He also found that animals which had been treated with 
the poison derived from B. coli are more resistant than con- 
trols to the injection of living organisms,-at least two fatal 
doses may be tolerated. Guinea pigs treated with the residue 
showed acquired immunity to at least eight times the fatal 
dose of living organisms. 
This protection, on the part of animals treated with the 
residue, I explain as being due to sensitization of the animal, 
with the result that upon subsequent injection of living organ- 
isms, a reaction occurs immediately after inoculation. The 
apparent immunity of such animals, is due to a condition of 
allergy. 
White and Avery9 have published the results of, and con- 
clusions based upon, an exhaustive series of experiments deal- 
ing with the nature of the toxic alcohol-soluble moiety of 
tuberculoprotein after treatment with alcohol hydroxide. They 
found the minimal fatal dose of the product to be approx- 
imately 1 to 1500 parts of body weight. They employed, as 
experimental animals, guinea pigs, weighing 250 grams or 
more. 
By means of the injection of the poison in suitable doses, 
and by various routes, it is possible to produce clinical man- 
ifestations of disease, including febrile reactions, which simu- 
late the various types of infectious disease. 
" During the active progress of an infectious disease, the 
body cells supply the ferment, the injecting organism con- 
"White and Avery: Jour. Med. Research, 1910, xxiii, 95. 136 
INFECTION, IMMUNITY, AND INFLAMMATION 
stitutes the substrate, the process is essentially destructive, 
the protein poison is set free, the symptoms of disease appear 
and life is placed in jeopardy." (Vaughan.) 
As pointed out by Zinsser10 it is to be noted that Vaughan 
does not take for granted the formation of the poisons under 
the influence of the sensitizer-alexin mechanism in the circu- 
lation ; and does not assume that the entire process necessarily 
takes place in the circulation. 
In discussing the work of Vaughan and Wheeler11 Zinsser 
makes the following remark: "In its general significance, 
this work ranks among the most important contributions to 
our understanding of hypersusceptibility, though the theo- 
retical deductions made from it have had to be subjected to 
considerable alteration." 
Peptone Poisoning 
Biedl and Krause12 have drawn a very close parallelism be- 
tween anaphylactic shock and petone poisoning in dogs. They 
have shown that injections of peptone (0.3 gr. to the kilo) 
give rise to the same clinical symptoms that characterize ana- 
phylaxis. It is accompanied also by typical fall of blood 
pressure, delayed coagulability of the blood, and leucopenia. 
These authors have also found that in guinea pigs, as well as 
in dogs, injections of peptone are followed by typical mani- 
festations of anaphylaxis. 
In guinea pigs, the symptoms of peptone poisoning are sim- 
ilar to those exhibited during anaphylactic shock. There 
is ruffling of the hair, respiratory distress and prostration. 
At autopsy the lungs are fully expanded and occasionally, 
subserous hemorrhages are observed. "The marked resem- 
blance between the gross and microscopic changes produced 
by injections of peptone and by injections of native proteins 
(in hypersensitive animals) furnishes another reason for con- 
sidering these two phenomena closely related." (Boughton.13) 
"Zinsser: Jour. Immunol., 1920, v, 265. 
lrVaugiian and Wheeler: Jour. Infect. Dis., 1907, iv. 
12Biedl and Krause: Wien. klin. Wchnschr., 1902, p. 11. 
"Boughton: Jour. Immunol., 1919, Iv, 381. ANAPHYLACTOID PHENOMENA 
137 
The irregular results obtained by different investigators re- 
garding the toxic manifestations following peptone injection 
may be assumed to be due to the fact that commercial peptone 
(Witte) is simply a mixture of protein degradation products. 
Brieger14 has found that those samples of Witte's peptone, 
which proved toxic, yield on extraction a substance which he 
had called "peptotoxin." 
Whipple and Cook15 found that proteose injections into 
fasting dogs are followed by a rise in nitrogen elimination to 
more than double the normal. 
Artificial proteoses produced by tryptic digestion of egg 
white, as well as other more complete degradation products 
of hydrolysis, do not sensitize guinea pigs. 
Heidenheim16 has noted an increase in the lymph flow dur- 
ing peptone poisoning. As pointed out by Zinsser, this is of 
especial interest in view of a similar phenomenon noted by 
Calvary17 in anaphylactic shock. 
Histamine 
Barger and Dale,18 as the result of an enquiry into the 
nature and characteristics of Popeilski's vasodilatine (derived 
from intestine), discovered that boiled acid extracts of intes- 
tine contain the salt of a base which is also obtained by the 
splitting off of carbon dioxide from histamine, and is B. 
imidazolethylamine. Dale and Laidlaw19 refer to the similar- 
ity of the reaction of this substance, which they call histamine, 
to that of the intoxicating agent in anaphylaxis, and have sug- 
gested that it may be the active principle concerned. Should 
the identity of these substances be proved, the value of the 
more recent experiments by Dale and Laidlaw20 upon the 
reaction of the tissues to histamine, will be greatly enhanced. 
Intravenous injection of 0.5 milligram of B. imidazolethyl- 
amine or histamine into large guinea pigs, results in respira- 
"Brieger: Die Ptomaine. 
''Whipple and Cook: Jour. Exper. Med., 1917, xxv, 461. 
''Heidenheim: Pfliiger's Arch., No. 49, 1891. (Quoted by Zinsser.) 
''Calvary: MUnch. med. Wchnschr., 1911, xiii. 
"Barger and Dale: Jour. Physiol., 1910, 11, 499. 
"Dale and Laidlaw: Jour. Physiol., 1910, li, 318. 
"Dale and Laidlaw: Med. Res. Com. Mem., on Shock, February, 1917. 138 
INFECTION, IMMUNITY, AND INFLAMMATION 
tory difficulties, convulsions and death. At autopsy disten- 
tion of the lungs, typical of anaphylactic shock, is found. 
Treatment of the animal with atropin diminished the severity 
of the reaction, just as Auer and Lewis21 found this to be the 
case in true anaphylaxis. In dogs, fall in blood pressure 
characterizes the reaction. It would seem then that substances 
representing cleavage of native proteins of highly complex 
nature, the result of proteolytic cleavage not very far ad- 
vanced, are probably concerned in the production of anaphy- 
lactic shock. 
Histamine has a synergetic relation to anaphylactic shock 
(M. I. Smith22). This may be either because the point of 
contact to histamine and the anaphylactic irritations are the 
same, or because they are closely related to one another. 
The chief respects in which histamine fails to account for 
all the phenomena of anaphylaxis are, according to Wells:23 
1. It fails to desensitize animals or tissues, yet produces 
strong reactions in the uterus strip that has been thoroughly 
desensitized. (Dale.24) 
2. Histamine does not produce the temperature reactions 
usual in anaphylaxis. 
3. Histamine does not produce the changes in coagulability 
of the blood usual in anaphylaxis. 
4. Quinine augments the susceptibility of sensitized animals 
to anaphylactic shock, but not to histamine poisoning. 
There is no reason for expecting that histamine, even though 
it be identical with the anaphylactic poison, should desensitize 
anaphylactic animals or tissues. The antibody which is ex- 
hausted during desensitization is the substance which is re- 
sponsible for the production of an irritant through its reaction 
with antigen. Up to the present no experiments have been 
attempted which would indicate that repeated sublethal in- 
jections of histamine induce tolerance, nor that tolerance is 
exhausted by histamine introduction. 
Since the effect upon temperature in anaphylactic experi- 
21Auer and Lewis: Jour. Am. Med. Assn., 1909, liii, 458. 
"Smith, M. I.: Jour. Immunol., 1920, v, 239. 
"Wells: Physiological Review, 1921, i, 44. 
"Dale: Jour. Pharmacol, and Exper. Therap., 1913, iv, 167. ANAPHYLACTOID PHENOMENA 
139 
ments is dependent largely upon the dose of antigen employed 
and the route of administration, the fact that typical tem- 
perature changes have not been observed in histamine poison- 
ing cannot be accepted as final proof that histamine shock and 
anaphylaxis are not related to one another. 
With regard to the fact that quinine augments the suscepti- 
bility of sensitized animals to the antigen it is altogether 
likely, as Wells points out, that it is the antigen-antibody re- 
action which is aided, and not an increased sensitiveness on 
the part of the tissue cells to the product of this reaction. 
Not only does histamine poisoning mimic anaphylactic 
shock in the guinea pig and in the dog, but also in the rabbit. 
Dale and Laidlaw25 have noted that the cause of death in 
histamine poisoning was pulmonary obstruction which leads 
to acute dilatation of the right heart. This in Coca's26 opinion 
is the cause of death in anaphylaxis in these animals. 
Taraxy (Novy). ''Nonspecific Anaphylaxis" 
Experiments by Novy and DeKruif,27 published in 1917, 
show that a type of shock indistinguishable, either clinically 
or at autopsy, from specific anaphylaxis may be produced by 
the addition of serum in vitro by a variety of substances, agar, 
peptone, inulin, kaolin, distilled water, organ extracts, and 
numerous other substances usually looked upon as nontoxic. 
Similar phenomena follow intravenous injection of suitable 
amounts of these materials. 
These observers suggest the hypothesis that in true specific 
anaphylaxis and ''peptone anaphylaxis," as well as in the 
type of nonspecific anaphylaxis which they have investigated, 
the matrix of the poison is not the antigen introduced, but is 
a normal constituent of the tissues (blood). The foreign sub- 
stance which induces the formation of the toxic body, whether 
these foreign substances be the result of the specific inter- 
action of some newly formed substance in the sensitized animal 
with the injected protein, or whether it be represented by the 
agar or distilled water of their experiments, acts as a catalyser 
"Dale and Laidlaw: Jour. Physiol., 1911, xliii, 182. 
"Coca: Jour. Immunol., 1919, iv, 219. 
27 Novy and DeKruif: Jour. Am. Med. Assn., 1917, Ixvii, 1528. 140 
INFECTION, IMMUNITY, AND INFLAMMATION 
in a manner similar to that of the inducing substance in the 
formation of fibrin from fibrinogen. These authors found a 
very important factor in the physical state of the agar, and 
that ferment action is probably not all it involved. 
Novy and DeKruif also found that occasionally transfusion 
of blood, from animals in which nonspecific anaphylactic shock 
had been produced, was followed by manifestations of toxic 
effects in recipient guinea pigs. 
Anaphylactoid Phenomena Due to Flocculation of Colloids 
A most interesting series of experiments have been carried 
out by Karsner and Hanzlik, and by Kopacrewski. These two 
groups of observers differ in their explanation of the phenom- 
ena which they have encountered, and in their relationship to 
the anaphylactic reaction. Karsner and Hanzlik have shown 
that agar and numerous other substances produce anaphylac- 
toid symptoms after intravenous injection. The symptoms, 
they believe, occur as a result of occlusion of the pulmonary 
capillaries. This is due to thrombosis or to agglutination of 
corpuscles or platelets. The capillary obstruction is demon- 
strated both by the identification of emboli, and by arrest of 
perfusion fluids injected into the pulmonary vessels. In con- 
sequence of this capillary obstruction, there may occur a 
marked bronchial spasm which causes asphyxia and permanent 
obstruction of the lungs. They state, "On the basis of the 
results obtained with atropin and epinephrin, the mechanism 
of the action of agar and similar agents bears no relationship 
to anaphylaxis or anaphlyactic shock." 
Concentrations of agar as low as 0.001 per cent cause agglu- 
tination in vitro: other colloids act in varying concentrations 
(e.g., acacia, 1.0; althea, 0.08; collargol, 0.005; gelatin, 0.05; 
nuclein, 0.5; beef serum, 0.005 per cent). "The quantity of 
agar necessary to produce profound effects, or even death, is 
remarkably small, namely, about 0.014 to 0.05 mg. per gram 
of body weight." 
In order to avoid confusion as the result of such occlusion 
of pulmonary capillaries, Wells has usually selected the intra- ANAPHYLACTOID PHENOMENA 
141 
peritoneal route for the performance of anaphylactic relations. 
For the same reason, Besredka has since 1907 employed the 
intracerebral method of injection of the exciting dose. 
Kopacrewski28 points out that widely diverse substances 
which have proved useful in the prevention and amelioration 
of anaphylactic shock all have one or two traits in common. 
All such substances either prevent flaking in the blood serum, 
or they dilate the blood vessels. Kopacrewski believes that 
his experiments prove that anaphylactic shock is the result of 
physical changes in the blood serum which permit flocculation 
of the molecules. Dark ground illumination has shown that 
flaking occurs in blood serum, when the latter is brought in 
contact with certain colloids. The surface tension of the 
serum of animals that have died from anaphylactic shock, he 
has found to be much reduced. This is a phenomenon which 
always accompanies colloidal flocculation. Kopacrewski is of 
the opinion .that capillary embolism in the lungs is character- 
istic of anaphylaxis, and that it is due to the flocculation. 
His explanation is that the introduction into the serum of a 
normal animal of one of a group of colloidal substances up- 
sets the colloidal balance, and there is flocculation of the mole- 
cules. The flakes, thus formed, obstruct the capillary network, 
and thus induce explosive asphyxia. Prophylaxis and treat- 
ment demand the administration of substances that reduce the 
superficial tension of the blood serum (saponia, soaps, bile 
salts, anesthetics, hypnotics, lecithin, etc.), or to render the 
serum more viscous (sugars, glycerin, acacia, carbonates, al- 
kalines, etc.) or to dilate the blood vessels and thus allow the 
passage of the flaked micella (calcium lactate, atropin, etc.). 
No facts have been so far discovered, he declares, which con- 
flict with this physical conception of anaphylaxis and anti- 
anaphylaxis. Kopacrewski injected into the blood of animals 
an amount of anesthetic which was equal to that found in the 
blood of an anesthetized animal, although the animal did not 
show signs of anesthesia. This animal was protected against 
anaphylactic shock in the same way as the anesthetized animal. 
"Kopacrewski: Ann. de Med., 1920, viil, 291. CHAPTER XIV 
SITE OF THE REACTION BETWEEN ANTIGEN AND 
ANAPHYLACTIC ANTIBODY 
With regard to the process of development, origin or site 
of the production of the anaphylactic toxic body, there are 
at the present time several theories, each of which is insuffi- 
ciently supported by experimental evidence. Upon one sub- 
ject, only, is there unanimity of opinion, namely, that the 
irritant substance, responsible for the manifestations of ana- 
phylaxis, is the result of an interaction between a specific 
antibody (anaphylactic-first order antibody), which is pro- 
duced by the animal tissues under stimulation, and the injected 
protein antigen. 
In "active" anaphylaxis the antibodies are present as the 
result of the reaction to a preceding antigen injection. In 
the "passive" condition they were conveyed with the in- 
jected antiserum (Zinsser). 
Two theories, in particular, have been advanced and much 
experimental data published in order to support each of the 
two views, respectively. 
The first of these theories, and one which obtained a keen 
and able protagonist on this Continent in the person of the 
late Richard Weil,1 assumes that the sensitive animal is such 
because certain of its tissue cells have produced sessile recep- 
tors, which have an affinity for the specific antigen: and that 
the protection from injurious action enjoyed by immune (tol- 
erant) animals is due to the fact that the blood plasma of 
immune animals contains free antibodies so that the fixed re- 
ceptors, attached to the cells, are guarded against the action 
of the injected protein. This hypothesis appears to assume 
that proteins, as such, are toxic to such cells as possess recep- 
'Weil: Jour. Med. Research, 1913, xxvii, 497. 
142 ANTIGEN AND ANAPHYLACTIC ANTIBODY 
143 
tors capable of fixing them, and that the hypersensitive, or 
anaphylactic, state is developed as the result of the produc- 
tion, on the part of the cells, under stimulation, of such fixing 
receptors. The further development of free receptors as the 
result of repeated sublethal injection, according to this point 
of view, results in the protection of the cells through an ab- 
sorption of the toxic protein by such circulating receptors. 
This theory is simple and is in accord with Ehrlich's hypoth- 
esis. It is, too, supported by a certain amount of experimental 
evidence. There are, however, certain established facts rela- 
tive to the nature of anaphylactic toxicity which are entirely 
disregarded by the supporters of this theory; which facts, 
moreover, are quite sufficient, in my opinion, to render such 
an hypothesis untenable. 
The fundamental differences between the so-called humoral 
and the cellular theory are as follows: According to the cellu- 
lar theory, it is assumed that only such antibodies as are fixed 
to, and have become integral parts of, tissue cells, are able 
to react with injected antigen in such a way as to injure the 
tissue cells. Antibodies free in the body fluid do not take part 
in any reaction which results in the production of an irritant. 
According to the so-called humoral point of view the reac- 
tion between antigen and antibody results in the development 
of a tissue irritant. This latter substance causes injury to, 
or at least induces reaction in, such cells as are susceptible to 
its action. 
Those investigators (Weil,2 Besredka3) who most earnestly 
support the conception of anaphylaxis and immunity as con- 
sisting simply in the primary production of "sessile recep- 
tors" and ultimately of free "immune bodies," lay great stress 
upon the fact that according to their theory, immune proc- 
esses are shown to be cellular and that any other point of 
view assumes that the process is entirely humoral. This atti- 
tude is, in the author's opinion, unreasonable, since it is obvi- 
'Weil: Jour. Med. Research, 1913, xxvii, 497. 
•Besredka: Compt. Rend, de la Soc. de Biol., 1907, Ixiii, 294. 
Besredka-Gloyne: Anaphylaxis and Anti-anaphylaxis, 1919, C. V. Mosby 
Co., St. Louis. • 144 
INFECTION, IMMUNITY, AND INFLAMMATION 
ous that whatever may be the correct explanation of these 
phenomena, the process must be due to cellular activity and 
ultimately to cellular irritation. 
Obviously all antibodies present in the body fluids must 
primarily have had their origin in tissue cells. Presumably 
also, it is only such cells as normally have the property of 
combining with foreign molecules that can be expected to 
produce such antibodies. Consequently, it is not surprising 
that at an early stage in the development of the anaphylactic 
state the antibodies responsible for the reaction are intimately 
associated with those tissue cells which are responsible for 
their production, and that, toward the period in which hyper- 
sensitiveness to the protein antigen is lost, only in those cells, 
which were primarily responsible for the production of the 
antibodies, will antibodies be present. 
According to the hypothesis of cellular sensitization, hyper- 
sensitiveness of the tissue occurs as the result of the develop- 
ment on the part of certain of the tissue cells of specific affin- 
ities or receptors. By reason of these acquired affinities, these 
cells fix or anchor the injected protein and thus accomplish 
their own injury. It would appear that according to this 
theory all foreign proteins must be assumed to possess injuri- 
ous properties for all cells able to anchor them. It must be 
further assumed that even though different protein molecules 
differ from one another in chemical arrangement they are all 
capable of affecting sensitized cells in a like injurious man- 
ner, since, in the same species of animal, the same symptoms 
of intoxication follow the injection of a large number of pro- 
teins from different sources. 
The so-called humoral theory, or the theory of antigen- 
antibody reaction, conceives the changes which occur in the 
animal body during the process of sensitization to be as fol- 
lows: Whereas the majority of complex proteins-albumins 
and globulins-are relatively innocuous when parenterally 
introduced into the tissues of normal animals, such injections 
are followed by the production, by certain tissue cells, of 
antibodies which so reaet with subsequently introduced anti- ANTIGEN AND ANAPHYLACTIC ANTIBODY 
145 
gen that a substance, which acts as an irritant to the tissue 
cells, is produced. 
The basis upon which these two hypotheses are termed cellu- 
lar and humoral, is derived from the result of transferred ana- 
phylaxis. Exponents of the "cellular" theory maintain that 
the injected animal is rendered anaphylactic by reason of the 
withdrawal of the free receptors present in the serum of re- 
peatedly inoculated animals from the circulating blood, and 
their fixation by the tissue cells. The so-called "humoralists" 
explain the occurrence of transferred or passive anaphylaxis 
by simply stating that the injected animal receives the pro- 
tein altering (splitting) substance produced by the tissues of 
the actively treated animal, and that, as a result, the specific 
antigenic protein, when subsequently introduced, is rapidly 
altered with the production of irritant substances (toxic split 
proteins). 
The chief stumbling block, interfering with the general ac- 
ceptance of the theory of antigen-antibody reaction as opposed 
to cellular sensitization, is that which arises from the fact 
that passive transfer of the anaphylactic state appears to 
require the lapse of a definite period of time between injection 
of the sensitizing serum and its antigen. Passive sensitization 
of normal animals is produced with great regularity if an 
interval-incubation period-is permitted to elapse between 
the introduction of the sensitizing serum and the intoxicating 
injection On the other hand, it has been found difficult to 
induce anaphylaxis if the transferred serum and the anti- 
genic protein are introduced immediately following one an- 
other. It is during the incubation period that the sessile 
receptors of the donor's serum are supposed to become fixed 
by the tissue cells of the recipient; thus, upon the basis of 
cellular hypothesis, this phenomenon (incubation period) is 
easily explained. 
According to the theory of antigen-antibody (humoral) 
reaction no such period of incubation should be necessary, 
although it does not seem unreasonable to suppose that the 
more intimately the injected antibodies are brought in con- 146 
INFECTION, IMMUNITY, AND INFLAMMATION 
tact with such cells as are susceptible to irritation by the 
product of antigen-antibody reaction, the more marked will 
be the manifestations of intoxication on the part of these cells. 
The question as to whether, in order that an animal may 
become hypersensitive, the injected anaphylactic antibodies 
must first become an integral part of the tissue cells, is of 
fundamental importance. Experiments performed by the 
author and published in 1914, as well as those by Doerr and 
Russ, have proved that, although more reliable Results are 
obtained in performing experiments of transferred anaphy- 
laxis, if an incubation period be allowed to elapse, such an 
incubation period is not essential. It is possible both by the 
simultaneous injection of sensitizing serum and antigen, and 
by the injection of mixtures of sensitizing serum and anti- 
gen, to induce immediate manifestations of anaphylactic shock. 
The "humoral" conception of anaphylaxis and immunity is 
based in part upon analogy, and in part upon direct experi- 
ment. The majority of native proteins are not poisonous to 
normal animals. It is now well established that the serum of 
sensitive and immune (tolerant) animals contains substances 
which are capable of inducing alteration of the protein mole- 
cule with the result that a highly toxic substance is formed or 
liberated. Degradation products of protein cleavage closely 
related to the peptones and proteoses, at least insofar as this 
relationship refers to the stage in the digestive process at 
which they are produced, are potent to produce, upon intra- 
venous injection into animals, symptoms which are indistin- 
guishable from those which characterize anaphylactic shock. 
The humoral theory assumes the hypersensitive state to be 
due to the presence in the tissues of the animal, of antibodies 
which react with the injected protein antigen in such a way 
that a product is formed which directly or indirectly induces 
manifestations of irritation on the part of the tissue cells. 
That these antibodies must be produced by the cells of the 
body is physiologically obvious, and that they should persist 
in close association with the cells responsible for their pro- 
duction so that animals remain sensitive even after demon- ANTIGEN AND ANAPHYLACTIC ANTIBODY 
147 
strable amounts are absent in the serum, seems, a priori at 
least, equally reasonable. That, moreover, following the pas- 
sive sensitization of normal animals the antibodies injected 
should become localized in certain cells does not appear to be 
entirely unlikely. Such facts, therefore, as the difficulty of 
producing transferred sensitization without the lapse of a few 
hours following the introduction of the sensitizing serum and 
the diminution-as proved by Weil and others-of the amount 
of circulating anaphylactic body in the serum, do not in any 
way disprove the adequacy of this hypothesis. 
By, perhaps, the majority of recent observers and students 
(Weil, Schultz, Zinsser) of the subject of anaphylaxis the fact 
that, in passive sensitization of guinea pigs, more reliable re- 
sults are obtained if an incubation period, of at least four 
hours following the injection of the sensitizing serum, is al- 
lowed to intervene before testing for hypersensitiveness, has 
been accepted as proof that the sensitizing antibody must be 
attached to suitable cells before anaphylaxis can be demon- 
strated. This view is opposed fundamentally to that cham- 
pioned by Friedemann and Friedberger, namely; that the ir- 
ritant substance is a result of a reaction between soluble cir- 
culating antibody and its specific antigen. 
Other important experiments, which appear at first sight 
to invalidate the humoral hypothesis, are those of Schultz. 
This author showed that isolated segments of intestine or 
uterus from sensitized animals react to the specific antigen by 
contraction. Schultz' observations have been further devel- 
oped by Dale and by the late Richard Weil. There are two 
explanations, each of which in part explains both the effect 
of the incubation interval and Schultz' experiments. On the 
one hand it is evident that, granted a given minimal amount 
of sensitizing antibody, its effect upon sensitive cells will be 
more evident, if that sensitizing body is present in the body 
fluids, bathing the cells or within the cells themselves. 
That the reaction between anaphylactin (first order anti- 
body) and antigen should be less effective if it takes place 
within the circulating blood, than if it is in closer association 148 
INFECTION, IMMUNITY, AND INFLAMMATION 
with the body cells, is to be expected. That it is necessary 
for the anaphylactic antibody to become an integral part of 
the cell in a chemical sense is, in the author's opinion, highly 
improbable. A more adequate conception of the nature of the 
reaction is obtained, in my opinion, if the animal body be 
looked upon as consisting of fluid in which the various cel- 
lular elements are suspended, and with which they are sat- 
urated. 
It may well be that the following is an explanation of the 
apparent fact that the unstriped muscle tissues of the body 
absorb proportionately more of the injected anaphylactin than 
do other tissues. There can be but little doubt that, to use 
the terminology of Ehrlich, the unstriped muscle tissues have 
receptors which make it possible for them to anchor circu- 
lating heterologous proteins from the body fluids with more 
avidity than other tissues. If this be the case, it is to be 
expected that when a foreign serum, e.g., rabbit serum, con- 
taining anaphylactic antibodies is injected into a guinea pig, 
more of the injected serum will be absorbed by the nonstriated 
muscle cells as in the bronchial walls, the hepatic vessels, and 
the uterus, than by other tissues. One of the natural results 
of such a determination of the injected antigen would be 
saturation of these cells by the antibody constituent of the 
injected serum to a greater degree than other cells of the body. 
Another possible explanation for the incubation period, and 
the one which is doubtless active when large doses of ''im- 
mune ' ' serum are used in transferred sensitization, is that both 
sensitizing and tolerant bodies are present in such sera, and 
that unless the relative proportions of sensitizing serum and 
antigen are exactly suitable in the dilutions, which exist in 
the circulating fluid, no manifestations of irritation are ex- 
hibited, until such time as, through a process of diffusion, the 
relative potency of the tolerant body has been diminished. 
The fact that isolated guinea pig uterus segments, even 
though thoroughly washed by perfusion experiments, still re- 
act to the presence, in the fluid in which they are suspended, 
of the specific antigen to which the animal, from which the ANTIGEN AND ANAPHYLACTIC ANTIBODY 
149 
uterus was removed, had been sensitized, may be explained 
as being due to the fact that the individual cells are them- 
selves filled with body fluid. It is obvious that it is impossible 
to prove this point by direct experiment since it would be 
argued that, if sufficient washing of the uterine segments were 
persisted in, to remove the intracellular body fluid, failure of 
the muscle to react would be interpreted as being due to death 
of the cell. 
Pearce and Eisenbrey report experiments in which, as a 
result of transfusion of the blood of a hypersensitive to a nor- 
mal animal, and from a normal to a hypersensitive animal, 
they attempted to induce anaphylactic shock in both animals. 
They found that when both the animals, each of which weighed 
about 7,000 grams, were injected with 5 c.c. of horse serum, 
the hypersensitive animal, which had had its blood replaced 
by transfusion from a normal animal, reacted immediately by 
a fall in blood pressure from 90 mm. to 24 mm. The normal 
animal, which had received blood from the hypersensitive dog, 
which had been treated by 5 c.c. of horse serum subcutaneously 
twenty-five days previously, showed no change in pressure 
except slight mechanical rise. 
These experiments are interpreted by their authors as prov- 
ing that the reaction between antigen and antibody occurs 
only when the latter are fixed to the cells. It must be pointed 
out, however, that this is not necessarily the case, since in 
an animal sensitized, as was dog B, with but one injection of 
horse serum, very few circulating antibodies are ordinarily 
present. The absence of reaction, therefore, in the recipient of 
such blood is of relatively little importance. On the other 
hand, although the hypersensitive animal had its circulating 
blood fluid removed and replaced by normal blood, the pro- 
portion of body fluid remaining in the tissues was subjected 
to relatively little diminution. 
Experiments by Doerr and Pick, which show that, even 
after all demonstrable antibodies have disappeared from the 
circulating blood in the rabbit, fatal anaphylactic shock may 150 
INFECTION, IMMUNITY, AND INFLAMMATION 
be produced, as pointed out by Wells, may be employed as 
proof of the humoral as well as for the cellular hypothesis. 
The evidence at present available indicates that the antigen- 
antibody reaction, responsible for the phenomenon of anaphy- 
laxis, takes place wherever these substances are brought in 
contact with one another. If the reaction occurs within the 
cytoplasm of susceptible cells, the manifestations of tissue 
irritation is more marked than if a similar reaction occurs in 
the circulating blood or in body fluid removed from the site 
of cells susceptible to the product of the antigen-antibody re- 
action. 
Wells4 objects to those experiments which have been re- 
ported that when suitable quantities of antigen and antibody 
are used it is sometimes possible to secure evidence of passive 
sensitization without the usual period of incubation, on the 
ground that the results are obtained only occasionally, are 
usually slight in character, and without the necessary regu- 
larity to be convincing proof of a fundamental principle. The 
author has attempted to show what may be the reason that 
regularity in reactions of this sort is difficult to obtain. Weil 
earnestly (see page 164) doubted the true anaphylactic char- 
acter of those reactions which have been observed. In my 
experiments the results obtained were typical of those ordi- 
narily characterizing anaphylactic shock in the guinea pig. 
In discussing the source of the toxic substance in the ana- 
phylactic reaction Wells states: "The 'anaphylatoxin' hy- 
pothesis fitted most of the known facts so well, and was so 
perfectly logical, that it seemed almost inevitable, yet at the 
present time it appears to be untenable, in the face of existing 
evidence, as the final explanation of anaphylaxis." The dem- 
onstration that from almost any protein a toxic moiety can be 
produced by cleavage which produced effects in animals, closely 
resembling anaphylaxis, and by Friedberger that mixtures in 
vitro of antigen-antibody and complement become highly poi- 
sonous as well as the similarity of "peptone" and anaphylactic 
shock, is at least suggestive that anaphylaxis is the result of 
•'Wells: Physiological Reviews, 1921, i, No. 1. ANTIGEN AND ANAPHYLACTIC ANTIBODY 
151 
a toxic substance resulting from proteolysis induced by the 
action of alexin, after sensitization of the antigen by the 
anaphylactic antibody. (Wells.) 
"On the other hand, there is no doubt that antigen-antibody 
reactions do produce, at least in vitro, substances that are 
eminently injurious, especially on intravascular injection, and 
it seems reasonable indeed to believe that such substances 
may be produced in the typical anaphylaxis reaction and play 
some part in it, even if we grant that the typical anaphylac- 
tic shock depends on reaction within certain tissue cells. For 
example, Manwaring and Kusama,5 found that although iso- 
lated lungs from sensitized guinea pigs exhibited strong bron- 
chial constriction when perfused with the specific antigen, 
they gave still stronger reactions when the blood of the sen- 
sitized animal was present in the perfusion fluid (Wells)." 
Wells sums up the points that have been advanced against 
the so-called humoral anaphylatoxin theory as follows: Pos- 
sible explanations of these objections are also quoted from 
Wells: 
1. "It does not fit with the latent period of passive sensi- 
tization. However, intracellular formation of anaphylatoxin 
might account for this phenomenon." As the author has 
elsewhere shown, this incubation period is not an essential 
characteristic of passive sensitization. Theoretically, the more 
reliable results which are obtained if a time interval be per- 
mitted to elapse can be explained. 
2. "Complement is not essential, since animals deprived 
of free complement in the circulating blood may still give 
anaphylactic reactions. Here again, one may suggest the 
presence of intracellular or reserve complement." It should 
be pointed out, moreover, that it is doubtful whether this 
statement is, in fact, correct. 
3. "All attempts to prove that complement is a proteolytic 
ferment have so far failed." Nevertheless, numerous experi- 
ments suggest that this is the case. 
'Manwaring and Kusama: Jour. Immunol., 1917, ii, 157. 152 
INFECTION, IMMUNITY, AND INFLAMMATION 
4. '1 Anaphylatoxin " activity has been produced in serum 
by digestion in the absence of complement, in the absence of 
antigen, and in the absence of antibody. On the other hand 
if antigen and the specific antibody are injected simultane- 
ously into the opposite jugular veins of a guinea pig, the 
animal shows no evidence of intoxication." In a separate 
section the fact that although the mechanism of "anaphyla- 
toxin" production by more specific methods may differ from 
that of ordinary anaphylaxis, the result may well be iden- 
tical, namely-degradation of protein with liberation of its 
toxic moiety. The author's experiments disprove the assertion 
contained in the second sentence of this paragraph. 
5. "In the anaphylatoxin experiments the existence of cap- 
illary embolism or endothelial intoxication has not been ex- 
cluded, and there is reason to believe that most of the ob- 
served symptoms are anaphylactoid rather than anaphylactic." 
6. "All attempts to demonstrate that the blood of animals 
in anaphylactic shock contains a poison responsible for the 
observed manifestations, have failed (see Weil6)." It is dif- 
ficult to imagine that, even though it be assumed that a sub- 
stance of the nature of "anaphylatoxin" be produced in the 
body fluid, the toxic substance should remain in the circulat- 
ing blood long enough to permit of its identification. 
It will be seen that, although Wells allies himself, in gen- 
eral, with those who are opposed to the humoral anaphylatoxin 
theory, he considers the question as not definitely decided. 
He writes: 
"But we cannot escape the fact that the manifestations of 
anaphylactic shock resemble in all respects those of an acute 
intoxication: furthermore, that histamine, the substance which 
produces the picture most closely resembling that of typical 
anaphylaxis, is a product of protein cleavage (see Abel and 
Kubota,7 Dale,8 Hanke and Koessler9). Not only does hista- 
mine cause bronchial spasm in guinea pigs, obstruction to 
®Weil: Jour. Immunol., 1917, ii, 399. 
'Abel and Kubota: Jour. Pharmacol, and Exper. Therap., 1913, iv, 167. 
8Dale: Bull. Johns Hopkins Hosp., 1920, xxxi, 257, 310. 
9Hanke and Koessler: Jour. Biol. Chem., 1920, xliii, 521-579. ANTIGEN AND ANAPHYLACTIC ANTIBODY 
153 
pulmonary circulation in rabbits and fall of blood pressure 
in dogs, but applied to the skin or mucous membranes, it 
causes marked local urticaria resembling closely that of skin 
reactions in sensitized persons, and it does all these things in 
extremely minute dosage, comparable with the dosage of pro- 
teins used in the anaphylactic reaction. Furthermore, its 
antecedent amino acid, histidine, is present in every known 
complete protein. Other pure chemical products of protein 
cleavage, such as methyl guanidine, have more or less similar 
effects." CHAPTER XV 
NATURE OF THE REACTION BETWEEN ANAPHYLAC- 
TIC (FIRST ORDER) ANTIBODY AND ANTIGEN 
In 1910 Rosenau and Anderson presented the following view 
of anaphylaxis in the guinea pig: 
Hypersusceptibility to a foreign protein consists in an in- 
crease in the normal power of assimilating this protein, espe- 
cially an increase in the rapidity of the reaction. This is due 
to the formation of a specific antibody (or antibodies), demon- 
strable both in somatic tissues (smooth muscle) and in the 
serum of sensitive guinea pigs. The action of this antibody 
upon its antigen is quantitative, and probably primarily pro- 
teolytic. The action of this antibody apparently needs to be 
aided by the nonspecific alexin of the blood. The structure 
of the antibody concerned is, of course, unknown, as is also 
the nature of the chemical changes produced by it. 
Rosenau and Anderson believed anaphylactic shock to be 
a disturbance of metabolic equilibrium due to temporary de- 
flection of the normal metabolic activity of the tissue cells, 
rather than the result of any specific toxic action. 
By certain observers, notably von Pirquet and Shick, it is 
thought that tissue irritation is the result of a reaction be- 
tween two bodies (allergin and antigen) with the formation 
of a toxic substance. Richet, too, believes this to be the case, 
and terms the antibody present in the serum, toxogenin; the 
end product he designates by the expression apotoxin. An- 
other series of observers, in particular Pfeiffer, Weichardt 
and Wolff-Eisner, regard the toxin as being preformed in the 
protein molecule, and to be merely liberated by the action of 
the antibody. According to this hypothesis, each bacterium 
or other protein substance contains a specific endotoxin. 
Whether the product of the reaction between first order 
antibody and antigen is a poison in the ordinary sense, or 
154 ANAPHYLACTIC ANTIBODY AND ANTIGEN 
155 
whether it represents a process which causes a discharge of 
energy after the nature of an electrical stimulus, is not known. 
That the explanation of the reaction between the antigen- 
antibody reaction product and the affected cell is to be found 
in an alteration in the colloidal state of the molecules con- 
stituting the latter, is not unlikely. That it acts as a tissue 
irritant is obvious. In the following pages are discussed the 
more probable methods whereby this tissue irritant may be 
developed. 
It has been recognized for a number of years that immunity 
treats of the adaptation of the body tissues to the presence of 
foreign proteins.1 Prolongation of life of the individual de- 
pends, in part, upon the ability of the organism, or certain 
specially differentiated parts thereof, so to act upon and alter 
complex protein molecules that they may be rendered useful, 
or at least not injurious to the individual's component cells. 
Native proteins in the circulation or body fluids of the 
higher animals are not only useless, but are often directly 
harmful to the tissue cells. Phylogenetically it might be ex- 
pected, and practically it may be proved, that the tissue cells 
are by no means helpless to protect themselves against such 
deleterious influences, for it has been proved, particularly by 
Alberhalden and his associates, that, within twenty-four hours 
after the injection of foreign proteins, digestive enzymes may 
be identified in the serum; although such ferments are not 
present in demonstrable amounts in the normal, noninjected 
animal. Direct evidence of the digestive activity of the sub- 
stances produced by the body tissues under such circum- 
stances has been obtained by Abderhalden by means of the 
polariscope and by dialysis experiments. 
Vaughan conceives the poison isolated by him to be the 
keystone or archon of the protein molecule. It is the pri- 
mary atomic group and is common to all protein molecules. 
One protein differs from another in the secondary and ter- 
tiary groups. Ordinary proteins are not poisonous because 
1The problems of Immunity narrow themselves down to special problems 
bearing upon the (parenteral) digestion and assimilation of unusual protein 
matter, or at least of the primary products of cell metabolism (Adami). 156 
INFECTION, IMMUNITY, AND INFLAMMATION 
in them the chemism of the primary group is satisfied by com- 
bination with secondary groups. When the secondary groups 
are stripped off by hydrolysis or ferment action, the primary 
group becomes poisonous on account of the avidity with which 
it combines with the secondary groups of other molecules. 
Injury to the cells, of which the latter molecules form a part, 
is thus accomplished. The specific serologic reactions which 
are provoked by protein antigens are due to the secondary 
groups of their molecules. 
In the author's opinion, the data at present at our disposal 
justifies the adoption of the following hypothesis of the im- 
munologic process. 
Large molecular protein complexes cannot be made use of 
by the tissues and are recognized as foreign bodies by the 
tissue cells. In consequence, certain cells produce substances 
which are known as antibodies (first order), whose function 
it is to bring about cleavage or disintegration of the complex 
protein. This is the first step in the immunologic reaction 
to the presence in the tissues of foreign proteins. Complete 
cleavage of the protein molecule to the stage of amino acid 
formation renders the protein not only harmless, but subject 
to utilization by the tissue cells. This stage of complete pro- 
tein degradation is not, however, accomplished by the first 
order of antibodies, which are potent only to cause partial 
cleavage. Partial protein degradation products (to the stage 
of peptone-proteose formation) cause symptoms of tissue irri- 
tation. 
When the tissues contain a considerable proportion of anti- 
body (first order) which is capable of disintegrating protein 
to the irritant stage, the animal is said to be hypersensitive 
to the parenteral introduction of the whole protein. At this 
time the rapid introduction of antigen into the blood stream, 
or by any other route which permits of rapid absorption of 
even small quantities of the whole protein, provokes anaphy- 
lactic shock. When susceptible to anaphylactic shock in this 
way, the animal is said to be in the anaphylactic state. 
Repeated introduction of a protein into the tissues stimulate ANAPHYLACTIC ANTIBODY AND ANTIGEN 
157 
the production of a second order of antibody, whose function 
is the more complete dissociation of the protein molecule. 
When this second order antibody is present in the tissues, the 
latter are not susceptible to injury consequent upon the paren- 
teral introduction of moderate quantities of antigenic protein. 
When in this state, the animal is said to be tolerant. 
The Theory of Parenteral Digestion 
Although several links in the chain of evidence, proving 
that the reaction which takes place between anaphylactic anti- 
body and specific antigenic protein consists in a cleavage of 
the latter, remain to be forged, a reasonable amount of data 
upon which to base such an hypothesis has already been 
accumulated. 
Briefly recapitulated, these data comprise the following 
observations: Cleavage products of complex proteins pro- 
duced by the action of heat or chemicals are potent to induce 
symptoms of intoxication in normal animals, which are in- 
distinguishable from those which occur in anaphylactic shock 
(Vaughan). Peptone and proteose mixtures produced by the 
digestive action of animal ferments possess similar proper- 
ties (Biedl and Kraus). If immune sera and antigenic protein 
be mixed, in suitable proportions, and incubated, a highly 
toxic substance is produced (Friedemann). Specific precipi- 
tates when dissolved in an excess of fresh normal serum dem- 
onstrate like properties (Friedberger). The author's experi- 
ments in the production of anaphylactic shock, by means of 
the simultaneous injection of antigen and antibody, show that 
a similarly irritant substance may be produced in the body 
of normal animals. 
It has been proved that anaphylaxis is a phenomenon, which 
occurs as the result of the repeated introduction of foreign 
protein substances parenterally into the tissues of an animal. 
Experiments suggest that it is possible that digestive processes 
may take place in the tissues of animals, analogous to those 
which occur normally in the alimentary tract. 
One of the chief natural foodstuffs of the animal organism 158 
INFECTION, IMMUNITY, AND INFLAMMATION 
consists of albumin in one or other form. These proteins are 
ingested as meats and various sorts of vegetable products and 
are digested in the alimentary tract. Subsequently, they are 
absorbed into the lymphatic and blood streams where they 
are available for the use of the tissue cells. The process of 
digestion of proteins consists essentially in hydrolysis, whereby 
the more complex albumin or globulin molecule is broken 
down to form first, peptones and histones, and ultimately 
polypeptids and amino acids, such as tryptophan, zein, cystine, 
etc. These amino acids, it has been proved, may be injected 
with impunity into the tissues, in which event not only are 
they innocuous, but they are subject to utilization by the 
body cells. 
Not so, however, the cleavage products which appear at the 
stage of peptone formation, which have been proved by Biedl 
and Kraus, and others, to be capable of inducing reactions 
similar to anaphylactic phenomena when injected into nor- 
mal animals. It has been shown by several observers, em- 
ploying different methods, that, during the process of proteo- 
clasis-by ferments, heat and chemicals,-there are developed 
degradation products of the protein molecule, which are ex- 
tremely toxic. (Biedl and Kraus,2 Vaughan, Jobling, Fried- 
berger, Rosenow, Dick.) 
These split products are developed at the stage in hydrol- 
ysis which corresponds to that at which peptones and pro- 
teoses are produced. The symptoms provoked by such split 
products correspond closely to those which occur during 
anaphylactic shock. Such being the case, and since similar 
phenomena are produced following the injection of the prod- 
ucts of the interaction of serum from immune animals and 
specific antigenic protein (Fricdberger, Friedemann), it is 
believed by many observers that the phenomenon of anaphy- 
laxis is a concomitant of the exhibition of parenteral digestion. 
When the sensitized or immunized animal is injected with a 
specific antigen, an increase of protein degradation products 
may be demonstrated both in the blood and in the urine. The 
sBledl and Kraus: Wien. klin. Wchnschr., 1909, No. 11, p. 363. ANAPHYLACTIC ANTIBODY AND ANTIGEN 
159 
recognition of these facts was in part responsible for the de- 
velopment of the theory that protein antigen, when submitted 
to the action of alexin after it has been sensitized by the 
specific antibody (first order) is broken down or digested. This 
process, when it occurs in the body-tissues, is called " paren- 
teral digestion." As has been noted, certain of the degrada- 
tion products of proteins, notably peptone, produce all the 
symptoms of anaphylaxis, w'hen injected into dogs. The con- 
ception, therefore, originated that parenteral digestion of for- 
eign proteins gives rise to intermediate products of protein 
degradation which are responsible for anaphylactic shock, and 
for the symptoms of infectious diseases. Friedberger gave 
these products the collective name of anaphylatoxins; Vaughan 
identifies them with the toxic moiety which he has developed 
by means of hydrolysis of proteins. 
Reasoning by analogy from other immunity experiments, and 
from the processes of intracellular digestion as carried out in 
the unicellulae, such as the amebae, it seems not unlikely that 
although certain tissues, notably those of the alimentary tract, 
are especially differentiated for the purpose of producing diges- 
tive substances, this same property of breaking down proteins 
is maintained, to a greater or less degree, by certain of the 
fixed tissue cells of the higher animals. 
Support is given to the conception of parenteral proteolytic 
digestion by the experiments of Abderhalden. This investiga- 
tor has been able to show by means of the refraction index of 
protein molecules, as determined by the polariscope, and by 
dialysis experiments, that the interaction of serum antigen and 
serum from a sensitized animal is followed by a breaking up 
of a certain proportion of the protein content of the serum 
antigen into simpler bodies. Dick has corroborated these find- 
ings, employing in place of serum antigen, protein material 
derived from the pneumococcus. 
In this process of protein cleavage highly active toxic sub- 
stances are produced. Bronfenbrenner has obtained similar 
results. Various authors in recent years, more particularly 
Zinsser, have discredited to a considerable degree the value of 160 
INFECTION, IMMUNITY, AND INFLAMMATION 
the Abderhalden reaction. Nevertheless, as pointed out by- 
Wells, 4'whatever may be said concerning the specificity of 
this reaction, there undoubtedly does commonly occur a greater 
amount of proteolysis in such mixtures with the specific antigen 
than if some other protein is present." Elsesser, working in 
Wells' laboratory, using Osborne's purified vegetable proteins, 
showed that "there is an obvious tendency for a substrate to 
react more often and yield stronger reactions when tested 
against its homologous immune serum, than when tested 
against a heterologous immune serum. We cannot afford to 
overlook the important fact that racemized proteins, which 
are characterized by being incapable of attack by enzymes in 
vitro, or of being digested and metabolized in vivo, are also 
incapable of serving as antigens, although derived from pro- 
teins which in the original state are highly antigenic." 
(Wells.3) 
The experiments of Friedmann and Isaak, and of Weichhardt 
and Schittenhelm make it appear "that, as measured by nitro- 
gen output, the cleavage of foreign protein injected into spe- 
cifically sensitized, or immunized, dogs occurred with much 
greater energy and speed than occurred in normal animals 
after first injection." (Wells.3) 
It has thus been established that proteolysis of specific an- 
tigens does occur when they are treated by immune serum. 
It is also known that intermediate products of protein cleavage 
are irritant. 
Heilner,4 basing his opinions upon the result of experiments, 
which proved that although the prompt metabolism of serum 
protein when fed by the mouth is evidenced by the appearance 
of its nitrogen in the urine, this is delayed for several days if 
introduced parenterally, assumes that the organism gradually 
responds to the introduction of such foreign proteins into the 
blood stream by the production of enzymes which are not ordi- 
narily present therein, but which are adapted to disintegrate 
the new protein. 
3Wells: Physiological Reviews, 1921, i, 44. 
4Heilner: Ztschr. J. Biol., 1912, Iviii, 332. ANAPHYLACTIC ANTIBODY AND ANTIGEN 
161 
That the process of parenteral digestion (or autolysis in 
vitro) results in the formation, by dissociation, of new com- 
pounds and not merely the liberation of a preformed toxic 
substance, is indicated by the similarity of the symptoms in- 
duced in animals by the introduction of split products pre- 
pared according to the method of Vaughan or by Rosenow's 
method of autolysis as well as the in vivo reaction of anaphy- 
laxis following the injection of various proteins. 
In Danysz's opinion, the immunologic reaction is the mani- 
festation of parenteral digestion. Anaphylactic phenomena, 
he believes, occur as the result of flocculation or precipitation 
of antigen under the influence of antibody.5 Active immunity, 
in his opinion, is a state of resistance of the organism to a 
certain part of the cell substance of infecting bacteria which 
is rapidly and easily digestible. It will be complicated by an 
anaphylactic hypersensitiveness whenever the compound of 
antigen with antibody is insoluble and, therefore, more or less 
difficult to digest. There will be no hypersensitiveness when 
this compound is soluble and neutral. 
A true and lasting immunity would consist in rendering the 
organism refractory to anaphylactic hypersusceptibility; that 
is to say, to render the organism capable of completely di- 
gesting bacteria or products of bacteriolysis. 
In the author's opinion, such true immunity is, in fact, ex- 
hibited when in consequence of repeated injections of such 
bacteria or other antigens, as are subject to lysis alone, the 
development of second order antibodies has been stimulated. 
Under such conditions the tissues are rendered tolerant to the 
irritant products of partial degradation of the bacterial pro- 
tein and complete cleavage of the latter is accomplished. 
Objections to the Theory of Parenteral Digestion 
Although I am of the opinion that the objections hitherto 
raised to the theory of parenteral digestion do not suffice to 
5It must be pointed out in this connection that the majority of immu- 
nologists exclude as examples of anaphylactic phenomena, all tissue reaction 
that are manifestly the result of flocculation and consequent vascular oc- 
clusion. The essential weakness of Danysz's contribution is, in my opinion, 
due to the fact that whereas all antigenic substances are colloids, Danysz 
assumes that all colloids act as antigens. In the great part of his experi- 
mental work he has employed non-protein "antigens." 162 
INFECTION, IMMUNITY, AND INFLAMMATION 
disprove the hypothesis, I think it proper that the more im- 
portant of the data which appear to indicate that this may, in 
fact, not be the proper explanation of the immunologic process 
should be included in this volume. It is of interest to bear in 
mind that, of the large number of investigators in recent years, 
few have made any suggestions as to what other mechanism 
may be responsible for the phenomenon of anaphylaxis. If 
we discard, says Wells, 4'the anaphylatoxin theory of anaphy- 
laxis, we are left without any explanation of the very striking 
phenomena of anaphylactic shock, for no satisfactory substi- 
tute hypothesis has been proposed." 
An important series of experiments, which cast a definite 
doubt upon the assumption that "anaphylatoxin" is produced 
by decomposition of the antigen,6 proved that, by the treat- 
ment of normal serum by numerous insoluble substances, such 
as barium sulphate and kaolin, as well as bacterial cell bodies, 
a toxic substance is produced which appears to be identical 
with those developed by Friedberger's method. Experiments 
of this type have been carried out by Keysser and Wasser- 
mann, and by Bordet. The experiments of the latter author, 
in the treatment of fresh guinea pig serum by agar, are of the 
greatest importance. Similar experiments have also been per- 
formed by Jobling and Petersen, and by Novy and DeKruif. 
Bordet has shown that the toxic substance, which is pro- 
duced when normal guinea pig serum is mixed with agar, is 
characterized chemically by exactly the same alterations as 
occur when an immune serum is incubated with its antigen. 
In 1917 Novy and DeKruif7 reported a series of investiga- 
tions, made by them on the nature of anaphylatoxin. They 
found that a disturbance similar to anaphylactic shock can 
readily be produced by the addition of almost any alien sub- 
stance to a serum, whether in the living animal or in the test 
tube. The substances which may be successfully employed 
«The author particularly desires to point out that the adoption of the 
hypothesis of the presence of two substances, anaphylactic (first order) anti- 
body and tolerant (second order) antibody, in the tissue of the immune 
animal or individual, is not dependent upon the solution of the problem 
as to whether the reaction between these antibodies and their protein anti- 
gen is in fact a cleavage of the latter or not. 
'Novy and DeKruif: Jour. Am. Med. Assn., 1917, lxvii, 1524. anaphylactic antibody and antigen 
163 
include bacteria, trypanosomes, organ cells and extracts, pep- 
tone, agar, starch, inulin, kaolin, silicic acid, barium sulphate, 
diverse salts and even distilled water. The result is a non- 
specific anaphylactic shock. 
These authors conclude that the poison produced does not 
come from the substance introduced, but that its matrix is a 
normal constituent of serum, and that the substances which 
convert it into anaphylatoxin act merely as inducers of accel- 
erators of the reaction. Since shock blood is incoagulable, 
they believe that this inducing substance also reacts with 
fibrinogen. 
They found that all bloods are toxic in the precoagulation 
stage. Thus, the blood of a normal rabbit, when rapidly 
transfused into the vein of a guinea pig, is usually harmless 
in a dose of 3 c.c. If, however, the blood is held in the syringe 
for three minutes before being injected, it becomes fatally 
toxic. The effects produced are those which characterize ana- 
phylatoxin activity. The production of '1 anaphylatoxin ' ' varies 
in different species of animals and in different individuals. 
The two reactions-blood coagulation and blood intoxication, 
in the opinion of Novy and DeKruif, are twin phenomena in 
which labile substances undergo intramolecular rearrange- 
ment. In the one case, the insoluble fibrin is produced, and 
in the other, the soluble "anaphylatoxin." 
Jobling, Petersen and Eggstein8 consider that the manifesta- 
tions of acute anaphylaxis are brought about by the cleavage 
of serum proteins and proteoses to the peptone stage through 
the action of a nonspecific protease. They explain the mech- 
anism of sensitization and anaphylactic shock in this way: 
"Serum ferments are practically unaltered by the primary 
injection of foreign protein. During the course of sensitiza- 
tion, the injection of antigen is followed by the mobilization of 
a nonspecific protease which increases in rapidity as the maxi- 
mum period of intensity is reached. Acute shock is accom- 
panied by the instantaneous mobilization of a large amount 
of nonspecific protease, decrease in antiferment, increased 
8Jobling, Petersen and Eggstein: Jour. Exper. Med., 1915, xxil, 401. 164 
INFECTION, IMMUNITY, AND INFLAMMATION 
in the noncoagulable nitrogen of the serum, increase in 
the amino acids and a primary decrease in serum proteoses. 
Later, there is a progressive increase in the noncoagulable 
nitrogen, in proteoses, and in serum lipase. The specific ele- 
ments lie in the rapid mobilization of a nonspecific protease 
and the colloidal serum changes which bring about the change 
in the antiferment titer." 
In other words, substances such as those mentioned above 
remove or absorb, the antienzymes which are normally present 
in the blood. In consequence, of this alteration in the relation- 
ship of antiferments to normal ferments in the serum, the 
latter bodies in the fresh serum act upon the serum protein 
with consequent cleavage of the protein molecule and the 
production of irritant split products. 
The fact that toxic split products are produced by autolysis 
of the tissue proteins when treated by various inert substances, 
which appear to remove antiferments from the body fluids, 
does not of necessity disprove the hypothesis that anaphylaxis 
is due to the cleavage of the protein antigen by the action of 
sensitizing substances plus alexin. There can be no doubt 
that wherever proteolysis takes place toxic substances may be 
formed. This is proved by the work of Vaughan and by 
Friedberger's and Friedemann's experiments and by the re- 
sults of protein cleavage by means of trypsin. 
The late Richard Weil9 opposed the views embodied in the 
theory of parenteral digestion most urgently. According to 
his interpretation of such experiments, it is not the antigen 
but the antiserum which undergoes chemical alteration when 
antigen and antibody react in vitro. The antiserum, itself, 
undergoes autolysis. He ignores all those experiments which 
have shown that it is possible to induce anaphylactic shock by 
the simultaneous introduction of antigen and antiserum. 
Jobling has shown that the blood of dogs during anaphy- 
lactic shock exhibits definite chemical evidence of protein dis- 
integration. This fact Weil disposes of by stating that the 
chemical changes are simply the harmless bi-products of the 
8Weil: Jour, of Immunol., 1916-17, xi, 525. ANAPHYLACTIC ANTIBODY AND ANTIGEN 
165 
anaphylactic reaction on the sensitized liver, and are compar- 
able to those which occur in chloroform or phosphorous poi- 
soning. 
By an ingenious set of experiments Weil9 injected the blood 
of dogs in the height of anaphylactic shock into normal dogs. 
No symptoms of any kind resembling anaphylaxis occurred. 
These experiments appear to prove that the blood of the dog 
in the anaphylactic state does not contain toxic substances. 
If such a toxic property of the blood during anaphylaxis be 
proved to exist, proof of the production of an irritant in con- 
sequence of the reaction between antibody and antigen will 
have been supplied. Negative results, however, cannot in 
the author's opinion, be interpreted as proof that a toxic sub- 
stance has not been produced in the tissues. 
Zinsser is of the opinion that "if an antigen participates 
at all in furnishing the substratum for the (anaphylactic) 
poison, this is probably less important than that furnished by 
the animal's own proteins.10 However, this does not weaken 
the importance of the knowledge that antigen-antibody reac- 
tions in the presence of normal serum, and certain anti- 
gens in the presence of normal serum alone, induce a reaction 
in the course of which such irritants are formed. And the 
fact that they can be produced experimentally in the peritoneal 
cavity of a living guinea pig, renders their participation in 
such reactions in the animal body a likely assumption. ' ' 
Dale believes that the chief objection brought to bear by 
his experiments upon the production of a toxic cleavage prod- 
uct, as the substance responsible for the anaphylactic reaction, 
is the time relation. The specific antigen acts on the isolated 
plain muscle with as little delay as a direct stimulant. If the 
effect produced were due to the action of a ferment, he says 
one would expect a gradual onset, and the gradual response 
to a maximum. But the onset is sudden and the rate of 
10Although it is possible to imagine that in constitutional reactions such 
as anaphylactic shock the substrate from which the tissue irritant is produced 
may be derived from the animal's own body proteins, this cannot be the 
cause of phagocytosis of the particulate protein in the hypersensitive animal. 166 
INFECTION, IMMUNITY, AND INFLAMMATION 
progress to the maximum is apparently limited only by the 
contraction rate of the plain muscle. 
Again Dale 11 points out that the possibility of the produc- 
tion of a poison by parenteral digestion is not by any means 
excluded by the demonstration of the specific response in 
tissues freed from blood, since, given the demonstrated at- 
tachment of antibody to muscle-cells, or its incorporation into 
them, a poison produced by the interaction between antigen 
and the antibody so situated, would arise under conditions 
ideal for the exhibition of its activity.12 
Explanation of the Phenomenon of Tolerance 
*'Immunity" (tolerance) is a state of relative insuscepti- 
bility to anaphylactic shock. ''It is characterized by an in- 
crease in the amount of free anaphylactic antibody. Whether 
the insusceptibility of an immune guinea pig is due to an excess 
of free anaphylactic antibody, to the formation of another free 
antibody, or to specific changes in the somatic cells, is an open 
question." (Anderson and Frost.) 
The animal which is not susceptible to anaphylactic shock 
when treated with moderate doses of antigen, but whose serum 
confers passive sensitization upon normal animals, is said to 
be tolerant. This is the state which had been referred to by 
different observers as immunity, or antianaphylaxis. The au- 
thor believes, however, that the employment of the term "tol- 
erant" is more suggestive and accurate. 
It has been proved experimentally that not only is a fre- 
quently treated animal tolerant, but that such tolerance may 
be transmitted passively to normal animals, or even to hyper- 
sensitive animals, by injection of sufficient quantities of serum 
from a tolerant animal. It is possible to passively sensitize 
normal animals by the transference of blood serum or tissue 
fluid of a treated animal. In order to passively sensitize an 
animal with the serum of another animal, which had received 
but one injection of antigenic protein, and which is, therefore, 
"Dale: Jour. Phar. and Exper. Therap., 1912-13, iv, 167. 
"This point of view has been amplified by the author on page 144. ANAPHYLACTIC ANTIBODY AND ANTIGEN 
167 
extremely sensitive to small doses of the same antigenic pro- 
tein, it is necessary to employ a large proportion-one-half to 
seven-eighths-of the total blood serum. On the other hand, 
the serum of animals which have received repeated large doses 
of antigenic serum, and which are consequently tolerant, suf- 
fices, in minute amounts-0.01 to 0.6 c.c.-to confer passive 
hypersensitiveness upon normal animals. 
The paradoxical phenomenon is thus noted that the animal 
in which hypersensitiveness is more readily demonstrated con- 
tains in its serum a much smaller amount of anaphylactic 
antibody than does the animal in whom proof of hypersensi- 
tiveness is obtained only with difficulty, i.e., by the employment 
of relatively large toxic or "exciting" injections. 
If an explanation of the phenomenon of anaphylaxis is 
difficult, that of tolerance is equally so. Friedberger early 
suggested that remnants of the antigen (injected protein) per- 
sist in the tissues and that these render the animal practically 
refractory. This view has since been very generally discred- 
ited by practically all observers including Friedberger himself. 
As is but natural, it has been suggested, by those who look 
upon anaphylaxis as essentially the result of parenteral diges- 
tion of proteins, that when large amounts of ferment are pres- 
ent in the blood and tissues, hydrolysis of the foreign protein, 
when the latter is reinjected, advances rapidly to a point which 
results in the production of nontoxic end products. Fried- 
berger has shown that the poison, prepared by him, may be 
destroyed by too long digestion or by an excess of anaphylactic 
serum. According to the conception advocated by Friedberger, 
this diminution in toxicity is due to the more complete ac- 
tivity of the antibody which is responsible for precipitin for- 
mation and for the development of the anaphylatoxin. The 
author believes that the assumption of the elaboration by the 
tissue cells of a second order of antibody is supported by the 
facts at our disposal more adequately than is the hypothesis 
which conceives the first order (anaphylactic) antibody to 
be potent to accomplish complete dissociation of the protein 
molecule. 168 
INFECTION, IMMUNITY, AND INFLAMMATION 
The author believes that in the light of our present informa- 
tion a larger number of disease phenomena can be explained 
if it be assumed that the process is essentially one in which 
a substance is produced which reacts with the product of the 
anaphylactic (first order) antibody-antigen reaction in such a 
way that it is rendered innocuous to the tissues. 
If it be assumed that the anaphylactic state is due to the 
presence in the animal body of specific proteolytic antibodies, 
which so react with their specific substrates that irritant prod- 
ucts are formed, it seems reasonable to suppose that the insus- 
ceptibility to anaphylactic shock demonstrated by tolerant 
(immune) animals may be due to a further exhibition of the 
property of parenteral proteolysis.18 
The hypothesis suggested by the author regarding the re- 
lationship of the anaphylactic to the tolerant state is as fol- 
lows: The parenteral introduction of protein antigens into 
the animal body is followed by the elaboration of specific anti- 
bodies which so react with the complex protein molecule that 
an irritant product is formed. This poisonous product is, 
perhaps, identical with the poisonous split product of Vaughan, 
or the anaphylatoxin of Friedberger. In consequence of the 
presence in the tissues of this first order antibody, the animal 
is hypersensitive to the re-injection of the specific protein, as 
the result of whose primary injection the production of anti- 
bodies was induced. Subsequent introduction of antigen, in 
sublethal doses, results in the stimulation of a second order 
of antibody, the activity of which renders the irritant, pro- 
duced by the first order antibody-antigen reaction, harmless to 
the tissues. 
According to the author's hypothesis, the animal becomes 
hypersensitive by virtue of the presence in its body fluids and 
its tissue cells of the first order antibody, which so reacts with 
its specific antigen that a substance, which acts as an irritant 
to certain tissue cells, is produced. The tolerant animal is 
"This may be due to the activity of an enzyme-like peptolytic substance. 
Such peptone-splitting ferments have not, heretofore, been demonstrated in 
the serum, although Smith has identified a ferment capable of dissociating 
the polypeptid,-glycyltryptophan. (Jour. Am. Med. Ass., xix, 539.) ANxVPHYLACTIC ANTIBODY AND ANTIGEN 
169 
insusceptible to anaphylactic shock in consequence of the 
presence in its tissues of a second order antibody, which is 
potent to so act upon the product of the reaction between the 
first order antibody and its antigen, that it no longer acts as 
an irritant to tissue cells. 
Two alternatives in explanation of the tolerant state seem 
possible; either the cells, which, in the anaphylactic or normal 
animal, are susceptible to the injurious action of the "ana- 
phylatoxin,"-lose their receptors and become incapable of 
absorbing, and hence are not injured by the irritant; or, there 
is developed an antibody capable of either neutralizing, by a 
process of synthesis, the anaphylatoxin, or of further dissociat- 
ing it into harmless substances. Loss or exhaustion of anaphy- 
lactic antibodies, undoubtedly, does occur. This is the condi- 
tion which has been discussed under desensitization. 
Vaughan refers to the condition as one of tolerance, but 
attempts no explanation of its possible nature. He states, spe- 
cifically, in speaking of his toxic split product, that when 
repeatedly injected in nonlethal doses the antibody does not 
elaborate an antibody-an antitoxin. He says, however, that 
the phenomenon requires further study, employing the method 
of passive immunization. I believe that experiments14 which 
were published in 1914 supply certain data believed by 
Vaughan to be necessary for a more adequate understanding 
of the subject. 
The difficulty which is experienced in provoking anaphy- 
lactic shock in passively sensitized animals without the lapse 
of a certain interval of time-six to twenty-four hours-has 
been interpreted, by many observers, as indicating that a 
reaction between antigen and circulating antibodies cannot 
induce symptoms of anaphylactic intoxication. The experi- 
ments reported by myself and others (Chapter IX) show that 
it is possible to induce anaphylactic shock by the action of 
the specific antisubstance and the antigen while both are 
circulating in the blood stream. 
The author's15 experiments were undertaken in the hope 
MGurd: Jour. Med. Research., 1914, xxvi, 205. 
"Gurd: Jour. Med. Research., 1914, xxvl, 205. 170 
INFECTION, IMMUNITY, AND INFLAMMATION 
of proving by direct methods the presence, in the serum of 
so-called immune animals, of a substance capable of protect- 
ing the sensitized animal against manifestations of anaphy- 
laxis. The results of these experiments proved the possibil- 
ity of passively transferring the tolerant state to normal 
animals. Inasmuch as these experiments which were pub- 
lished in 1914 are not generally known, several protocols are 
republished. 
Experiment A.137.-A series of guinea pigs, weighing about 340 grams 
each, were injected with immune rabbit serum (38) of such a titer that 
0.6 c.c. injected intraperitoneally sensitized animals (250 grams) so that 
upon the following day 5 minims of sheep serum caused typical anaphy- 
lactic death; 0.5 c.c. of the rabbit serum was insufficient to passively 
sensitize so that death supervened, although marked symptoms developed. 
GUINEA 
PIG 
NUMBER 
FIRST INJECTION 
INTERVAL 
SECOND INJECTION 
RESULT 
109 
.6 c.c., I.R.S., i.p. 
24 hours 
.35 c.c., i.v., S.S. 
Marked symptoms 
Recovery. 
110 
.6 c.c., I.R.S., i.p. 
24 " 
.45 c.c., i.v., S.S., 
Typical anaphylac- 
tic death 6 min- 
utes. 
103 
4.0 c.c., I.R.S., i.p. 
12 hours later 
4.5 c.c., i.p., 
I.R.S. 
25 " 
Sheep Serum .5 
c.e., i.v. 
Slight malaise. 
99 
1.0 c.c., I.R.S., i.p. 
7 days 
.3 c.c., S.S., i.v. 
Very severe symp- 
toms. 
100 
1.0 c.c., I.R.S., i.p. 
7 " 
3.5 c.c., I.R.S., i.v., 
.4 c.c., S.S., i.v. 
Very slight symp- 
toms. 
147 
.5 c.c., I.R.S., i.p. 
24 hours 
.5 c.c., S.S., i.v. 
Typical death 4 
minutes. 
148 
.75 c.c., I.R.S., i.p. 
24 " 
.5 c.c., S.S., i.v. 
Typical death 3 
minutes. 
149 
2.5 c.c., I.R.S., i.p. 
24 " 
.5 c.c., S.S., i.v. 
Marked symptoms 
Recovery. 
I.R.S.-Immune Rabbit Serum ; 
i.p. -Intraperitoneal injection ; 
i.v. -Intravenous injection ; 
S.S. -Sheep Serum. ANAPHYLACTIC ANTIBODY AND ANTIGEN 
171 
In the foregoing experiments the animals were allowed to 
pass through the so-called "incubation stage." As is seen, 
the injection of larger quantities of serum was sufficient to 
protect the animal (103) against the anaphylactic shock which 
followed in the other two animals. 
The following protocol shows the effect of immediate toxic 
injections in passively sensitized guinea pigs; it is even more 
striking, although none of the animals died: 
111. 280 grams. Received .9 c.c. of rabbit serum (38) i.v., within two 
minutes 7 minims of sheep serum i.v.-marked immedi- 
ate symptomsi for ten minutes-rapid recovery. 
113. 275 " Received .5 c.c. of rabbit serum (38) i.v., within two 
minutes 7 minims of sheep serum i.v.-immediate onset 
of marked symptoms progressing to convulsions and 
paralysis, apparently dying, but recovered. 
112. 280 " Received 2.75 c.c. of rabbit serum (38) i.v. within two 
minutes 7 minims sheep serum i.v.-no symptoms. 
The following series of experiments is quoted from Weil. 
It also shows the protective effect of larger doses of immune 
rabbit serum injected into normal guinea pigs: 
GUINEA 
PIG 
SENSITIZING 
INJECTION 
INTRAVENOUSLY 
TOXIC INJECTION 
NEXT DAY 
INTRAPERITONEALLY 
RESULTS 
1 
c.c. 
0.3 
C.C. 
2.5 
No symptoms. 
2 
0.5 
2.5 
After 20 minutes paretic, atac- 
tic, mild convulsions. Re- 
covered in two hours. 
3 
0.5 
2.5 
Similar to above. 
4 
0.7 
2.5 
Respiratory and cutaneous 
symptoms. Severe prostra- 
tion. Died during day. 
5 
0.8 
2.5 
Died in 40 minutes. 
6 
1.0 
2.5 
Immediate dyspnea and pare- 
sis. Convulsions; death in 
12 minutes. 
7 ) 
8 i 
2.0 
2.5 
Very mild symptoms. 172 
INFECTION, IMMUNITY, AND INFLAMMATION 
These results were interpreted by Weil as indicating that 
"larger injections of the serum leave so considerable a resi- 
due of antibody in the circulating blood that the animal is 
protected against the anaphylactic effects of peritoneal injec- 
tions of antigen." According to the hypothesis brought for- 
ward by the author, this protective effect of larger doses of 
transferred serum is due to the presence of tolerant, or second 
order, antibodies in sufficient quantity to protect the animal 
against the effect of the interaction of antigen and first order 
antibody. 
These experiments prove that the blood serum of immune 
animals contains, not only sensitizing bodies, but also some 
substances which are potent to protect the animal from the 
effects of the reaction between anaphylactic (first order) anti- 
body and antigen. Theoretically, this substance might con- 
sist of an antiferment, an excess of the "anaphylactic ferment" 
which latter must, in this case, be assumed to be capable of 
more or less completely digesting the toxic split product into 
simpler harmless substances, or there is produced, following 
the reinjection of sensitive animals, a second type of antibody 
which exhibits the property of inactivating the irritant prod- 
uct of the reaction between first order body and antigen. 
The likelihood of antiferment action being responsible for 
the protection induced is very remote; there is little to sup- 
port this view and many observations would indicate that it is 
not the correct one. That an excess of the same enzyme-like 
substance, which may be responsible for the further cleavage 
and consequent detoxication of the poison, seems more reason- 
able, but this view also fails to explain certain phenomena 
which will be referred to presently. 
The explanation of this phenomena, offered by exponents 
of the "cellular" theory, is as follows: They assume that 
the sensitive animal is such by virtue of the production of 
sessile receptors and that the sensitizing bodies present in the 
serum are of the nature of protective antibodies, in the sense 
that these free circulating bodies bind the introduced anti- 
genic protein and thus make it impossible for the antigen to ANAPHYLACTIC ANTIBODY AND ANTIGEN 
173 
affect the fixed receptors attached to the cells. The chief ob- 
jections to this hypothesis are: 
(1) That such a theory assumes an essential toxicity for 
complex proteins-albumins and globulins. 
(2) That the mixture in vitro, or in vivo, of serum, con- 
taining free receptors and* antigenic protein, results in the 
formation of a toxic substance. 
(3) That the number of units of sensitizing bodies-free 
receptors-in the blood serum is much greater than is the 
capacity of the animal for withstanding injections of anti- 
genic protein.16 
The humoral theory requires the assumption of an interme- 
diate toxic product resulting from the action of antibody upon 
antigen which, secondarily, affects the cells. 
lsWeil has shown that about 30 or more units must be present in order 
to protect the fixed cellular receptors. CHAPTER XVI 
ALLERGIC REACTION 
When the hypersensitive animal receives an injection of a 
suitable dose of the specific antigenic protein, to which it has 
been sensitized, the nature of the reaction which is exhibited 
is dependent upon the route of administration. If injection 
of a soluble protein be made into a vein, severe symptoms, 
respiratory in the case of the guinea pig, or circulatory in 
the case of the dog, immediately take place and the animal 
dies. If the protein be injected into tissues such as the mus- 
cles, serous cavities, or subcutaneous tissues, in addition to 
constitutional manifestations of intoxication, focal evidences 
of irritation may be exhibited. It is possible, in this way, by 
means of the subcutaneous injection of either soluble or par- 
ticulate proteins, to induce all the manifestations of inflam- 
mation, i.e., hyperemia, swelling, and leucocyte accumulation. 
In the human tissues, well marked examples of acute cellu- 
litis are readily provoked, in individuals hypersensitive to 
horse serum, by the subcutaneous injection of small doses of 
this antigen. 
In the previous pages we have studied chiefly the systemic 
reaction which occurs in sensitized animals following the 
parenteral injection of soluble proteins. Coincidentally with 
the study of this reaction by Rosenow and Anderson, by 
Richet, and by Otto, von Pirquet and Shick had observed 
and studied a phenomenon to which they applied the name 
"allergy" {alios-altered, ergeia-reaction). The essential 
characteristics of the allergic reaction are that, when anti- 
genic protein, whether particulate or insolution and whether 
viable or inanimate, is injected into the soft tissues of hyper- 
sensitive individuals or animals, there is an alteration in the 
morphologic reaction which occurs, as compared with that 
exhibited, following similar parenteral introduction into nor- 
174 ALLERGIC REACTION 
175 
mal animals. The fundamental alteration consists of a short- 
ening or elimination of the incubation period, and if viable 
antigen be employed the degree of reaction is minimized. 
Von Pirquet's original statements were based upon a study 
of vaccinia vaccination and serum sickness. He noted that 
the individual who has not previously been vaccinated or 
been the subject of smallpox infection, reacts to the inocula- 
tion of cowpox virus in a typical manner. One important 
characteristic of this typical reaction is that a definite num- 
ber of days elapse before the reaction becomes evident. In 
such individuals, not only is the reaction delayed but, once it 
has commenced, it continues for a number of days so that a 
definite cycle of tissue changes which last for a period of two 
weeks or longer is noted. 
On the other hand, if an individual who has been previously 
successfully inoculated, is subjected to a second vaccination, 
the onset of the stage of hyperemia is developed very soon 
after the inoculation of the virus. The alteration in the time 
of onset of the reaction may be such that but one or two hours 
intervenes between the introduction of the virus and the on- 
set of the inflammatory reaction. Furthermore, the charac- 
teristic series of changes, namely, vesiculation, pustulation, 
and scab formation, do not take place. Von Pirquet recognized 
in this phenomenon a principle that has become one of the 
utmost importance both in the diagnosis of infective condi- 
tions and in our appreciation of disease phenomena. 
Briefly stated the essential characteristic of the phenomenon 
studied by von Pirquet is that, as a result of a previous in- 
jection of antigen, or an antecedent infection, some change is 
brought about in the body tissues as a result of which, if the 
individual be reinoculated with living microorganisms, reac- 
tion takes place much more promptly than in the normal 
individual. The severity of the reaction is, moreover, less 
marked. The incubation period is shortened and the reaction 
is minimized. 
In the normal individual the introduction of a pathogenic 
microorganism is immediately followed by its proliferation. 176 
INFECTION, IMMUNITY, AND INFLAMMATION 
Multiplication of the injected units continues, until such time 
as the body develops a sufficient number of antisubstances to 
stimulate a reaction. Von Pirquet believes that as a result of 
the reaction between virus or antigen and antibody, there is 
produced a toxic substance which stimulates vascular and 
cellular reaction. Since, in a previously inoculated individual, 
there already exists at the time of the second introduction a 
considerable quantity of antibody, this combination of antigen 
and antibody with the formation of a toxic product, super- 
venes very soon after introduction of the virus. In conse- 
quence a morphologic inflammatory reaction is stimulated 
almost immediately. Since this reaction takes place very soon 
after inoculation, proliferation of the virus in situ has not 
had time to take place. A prolonged or marked reaction is, 
therefore, not necessary in order that the infectious agent 
may be eradicated. 
Since von Pirquet's original contribution upon this sub- 
ject, numerous observers have proved that clinical manifesta- 
tions of the allergic phenomenon are very common. It is the 
basis of the cutaneous reaction to tuberculosis, to which the 
name of von Pirquet is applied, the luetin reaction of Noguchi, 
the gonococcus reaction of Irons, the mallein reaction in cat- 
tle, and tests for protein hypersensitiveness in such conditions 
as asthma and pollenosis. I employ the intradermic allergic 
reaction as a routine in determining the dose, and time inter- 
val, in the employment of vaccines for therapeutic purposes 
(See Chapter XXV). 
If two individuals, one of whom was vaccinated against 
cowpox two years previously, and the other has never been 
infected with either vaccinia or smallpox, be vaccinated at 
the same time, the phenomena which develop in the two cases 
differ in a typical manner. At the end of twenty-four hours 
the previously inoculated person exhibits on the arm a small 
elevated inflamed and itching scratch, whereas the newly 
vaccinated person shows but a trivial scab unaccompanied by 
evidences of inflammation. It appears at this time as though 
the previous vaccination had rendered the individual more ALLERGIC REACTION 
177 
susceptible to vaccinia virus. The subsequent course of 
events, however, shows that this is not the case. The papule 
on the previously vaccinated case rapidly subsides and dis- 
appears, whereas the normal individual exhibits, after the 
lapse of several days, a larger inflamed area which pro- 
gresses to vesicle formation and pus accumulation. In the 
first individual no fever or other constitutional manifestation 
of disease is exhibited, whereas the previously unvaccinated 
patient manifests moderately severe symptoms of intoxication. 
Von Pirquet's Studies upon Vaccinia17 
Since the inoculation of viable pathogenic microorganisms 
is rarely justifiable in the human subject the experiments of 
von Pirquet and Shick are of the greatest importance. The 
alterations in the reaction which occurs when hypersensitive 
individuals are subjected to vaccinia virus inoculation have 
been thoroughly studied by these observers. 
Of all infectious diseases in man, cowpox is best suited to 
exact clinical and experimental study. The first vaccination, 
in healthy children, shows a constant symptom-complex. Some 
minutes after the vaccination, a traumatic reaction, in the 
form of a very slight redness, appears. This reaction per- 
sists for approximately twenty-four hours and leaves a small 
scab surrounded by normal skin. On the third or fourth day, 
a small red papule appears, which indicates the beginning of 
the specific reaction. Between the fourth and the sixth days, 
the middle portion of the papule becomes more elevated, the 
outer part becomes flat, and forms a narrow red circle around 
the papule. From now on, the papule increases in size quite 
regularly, about 1 millimeter a day, and the solid papule is 
transformed into a blister. The aureola remains of the same 
width and is protruded only by the extension of the papule. 
Between the eighth and the eleventh days, the aureola in- 
creases to a large slightly elevated inflammatory plaque. The 
papule ceases to grow and becomes yellow. Between the 
17This section is abstracted with but few alterations from von Pirquet's 
article. Arch. Int. Med., 1911, vii, 260. 178 
INFECTION, IMMUNITY, AND INFLAMMATION 
eleventh and the fifteenth days the aureola reaches its high- 
est development and then disappears slowly, whereas the pap- 
ule dries and a large scab falls off, leaving a scar. During 
the time of aureola formation general symptoms appear in 
association with this local reddening. The special features 
are fever and leucopenia. 
On revaccination, characteristic changes of reactivity are 
seen. If daily vaccination be made for a fortnight upon the 
same individual, the allergy evinces itself most distinctly. The 
most striking feature is that this inflammation appears on all 
the vaccination points simultaneously. Although the inocula- 
tions were made on successive days, the aureola develops 
around all the vaccination points at the same time, that is, at 
the time when its development is due on the first vaccination 
point. From now on, the papules also of the later vaccinations 
stop growing, as does the papule of the first vaccination. In 
those vaccinations which have been made from this time on, 
the state of papule formation is no longer reached. It is thus 
seen that if the tissues have been recently exposed to the 
presence of antigen, the reaction which accompanies reinocu- 
lation is exhibited at once. This is the ''immediate reaction" 
of von Pirquet's terminology. 
Another type of reaction occurs, when a few months inter- 
vene between the primary and second inoculation. This is 
called by von Pirquet the "early reaction." In this reaction 
a papule is formed, which reaches its maximal development 
in twenty-four hours. 
If several months or years have elapsed between the first 
and second vaccinations this type of very early reaction is 
replaced by another. Here the reaction occurs somewhat 
later, within the second day, reaching its maximum on the 
third or fourth day ("torpid early reaction"). 
The longer the interval of time between the first and second 
vaccinations, the more frequently are intense reactions noted, 
perhaps, even with the formation of papule and aureola. Nev- 
ertheless, these reactions following reinoculation still show 
some difference from a primary vaccination, inasmuch as the ALLERGIC REACTION 
179 
aureola develops more promptly and the growth of the papule 
is interrupted at an earlier stage ("accelerated reaction"). 
Comparing the sum total of the events of a first vaccination 
with those of revaccination, the individual vaccinated for the 
first time suffers from extensive local inflammation, fever, and 
other general symptoms. The revaccinated person overcomes 
the infection with a very slight local reaction a few milli- 
meters in size. But observing the reaction on the day follow- 
ing the vaccination, it is evident that the revaccinated is 
hypersensitive because at this time the person vaccinated for 
the first time does not show any reaction, while the revac- 
cinated individual responds with a local inflammatory process. 
"Repeating the vaccination very frequently on the skin of 
my [von Pirquet's] lower arm, I finally became hypersensi- 
tive to such a degree that within twelve hours a papule of 9 
millimeters in diameter developed, a size which after a first 
vaccination, is not reached before the seventh day." 
Von Pirquet noted that the size of the allergic reaction 
depends quantitatively upon the amount of vaccinia used. 
With fresh diluted lymph early reactions, 3 centimeters in 
diameter, were obtained with the formation of vesicles. When 
the lymph is diluted, the size of the reactions is less. The 
phenomena which accompany revaccination of the previously 
vaccinated person, differ in this respect from those of the 
first vaccination. 
When the individual is vaccinated for the first time the 
amount of vaccine does not influence appreciably the size of 
the reaction. The previously inoculated individual is sensi- 
tized to the vaccinia protein. In consequence the tissues im- 
mediately react to the introduction of the antigen. The larger 
the amount of antigen introduced the more extensive is the 
inflammatory reaction which is stimulated. The normal indi- 
vidual, on the other hand, who is not hypersensitive to the 
virus protein, does not react immediately. The virus continues 
to proliferate so that, by the time the incubation period is 
past, and the tissues become hypersensitive, a sufficient amount 180 
INFECTION, IMMUNITY, AND INFLAMMATION 
of virus protein antigen had been produced to necessitate an 
extensive area of reaction. 
Von Pirquet next directed his attention to the study of the 
allergic reaction in other diseases, more particularly tubercu- 
losis, and has been successful in establishing the alteration of 
the reaction on the part of the tissues to the reinjection of 
antigen as a biologic law. He showed that not only does the 
body react in an altered manner to inoculation by a viable 
microorganism, but that the previously infected and hence 
sensitized individual will react, morphologically-as shown by 
papule formation and other evidences of inflammation, within 
a very short period-one to thirty-six hours-after the intro- 
duction into the skin of nonviable bacterial proteins. The 
normal individual, whose tissues are not hypersensitive to the 
bacterio-protein, does not react in any visible fashion to the 
introduction of moderate quantities of the antigen (tuberculin). 
Weil18 describes an interesting local allergic reaction, which 
occurs in the liver of hypersensitive dogs. A dog was sensi- 
tized by the intravenous injection of 5 c.c. horse serum. After 
an interval of three weeks, the animal was put under ether 
and the abdomen opened by a median epigastric incision. The 
surface of the liver was punctured by a very fine needle at- 
tached to a hypodermic syringe, and a drop of a 10 per cent 
solution of horse serum was injected, just below the surface. 
Almost immediately the point of injection became the site of 
an intense and sharply localized congestion, measuring per- 
haps % inch in diameter, and over this area the surface of 
the liver was distinctly raised. The duration of this reaction 
was not accurately determined by Weil; it did persist for 
more than one-half hour. 
Another dog was sensitized by the intravenous injection of 
5 c.c. of horse serum. Two weeks later the dog was etherized 
and the liver exposed by a median epigastric incision. A sub- 
surface injection of a minute amount of horse serum into the 
"Weil: Jour. Immunol., 1916-17, xi, 538-540. ALLERGIC REACTION 
181 
liver provoked an immediate congestive reaction. Into the 
right branch of the portal vein 0.5 c.c. of horse serum was then 
injected. The right lobe of the liver at once became intensely 
congested, while the left lobe showed no change. Blood was 
aspirated from the jugular vein five minutes later and was 
found to be incoagulable. After fifteen minutes, although 
etherization had been discontinued at the moment of portal 
injection, the animal appeared to be in shock, and the carotid 
pulsation was very small. The dog was killed and the organs 
examined. The large abdominal veins were distended, but the 
abdominal viscera were not congested, with the exception of 
the liver. The right half of the liver was deeply congested, 
cyanotic in color, and firm to pressure, and the cut surface 
bled freely. The left half was only slightly, if at all, con- 
gested. 
A similar and very interesting type of local allergic reac- 
tion has been noted by Auer.19 The essential difference be- 
tween the reaction which follows injection of antigen into soft 
tissues and Auer's reaction is that in the latter the antigen 
was brought in contact with the local tissues by what may be 
called a process of autoinoculation. 
Auer noted, in testing the sensitiveness of dogs that had 
been treated with horse serum some years previously, that a 
peculiar edema developed at the site of the operation wound 
in the inguinal region. There occurred about two days after 
the test a fairly extensive thick brawny edematous mass of 
tissue; no discharge from the wound occurred. Auer as- 
sumed tentatively that the following reaction had occurred. 
The foreign protein (horse serum) was circulating, due to the 
reinjection. A certain amount of this protein passed into 
the tissues adjoining the wound during the development of 
the ordinary wound edema which always follows an operation. 
As the dogs were sensitized to the foreign protein an anaphy- 
lactic (allergic) reaction to the local autoinoculation to the 
horse serum occurred. Auer confirmed these findings by a 
very interesting observation in which he induced a moderate 
19Auer: Jour. Exper. Med., 1920, xxxii, 427. 182 
INFECTION, IMMUNITY, AND INFLAMMATION 
inflammatory reaction in the rabbit's ear by means of xylol. 
Ordinarily this reaction disappears in a short time without 
serious injury to the skin. The effects are quite the same in 
a rabbit that has been sensitized to a foreign protein, but in 
rabbits that have been sensitized and then reinjected with the 
same protein the xylol commonly produces a violent reaction, 
with exfoliative dermatitis followed by dry gangrene of the 
tips of the ears. The explanation of this striking effect seems 
to be simple. The slight inflammation produced by the xylol 
leads to a certain amount of inflammatory exudate. In the 
sensitized animals which have been recently reinjected with 
the sensitizing protein, the blood contains free antigen; a 
minute amount of this antigen is poured out into the tissues 
with the exudate. Here it produces a local reaction in the 
sensitized tissues, quite the same as if it had been locally in- 
jected. Presumably similar effects could occur in any other 
tissue or organ. "The importance of this observation lies in 
the recognition of a hitherto unappreciated mechanism by 
which anaphylactic reaction may be caused." (Wells.20) 
Factors Determining Specific Types of Allergic Reaction 
When normal rabbits are injected with killed cultures of 
the staphylococcus aureus of the bacillus tuberculosis, prac- 
tically no reaction of any sort is noted. It is of compara- 
tively little importance whether the bacterial suspensions are 
injected into the blood stream, intraperitoneally, or into the 
subcutaneous tissue. Experiments of this nature prove the 
absence of any very potent essential toxin on the part of 
either of these microorganisms. If, on the other hand, two 
rabbits are inoculated with living cultures injury to the an- 
imals is noted and there are exhibited manifestations of reac- 
tion on the part of the tissues. After an interval, which is 
known as the incubation period, the rabbit which received an 
inoculation of the staphylococcus aureus shows focal and sys- 
temic reactions of an acute type. The reaction is evidenced 
20Wells: Physiol. Review, 1921, i, 81. 183 
ALLERGIC REACTION 
by increase in pulse rate, pyrexia, leucocytosis; focal destruc- 
tion of tissues, and pus cell accumulation at the site of injec- 
tion occurs. 
The other rabbit, which was injected with viable tubercle 
bacilli, remains apparently well for a much longer period 
than does the animal which has been injected with the coccus. 
After this longer incubation period a reaction occurs which is 
characterized not by polymorphonuclear infiltration of the 
part, but by necrosis and by the accumulation and prolifera- 
tion of cells of the lymphoid and plasma, and "epitheloid" 
type. In other words a tubercle is formed in the tissues. The 
constitutional disturbances which accompany the focal reac- 
tion are less fulminant and less severe than those exhibited 
by the coccus injected rabbit, but persist for a longer period. 
They eventually lead, after a period of from five to eight weeks, 
to death of the animal in an extreme state of emaciation. 
By another set of experiments it may be proved that al- 
though the normal rabbit does not react to injections of dead 
bacteria of either of the types employed in the above experi- 
ments, it is possible to induce similar reactions focally upon 
the part of the tissues, if, after an interval of two weeks fol- 
lowing the introduction of a devitalized bacterial suspension 
into the subcutaneous tissues, a second injection of the same 
dead bacteria is made. The reaction which occurs is similar, 
in each case, to that which took place when the living micro- 
organisms were employed for injection. There is, however, 
an absence of incubation period, and the reaction persists for 
a relatively short time. 
These three sets of experiments prove that, although the 
staphylococcus aureus and the tubercle bacillus are not in 
themselves toxic to normal animals, there is developed by 
their presence in sensitive animals, a toxic substance. It is, 
furthermore, proved that the type of reaction which is stimu- 
lated on the part of the tissues, is specific for each of the two 
bacteria. 
There is every reason for believing that the irritant sub- 
stance which is responsible for the reaction is developed from 184 
INFECTION, IMMUNITY, AND INFLAMMATION 
the bacterial protein.21 That it is only developed in the pres- 
ence of a specific substance in the body fluids or tissue cells 
is evident from the fact that if a rabbit which has previously 
received a dose of staphylococcus aureus be subsequently in- 
jected with devitalized tubercle bacilli, no reaction takes place. 
Similarly, if the bacillus tuberculosis suspension be first in- 
jected, no reaction takes place upon the subsequent introduc- 
tion of the coccus. It is apparent, therefore, that because of 
differences in the morphology or chemistry of bacterial cells, 
toxic products of different irritative potency, or concentra- 
tion, are liberated. 
Other experiments indicate that no matter what the chem- 
ical composition of the protein molecules constituting the cyto- 
plasm, the irritating substance produced as the result of in- 
teraction of the antigen and antibody is the same. It is, 
therefore, probable that, with the exception of specific toxins 
developed by certain bacteria during their growth (e.g., B. 
diphtheria, B. tetani), the irritative properties exhibited by 
bacteria in the tissues of sensitive animals is the result of an 
antigen-antibody reaction. It is also probable that no mat- 
ter what the source of the protein antigen may be, the irritat- 
ing substances so developed are identical in nature. We are 
led to the conclusion, therefore, that it is the physical (e.g., 
relative solubility, thickness of ectoplasm or the presence of 
capsule either mucoid or waxy), rather than the chemical, 
characteristics of individual species of bacterium which de- 
termine its relative irritative properties, and that consequently 
induce specific vascular and cellular reactions on the part of 
the tissues. In discussing the morphologic characteristics of 
bacteria in an earlier chapter, the importance of the waxy 
covering of the tubercle bacilli has been indicated. 
"Although I have considered the possibility of the irritant product being 
derived from the animal's own tissue proteins, I am of the opinion that 
the data available justifies the adoption of the view expressed in this para- 
graph as correct. CHAPTER XVII 
THE FUNCTION OF THE LEUCOCYTES IN 
IMMUNOLOGIC PROCESSES 
In addition to the property of specific antibody production, 
the body has at its disposal a second process whereby infecting 
bacteria may be destroyed. This consists in the exhibition of 
phagocytic activity by various tissue cells. 
The function of the polymorphonuclear leucocyte, or pus 
cell-so called since it is the most constant cellular component 
or purulent material-is two-fold, namely, phagocytic and se- 
cretory. If small particles of irritant protein substances, as, 
for instance, bacteria, be sufficiently irritating to stimulate the 
pus cell to activity, the latter throws out pseudopodia and 
engulfs the irritant body. Subsequently, it attempts to destroy 
and digest the ingested material in its cytoplasm by means of 
a ferment, present in its cell substances, known as leuco- 
protease. 
Phagocytosis of inert material is accomplished by the mono- 
nuclear cells. This phenomenon is commonly noted in the 
lungs and bronchial lymph nodes in which are cells which 
take up carbon pigment. 
If pus from a case of gonorrheal urethritis be examined 
microscopically, it is found to consist chiefly of polymorpho- 
nuclear leucocytes similar to those found in the blood. Many, 
or most of these cells are seen to contain in their protoplasm, 
larger or smaller, numbers of gonococci. Either these bacteria 
are within the cells as a result of their own growth and 
migratory activities, or the cells have engulfed the bacteria. 
That the latter alternative actually takes place is demonstrated 
by the fact that if a suspension of dead bacteria (e.g., staphylo- 
cocci or gonococci) be injected into the subcutaneous tissues 
185 186 
INFECTION, IMMUNITY, AND INFLAMMATION 
in suitable subjects,1 a small pus collection forms, the com- 
ponent cells of which are found to have ingested a certain 
number of bacteria. 
The principles underlying the phagocytic reaction are per- 
haps not clear; there are, however, certain facts which appear 
incontrovertible. Of the possible factors which might influence 
phagocytosis there may be active one or more of the following: 
1. The pus cells may have acquired an increased avidity 
for the type of bacterium used in the experiment as the result 
of some physiologic change in themselves. 
2. Stimulated by some substance present in the serum the 
cells may be induced to function to an unusual degree. 
The fact that cells from normal individuals and cells from 
immune persons, if washed with salt solution and treated with 
the same serum, exhibit equal phagocytic power disproves the 
likelihood of the former alternative. 
3. It is possible that the bacteria are so affected, by some 
antibody in the serum, that they are rendered more likely to 
be attacked by the leucocytes. That this view is correct is 
proved by the fact that if the bacteria be washed, after having 
been exposed to the action of the immune serum, and be sub- 
sequently added to a mixture of leucocytes and fresh normal 
serum phagocytosis proceeds as in control experiments in 
which specific immune serum is employed. 
It may, therefore, be assumed that phagocytosis of bacteria, 
when the latter are treated with immune serum, is due to an 
alteration in the bacterial cell bodies. 
The change which takes place in the bacteria which are made 
the subject of experimentation may conceivably be of one or 
other of two forms. Resistance of the bacterial cell to inges- 
tion may depend upon production by the bacteria of toxins, or 
substances of a similar nature, which prevent phagocytosis or 
*The suitability of the subject depends upon his state of hypersensitive- 
ness to the bacterial protein. In another chapter it is shown that there is 
reason for believing that it is only in so far as the individual's tissues are 
hypersensitive to the bacterial protein that the bacterial body becomes ir- 
ritating to the tissues, and consequently stimulates reaction on the part 
of the body cells. FUNCTION OF LEUCOCYTES IN IMMUNOLOGIC PROCESSES 
187 
repel the leucocyte (aggressins).2 On the other hand it may 
be that the normal bacterial cell body is not sufficiently irri- 
tating to stimulate the leucocytes to activity. In the termin- 
ology of Metchnikoff absence of phagocytic activity may be 
due to a "negative chemotaxis" exhibited by the bacterial, or 
merely lack of "positive chemotaxis." 
The author believes that sufficient proof is available to 
justify the conception that phagocytosis of bacterial cells oc- 
curs in direct proportion to the irritant properties exhibited 
by the bacterial cytoplasm. As a rule variations in actual 
irritative property depends upon hypersensitiveness of the 
tissues to the baeterioprotein. 
In consequence of the reaction between the first order anti- 
body (anaphylactin) and the bacterial protein the relatively 
innocuous bacterial cell body is transformed into a highly 
irritant substance which stimulates leucocytic activity and 
leads to ingestion of the bacterial cell. Within the cytoplasm 
of the phagocytic cell more complete degradation of the pro- 
tein and consequent dissolution of the bacterium takes place. 
Certain experimental data, in which nonviable and non- 
toxic substances are employed, throw light upon the subject. 
If a slowly soluble nontoxic substance, such as catgut or animal 
charcoal, be broken up and injected into the subcutaneous 
tissues, or peritoneum, of a guinea pig, no cellular reaction 
other than the accumulation of macrophages takes place. (See 
page 241.) If, however, the catgut or charcoal be impregnated 
with some irritant substance such as turpentine, its injection 
is followed by a rapid and progressive accumulation of pus 
cells. Evidently, therefore, increased toxicity or irritant quali- 
ties of foreign particles determines more active leucocytic ac- 
cumulation and phagocytosis. 
In studying chemotaxis of phagocytes, Metalnikow3 has 
noted the close relationship between this phenomenon and ana- 
phylaxis. The introduction of a specific antigen into the 
2Aggressin is the name given to a hypothetical substance which is sup- 
posed to protect the bacterium from the action of leucocytes and anti- 
bodies. 
'Metalnikow: Compt. rend, de la Soc. de Biol., May 21, 1921. 188 
INFECTION, IMMUNITY, AND INFLAMMATION 
hypersensitive animal gives rise to an excessive inflammatory 
reaction. Guinea pigs and rabbits were rendered hypersensi- 
tive by repeated injections, and two weeks after the last injec- 
tion small capillary tubes were introduced into the peritoneum 
and subcutaneous tissues. Some of the tubes were filled with 
specific antigen, while others contained an inert fluid. After 
ten to twenty-four hours the tubes were removed. Microscopic 
examination of the contents showed that very few leucocytes 
were present in the inert fluid, while those which contained 
antigen were packed with leucocytes. Further experiments 
showed that desensitization of the animals by means of injec- 
tions of antigen inhibited leucocyte accumulation in the tubes. 
Metalinkow has proved the positive chemotactic influence of 
antigen toward leucocytes in hypersensitive animals. He be- 
lieves that in anaphylactic shock there is an accumulation of 
leucocytes at the focus of injection. There is a consequent 
leucopenia in the circulating blood. 
If the tissues have been exposed to a previous parenteral 
introduction of the bacterial protein, they become hypersensi- 
tive to this protein, and there is present in the tissue and body 
fluids an antibody (first order antibody). Subsequent intro- 
duction of the bacterial protein is followed by an immediate 
reaction between this antibody and the bacterial antigen. In 
consequence of this reaction irritant products are developed; 
each individual bacterial cell thus becomes an irritant focus. 
As a result of this acquired irritative property the leucocytes 
are stimulated to move towards, and to ingest, the bacteria. 
Experiments prove that it is not essential that bacteria be 
devitalized in order that they may be phagocytized by leu- 
cocytes. It is thus seen that even though, in consequence of 
either an inadequate concentration of proteolytic antibodies 
in the body fluids or special protective properties on the part 
of the bacterium, the body fluids alone are unable to destroy 
the microorganisms, nevertheless, a sufficient concentration of 
antibody may be present to indirectly accomplish destruction 
of the bacterium through the stimulation of cellular phagocytic 
activity. FUNCTION OF LEUCOCYTES IN IMMUNOLOGIC PROCESSES 
189 
Obviously, other things being equal, such bacteria as are 
protected by a surrounding capsule of either mucoid or waxy 
material (pneumococcus, streptococcus mucosus, B. leprae), are 
less likely to be acted upon by anaphylactic bodies present in 
the body fluids than are those which are not thus protected. 
In consequence we find that, in vitro, phagocytosis of such 
bacteria takes place but indifferently and that, clinically, such 
bacteria are allowed to proliferate and spread through the 
tissues before adequate vascular and cellular reactions take 
place. 
Opsonin.-In 1902 Wright discovered that washed leucocytes 
ingested a larger number of bacteria from a suspension of the 
latter when in the presence of immune, as compared with 
normal, serum. For example, when, to a suspension of staphy- 
lococcus aureus, there is added a suspension of polymorpho- 
nuclear leucocytes, washed free from serum, few if any of the 
cocci are ingested by the cells. If to the mixture of cocci and 
leucocytes in salt solution, there is added a small quantity of 
fresh normal serum, each of the cells ingests a small number 
of bacteria. If, however, serum from an "immune" individual 
be employed, it is found that the average number of bacteria 
taken up by the cells is markedly increased. 
As a result of his experiments Wright assumed the presence 
in the body fluids of a specific antibody as a result of the 
activity of which bacterial cell bodies were rendered more 
liable to phagocytosis by the leucocytes. He employed the 
word "opsonin" (opsono-I prepare food for) to designate 
this antibody. 
Obviously, in the use of the word opsonin, Wright believed 
that the action of the antibody upon the bacterium resulted in 
the latter becoming more easily phagocytized by the leucocytes. 
In my opinion the action of "opsonin" upon antigen consists 
in so altering the bacterial cell protein that it acts as an irri- 
tant to the tissue cells. As has been previously pointed out, 
the majority of bacterial cells possess but little essential tox- 
icity, or irritability, for normal tissues. 
The number of bacteria ingested by polymorphonuclear leu- 190 
INFECTION, IMMUNITY, AND INFLAMMATION 
cocytes in the presence of immune serum, as compared with 
the average number taken up by the same leucocytes when 
treated with normal serum, constitutes the opsonic index. 
Wright found that, if too great a quantity of immune serum 
was added to a suspension of leucocytes and bacteria, phago- 
cytosis of the latter was inhibited, as compared with the mani- 
festation of phagocytosis exhibited when smaller quantities 
were employed. According to the author's hypothesis, such 
results are explained by the assumption of the presence in the 
serum of a sufficient amount of second order (tolerant) anti- 
body to render nonirritating the product of the reaction be- 
tween the first order antibody and antigen. 
It is thus seen that, in the author's opinion, the opsonin of 
Wright is, in fact, identical with the anaphylactic or first order 
body; the degree of phagocytosis which occurs in vitro is de- 
pendent upon, either the absolute amount of first order body 
present, or the relative amount of second order body. 
When an individual suffering from furunculosis is subjected 
to an injection of staphylococcus protein (vaccine) the follow- 
ing phenomena are noted. Within twelve hours, and continu- 
ing during the ensuing thirty-six hours or longer, the individ- 
ual furuncles increase in size, the hyperemic zone becomes 
wider, and the lesions become more painful and tender. Small 
red papules may arise at points which had previously shown 
no evidence of infection. The patient may suffer from malaise. 
If the serum be examined, twenty-four hours after injection 
of the bacterial antigen, the opsonic index may be lower than 
before the administration of the vaccine. This is the con- 
dition described by Wright as the negative phase. 
If Wright is correct in his conception that the negative phase 
is injurious to the injected individual, we must, if possible, 
guard against its occurrence. According to the author's con- 
ception of the negative phase, insofar as this refers to clinical 
manifestations, it indicates a stage of stimulation of morpho- 
logic tissue reaction consequent upon exhaustion of the second 
order (tolerant) antibodies. In the author's opinion, it is only 
insofar as the phenomena, which characterize the so-called FUNCTION OF LEUCOCYTES IN IMMUNOLOGIC PROCESSES 
191 
negative phase, are produced, that useful results are to be 
expected in the treatment of focal infections. It is the duty 
of the physician or surgeon, to so employ bacterial proteins 
(vaccines) that he is able to stimulate, and at the same time 
control and guide, the inflammatory reactions at the foci of 
infection throughout the body. 
It is evident that it is only when a suitable dose of bacterio- 
protein is injected that a favorable result at the focus of in- 
fection is to be expected. If too small a dose of bacterio- 
protein be injected to depress, to any considerable degree, the 
second order body, no alteration in the inflammatory reaction 
at the bacterial focus takes place. In such an event, the injec- 
tion is harmless, but except for whatever slight effect may be 
exerted upon the production of antibodies by the tissues by 
virtue of the added stimulus, no useful effect is accomplished. 
On the other hand, it is quite possible to so exhaust the second 
order body that a dangerously excessive inflammatory reaction 
may take place at the focus of infection. This untoward re- 
.sult may be due to the development of diffuse edema in a 
vital organ, such as the brain or the kidney, with consequent 
destruction of the individual, or, it may be in the nature of an 
excessive reaction in the sense of so increasing interstitial 
tension that circulation through the part may be interfered 
with and edema, with consequent liability to necrosis of tissue, 
ensue. 
It is obvious, therefore, that extreme care must be taken in 
order to determine the proper dose of vaccine to be employed 
in treatment. In order that a suitable dose may be employed, 
it is necessary that the physician who attempts to alter the 
tissue reactions, should know the state of the tissues with 
reference to their hypersensitiveness and tolerance. It is also 
of the utmost importance, if it is the intention of the vaccine 
administrator to induce a severe reaction, that the possibility 
of focal accumulations of bacteria in vital organs, or in tissues 
in which interstitial edema is not well tolerated, be carefully 
excluded. In the treatment of infective lesions of the internal 
organs, but minimal increases in the hypcremic and cellular 192 
INFECTION, IMMUNITY, AND INFLAMMATION 
reaction should be provoked. It must, moreover, be realized, 
that if multiple or extensive lesions be present, the multiple 
discharge of actively irritant substance, when the second order 
body is exhausted, may suffice to induce injuriously severe 
constitutional intoxication. 
The author's observations have led him to believe that it is 
possible by means of the employment of the cutaneous, or 
better, the intradermic introduction of the bacterioprotein, and 
a close observation, during a forty-eight hour period following 
injection, of the reaction which occurs, to determine the rela- 
tive proportion of first and second order bodies. 
The protective property of leucocytes is exalted clinically by 
means of the induction of a leucocytosis by injections of cer- 
tain substances, such as nuclein, collargol, olive oil, etc., which 
have been found to bring about an increase in the number of 
circulating leucocytes. Following the introduction of such 
materials, whether intravenously, intraperitoneally, subcutane- 
ously, or per rectum, there ensues a period during which clini- 
cally there is a greater resistance against infection and the blood 
shows an increase in the number of leucocytes. Examination 
of the marrow, under such circumstances, demonstrates an 
increased myelogenous activity in this tissue. This phenom- 
enon, which was first noted by Isaeff, is known as the resistance 
period, and has constituted one link in the chain of evidence 
giving to the leucocytes their place among the protective prop- 
erties at the disposal of the body. 
It may not be out of place to note at this point that the 
induction of reactions by means of the injection of peptone or 
partially autolyzed bacterial suspensions, and horse serum, 
owes its practical usefulness to a great extent to the stimula- 
tion of leucocytic production in this way. 
Such methods of nonspecific protein therapy are also of prac- 
tical value since their injection results in exhaustion of tolerant 
bodies and consequently the development of positively irritant 
properties on the part of bacterial foci in the body. Inflam- 
matory-allergic-reactions with the exhibition of phagocy- 
tosis by the accumulated leucocytes may be thus stimulated. FUNCTION OF LEUCOCYTES IN IMMUNOLOGIC PROCESSES 
193 
By means of the injection of bacterioproteins or vaccines 
various results may be obtained, depending upon (1) the state 
of the individual injected; (2) the dose of bacterioprotein in- 
jected and (3) the interval allowed between injections. Thus 
any one of the following alterations in the hypersensitive state 
of the tissues may occur. 
1. Hypersensitiveness may be induced if such be absent, or 
increased if already present. 
2. Hypersensitive individuals may be desensitized. 
3. Hypersensitiveness may be exalted and tolerance may be 
engendered by means of repeated injections. 
4. In chronically infected individuals whose tolerance suf- 
fices to mask the hypersensitive state the immunizing bodies 
may be depressed so that their hypersensitiveness becomes 
more apparent and allergic reactions are stimulated. 
5. Both sensitizing and tolerant bodies may be depressed to 
such a degree that all cellular and vascular reactions cease. 
Relationship of Hypersensitiveness and Tolerance to the 
Phagocytic Reaction 
It would appear that, although the body fluids are capable, 
under proper conditions, of digesting numerous foreign pro- 
teins including many bacteria, this method of bacterial de- 
struction is not the one which is most efficacious and econom- 
ical of body effort. Whenever possible the blood, or tissue, 
cells, more particularly the polymorphonuclear leucocytes, are 
employed in the reaction against insoluble particulate proteins. 
The anaphylactic or allergic reaction plays an important 
part in stimulating phagocytosis. In the author's opinion this 
is explained in the following way. It is obvious that the 
phagocytic cells, more particularly the leucocytes, need some 
particular form of stimulus to induce them to migrate towards 
and to ingest, foreign substances. Now if we assume, as we 
have every reason to believe, that the majority of bacterial 
cells do not secrete, or excrete, any very potent essential toxin 
we may liken the inoculation of bacteria into nonsensitive ani- 
mals to the introduction of plain catgut. Thus we find that 194 
INFECTION, IMMUNITY, AND INFLAMMATION 
the intraperitoneal or other injection of dead tubercle or 
typhoid bacilli, staphylococci, etc., into normal animals or into 
man is not followed by vascular dilatation or leucocyte ac- 
cumulation until after the lapse of a certain length of time, 
which corresponds to the period necessary for the anaphylactic 
state to develop. If, however, the animal employed has pre- 
viously received a sensitizing dose of a like bacterial protein, 
we note that the phenomenon of allergy is demonstrated locally 
and, if a sufficient quantity be employed, systemic manifesta- 
tions of intoxication are exhibited. The leucocytes from such 
an accumulation are found, moreover, to have ingested large 
numbers of microorganisms. 
The explanation of these phenomena appears to be that as 
a result of the presence of specific first order antibodies (ana- 
phylactin), in the body fluid of the sensitized animal, the 
injected bacterial cell is so acted upon by this substance that 
irritant products are liberated. In consequence the previously 
innocuous bacterial cell becomes at once an irritant focus, and 
so stimulates the leucocytes to activity. Phagocytosis of the 
bacteria and their subsequent complete proteolysis within the 
pus cell results. Granted that a sufficient number of bacteria 
be not ingested to bring about death of the cell itself this type 
of reaction is the most economical and most rapidly leads to 
the elimination of the invader. 
In the ordinary course of chronic infections, such as tuber- 
culosis, and staphylococcus infections, e.g., furunculosis, we 
have present in the serum not only antibodies capable of re- 
acting with antigen so that substances are produced, (that is, 
not only is the individual sensitized to the tubercle bacilli or 
the staphylococcus as the case may be), but there is also 
present in its serum a substance which we have termed the 
second order antibody or " antianaphylatoxin. " This sub- 
stance is potent to neutralize and render innocuous to the tis- 
sues the irritant products arising from the reaction between 
antigen and first order antibody. If the proportion of the 
second order antibody to antigen be sufficient, the "anaphy- 
latoxin," or allergic irritant product, is immediately neutral- FUNCTION OF LEUCOCYTES IN IMMUNOLOGIC PROCESSES 
195 
ized. Under such conditions cellular phagocytosis does not 
act as an irritant focus. 
In such an event an increase in cellular activity can be 
stimulated by a depression or exhaustion of the second order 
antibody (tolerant antibody). 
This point can, perhaps, be made more clear by a study of 
the changes which occur when tuberculin is injected sub- 
cutaneously into an individual suffering from a localized tuber- 
culosis. We will assume that the individual is suffering from 
a small tuberculous collection in one of the cervical lymph 
nodes, but that he demonstrates no evidence of constitutional 
toxemia, such as increase of pulse rate or pyrexia. The sub- 
cutaneous introduction of .001 milligram of tuberculin (T.R.) 
is followed after a period of six hours or less with the onset 
of symptoms of constitutional toxemia, rapid pulse, elevation 
of temperature, headache, malaise and anorexia. Locally, at 
the point of injection there is slight swelling with a surround- 
ing hyperemic zone of from 2-4 centimeters in diameter. This 
inflammatory area is tender and possibly painful. Focally in 
the neck the lymphnode becomes swollen and painful and 
may become the site of a definite collection of pus cells, i.e., 
abscesses may develop. 
What changes have been brought about in this individ- 
ual by the subcutaneous introduction of the tuberculin? We 
know from experimental evidence that a tuberculous individ- 
ual contains in his serum first order antibodies (anaphylactin) 
or certain substances capable of so sensitizing guinea pigs that 
immediate anaphylaxis can be induced. Why does not this 
individual whose serum contains the sensitizing substance ex- 
hibit symptoms of tissue intoxication since there is present in 
his body a focus of tuberculoprotein ? Two factors appear to 
me to be instrumental in permitting him to be free from 
fever and other symptoms of intoxication. In the first place, 
we know that under certain circumstances an animal loses its 
sensitiveness to small doses of protein antigen even though its 
serum contains a sensitizing body. This we assume to be due 
to the presence in the body of a second substance, which we 196 
INFECTION, IMMUNITY, AND INFLAMMATION 
have termed the second order antibody (antianaphylatoxin), 
which has the property of detoxicating or rendering inert the 
product of the antigen-anaphylactin (first order antibody) 
reaction. This is sufficient to neutralize the comparatively 
small amount of irritant product which is liberated from the 
focus. A minimal reaction between antigen and antibody is 
likely to occur since the tuberculous nodule is, characteris- 
tically, poorly supplied with blood. The quantity of irritant 
body, by virtue of the fact that it is being constantly neu- 
tralized by the second order body (tolerant body) at the 
focal collection of tubercle bacilli, does not stimulate cellular 
reaction. 
Upon the subcutaneous introduction of the tuberculo-protein 
there at once occurs a reaction between this antigen and the 
first order antibodies with the liberation of irritant products. 
If the amount of antigen introduced is sufficiently large, an 
excess of "anaphylatoxin" over available second order body 
will be present in the serum. As soon as this occurs the tu- 
berculous focus assumes a definitely toxic property. As a 
result vascular and cellular activity at the point of infection 
is stimulated. There results, therefore, a triple manifestation 
of the reaction to a single injection of a bacterial protein in 
an infected individual, namely, focal inflammation at the site 
of infection, constitutional febrile reaction, and local inflam- 
mation at the site of injection. 
Numerical values may be employed to explain the tissue 
changes that are exhibited. If the tissue of an individual suf- 
fering from tuberculous cervical lymphadenitis contain one 
thousand units of the first order body and fifty units of the 
second order body, and if the tuberculoprotein situated in the 
glands of the neck be so walled off by fibrous tissues that but 
twenty units of antigenic protein are brought in contact with 
the circulating body fluids, the patient manifests no evidence 
of constitutional intoxication, such as fever or malaise. The 
infected lymph nodes, moreover, are not tender, and show but 
little evidence of inflammation. If, into such an individual, 
a dose of tuberculoprotein,'representing thirty-five units, be FUNCTION OF LEUCOCYTES IN IMMUNOLOGIC PROCESSES 
197 
injected subepidermically, the available second order bodies 
are exhausted and five units of anaphylatoxin are liberated 
from the artificial focus and the infected focus combined. If 
the injection has been made into the flexor surface of the 
forearm, the evidence of tissue irritation is manifested within 
a few hours by hyperemia and exudation of fluid into the 
tissues. In this way a red swollen nodule is produced. A 
similar reaction, though usually invisible, takes place in the 
glands of the neck. 
If, instead of a dose of thirty-five units of tuberculoprotein, 
a dose of but ten units had been injected, the addition of the 
ten units to the twenty units which are being acted upon in 
the glands, would not have sufficed to exhaust or sufficiently 
depress the available second order bodies, to induce a reac- 
tion. In such an event no reaction occurs either at the site 
of injection, or in the focal lesions. On the other hand, if a 
dose of 600 units of protein antigen be injected, the amount 
of anaphylatoxin available, after exhaustion of the second 
order bodies, would be 570 units. We will assume that this 
number of units represents a relatively enormous dose of 
the irritant substance. In consequence, the forearm becomes 
much swollen, very red and painful, a lymphangitis is seen 
spreading up the arm and the glands in the axilla become 
tender. The affected glands in the neck undergo a similar 
reaction, pus cells are poured out, interstitial tension becomes 
extreme, and abscess formation and necrosis take place. At 
the same time, the patient suffers from hyperpyrexia and its 
concomitant exhaustion. 
Obviously it is possible to administer so little bacteriopro- 
tein that no focal reaction is stimulated, or to inject so large 
an amount that an excessive reaction, both focally and con- 
stitutionally, is induced. It is likewise possible to so grade 
the dose of antigen introduced into the tissues that an ade- 
quate, but controlled, focal inflammation is stimulated. The 
aim of the clinical immunologist is to induce such an adequate 
reaction. CHAPTER XVIII 
PROTEIN-LYSIN IMMUNITY. ALEXIN (COMPLEMENT) 
AND SENSITIZING SUBSTANCE (AMBOCEPTOR) 
In addition to the simple type of immunity reaction which 
is exemplified by the neutralization of toxin by antitoxin, a 
reaction occurs in which two serum bodies, acting together, 
destroy or otherwise alter the antigen. When certain particu- 
late proteins, such as red blood cells or gram-negative bacilli, 
e.g., cholera vibrios, are treated with fresh immune serum, 
lysis of the antigen occurs. If the immune serum has been 
heated, such lysis does not take place; the addition of fresh 
normal serum, however, is followed by destruction of the 
antigen. The individual particles become obscure, and finally 
go into solution. It may also be proved that fresh normal 
serum is without effect on the antigen. By such a series of 
reactions, it was discovered that in order that lysis of a par- 
ticulate antigen may be accomplished, two substances are 
necessary. 
One of the serum bodies involved in this type of reaction is 
present in normal serum and is not affected in nature or 
quantity by immunity processes. This normal constituent of 
serum has been termed alexin (Bordet) or complement 
(Ehrlich). 
The other antibody is specific in its action and is increased 
to a marked degree in the process of immunization. Since 
he conceived this substance to act as a link which unites anti- 
gen and complement, so that the latter may act upon the for- 
mer, it was called by Ehrlich, amboceptor or midpiece. Ac- 
cording to Bordet's conception the specific immune body 
renders antigen susceptible to the destructive action of alexin. 
He, therefore, applies to the amboceptor of Ehrlich, the term 
sensitizing substance (substance sensibilatrice). It is evident, 
from the use of the terms employed by these authors, that 
198 PROTEIN-LYSIN IMMUNITY 
199 
according to Ehrlich's hypothesis, the antigen-amboceptor- 
complement reaction is accompanied by a building up, or 
synthesis, of the reacting substances, whereas Bordet believes 
that destruction, or dissolution, of antigen is accomplished 
by alexin when the former is rendered sensitive to the de- 
structive effect of the latter through the action of the immune 
body. 
Alexin or Complement.-The alexin is the most potent fac- 
tor in the phenomenon of lysis; albeit, its activity cannot be 
exhibited unless the antigen has been rendered sensitive to 
its action as a result of a reaction with the specific immune 
body. 
Alexin, or complement, is a normal constituent of serum 
and is not affected by processes of immunization. It is, more- 
over, remarkably constant in quantity, and is but little af- 
fected by differences in age, sex, etc., of individuals. 
Alexin is a labile substance. It is destroyed by exposure 
to 56° for a period of one-half hour. It disappears, more- 
over, from serum in a comparatively short time, at ordinary 
temperatures. Its rate of diminution is more rapid at tem- 
peratures approaching that of body heat than in the ice chest. 
When exposed to temperatures of 17° to 27° C., a period of 
eight to twelve hours is sufficient to materially inhibit its 
activity. In the ice chest-3° to 5° C.-if stored in abso- 
lutely clean vessels, it usually maintains its activity practi- 
cally unaltered for twenty-four hours, but should not be 
employed in serum reactions after such a period of time. 
The actual cause of the disappearance of complement from 
unheated serum has not been definitely determined; it is 
probable, however, that it does not simply disappear, or that 
it is not destroyed by substances in the serum, but, rather, 
that it actually takes part in a nonspecific proteolysis which 
takes place following removal of blood from the body. 
Fresh unheated serum which contains alexin (complement) 
is said to be "active." Destruction of the complementary 
body by means of heat (or other means) "inactivates" the 
serum. 200 
INFECTION, IMMUNITY, AND INFLAMMATION 
The activity of serum may be maintained if the serum be 
dried, especially if desiccation be carried out in vacuo and at 
a low temperature. This fact also suggests that the deteriora- 
tion in activating power in fluid serum is due to the occurrence 
of nonspecific proteotropic reactions. 
The complementary activity of serum is destroyed by a 
number of simple chemical substances such as bichloride of 
mercury, silver nitrate, and by acids and alkalies. In the 
practical employment of complement in quantitative reactions 
it is essential that the glassware, rubber tubing, and other 
utensils employed, be perfectly clean. 
Origin of Alexin.-There has existed for some time a dif- 
ference of opinion with regard to the presence, or absence, of 
alexin, in the form in which we recognize it in vitro, in the 
circulating blood. A large number of observers, including 
Domeny,1 Sweet,2 Hewlett,3 Lowit and Schwartz,4 and Addis5 
and Dick, believe that their experiments prove the presence 
of complement as a normal constituent of plasma. Others, 
among whom are Gengou,6 Hermann,7 and myself,8 have, as 
the result of their experiments, been led to adopt the view 
that complement, as usually studied, does not exist in natural 
plasma, but that it is developed as the result of subtle changes 
occurring in the blood following its removal from the body. 
The reasons for such diverse opinions are that the methods 
adopted for the estimation of complement quantitatively, and 
also qualitatively, are liable to afford possibilities of error 
which are of the greatest importance. 
It would be out of place in a work of this nature to enter 
into a prolonged discussion of the relative merits of these 
two points of view: since, however, I believe that the question 
is not without practical bearing upon several disease phenom- 
'Domeny: Wien. klin. Wschnschr., 1902, xl, 105. 
'Sweet: Centralbl. f. Bakteriol. I Orig., 1903, xxxiii, 208. 
'Hewlett: Arch. f. exp. Path. u. Pharmakoi., 1903, xlix, 307. 
♦Lowit and Schwartz: Ztschr. f. Heilkunde, 1903, xxiv, 205, 301. 
'Addis: Jour. Infect. Dis., 1912, x, 200. 
6Gengou: Ann. de 1'Inst. Pasteur, 1901, xv, 232. 
'Hermann: Bull, de 1'Acad. Roy. de Med., 1904, 157. 
8Gurd: Jour. Infect. Dis., 1912, ix, 225-234. PROTEIN-LYSIN IMMUNITY 
201 
ena, a short resume of my own opinions upon the subject is 
given. It is my belief that complement, as we are accustomed 
to consider it, does not exist as such in the circulating plasma, 
but that a body, which may be termed complementogen, is 
present in practically constant amounts. This complemento- 
gen is rendered active only as a result of the liberation of 
some substance, probably similar in effect to thrombokinase, 
which is produced by certain tissue cells,-in all probability 
the polymorphonuclear leucocyte. It is evident, if this hy- 
pothesis be correct, that as is the case with thrombinogen, an 
infinitely small quantity of the kinase is sufficient to render 
active a comparatively large amount of complementogen. 
These views are based upon the facts observed,-that the 
amount of complement demonstrable in serum varies with the 
length of time and the temperature at which the blood is 
kept. This suggests that it is developed following removal of 
the serum from the body, the more so, since a temperature 
of 37.2°, or slightly higher, is more uniformly followed by a 
more rapid production of the substance than if a lower tem- 
perature be employed.9 
There is no reason for believing, according to this hypothe- 
sis, that complement may not be produced, as occasion may 
arise, within the body, owing to the interaction in vivo of the 
two substances (complementogen and kinase). 
It is not likely that the favorable results, occasionally ob- 
tained, in the treatment of infections by such nonspecific sub- 
stances as horse serum, milk proteins, and perhaps the so- 
called Schaffer vaccines, are due in part to the stimulus 
afforded in this manner to the development of alexin in the 
body. It is noteworthy in this connection that the source of 
the kinetic body need not be from the same species as that 
from which the complementogen is derived. 
Relationship of Complement to Leucoprotease.-In 1893 
Buchner noted that aleuronat exudates, produced intrapleu- 
rally in rabbits and dogs, possessed a bactericidal value for 
Bacillus coli communis which exceeded the bactericidal power 
'Gurd: Jour. Infect. Dis., 1912, ix, 225. 202 
INFECTION, IMMUNITY, AND INFLAMMATION 
of the blood serum itself. Similar results were reported by 
Hahn, who employed B. typhosus. 
Denys found that pleural exudates in rabbits, obtained by 
the injection of dead staphylococci and from which the cells 
were removed by centrifugalization, are more highly bacteri- 
cidal for staphylococci than is the blood serum of the same 
animals. For a time, this increased bactericidal activity was 
believed to be due to the production of alexin on the part of 
the leucocytes themselves. It was, moreover, thought that 
alexin was identical with the proteolytic substance which may 
be extracted from washed leucocytes. That the presence of 
leucocytes in the exudates may, perhaps, result in the more 
rapid development of a maximum alexin content in the fluid 
is possible; that, however, alexin is identical with the leuco- 
cytic enzyme-leucoprotease (Opie)-is practically disproved. 
"The enzyme of the polymorphonuclear leucocytes may be 
precipitated with alcohol and after drying may be preserved 
almost indefinitely. In the moist state it is destroyed by a 
temperature of from 70° to 75° C.; a lower temperature, 
50° to 60° C., increases its activity. It acts in an alkaline or 
neutral medium, but is inhibited by acid. It is less active than 
trypsin in vitro and is not identical with alexin or comple- 
ment." (Opie.10) 
These findings of Opie, with reference to thermostability of 
leucoprotease, are in accord with those of Schattenfroh,11 
Moxter,12 Petterson,13 and others. 
A more recent study of this subject is that by Zinsser,14 
whose conclusions are abstracted in the following paragraph. 
Extracts of normal rabbit leucocytes, both those obtained 
by queous extraction and those obtained by freezing in salt 
solution, have distinct bactericidal powers for pyogenic staph- 
ylococci and B. typhosus. There is considerable uniformity in 
the action of various lots of such extracts upon the same strain 
10Opie: Jour. Exper. Med., 1905, vii, 316; 1906, viii, 410. 
uSchattenfroh: Arch. f. Hyg., 1897, xxxi, xxxv. 
"Moxter: Deutsch, med. Wchnschr., 1899, p. 687. 
13Petterson: Centralbl. f. Bakteriol, 1905, i, No. 39; 1908, No. 46. 
"Zinsser: Jour. Med. Research, 910, xxii, 397. PROTEIN-LYSIN IMMUNITY 
203 
of microorganisms, and it is apparent that separate strains of 
the same species show no decided variation in their susceptibil- 
ity to the bactericidal substances contained in the extracts. 
Immunization does not enhance the power of leucocytic sub- 
stances. Fresh leucocytes have no power of reactivating in- 
active serum. 
Multiplicity of Alexins.-Although the fact that there must 
exist a multiplicity of amboceptors is obvious, the question as 
to whether there is more than one type of complement is less 
easily answered. That the complementary bodies in different 
species of animals are not of identical structure with one an- 
other, or at least possess diverse affinities, is evident from the 
fact that the activating power of fresh sera from different 
species, e.g., the goat and guinea pig, upon another amboceptor 
containing serum,-e.g., the rabbit,-is not constant. Fresh 
goat serum contains a considerable quantity of complement 
as can be proved by means of experiments in which it is 
employed to activate hemolytic amboceptor derived from the 
goat. Goat serum is, however, of comparatively little potency 
in the reactivation of inactivated rabbit serum. 
Although it is a fact that the complementary body derived 
from different animal species is variable in structure, there is 
no proof that one and the same serum contains more than one 
body of this nature. Experiments which have been inter- 
preted as supporting the view of multiplicity of complement 
are all subject to other interpretation. 
Sensitizing Substance (Amboceptor).-The specific substance 
as the result of whose presence in immune serum complement 
or alexin is bound to foreign cells, bacteria and heterologous 
proteins, has been termed by Ehrlich, the amboceptor. This 
name was chosen since Ehrlich believed that the substance 
acts by virtue of the formation of a link between antigen and 
complement. 
Other observers have applied various terms to Ehrlich's 
amboceptor, each of which is suggestive of the activity of 
that body. Since it is the most important antisubstance pro- 
duced during the process of immunization, it is commonly 204 
INFECTION, IMMUNITY, AND INFLAMMATION 
called the immune body. Bordet, realizing that it attached 
itself to antigen and thus prepared the latter for the lytic 
action of alexin, calls it the sensitizing substance (substance 
sensibilatrice). Simple translation of the classic term ambo- 
ceptor gives us "intermediate body" or "mid-piece." 
The antibodies which determine the occurrence of such phe- 
nomena as cyto and bacteriolysis, phagocytosis, and anaphy- 
laxis, are of the nature of amboceptors. The term ambocep- 
tor does not, therefore, indicate the nature of the end result 
of the activity of the substance, but simply the fact that we 
are dealing with a substance developed in tremendous excess 
during the process of immunization, but which requires the 
presence of alexin or complement in order that its action may 
be manifest. 
Resistance of Amboceptor to Heat and Desiccation.-Ambo- 
ceptors are relatively stable bodies. They resist a tempera- 
ture of 60° C. for at least one hour, but with a distinct dimin- 
ution in potency (about one half). They are quickly destroyed 
by a temperature of 75° to 80° C. 
When serum containing specific amboceptors is preserved, 
under sterile precautions in the dark and at a low tempera- 
ture, 5° to 8° C., the properties of the substance are main- 
tained over a period of many months with but little deterio- 
ration. 
Desiccation, in vacuo, does not injure the amboceptor con- 
tent of serum and, when dried, the material may be preserved 
almost indefinitely without much diminution in strength. 
Amboceptors consist of, or are closely related to, the globu- 
lins and may be procured in concentrated form by means of 
precipitation or "salting out" of the latter substances from 
sera. 
Sensitizing Experiments.-If activated antisheep erythrocyte 
rabbit serum be added to a suspension of sheep's red blood 
cells and incubated for one hour, or placed for a longer period 
in the ice chest, subsequent centrifugalization of the mixture 
proves that the specific bodies have been removed from solu- 
tion and that the cells have become sensitive to the action of PROTEIN-LYSIN IMMUNITY 
205 
complement. In mixtures, therefore, of specific amboceptor 
and antigen, the latter absorbs or binds the former, even 
though no obvious change in the structure of the antigen 
occur.15 
Reciprocal Activity of Complement and Amboceptor.-To 
a certain extent, the reaction between antigen, amboceptor 
and complement is one which can be accurately estimated 
quantitatively. Thus the proportions of each may be so deter- 
mined that it can be stated that one unit of amboceptor plus 
one unit of antigen will require one unit of complement to 
produce complete lysis of the antigen (e.g., sheep's red blood 
cells). Three units of each of the three substances, like- 
wise, result in a complete reaction. If, however, in place of 
one unit of complement and amboceptor, respectively, one half 
unit of either reagent be employed, it is found that the defi- 
ciency in amount of the one body can be compensated for 
by means of an increase in the quantity of the other serum 
used. 
Multiplicity of Amboceptors.-It is evident from what has 
already been stated, with reference to the specificity of ambo- 
ceptors, that the serum from one individual may contain an 
almost unlimited number of different amboceptors. It is, more- 
over, possible by means of absorption experiments to remove 
these separately from the serum. It must be noted, however, 
that the same phenomenon of group antibodies is noted with 
regard to amboceptors as is the case with other immune bod- 
ies, agglutinins, precipitins, etc. 
It is noteworthy in this connection to refer to the fact that 
the continuous accumulation of experimental evidence bear- 
ing upon this subject indicates that although the various am- 
boceptors-lysins, anaphylactins, etc.-are specific in their 
action, they are all very closely related to one another and 
that structurally they resemble one another very closely. It 
is not improbable that these various substances are, in fact, 
identical and that the fact that different names have been ap- 
"If the antigen be in particulate form, agglutination may be exhibited; if 
in solution, precipitation may be obtained. 206 
INFECTION, IMMUNITY, AND INFLAMMATION 
plied is due to the different forms of experiment which have 
been employed for their identification.16 
Complement Fixation or Binding.-One of the most impor- 
tant, and most commonly employed, diagnostic serum reac- 
tions depends upon the fact, as first demonstrated by Bordet, 
in 1904, that sensitized antigen will bind with, or fix, comple- 
ment if such be added, even though the amounts of serum 
employed be insufficient to bring about lysis of the antigen 
employed. 
The usefulness of this reaction becomes evident, if by means 
of a hemolytic series minus complement, the presence or ab- 
sence of free complement in a mixture can be demonstrated. 
Since this principle is so widely employed in the diagnosis of 
syphilis (Bordet-Wassermann reaction) at the present time, 
it is the subject of more extensive consideration in the next 
section. 
Complement Binding Reactions 
Bordet-Wassermann Reaction.-In 1904 Bordet and Gengou 
published from the Pasteur Institute in Paris, a method of 
serum examination whereby the presence of specific sensitizing 
bodies (amboceptors) in tested sera may be determined with 
very great accuracy. 
This method consists in the application of principles, re- 
ferred to in the last section, whereby the presence or absence 
of free alexin (complement) in a mixture of antigen, tested 
serum, and complement containing serum is discovered by 
testing the effect of the mixture, after incubation, upon sen- 
sitized red blood cells, or upon a suspension of red blood cells 
and a specific hemolytic amboceptor. That red blood cells 
are employed, with a specific hemolysin, as an indicator is 
merely a matter of convenience, such as the use of phenol- 
phthalein, or litmus, in titrations for acidity. 
Bordet's method of performing the reaction consists in the 
addition of inactivated serum to be tested, and fresh guinea 
pig serum (containing a known quantity of complement) to 
J'See Chapter XX. Identity of Antibodies. PROTEIN-LYSIN IMMUNITY 
207 
a suspension, or extract, of the suspected microorganism. 
This mixture is incubated at 37° to 38° C. for one hour.17 
At the end of this time, a known quantity of sensitized 
erythrocytes (sheep) is added and the whole placed in the 
incubator for one hour. 
If the tested serum contain specific amboceptors or sensi- 
tizers for the microorganism used, a union of antigen and 
amboceptor takes place and the complement present is ab- 
sorbed or bound. The subsequent introduction of the sensi- 
tized blood corpuscles is not, therefore, followed by lysis. 
If such specific antibodies are absent from the tested serum, 
the complement present is not bound or fixed and is, there- 
fore, able to exert its lytic action upon the sensitized 
erythrocytes. 
The principle underlying the reaction is simple, but in actual 
practice great care must be exercised, and considerable ex- 
perience is necessary, if the results of complement binding 
reactions are to be relied upon. 
The more important points which require attention and 
the most serious sources of experimental error include the 
following: 
1. Since so many human sera contain small quantities of 
a multitude of proteotropic as well as lipotropic complement 
binding bodies, the presence of complement binding bodies 
can only be accepted as diagnostic of infection, if they be 
present in abnormal quantities. 
The various reagents employed must accordingly be stand- 
ardized not only qualitatively, but also quantitatively. 
2. Since certain of the reacting bodies, at least, bear a 
reciprocal relationship to one another, they must be standard- 
ized against one another. At least two known factors must 
be at the command of the experimenter in order that the re- 
maining materials may be standardized. 
3. Although the normal complement content of guinea pig 
serum is remarkably constant in amount, it is very easily 
17Complement is also bound, but more slowly, at lower temperatures. In- 
deed greater specificity is probably obtained if a temperature of 7° C. be em- 
ployed. 208 
INFECTION, IMMUNITY, AND INFLAMMATION 
destroyed if not properly preserved and if clean glassware be 
not used. It must always be titrated before use. 
Before attempting to perform a test it is necessary that the 
potency of the hemolytic amboceptor be determined. Since 
fresh guinea pig serum, if procured and preserved in a con- 
stant manner, contains a very constant amount of complement 
and since the number of erythrocytes employed can be ac- 
curately determined, this is not difficult. 
The unit quantities of tested serum have been determined 
experimentally for the different symptoms employed. Wasser- 
mann employed 0.2 c.c. of inactive patient's serum. If 0.2 c.c. 
of inactive patient's serum be accepted as a unit and 0.1 c.c. 
of normal fresh guinea pig serum as the amount of comple- 
ment, the antigen must be so prepared, and used in such quan- 
tity, that the serum of known infected individuals consistently 
binds complement, in the presence of the antigen, and the 
serum from normal individuals gives regularly a negative re- 
action. 
Bordet's technic for the identification of antibodies is em- 
ployed in the diagnosis of disease and in the differentiation 
of antigen. In practice such reactions are used more espe- 
cially for the purpose of determining the presence of antibodies 
to the gonococcus and the tubercle bacillus, as well as in the 
serum diagnosis of syphilis. 
The serum diagnosis of syphilis since its description by 
Wassermann in 1906, has risen, comparatively rapidly, out of 
the class of experimental procedures. Its usefulness in diag- 
nosis and also in the control of treatment has been established 
and the reaction has now taken a firm place among clinical 
laboratory aids. This method is known as the Bordet-Was- 
sermann reaction. 
Wassermann prepared a syphilitic antigen by shaking up 
chopped syphilitic liver mixed with sand in salt solution in 
the proportion of one to five to which one-half part of 5 per 
cent carbolic acid solution had been added. The precipitate 
is allowed to settle and the supernatant fluid employed as 
antigen. PROTEIN-LYSIN IMMUNITY 
209 
Since Wassermann's original communication in 1906, of a 
method for the diagnosis of syphilis by means of the identifica- 
tion of specific bodies present in the serum of luetic individ- 
uals, many unnecessary changes and several important and 
valuable improvements in technic have been brought forward. 
Of the modifications suggested, and proved valuable, that of 
the more precise determination of the active principle of the 
antigen has been universally recognized. Soon after the orig- 
inal communications it was shown both by Wassermann him- 
self, and by others (Levaditi and Landsteiner), that extracts 
of the spirochetes as prepared from syphilitic livers were not 
essential constituents, but that lipoid bodies capable of ex- 
traction, both from the liver and from other organs, preferably 
the human heart, were more potent. To Noguchi in particular, 
recognition is due for the demonstration of the role played by 
the phosphatid group of lipoids in the binding of complement 
in the presence of the so-called syphilitic antibodies. CHAPTER XIX 
AGGLUTININS AND PRECIPITINS 
The serum of the immune animal exhibits certain properties 
which are being constantly made use of by the clinician, the 
bacteriologist, and the biologic chemist, in the diagnosis of 
disease, the recognition of proteins from different sources, and 
the differentiation of bacterial strains. Two of the phenomena 
are due to the presence of substances which are known respec- 
tively as agglutinins and precipitins. 
Agglutinins 
The first report of systematic research upon the subject of 
agglutinins was published in 1896 by Gruber and Durham.1 
It was noted by these observers that the serum of an animal 
which had received repeated injections of a suspension of a 
certain strain of bacteria, as for instance the B. typhosus, con- 
tains substances which so act upon suspensions of typhoid 
bacilli in normal salt solution that the individual bacterial 
cells come together to form clumps. Since the bacteria which 
are clumped in this manner are said to have agglutinated, the 
antibodies, as the result of whose presence the phenomenon 
occurs, are called agglutinins. A similar reaction occurs when 
nonbacterial particulate protein substances, such as red blood 
cells, are employed as antigen. The viability, or otherwise, of 
the bacteria in suspension does not affect the result of the 
experiment. If the bacteria belong to a motile species, they 
first of all lose their motility and subsequently clump. 
The observations of Widal upon the development of the ag- 
glutination reaction in the course of typhoid fever placed this 
method of diagnosis upon a sound basis. In practice the 
Xlruber and Durham: MUnchen. med. Wchnschr., 1896, pp. 213, 285. 
210 AGGLUTININS AND PRECIPITINS 
211 
method is universally used for the differential diagnosis of 
typhoid from similar fevers and is known as the Widal reaction. 
Macroscopically, the clumps of bacteria become apparent 
after a greater length of time than if the suspension is exam- 
ined under the microscope. If the suspension contain a suffi- 
ciently large number of microorganisms and the serum be 
sufficiently concentrated, the clumps become visible very 
quickly-in one or two minutes. This fact has been taken 
advantage of in the technic devised by Bass for the bedside 
diagnosis of typhoid fever. It should be noted, also, that if the 
bacterial suspension is shaken the cells are more intimately 
brought in contact with one another and agglutination conse- 
quently occurs more rapidly. 
Normal sera contain very little agglutinin; the property of 
producing agglutination is, however, rapidly and extensively 
acquired during the process of immunization. Agglutinins 
appear within three to six days after injection and increase in 
quantity very rapidly. Whereas, normal sera rarely aggluti- 
nate bacterial cells (in suspensions containing 500 million 
microorganisms per cubic centimeter), when diluted in nine 
parts of salt solution, it is possible to induce the production of 
these antisubstances to such a degree that clumping of bac- 
teria occurs even though only one part of serum be added to 
100,000, or even 1,000,000 parts of salt solution, containing 
bacteria. 
Group Agglutinins 
The reaction of agglutination is a specific one but demon- 
strates, even more clearly than many other immunity reactions, 
the group relationships of many bacteria. Thus if an animal 
receives repeated doses of the B. typhosus its serum will be 
found to possess the property of agglutinating the colon bacil- 
lus, the dysentery bacillus and the paratyphoid microorgan- 
isms, although its agglutinating power, when treated with the 
homologous antigen, is exhibited in much greater dilutions. 
That this phenomenon is due to the presence of group ag- 
glutinins in addition to specific antibodies is proved by the 212 
INFECTION, IMMUNITY, AND INFLAMMATION 
fact that by a process of absorption it is possible to remove 
the group agglutinins and to leave specific bodies in the 
serum. If a serum, as, for instance, that against the typhoid 
bacillus in the above table, be treated successively with colon 
and typhoid bacilli, it is possible to cause agglutination to a 
limited extent of each type of bacillus. If the suspension of 
colon bacilli in salt solution plus serum be centrifugalized, and 
the bacteria thrown down and removed, it is found that the 
serum still maintains to a considerable degree its property of 
agglutinating the B. typhosus. Durham2 has explained this 
Relative Agglutinating Power of Sera from Immune Animal When 
Treated with Homologous and Heterologous Types of Bacteria 
SERUM 
B. COLI 
COMMUNIS 
B. TYPHO- 
SUS 
B. DYSEN- 
TERIAE 
B. PARA- 
TYPHOID A. 
B. Typhosus 
4,000 
100,000 
100 
14,000 
B. Coli 
120,000 
10.000 
1,200 
15,000 
B. Dysenteriae 
5,000 
2,000 
200,000 
100 
B. Paratyphoid a. 
7,000 
15,000 
100 
100,000 
phenomenon of group agglutination by assuming that when 
an animal is inoculated with immunizing doses of typhoid 
bacilli there are produced agglutinins which may be desig- 
nated, A, B, C, D, and E; if paratyphoid bacilli be used there 
develop agglutinins B, C, D, E, and F; in the same way B. coli 
induces the production of C, D, E, F, and G; B. dysenteriae 
D, E, F, G, and H, etc. The result is that when antityphoid 
serum is treated with an excess of colon bacilli they are re- 
moved from the serum group C, D, and E, whereas A and B 
remain intact. This theory, of course, is entirely hypothetical, 
but well explains the reactions as they actually occur. 
Nature of Agglutinin Reaction 
As already stated the manner in which agglutinins bring 
about agglutination and the reason for their production is so 
far not properly understood. It has been determined, how- 
ever, that in order that clumping may take place, it is neces- 
'Durham: Jour. Exper. Med., 1901, v, 353. AGGLUTININS AND PRECIPITINS 
213 
sary that the serum and cells be brought together in salt 
solution. It is supposed that the reaction represents a change 
in ionization of the bacterial cells. This results from a chem- 
ical (colloidal) change occasioned by the action of the anti- 
bodies upon the antigen. Bordet believes, and his opinion is 
very generally accepted, that as the result of a decrease in 
the solubility of certain components of the bacterial cell, there 
is an altered molecular attraction or tension between the ob- 
jects themselves and the fluids which bathe them. This is 
evidenced by a diminution in surface tension which predis- 
poses to agglutination. A similar phenomenon is exemplified 
when a suspension of clay which remains diffuse in distilled 
water clears as the result of clumping and sedimentation when 
salt is added. 
The most usual method of estimating the agglutinating prop- 
erty of a serum or the agglutinability of a given strain of 
bacteria is by varying the dilution of the serum in the finished 
mixture. It has been pointed out, however, by Bass that, in 
order that this method may be reliable, it is necessary that the 
number of bacteria employed be accurately determined. Thus, 
it is found that, the larger the number of microorganisms, the 
smaller the amount of agglutinin which is available for action 
upon each individual bacterium. On the other hand, the fur- 
ther apart the individual cell units are, the more agglutinin 
is necessary to induce clumping. The technic recommended by 
Dreyer is based upon his appreciation of these facts. This 
author lays emphasis upon the necessity for employing sus- 
pensions that have been standardized by enumeration of the 
bacterial cells. 
Precipitins 
In 1897 Kraus3 discovered that there develops in the serum 
of the immunized animal a substance which precipitates a 
cloudy deposit when added to a solution of the specific protein 
antigen by means of which the animal has been immunized. 
These substances are called precipitins. 
'Kraus: Wien. klin. Wchnschr., 1897, p. 736. 214 
INFECTION, IMMUNITY, AND INFLAMMATION 
Precipitins are produced against a large number of soluble 
protein substances-albumins and albumoses. The reaction is 
extremely specific, but results in the development of group 
precipitins, as is the case with other immune bodies. 
Precipitins resemble other immune bodies in the manner and 
rate of their production. By means of fractional methods of 
precipitation of serum with ammonium sulphate it has been 
demonstrated that precipitins are closely allied to the globulins 
as are other antibodies. 
As is the case with agglutinins, precipitins lose their power 
of inducing precipitation when heated to 60-70° for from five 
to ten minutes, nor can they be reactivated, by the addition 
of fresh normal serum (alexin). 
The presence of alexin is not necessary for precipitation to 
take place. Mixtures of precipitin and antigen, on the other 
hand, do possess the property of removing complement, if such 
be added, from the mixture. 
The fact that, by the action of complement upon precipi- 
tated proteins, there is developed a soluble toxic substance has 
received attention elsewhere (Anaphylatoxins, see page 130). 
Precipitins are capable of absorption in the same manner as 
agglutinins. This might well be expected in view of this prob- 
able identity of the two substances. 
The most commonly employed practical use of the precipitin 
reaction is that of the identification and differentiation of pro- 
teins, as for instance, in criminological investigations. In order 
to discover the origin of bloodstains, the material from the 
stain is dissolved in salt solution, and treated in series with 
sera from animals (rabbits) immunized respectively against 
sera from several sources-horse, dog, swine, cattle, man, etc. 
If the stain be due to deposit of dog's blood, no precipitation, 
in high dilutions, occurs, unless the questionable material is 
treated with serum from a rabbit which has been immunized 
by the repeated injections of dog's blood. CHAPTER XX 
RELATIONSHIP OF ANAPHYLACTIN TO OTHER 
IMMUNE BODIES 
Identity of All First Order Antibodies 
The properties of neutralization of toxins, and lysis of pro- 
teins, which are assumed by the body fluids during the process 
of immunization, are due to the production by certain tissue 
cells of antibodies which are discharged into the body fluids. 
There are two main types of antibody reaction: (1) toxin- 
antitoxin reactions; and (2) proteolysis. The second type is 
again divided into two orders: (1) anaphylactic (first order) 
and (2) tolerant (second order). The reaction between toxin 
and antitoxin is a simple one: insofar as we know at present, 
the thermostable immune body-antitoxin-reacts with, and 
neutralizes, its antigen-toxin-without the help of any com- 
plementary body such as alexin. The antigenic substances 
which take part in such reactions are the true toxins of bac- 
teria, snake venoms, enzymes, and numerous poisonous vege- 
table proteins. "It is to be noted that these active substances 
are all similar to one another in being classed as large colloidal 
aggregates resembling proteins, but not yet identified as pro- 
teins" (Wells). 
The second type of immunity reaction is that in which the 
tissues produce antibodies against foreign proteins, whether 
essentially toxic or nontoxic, or whether soluble (serum or egg 
albumen) or particulate (bacteria, red blood corpuscles, tissue 
cells). In this type of reaction "we deal with processes that 
tend to alter the colloidal state of the foreign proteins by 
making them larger aggregates (precipitation, agglutination) 
or smaller aggregates (proteolysis, hemolysis, bacteriolysis, 
cytolysis), and in each case the reaction consists of two sep- 
arate steps, sensitization and reaction." (Wells.) 
The author believes that, in addition to the anaphylactic 
(first order) antibody, the tissues produce, in order to com- 
215 216 
INFECTION, IMMUNITY, AND INFLAMMATION 
plete proteolysis, a second order antibody, the function of 
which is to supplement the proteoclastic activity of the first 
order antibody, and thus to render nonirritating the product 
of the first order antibody-antigen reaction. The state of the 
individual or animal whose tissues contain the second order 
antibody is described in this volume as that of tolerance. 
Although the subject is not yet finally settled by direct 
evidence, there are many observations which indicate that 
precipitin, agglutinin, and sensitizing antibody, as well as 
opsonin, run parallel in their content in immune serum. Ex- 
periments which support this point of view have been carried 
out by Friedberger, Doerr and Russ, Wells, Coca, and Weil. 
There is much to support the conception referred to by Zinsser 
as the "Unitarian theory," which accepts the probable identity 
of the various immune bodies. The names applied to them, 
namely, agglutinin, precipitin, opsonin, sensitizing body (ana- 
phylactic antibody) and complement-binding body, depend 
upon the nature of the phenomena which occur under varying 
conditions of experiment for their identification, rather than 
upon essential differences in the nature of the antibody respon- 
sible for the phenomena produced. In this volume the author 
has employed the expression "first order antibody" to desig- 
nate this immune body. 
At first sight the hypersensitiveness, which characterizes ana- 
phylaxis, suggests that we are dealing with a phenomenon 
which is the very antithesis of immune body production. Upon 
further study, however, we find that, not only are the bodies 
which are responsible for its development subject to the same 
laws, insofar as these are known, as other immune bodies, but 
we are led to realize that the reaction, paradoxical as it may 
seem, is in reality a protective one. 
The presence of specific antibodies free in the serum of 
sensitized and immunized guinea pigs is indicated by the fol- 
lowing facts: (1) passive transference; (2) the prevention of 
passive anaphylaxis by the saturation of the anaphylactic 
serum with antigen; and (3) only by the assumption of specific 
antibodies in the blood can we satisfactorily account for the 
production of immediate anaphylactic shock in normal guinea 217 
ANAPHYLACTIN AND OTHER IMMUNE BODIES 
pigs by the injection of a mixture of antigen and sensitive 
serum. 
As with other immune bodies, for example, precipitins and 
agglutinins, we find that a definite period of time (incubation 
period) must elapse before the amount of anaphylactin present 
in the blood reaches its maximum. Furthermore, it is noted 
that, once the production of the anaphylactic substance has 
been stimulated, it may be demonstrated in the blood for a 
longer or shorter space of time, up to seven or ten years or 
longer. 
If the serum from a rabbit, which has been treated by re- 
peated injections of sheep's red blood cells, be added in 
suitable quantity to a salt solution suspension of sheep's red 
blood cells, one or other of two effects will be noted. The 
difference in the results obtained depends upon whether or 
not the rabbit's serum has been exposed to the effect of heat. 
If the serum has not been heated, its action upon the red 
blood cells is exhibited by lysis of the latter. The cloudy 
suspension becomes clear, and pink in color, in consequence 
of the destruction of the cell bodies and solution of their 
hemoglobin content. 
If, on the other hand, the serum has been inactivated by 
exposure to a temperature of 56° C., no alteration in the 
color of the mixture occurs. The cells maintain their identity, 
so that a suspension of cells in salt solution remains. That 
the cells are not unaffected is, however, shown by the attrac- 
tion of cells to one another, so that clumping of cells-aggluti- 
nation-takes place. If the cells be washed, so as to free them 
from the rabbit's serum, the fact that they have been altered, 
while in contact with the immune serum, is easily proved by 
one or other of the following experiments. 
When a small quantity of normal fresh washed rabbit's or 
guinea pig's serum is added to a suspension of the washed 
sensitized erythrocytes in salt solution, lysis of the cells takes 
place. Again, if the sensitized cells be injected into a normal 
guinea pig, the animal shows symptoms of intoxication similar 
to those exhibited when the hypersensitive animal is 
"shocked" (Friedeman). These experiments indicate that the 218 
INFECTION, IMMUNITY, AND INFLAMMATION 
substance responsible for the production of the anaphylactic 
phenomenon requires for an exhibition of its activity the pres- 
ence of alexin (complement); also, that it is possible for it to 
bind with its specific antigen in vitro, even though no alexin 
be present. 
That the content of precipitin and sensitizing antibody runs 
parallel in immune sera has been noted by several observers 
(Friedberger, Doerr and Russ). Wells has observed that pre- 
cipitins appear at the same time as the capacity to confer 
passive sensitization (to anaphylactic shock). Both Weil and 
Coca performed experiments that appear to prove the identity 
of precipitin and sensitizing (anaphylactic) antibody. Fried- 
berger's experiments in the production of "anaphylatoxin" 
through the action of alexin containing serum upon sensitized 
protein indicate that the complement binding antibody and 
anaphylactin are identical.1 
Precipitation and agglutination are phenomena which may 
be induced by the treatment of antigen with heated serum. 
In other words, the thermolabile constituent of normal serum, 
known as alexin or complement, is not necessary for the ex- 
hibition of the phenomena of precipitation or agglutination. On 
the other hand, the lytic phenomena are dependent upon a reac- 
tion between the specific thermostable immune substances and 
antigenic protein, in consequence of which the later is rendered 
susceptible to the lytic activity of alexin. The end product of 
the reaction between first order antibody-antigen and alexin 
(complement) acts as an irritant which, especially in the case 
of antigens in particulate form, stimulates phagocytic cells to 
functioning activity (see opsonin). In this event complete 
dissolution of the antigenic molecule is accomplished within 
the cell cytoplasm by the action of enzymes (e.g., leuco- 
protease) . 
In Zinsser's opinion the relationship of the various anti- 
Ut should be mentioned in this connection that Friedberger's view, that 
the "anaphylatoxin" which is produced in this way is, in fact, the same sub- 
stance which is responsible for the manifestations of anaphylaxis, has not 
been universally accepted by immunologists. Wells points out that "although 
many facts appear to support this hypothesis, there are others that do 
not harmonize with it, notably the lack of constant quantitative relations 
between the different reactions produced by the same immune serum, and 
as yet it is neither established nor completely disproved." ANAPHYLACTIN AND OTHER IMMUNE BODIES 
219 
bodies to one another is 4'that much reasonable evidence points 
to the fact that the so-called precipitins are in truth protein- 
sensitizers, in structure and function identical with the sen- 
sitizers, or amboceptors, of cytolytic processes." The fact that 
precipitation occurs, when these antibodies are added to the 
homologous dissolved antigen, is merely a secondary colloidal 
phenomenon. Antigen and antibody react, forming a complex 
which is then amenable to the action of alexin. Since they 
are colloidal in nature, if they are mixed under suitable quan- 
titative and other conditions which favor flocculation, they 
precipitate. This point of view, which identifies the so-called 
precipitins with the protein sensitizers or albuminolysins, was 
first hypothetically suggested by Gengou. It leads necessarily 
to the conception that in cytolysis as well as in proteolysis, in 
fact in all reactions in which antigen is sensitized to the action 
of alexin, there is functionally but one variety of antibody- 
the sensitizer, precipitation and agglutination being incidental 
physical phenomena and not dependent upon special antibodies 
as heretofore supposed. In this sense, then, the "precipitins" 
or albuminolysins may be regarded as identical with the ana- 
phylactic antibody. (Zinsser.) 
The anaphylactic antibody is thermostable and is not de- 
stroyed by a temperature of from 50° to 58° C. for one hour 
(Lewis, Anderson and Frost). In this respect this antibody 
simulates the immune bodies which are identified by other 
methods. 
Experiments prove that the reaction between anaphylactin 
and protein is similar to that between amboceptor, sensitizing 
substance (Bordet) and antigen, inasmuch as alexin must ap- 
parently be present in order that the reaction be brought about. 
The phenomenon of absorption (Bordet), which is noted as 
a characteristic of other immune bodies, also occurs in the 
interaction of antigen and anaphylactin. If to 4 c.c. of sen- 
sitive guinea pig serum .01 c.c. of the protein antigen be 
added, experiments prove that the serum has lost its property 
of transferring the hypersensitive state. Similarly, the in- 
jection of a small dose is sufficient to render an animal refrac- 
tory, even though practically no symptoms have been elicited. CHAPTER XXI 
HEMOCELLULAR REACTION. THE LEUCOCYTE COUNT 
IN DIAGNOSIS AND PROGNOSIS 
As the result of any alteration in the degree of stimulation 
of leucocyte activity, there occur characteristic changes in the 
number of circulating white blood cells. According, also, to 
the nature of the stimulus, the increase, or decrease, of cells is 
found to be confined to one or more special types. The recog- 
nition of certain broad principles underlying these variations 
has proved to be of great clinical usefulness, since by means of 
the simple procedure of counting the total number of cells in 
a given quantity of blood and estimating the proportion 
of each of the several types, it is not infrequently possible to 
diagnose with remarkable accuracy the nature of a disturbance 
in hidden parts of the body. 
The value of leucocyte counts in infectious diseases depends 
upon the fact that, when leucocytic accumulation about an 
infected focus is stimulated, there occurs a corresponding in- 
crease in the number and type of cells discharged from the 
myelogenous tissues into the blood. Bacterial invasion by 
such microorganisms as the staphylococcus aureus, B. coli, B. 
pyocyaneus, pneumococcus, and streptococcus are usually met 
by focal accumulations of polymorphonuclear leucocytes. The 
reaction to these infections is, likewise, accompanied by an 
increase in the number of polymorphonuclear leucocytes in 
the blood. Similarly, certain infections, such as pertussis and 
frequently also tuberculosis, call forth an increase in the num- 
ber of lymphocytes with little or no change in the number of 
other cells. Again the presence in the gastrointestinal canal 
of parasites and certain skin affections stimulate a more active 
manufacture and discharge from the bone marrow into the 
circulating blood of eosinophiles. 
220 HEMOCELLUbAR REACTION 
221 
It is thus seen that, in a broad way, the nature of an infec- 
tion is indicated by a study of the type or cell, which has been 
stimulated to appear in the blood stream in increased numbers. 
In the diagnosis of the nature and extent of acute inflam- 
matory reactions, in which the process cannot be visually 
demonstrated, there is no single source of evidence so useful 
as that derived from the examination of the blood. In order, 
however, that correct inferences as to the nature of the in- 
fective process may be made, it is necessary that adequate 
clinical data, such as the age of the individual, duration of 
the disease, record of pulse and temperature and results of 
careful physical examination should be studied in relationship 
to the blood findings. The total leucocyte count by itself is 
of less value than the differential count. For diagnostic pur- 
poses, moreover, it is essential that both total and differential 
counts be obtained. 
Physiologic Variations in Circulating Leucocytes 
The total count, and to a less extent, the differential count 
is influenced by several physiologic states, more particularly 
digestion, pregnancy, parturition, violent exercise and massage 
in each of which there is an increase in the number of white 
cells. 
The total count indicates, therefore, the individual's power 
of reaction, either in response to natural physiologic demands, 
or against infecting microorganism. "The relative polymor- 
phonuclear leucocyte count is an index of the degree of, or 
severity of, an infection." (Hewitt.2) 
Quoting again from Hewitt: "If we have a relative poly- 
morphonuclear count ranging between 75 per cent, and 80 per 
cent, infection is usually found; if above 85 per cent, infection 
is almost invariably encountered and this regardless of the 
total number of leucocytes. ' ' 
The information usually desired by the surgeon when making 
a leucocyte count, comprises the following: 
2Hewitt: Annals of Surg., 1911, liv, 721. 222 
INFECTION, IMMUNITY, AND INFLAMMATION 
1. The resisting power of the individual, thus indicating the 
reserve force at the command of the body. 
2. The severity of the infection, or the virulence of the in- 
fecting microorganism. 
3. The localization, or diffusion, of the infecting agent and 
the accompanying reaction. 
Gibson3 suggests the use of a chart4 whereby the dispropor- 
tion of total count and relative polymorphonuclear count may 
be clearly shown. His chart is based upon the assumption 
that 10,000 white blood cells per cubic millimeter is the maxi- 
mum normal count, and that 75 per cent is the highest per- 
centage of polymorphonuclear leucocytes which should be con- 
sidered normal. "In inflammatory lesions which are well 
borne, the polymorphonuclear cells are increased one per cent 
above 75 per cent for every 1,000 total leucocytes above 
10,000." By estimating the nature of infection and resistance 
according to this hypothesis, valuable information may be 
obtained. 
If an infection is well resisted, i.e., the reactive reserve 
force is adequate to control, for the time being at least, the 
spread of the invading bacteria,-the chart shows a parallel 
line, or one in which the decline is towards the right. If the 
line be level and placed high, it indicates a severe infection, 
but accompanied by a correspondingly marked or adequate 
reaction. 
In those cases in which clinical symptoms and signs indicate 
an important affection, the presence of a line ascending toward 
the right suggests a bad prognosis. This is the observation 
commonly derived from blood counting in cases of diffuse or 
general peritonitis, and demands as a rule, immediate opera- 
tive interference, and the employment of other measures indi- 
cated in such cases. 
'Gibson: Annals of Surg., 1906, xxxiv, 485. 
4Gurd: New Orleans Med. and Surg. Jour., 1914, Ixvii, 67. CHAPTER XXII 
FOCAL VASCULAR AND CELLULAR REACTION TO 
IRRITANTS. INFLAMMATION 
As a result of the presence in the animal tissues of irritant 
substances, there occur morphologic changes which have for 
their purpose the control and elimination of the injurious 
agent. These changes consist primarily in dilatation of blood 
vessels in the part. This applies to the capillaries as well as to 
the arterioles and the venules. Inasmuch as, under normal 
circumstances, only a part of the total number of capillaries 
function as blood channels, their dilatation results in the pres- 
ence of an increased amount of blood in the part, although 
other factors may interfere with an adequate circulation of 
blood through the part. If sufficient stimulation be present, 
new blood vessels (capillaries) form, as the result of budding, 
from the walls of existing capillaries. The second phenomenon 
which occurs, consists of an exudation of blood fluid from 
the vessels into the surrounding tissues. The third essential 
phenomenon of inflammation is manifested by an accumulation 
in the interstitial spaces of an increased number of cells. 
Clinically, this hyperemia, accumulation of interstitial fluid, 
and focal cellular increase, is manifested by swelling (edema), 
redness, and perhaps pus accumulation. It is this local reac- 
tion upon the part of the tissues against injurious substances 
which is known as inflammation. 
Inflammation is the process by means of which cells and 
serum accumulate about an injurious substance and tend to 
remove and destroy it; this process does not includes the regen- 
erative changes which replace injured tissue by newly formed 
parenchymatous elements or by new interstitial tissue (Opie). 
Practically all foreign substances, when introduced paren- 
terally into the tissues, cause an accumulation of more or less 
serum, and attract a larger or smaller number of new cells to 
223 224 
INFECTION, IMMUNITY, AND INFLAMMATION 
the part. The process is in many respects similar to that which 
occurs normally in the alimentary tract; indeed, in many of 
the lower animals (protozoa and infusoria), the method by 
which the cells are normally nourished, is similar to that which 
occurs in man and in the higher types of mammals only during 
the inflammatory process. 
In general the purpose of the inflammatory reaction is to 
neutralize or dilute toxic soluble substances, to liquefy and 
absorb digestible substances, and to engulf by cellular activity 
such materials as cannot be rendered soluble by the action of 
the fluids of the body alone. 
It must be remembered by the practicing surgeon that in- 
flammation is, in purpose, conservative and protective in na- 
ture, and that any operative or other interference must be 
undertaken only after careful consideration of the effect of 
such procedure upon the reacting process. 
It is the duty of the surgeon to see to it that, insofar as 
the effects of inflammation are useful, they should be con- 
served, and, if possible, stimulated to increased activity, but 
also to recognize that, when carried to extremes, the inflam- 
matory reaction may not only be ineffective, but may in itself 
do harm. Steps should be taken to prevent, insofar as pos- 
sible, such injurious effects. Inasmuch, moreover, as the repar- 
ative reaction may also be followed by serious disability, the 
necessity of excessive tissue fibrosis should be prevented by 
early interference, having as its aim the elimination of the 
necessity of organization by granulation and consequent 
fibrosis. 
Since inflammation consists in the local accumulation of 
serum and cells, it is essential, if the reaction is to be under- 
stood, that (1) the nature of the essential qualities of the 
serum, and (2) the nature and method of action of the cells 
taking part, be appreciated. 
The manner of accumulation of both cells and serum, more- 
over, is of the greatest importance, since it is in the surgeon's 
power,5 by means of incision, immobilization, hot and cold 
"See Chapter XXVI on the Therapeutic Guidance of the Acute Inflam- 
matory Reaction. INFLAMMATION 
225 
applications, active and passive hyperemia, and the employ- 
ment of vaccines, to influence to a considerable extent the 
factors which determine an adequate hyperemia, and serum 
and cellular exudate. 
Nature and Qualities of Serum 
The focal accumulation of body fluid, which takes place in 
inflammatory reactions, is valuable inasmuch as the blood and 
lymph contain, in solution, substances which are capable of 
causing alterations in the composition of complex proteins, 
neutralizing toxic materials, and of stimulating phagocytosis 
of insoluble bodies. 
In addition to the foregoing specific resisting properties of 
body fluid, the increased circulation of blood and interstitial 
fluid (lymph), through the inflamed focus, aids in dilution of 
toxic substances, whether these be due to bacterial activity or 
are the result of breaking down of tissue proteins. Increased 
blood circulation through the part is automatically accom- 
panied by an increased nutrition of the fixed tissue cells; also, 
there is brought to the part a larger number of polymorpho- 
nuclear leucocytes than under normal conditions. As a result 
of the exudation of plasma from the vessels into the inter- 
stitial tissues, or into potential cavities, fibrin is deposited. 
Occasionally the fibrin deposited in this way serves a posi- 
tively useful purpose, as, for instance, in sealing openings in 
the abdominal viscera, and in delimiting the spread of infec- 
tion in serous and synovial cavities. The presence of fibrin, 
on the other hand, acts as a direct stimulus to fibroblastic 
proliferation, and thus to the development of permanent ad- 
hesions in joint surfaces, between coils of intestine, or about 
the foramina at the base of the brain, thus leading to their 
occlusion. 
The fluid constituent of inflammatory exudate is usually of 
a higher specific gravity, and of a higher protein content, than 
is the blood plasma. This fact must be assumed to be due to 
some selective action on the part of the vessel endothelia. 226 
INFECTION, IMMUNITY, AND INFLAMMATION 
Phenomena of Inflammation 
Accumulation of Serum.-Although the inflammatory reac- 
tion consists, in addition to hyperemia, in a local accumulation 
of cells and serum, the amount of serum and the number and 
type of cells varies according to the nature of the irritant and 
its concentration. 
The purpose, therefore, of the reaction which is manifested 
by the development of hyperemia and interstitial edema, is the 
dilution, neutralization, and lysis, of the irritant. It is evi- 
dent that, if the maximum benefit is to accrue from the action 
of the serum antibodies, not only is it essential that an in- 
creased amount of fluid find entrance to the zone of irritated 
tissue, but that removal of exhausted fluid and its replacement 
by fresh plasma take place at as short intervals as possible. 
In order that this may be accomplished, there occurs: (1) an 
increase in the blood supply to the part; (2) an increase in 
the amount of fluid passing from the arterioles into the extra- 
vascular tissues; and (3) the rate of removal of fluid from the 
inflammatory focus by means of the veins and lymphatics 
becomes more rapid. 
In order that an increased amount of fluid may be discharged 
into the tissues, the afferent vessels (arterioles) of the part 
dilate, many capillaries which normally do not contain blood 
commence to function, and often new blood vessels develop 
by a process of budding. 
Even though there be an increased local afferent blood 
supply and a greater tendency than normal exhibited for the 
passage of fluid from the vessels, the possibility of continued 
and rapid circulation of blood through the vessels and con- 
tinued exudation of fluid will depend upon (1) an efficient 
drainage of the inactivated fluid from the part by means of 
the veins and lymphatics, and (2) the capacity of the tissues 
to expand sufficiently to accommodate an increased amount of 
fluid without raising the extravaseular pressure above that in 
the venules and arterioles. In other words, the continuation 
of the exudative process depends largely upon the relation of 
intravascular to interstitial pressure. INFLAMMATION 
227 
In the presence of excessive exudate in the interstitial tis- 
sues, with consequent increase in extravascular tension, very 
little blood is permitted to flow through the part. As pointed 
out by Opie, this fact helps to explain the obvious truth that 
accumulations of fluid in the subcutaneous tissues, in response 
to irritation, are quickly self-limited, whereas the same sub- 
stances, which cause such accumulations, may be able' to induce 
the exudation of an immense amount of serous fluid when 
introduced into a serous or synovial cavity. 
Clinically, the presence of interstitial fluid is evidenced by 
a swelling which characteristically "pits" upon pressure. Oc- 
casionally, however, this phenomenon is not noted, and there 
occurs a condition which is often referred to as a brawny 
swelling or induration. In certain instances this may be due 
to the presence of an excessive fibrosis. Recent experiments 
(Fischer), however, suggest that under certain circumstances 
of relative acidity of the tissues, the collagenous fibers of the 
connective tissue, which are composed of a colloidal protein 
material, become "fixed" through the absorption of fluid in 
a manner similar to that of agar-agar in the preparation of 
media. 
As may be easily understood, the stretching of the blood 
vessel wall and the injurious action of the irritant substance 
may occasionally result in the passage through it not only of 
the blood plasma, but also of the blood cells. Clinically and 
experimentally, we note that such hemorrhagic phenomena are 
found in the presence of the more potent irritants, e.g., in in- 
fections due to the streptococcus hemolyticus or the bacillus 
aerogenes capsulatus-since these agents appear to injure di- 
rectly the vessel walls. 
Nature and Origin of Cells Which Take Part in the 
Inflammatory Process 
Polymorphonuclear Leucocytes.-The most active and ap- 
parently most powerful cells which take part in the defense 
of the tissues against foreign irritants, more especially bacteria, 
are the neutrophile polymorphonuclear leucocytes of the blood. 228 
INFECTION, IMMUNITY, AND INFLAMMATION 
These cells are produced in the bone marrow, discharged 
thence into the blood stream, and attack irritants situated in 
the interstitial tissues. Under the microscope they may be 
seen leaving the capillaries between the endothelial cells by a 
process known as diapedesis. 
Once the polymorphonuclear leucocyte has been discharged 
into the blood stream from the bone marrow, there is no proof 
that it retains the power of reproduction, so that in inflamma- 
tory foci the accumulation of cells is believed to be possible 
only by the passage of new cells from the blood stream into 
the extravascular tissues. The polymorphonuclear leucocyte 
does not appear to take part in reparative processes. 
That the polymorphonuclear leucocytes have an inherent 
bactericidal power is proved by experiments first performed 
by Powlowski, namely, that sterile inflammation accompanied 
by purulent exudate is highly protective against subsequent 
infection. This is in all probability explanatory of the results 
which follow injections of sterile irritants, such as formalized 
glycerine into the knee joint, in the treatment of chronic and 
subacute infections of synovial cavities. 
Not only does the polymorphonuclear leucocyte employ its 
leucoprotease content to digest ingested material, but it dis- 
charges a certain amount of this substance into the tissues 
about itself. Under ordinary circumstances this excreted fer- 
ment is inactivated by an antiferment which is present 
in normal body fluid. If the number of leucocytes be rela- 
tively great, as compared with the amount of body fluid 
(serum), there is exhibited an excess of leucoprotease. Such 
a purulent material affects not only irritant protein substances 
but even living tissue may be injured. It is, in part, on ac- 
count of the presence of this enzyme, whose nature has been 
studied particularly by Opie, that the phenomenon of burrow- 
ing on the part of pus collections occurs. 
It does not appear, however, that the enzyme constituent of 
pus is the chief cause for the spread of suppuration. Tension 
in the tissues, as the result of increased extravascular fluid, 
is the most obvious reason for the phenomenon. This is clearly INFLAMMATION 
229 
exemplified by the prompt subsidence of a spreading lymphan- 
gitis of the forearm and arm, when the focal lesion in the 
finger is adequately incised. Another important cause, and 
one which is not infrequently overlooked in surgical procedure, 
is the force of gravity in determining the spread of pus. In 
the author's opinion, this is one of the chief objections to the 
employment of the extension-suspension method of treating 
infected compound fractures of the extremities. I have fre- 
quently seen burrowing abscesses between the muscle sheaths 
in the thigh, in cases of gunshot fractures of the femur, which 
had been spreading up the thigh and even into the buttock 
while the limb was elevated, quickly cease to spread and the 
purulent process subside, when, instead of elevation of the 
foot, the head of the bed was raised and the foot placed at a 
lower level than the hip joint. 
Residual pus in the tissues acts as a foreign body and, in 
addition, as a pabulum for growth of microorganisms. It is 
a primary principle of surgery that sterilization of the tissues, 
whether the body's resisting forces are alone relied upon, or 
whether these properties are augmented by the employment 
of adjuvants, such as Dakin's solution, according to Car- 
rel's technic, B.I.P.P., flavine, or other method, is impos- 
sible so long as foreign bodies are present which may injure 
the tissues. It is of no practical importance whether such 
foreign bodies consist of shell fragments, rubber tubes, necrotic 
fascia, sequestra, or devitalized body fluids (pus). Protected 
by the injurious effect of such foreign bodies upon the tissue, 
bacteria are enabled to proliferate, and from the focus thus 
produced to invade the surrounding tissue. CHAPTER XXIII 
CLASSIFICATION OF INFLAMMATORY REACTIONS 
Inflammatory reactions have been for many years divided 
into three groups-acute, chronic, and granulomatous, and 
since such a classification of individual lesions is usually pos- 
sible and likewise profitable, such a method of division has 
been employed in this chapter. 
In acute inflammation, serum and polymorphonuclear leuco- 
cytes accumulate at the site of irritation. It is the method 
employed by the tissues in their attack upon most bacteria, 
more especially the so-called pyogenic cocci, although it must 
be remembered that, granted the irritative property of a sterile 
body equal to that of pyogenic bacteria, the character and 
sequence of the inflammatory events are identical, except 
insofar as the absence of a proliferating irritant influences 
the spread and continuation of the reaction. 
The use of the terms "acute" and "chronic" is based upon 
the fact that the former is usually more or less fulminant and 
short lived. Chronic inflammatory lesions, on the other hand, 
are, at their maximum, relatively mild in clinical manifesta- 
tions and are usually prolonged. It should be noted that the 
acute reaction is very frequently followed by a chronic process. 
Chronic inflammatory reactions are those in which the most 
prominent part is taken by cells of the lymphoid group, and 
by the so-called macrophages, to the relative exclusion of the 
polymorphonuclear leucocytes. There is usually a minimal ac- 
cumulation of interstitial serum. This is the type of reaction 
which is found in the presence of mildly toxic insoluble sub- 
stances, notably those resulting from the destruction of body 
tissue in situ, and usually accompanies reparative changes. 
•Certain types of bacteria which possess but little essential 
toxicity, whose rate of growth is slow, and which, owing to 
a thickened ectoplasm or capsule protection, are but slowly 
230 CLASSIFICATION OF INFLAMMATORY REACTIONS 
231 
acted upon by serum antibodies, also induce such a reaction, 
which, since it often resembles granulation tissue, is known as 
the granulomatous reaction. Since many of the cells which take 
part in the reaction of these types multiply in situ at the focus 
of accumulation, this type of reaction is also called prolifera- 
tive, in contradistinction to the exudative (acute inflammatory) 
lesion. 
Acute Inflammation 
Accumulation of Polymorphonuclear Leucocytes.-It is found 
in studying inflammatory processes that, if the foreign sub- 
stances present in the tissues be sufficiently irritating, the 
polymorphonuclear leucocytes are the cells which play the 
major part. A study of the living tissue when subjected to 
irritation shows that the following changes are exhibited. 
Lister in 1855 was the first to record the vascular phenomena 
which characterize the reaction of the tissues to irritants. Co- 
incident with the dilatation of the blood vessels there is a slow- 
ing of the blood stream; leucocytes collect upon the inner 
wall of the vessel (margination of leucocytes). 
The leucocytes then commence to insinuate themselves be- 
tween the endothelial cells, and pass by active ameboid move- 
ment-diapedesis-through the vessel wall and toward the irri- 
tant substance. It frequently happens that large numbers of 
cells are sacrificed, and, if the process continues sufficiently 
long, a collection of creamy fluid material accumulates. 
Surrounding a purulent focus there is usually present a wall 
composed of new blood vessels and edematous tissue, in the 
meshes of which there are embedded numerous cells, chiefly 
polymorphonuclear leucocytes. This delimiting zone is known 
as the pyogenic membrane. 
The process whereby pus accumulation takes place is known 
as suppuration. Pus is composed of varying proportions of the 
following substances: 
(a) Foreign bodies-usually bacteria and their derivatives 
(e.g., toxins, protein split products). 
(b) Fixed tissue debris-necrosis of tissue, due to ischemia 
and caused by the toxic action of bacteria. 232 
INFECTION, IMMUNITY, AND INFLAMMATION 
(c) Serum-from which the original antibodies have been 
largely exhausted, and to which leucoprotease has been added. 
(d) Polymorphonuclear leucocytes-for the most part dead 
or much injured. 
The fluid property of pus is due to the presence of serum 
exudate from the vessels and the results of cytolysis. In this 
fluid is suspended larger or smaller numbers of cells, and a 
variable quantity of colloidal substances. Its consistency de- 
pends upon the ratio of fluid to cells and colloid. The color of 
the purulent fluid depends upon the color of the cells, and the 
presence or absence of colored products of bacterial activity. 
As a rule, staphylococcic infections result in the accumulation 
of a relatively larger number of polymorphonuclear leucocytes, 
and, since these organisms produce but little coloring matter, 
the typical staphylococcic pus is of a creamy or somewhat 
thicker consistency, and of a slightly greenish-grey or creamy 
color. Characteristically, also, purulent accumulation in 
staphylococcic infection is of a pasty odor. Since, as a rule, 
reaction to streptococci is usually less rapidly effective, and a 
limited pyogenic membrane is less constantly developed, there 
is a relatively larger quantity of serum than in the purulent 
fluid consequent upon infection by the staphylococcus aureus. 
Also, since the toxins of the streptococcus, and its variants, 
are more prone to lead to severe injury to the vascular endo- 
thelium with consequent extravasation of erythrocytes, pus 
from such lesions is characteristically more fluid and is likely 
to be blood-stained. 
Organisms such as the B. pyocyaneus, which produce a com- 
paratively large quantity of diffusible coloring matter, stain 
the reactive exudate, which is creamy in consistence, a 
bluish green color. Pus arising in the course of pyo- 
cyaneous infections is of a very characteristic musty unpleas- 
ant odor. It is usually possible to diagnose infection of wounds 
by this bacterium without visual examination. 
Organisms such as those belonging to the "colon" group 
and many of the anaerobes, which liberate foul-smelling gases 
in the process of growth, are often suggested by the presence CLASSIFICATION OF INFLAMMATORY REACTIONS 
233 
of the odor of the pus alone. Since proteolytic microorgan- 
isms of the aerogenes and malignant edema groups actually 
destroy and liquefy the tissues in which they are growing, the 
discharges from such tissues are usually watery and blood- 
stained. 
Chronic Inflammation 
As stated in the last section, if the irritant be sufficiently 
toxic, there is induced in the tissues a reaction which is es- 
sentially exudative in character. The participating cells, as 
well as the serum, are derived from the circulating blood. 
Such a type of inflammation takes place only in the presence 
of certain virulent bacteria and a comparatively small number 
of toxic inanimate substances. On the other hand, substances 
which are mildly irritating to the tissue cells do not determine 
the accumulation, to any considerable degree, of polymorpho- 
nuclear leucocytes. As a rule, in such cases, very large ac- 
cumulations of extravascular serum do not take place. The 
presence of mildly irritating substances does, however, induce 
a reaction which is characterized by the collection at the site 
of the foreign material of cells of the lymphoid and macrophage 
groups and an increase in the flow of fluid through the part; 
although, only infrequently does it result in the development 
of a "pitting" edema. 
Since the cells of these groups increase at the inflammatory 
focus chiefly, if not exclusively, by multiplication in situ, reac- 
tions of this type are known as proliferative lesions. 
In order to study the phenomena which characterize this 
type of reaction, let us note the changes which occur in the 
presence of a collection of dead tissue cells, such as occur fol- 
lowing the cutting off of blood supply (infarction). Since the 
necrotic tissue cells occupy space which nature attempts to 
replace by more or less useful tissue, and since also the dead 
cells themselves assume irritant properties on account of the 
development of protein degradation products, it is necessary 
that they be removed. The means adopted for the absorption 
of such material is the proliferative reaction, and absorption is 234 
INFECTION, IMMUNITY, AND INFLAMMATION 
accomplished by the accumulation of lymphoid and plasma 
cells and macrophages, including, if the occasion demand, the 
so-called foreign body giant cells. 
There is some doubt as to the origin of these cells. There 
is, however, no doubt but that they increase in number as the 
result of proliferation, in situ. As a class, these types of cells 
are phagocytic for tissue debris and produce enzymes which 
lead to liquefaction of the digestible portions of necrotic ma- 
terial. This broken down or dissolved material is removed 
from the part, as a result of the increased flow of fluid through 
the part. This increase in blood circulation is supplied by 
means of an increase in the number of blood vessels by bud- 
ding. In consequence of the accelerated blood flow through 
the part and an increase in the amount of fluid poured into 
the tissues, there occurs an active efferent lymphatic flow 
which carries with it soluble products of cell disintegration 
and also a larger or smaller number of phagocytic cells con- 
taining insoluble or poorly soluble substances. These in- 
gested materials, whether bacterial or of other origin, are 
commonly carried to, and deposited in, the neighboring lym- 
phatic glands. 
Other macrophages, having phagocytized as much foreign 
material as they can contain, -wander into the surrounding 
tissues where, if insoluble and nondigestible, the substance 
remains, upon the death of the cell, as a deposit. 
Coincident with the absorption of portions of the necrotic 
mass there commences fibroblastic proliferation of the fixed 
tissue cells; in other words, reparative changes progress hand 
in hand with the inflammatory reaction. Occasionally, also, 
there is an attempt made on the part of the tissues to re- 
place the destroyed tissue by parenchymatous elements. It is 
but rarely that this effort at regeneration is successful in 
man. 
The microscopic lesion in chronic inflammation consists of 
an increased number of blood vessels, moderate interstitial 
edema, and masses of proliferated lymphoid and plasma cells, 
and larger or smaller numbers of macrophages. Surrounding CLASSIFICATION OF INFLAMMATORY REACTIONS 
235 
the inflammatory focus there is usually a fibrous tissue zone, 
and, since a certain quantity of the material removed by the 
lymphatics retains its toxicity, there is frequently exhibited 
a perivascular infiltration at a considerable distance from the 
original focus of irritation and a series of changes in the 
neighboring lymph nodes. 
This type of reaction is developed in order that useless inert 
tissue, such as necrotic cells, hemorrhagic material, and sterile 
exudates, may be absorbed. A similar reaction is induced by 
the presence in the tissues of microorganisms whose virulence 
has been attenuated, or by those whose essential or allergic 
toxicity is relatively low. 
As a means of combating bacterial or protozoan infection, 
the proliferative type of lesion is relatively ineffective. We 
thus find that, in the presence of bacteria which induce no 
polymorphonuclear exudation, the pathogenic process runs 
a very chronic course. It is the surgeon's duty to attempt to 
stimulate, if possible, the development of exudative lesions, 
if such can be accomplished without harmful sequelae. It 
would appear that it is only insofar as polymorphonuclear 
phagocytosis can be stimulated, that the eradication of focal 
bacterial collections can be accomplished by the tissues. 
The usefulness of bacterial vaccine injections in chronic 
diseases depends upon the fact that acute inflammatory reac- 
tions may be thereby induced in the foci harboring the bac- 
terioproteins. Clinically, the chronic, or proliferative, lesion 
is differentiated from the acute reaction by the relative ab- 
sence of redness and "pitting edema," and by its greater 
density or firmness upon palpation. The characteristic hard 
sore or chancre of syphilis is typical of a pure chronic lesion; 
its firm consistence is due to enormous infiltration of the tis- 
sues with lymphoid and plasma cells, and the absence of 
necrosis and free serum collections. Since, moreover, repara- 
tive changes are more likely to occur along with chronic 
reactions, the lesion attains density through the formation 
and contraction of fibrous tissue fibrils. 
In certain subacute conditions, especially those stimulated 236 
INFECTION, IMMUNITY, AND INFLAMMATION 
by the presence of the gonococcus and bacilli of the colon 
groups, polymorphonuclear leucocytes as well as eosinophiles 
infiltrate the tissue in comparatively large numbers. 
Granulomata 
Certain specific irritants, more particularly the B. tubercu- 
losis, B. leprae, and the Treponema pallidum, and certain of 
the parasitic yeasts, induce reactions of a characteristic type. 
Inasmuch as, in a superficial way, the reactive tissue result- 
ing from the activity of these microorganisms resembles gran- 
ulation tissue, and as there is a tendency for a definite mass 
of permanent new tissue to persist at the site of the reaction, 
the lesions resulting from the presence in the tissues of these 
organisms are called granulomata. Although all the granu- 
lomata have many features in common with one another, and 
with other types of chronic inflammation, there are important 
differences between them which can be made use of in histo- 
logic diagnosis, and which help to explain the clinical course 
of the affections in which they are found. 
Tuberculosis 
Following invasion of the tissue by the tubercle bacillus, 
there occurs a reaction which is essentially proliferative in 
type, and which is accompanied by lymphoid and plasma cell 
infiltration. These cells surround the foci of bacilli, and in- 
crease in number, forming a small nodule, in which the cells are 
arranged in a concentric manner. At the same time a different 
type of cell appears-a mononuclear cell with a pale staining 
vesicular nucleus and moderately abundant acidophilic cyto- 
plasm-known as an "epithelioid" cell, since it resembles 
certain types of epithelium. This cell is found, characteris- 
tically, in the center of the lymphoid and plasma cell masses. 
As the result of two factors, namely, the separation of the 
central cells of the proliferated mass from the nutrient blood 
vessels and the presence of the microorganisms, necrosis oc- 
curs in the inner zones. The necrotic mass, known as caseous 
material, is composed, therefore, of dead fixed tissue and in- CLASSIFICATION OF INFLAMMATORY REACTIONS 
237 
flammatory cells together with a larger or smaller amount 
of serum. 
The characteristic tubercle consists of a central area of 
necrosis surrounded in turn by epithelioid cells and by lym- 
phoid and plasma cells. Only outside the latter zone are blood 
vessels present. As the result of the fusion or coalescence of 
tubercles, large irregular areas of necrosis may result. 
If the cellular reaction is successful in controlling the ac- 
tivity of the bacilli, an effort at repair ensues. Fibroblasts 
arise in the surrounding fibrous tissue, with the result that the 
tubercle may be completely walled off, or even replaced by 
fibrous tissue similar to that which results from the granula- 
tion repair of tissue destroyed by other agents. Under such 
circumstances calcium salts are often laid down in the dead 
tubercle, so that larger or smaller calcareous masses result. 
It must be remembered, also, that, if the individual be suf- 
ficiently sensitive to the tuberculo-protein, polymorphonuclear 
leucocyte invasion may take place and abscesses may develop. 
Although the amount of serum which accumulates in the 
reaction against the tubercle bacillus is usually minimal, this 
is by no means always the case. An increased collection of 
fluid is determined apparently by two factors, namely, the 
virulence of the bacillus (see page 46) and the ease with 
which fluid may accumulate without increasing to any con- 
siderable degree the extravascular tension. Thus, in the pleu- 
ral and peritoneal cavities, as well as beneath the arachnoid 
membrane, very large collections of serum not infrequently 
develop. 
Syphilis 
The lesions which result from the presence of the Trepo- 
nema pallidum in the body are of several types. The com- 
monest type, which is characteristic of the primary and the 
majority of the secondary manifestations, is a simple lymphoid 
and plasma cell proliferative lesion, accompanied by dilata- 
tion of vessels and a moderate amount of serum exudate. In 
general, the plasma cells form the greater proportion of the 
new tissue. 238 
INFECTION, IMMUNITY, AND INFLAMMATION 
The spirochete appears to have a tendency to affect blood 
vessels in a characteristic manner. The perivascular tissues 
are especially attacked, and are the site of an intense plasma 
and lymphoid cell infiltration. In addition, the endothelium 
of the smaller arterioles and the capillaries is stimulated to 
proliferate. As the result of one or other or of both of these 
reactions, the lumen of the smaller vessels is frequently ma- 
terially encroached upon and sometimes obliterated. Follow- 
ing such vascular occlusion the tissues supplied are deprived 
of nourishment and necrosis takes place. This is the type of 
lesions which leads to atheroma of the aorta and aneurysm 
formation. In these affections the vassae vasorum are pri- 
marily affected. 
The vascular changes take place in all stages of the dis- 
ease. In the earlier and more active lesions necrosis rarely 
occurs, since there is commonly sufficient increase in the num- 
ber of vessels to protect the tissues from complete ischemia. 
In the later stages, those customarily termed tertiary lesions, 
comparatively large infarctions of tissue not infrequently arise 
in this manner, as for instance in cerebral thrombosis. Many 
of the lesions commonly termed gummata are of this nature. 
There is a third syphilitic lesion for which this special des- 
ignation (gumma) should, in my opinion, be reserved. This 
lesion is similar in appearance to that of tuberculosis and is 
the true gumma of syphilis. There is the same central area 
of necrosis with epithelioid and small round-celled layers. 
As with other chronic inflammatory lesions, following the 
destruction of the irritant by mercury, salvarsan, or by par- 
tial eradication by the tissue cells, reparative fibrotic changes 
take place. It is the chronic reaction, followed by fibrous tis- 
sue repair, which accounts for many of the late manifestations 
of syphilitic infection, e.g., tabes, interstitial nephritis, and 
cirrhosis hepatis. 
Leprosy 
The histologic lesion induced in the human tissues by the 
presence of the B. leprae consists of collections of lymphoid CLASSIFICATION OF INFLAMMATORY REACTIONS 
239 
and plasma cells, followed by proliferation m situ of large 
cells resembling in appearance endothelia. These cells have 
a pale-staining, nongranular protoplasm, and a more or less 
oval or kidney-shaped nucleus with a distinct chromatin net- 
work. The protoplasm of most of these cells is vacuolated: 
in some the vacuoles are single and large, completely filling 
the cell and pushing the nucleus to one side; in others the 
vacuoles are multiple and small. In thick sections the vacuoles 
from one cell can apparently be traced by direct continuity 
to another. These vacuoles represent a degenerated area 
within the cell cytoplasm. They are the result of the action 
of the bacilli which are usually found within the clear area. 
In the earlier lesions, and especially in those experimentally 
produced in mice, the plasma and lymphoid cell elements are 
the predominant cells present. I am of the opinion, as al- 
ready stated,1 that lymphoid, plasma, and "epithelioid" cells 
are intimately related to one another; the last mentioned is 
developed in larger numbers in proportion to the duration 
and intensity of the irritant. 
Mast cells are usually present as well as eosinophiles. Neu- 
trophile-polymorphonuclear leucocytes are not infrequently 
found in small numbers, and in one case, reported in 1911,2 
they were present in such numbers as to form distinct ab- 
scesses, although no organism other than the leprosy bacillus 
was present in the lesion (see Immunity). 
There are also usually present, especially in the early lesions, 
giant cells of the Langerhans type, which exhibit a large 
amount of irregular granular protoplasm and contain numer- 
ous nuclei. These are usually situated towards one end of 
the cell and are frequently arranged in a horseshoe manner. 
Division by amitosis in these cells is frequently seen. In cells 
of the epithelioid type karyokinetic figures are occasionally 
found. In addition to these distinct giant cells, irregular 
agglomerations of cells of the epithelioid type occur. The dif- 
ference in the arrangements of the nuclei in such cells and the 
*Gurd: Jour. Med. Research, 1910, xxiii, 151. Jour. Path, and Bacteriol., 
1911, xvi, 1. 
2Gurd: Jour. Inf. Dis., 1911, viii, 39. 240 
INFECTION, IMMUNITY, AND INFLAMMATION 
absence of granular protoplasm make their differentiation 
from the true giant cells easy. 
A feature differentiating the giant cell of the leprous lesion 
from that found in tuberculosis is the presence in the great 
majority of cells of round vacuole-like spaces. These spaces 
vary in shape from spherical to sausage-shaped bodies, and 
vary in size from 4 to 100 or more microns in thickness. Many 
vacuoles are present which do not show any nucleolated cell 
body, although in all cases there is a narrow margin of gran- 
ular protoplasm. This appearance is the result of the cutting 
of the cell in such a way that the nuclei are not brought into 
the section. That this is the case can be proved by means of 
serial sections. A certain number of cells of this nature ap- 
pear to have been completely replaced by the vacuole-like body. 
Practically all the bacilli seen in sections of leprous tissue 
are situated within the protoplasm of the tissue cells. Not 
only are they present in the two types just described, but they 
are also found lying within lymphoid, plasma, and connective 
tissue cells, in the superficial layers of the corium, and in the 
fat cells. They are also constantly present in the cells of the 
adventitia of the vessels. In many instances the masses of 
bacilli are continuous from one cell to another, forming in 
this way irregular branching bodies. 
A narrow zone of normal-looking corium is always present 
immediately beneath the epidermis. Although this zone is 
free from inflammatory cells, bacilli are not infrequently found. 
Material scraped from the surface of an incised leprous 
tubercle always contains enormous numbers of leprosy bacilli. 
A certain number of scattered organisms are usually present, 
though the greater number are in the form of spherical masses 
(globi) and irregular branched collections. As a rule no cell 
bodies or nuclei are noted in direct relationship to the masses 
of bacilli. The shape of the cell body, however, and the spaces 
occupied by the nucleus of the cells from which the branched 
forms are derived can always be made out. That only a small 
number of nuclei and cell bodies is found is explained readily 
by the study of the tissues themselves. Everywhere between 
the epithelioid cells are found collagenous fibrils, which act as 241 
CLASSIFICATION OF INFLAMMATORY REACTIONS 
a support to the cell protoplasm. The epithelioid cells, and 
more particularly the giant cells, have an extremely irregu- 
lar outline, numerous prolongations of the protoplasm pro- 
truding everywhere between neighboring cells. In view of 
this fact and the fact that the cell membrane, as demonstrated 
in stained preparations, is very thin and the vacuoles filled 
with bacilli are proportionately large, it is easy to understand 
why the bacilli are thrown off from the cells as a result of 
the trauma of incision; whereas the cells themselves, owing 
to their projections, are more firmly attached and do not 
exude so readily. 
Other Granulomata 
In addition to tuberculosis, leprosy, and syphilis, there are 
a certain number of diseases in which a lesion of the granu- 
lomatous type is found. Infection by the actinomyces, sporo- 
trichoses, B. mallei, and blastomyces, may produce lesions 
which closely resemble those which characterize tuberculosis. 
Fortunately these infective agents are comparatively readily 
demonstrated and recognized, so that they do not as a rule 
offer difficulties in diagnosis. 
Protective Effect of Macrophages upon Certain 
Microorganisms 
Although hypersensitiveness to bacterioprotein usually de- 
termines protection of the tissues from infection by the bac- 
terium, it occasionally happens that, in consequence of cer- 
tain physicochemical characteristics of the bacterial cell body, 
such is not the case. I3 have already expressed the opinion 
that with regard to infection of certain animals, notably goats, 
by the leprosy bacillus, the reaction which develops in con- 
sequence of a moderate degree of hypersensitiveness to the 
bacterial protein may suffice to permit the bacterium, under 
conditions of massive experimental inoculation, to obtain a 
foothold. 
Attempts to infect normal goats with the leprosy bacillus 
(Duval) were attended uniformly by failure upon the first 
'Duval and Gurd: Jour. Exper. Med., 1911, xiv, 181. 242 
INFECTION, IMMUNITY, AND INFLAMMATION 
attempt. Nor did inflammatory reactions of any sort occur 
in the tissues, if moderate doses were employed. If, however, 
the animals had been rendered hypersensitive by means of 
the introduction of one or more massive doses of bacterial 
emulsions or extracts, subsequent subcutaneous injections of 
moderate doses of viable bacilli were followed by the appear- 
ance of inflammatory nodules. These nodules were charac- 
terized by hyperemia and mononuclear cell accumulations, as 
well as by the presence of moderate numbers of multinucleated 
cells. These last mentioned cells appear to ingest the bacilli 
and, having ingested them, are unable to complete their de- 
struction. The bacilli, therefore, continue to live, and appar- 
ently to multiply, in the protoplasm of the giant cells, and 
form the characteristic globi. 
My explanation of these observations is that the leprosy 
bacillus (Duval) is unable to live in the tissues if the goat is 
exposed to the circulating body fluids, nor is it irritating to 
the normal goat tissue. In consequence there is an absence 
of inflammatory reaction about the foci of bacilli. If, on the 
other hand, the animal has been rendered moderately hyper- 
sensitive, the characteristic macrophages accumulate. 
These cells ingest the bacilli, but are unable to bring about 
their devitalization. The ingested bacteria, therefore, con- 
tinue to proliferate in the protoplasm of the cell. At the 
same time the microorganisms are protected from adequate 
action of the substances in the serum, which, experiments ap- 
pear to prove, are injurious to their metabolism. The bacilli 
consequently are enabled to persist and to grow in the cyto- 
plasm of the giant cell. The typical globi which characterize 
the tissues are thus produced. 
The extent to which other microorganisms are thus pro- 
tected by inclusion in the cytoplasm of cells which are not 
capable of destroying the invading virus is not known. The 
microscopic appearance of lesions consequent upon infection 
by the blastomyces, in which budding cells are more fre- 
quently seen in sections of macrophages, suggests that this 
may be the case in infection by this yeast. CHAPTER XXIV 
ANAPHYLAXIS IN MAN 
Reactions to the Parenteral Introduction of Horse Serum in 
Man-Serum Sickness 
In man the parenteral introduction of foreign protein1 in 
the form of antiserum is accompanied in a large proportion 
of cases by local and constitutional manifestations of irritation 
or intoxication. Such symptoms consist, in the majority of 
cases, in the development of urticarial and erythematous erup- 
tions, joint or muscle pains, pyrexia and occasionally vomiting. 
Such symptoms, though they may be annoying to the af- 
fected individual, and although, occasionally, the onset of an 
unexplained pyrexia in the course of the treatment of the 
wounded may cause anxiety to the surgeon in charge, are of 
comparatively little importance. Unfortunately, however, 
there occasionally occur, within a short time after the injection 
of the serum, more serious reactions. The symptoms in these 
cases comprise collapse, tachycardia, drop in blood pressure, 
unconsciousness, and occasionally difficulty or arrest of res- 
piration with consequent cyanosis and air hunger. Such cases 
are often fatal. 
It is evident from a study of human cases that three types 
of reaction are exhibited, namely, urticaria and cellulitis, as 
in the rabbit; splanchnic dilatation, as in the dog; and re- 
spiratory anaphylaxis, as in the guinea pig. It would appear 
that, both as a primary cause of death and also as subjecting 
the patient to the danger of a delayed reaction, the splanchnic 
type is of most importance. 
When an injection of horse serum is made into the human 
'For a more complete discussion of this subject, the reader is referred 
to an article by the author, Gurd: Arch, of Surg., 1921, ii, 409. 
243 244 
INFECTION, IMMUNITY, AND INFLAMMATION 
tissues, various results may be noted depending upon the state 
of the tissues in relation to the serum protein. 
1. If the individual be normal, no immediate result is noted, 
but his tissues are stimulated to elaborate a substance (first 
order antibody) which has the property of altering the protein 
molecule so that it acts as a tissue irritant. 
During that period immediately following the introduction 
of the horse serum the amount of available antibody is not 
sufficient to liberate, at any one time, a sufficient amount of 
toxic substance to irritate the tissues either locally or con- 
stitutionally. After the sixth day, the amount of antibody 
available has reached such concentration that a larger quan- 
tity of protein is split. In consequence, the focus into which 
the serum has been injected becomes irritating. As the result 
of irritation hyperemia develops so that a large amount of 
blood is brought into contact with the serum collection. As 
a result, then, of a greater concentration of first order anti- 
body, in the body fluids, and an increased circulation through 
the focus, there is a marked increase in the amount of irritant 
substance developed. Symptoms of constitutional intoxication 
then occur. These manifestations consist of fever, skin erup- 
tions, swelling of the synovial membrane with consequent joint 
pains, and occasionally nausea or vomiting, and diarrhea. 
At the site of serum injection and in the neighboring lymph 
nodes, evidences of inflammation, hyperemia, interstitial edema, 
pain and tenderness are noted. 
2. If the individual is hypersensitive to horse serum, either 
because he has previously received parenteral injections of 
horse serum, or from any other cause, the injection of the 
antigen into his tissues is immediately followed by a reaction 
between the first order antibody already present and the in- 
jected protein. 
The severity of the reaction which takes place depends 
upon several factors, viz.: 
a. The degree of sensitiveness of the patient. 
b. The route of injection (intradermic, subcutaneous, intra- 
muscular, intrathecal or intravenous) ; this is important, since ANAPHYLAXIS IN MAN 
245 
depending upon the nature of the tissue into which the serum 
is injected, there will be a variation in the available propor- 
tion of the amount of antibody present in the body. 
c. The amount of serum injected. 
d. The rate of injection. If the serum be very slowly in- 
jected into the blood stream, the total quantity of antibody 
available may be exhausted by a very small amount of serum. 
The amount of serum which is capable of absorbing all the 
available antibody may not be able to supply a sufficient quan- 
tity of toxic product to materially injure the individual. 
2-a. If the individual be very sensitive, the route of injec- 
tion be intravenous, and the dose injected sufficient to pro- 
duce an excessive amount of anaphylactic irritant, there occurs 
an almost instantaneous liberation of the irritant product 
with immediate manifestations of grave intoxication of the 
individual. Death may supervene within a comparatively few 
minutes, either as the result of drop in blood pressure and 
arrest of circulation, as is seen in anaphylactic shock in the 
dog, or the reaction which occurs in respiratory, as in the 
guinea pig. In man it would appear that this respiratory 
type of reaction, though very terrifying, is less likely to lead 
to a fatal outcome than is the splanchnic reaction. 
In a certain proportion of cases which are shocked by the 
parenteral introduction of serum there occurs the recurrent 
splanchnic reaction, after the lapse of several hours, which 
may prove fatal. 
2-b. If the serum be injected intradermally in small quan- 
tities, e.g.,0.25 c.c., the reaction which occurs is almost en- 
tirely focal. It commences within two or three minutes and 
is characterized by a well marked cellulitis of the tissues sur- 
rounding the injected area; it is accompanied, not infrequently, 
with lymphangitis and lymphadenitis. 
2-c. If the serum be injected intramuscularly, it is brought 
in contact with less blood than if given intravenously; in 
consequence the reaction which occurs is, other things being 
equal, less severe and more prolonged than following intra- 246 
INFECTION, IMMUNITY, AND INFLAMMATION 
venous administration, though more severe than following 
intradermic injections. 
3. If the individual has been desensitized by a recent injec- 
tion of horse serum (a few hours to four days previously), the 
injection of a subsequent dose finds the tissues free from any 
considerable amount of first order antibody. In this event, 
the injected serum is not immediately altered, as in the hyper- 
sensitive individual, but remains unaltered pending the accu- 
mulation, through the activity of the tissues, of a fresh supply 
of antibody. Since the tissues have already been stimulated 
to produce the antibody, the development of amounts suffi- 
cient to cause the liberation of an amount of irritant capable 
of injuring the tissues, requires a shorter period than in the 
normal individual. In consequence, the outbreak of clinical 
manifestations of irritation is not delayed for eight or nine 
days, but appears at the expiration of a shorter period. 
4. If the individual has received frequent large doses of 
serum within a few weeks or months, he is to a certain extent 
(tolerant) immune to the toxic effects of the reaction between 
the first order antibody and the serum protein. Such a case 
may be injected by any route with a small dose of serum 
without the development, either immediately or later, of man- 
ifestations of intoxication. In such a case the injected serum 
protein is acted upon (split) by the first order antibody, but 
there is also present in the tissues a substance which is capa- 
ble of neutralizing the toxic product-second order antibody. 
The fact that it is possible to inject hypersensitive individ- 
uals with a small dose of the protein to which they are hyper- 
sensitive, without the development of symptoms of tissue irri- 
tation, must be borne in mind. Should the injection of a test 
dose in an individual, who is suspected to be hypersensitive 
to horse serum, e.g., an individual known to be asthmatic, or 
to have previously received injections of horse serum, prove 
negative, the evidence thereby gained should not be accepted 
as final. The person should again be injected with a second 
test dose, larger in quantity, before it is assumed that he is 
not hypersensitive. ANAPHYLAXIS IN MAN 
247 
In my opinion, the fact that the hypersensitive individual 
may also be tolerant to the irritant product of the first order 
antibody antigen reaction, and consequently his hypersensi- 
tiveness may not be evident if too small an amount of the 
test serum is introduced, is an important argument against 
the exclusive employment of the cutaneous method of testing 
for hypersensitiveness as used by Walker and others. By 
the employment of the subepidermal method of injection, more 
clean cut reactions are induced, and the quantitative element 
which is lacking in the cutaneous method is obtained. The 
method, moreover, is of real value in commencing desensiti- 
zation of the individual. 
Novotny and Schick2 report the successful transference of 
passive anaphylaxis to guinea pigs with the serum of two chil- 
dren who had received injections of horse serum, seventeen 
and twenty-three days, respectively, previous to being bled; 
these, however, are the only positive results in a considerable 
number of experiments. They were unsuccessful in attempts 
to transfer anaphylaxis passively from dog to rabbit, and 
from guinea pig to rabbit. 
Determination of Hypersensitiveness and Method of Desen- 
sitization.-At the present time, there are not sufficient data 
available to permit one to state with positiveness the optimum 
dosage of horse serum which should be employed in the deter- 
mination of hypersensitiveness or in the induction of desensi- 
tization. I have employed a method which has apparently 
proved satisfactory. For the test dose, 0.253 c.c. of serum is 
introduced subepidermally. In performing the test, I have been 
accustomed to employ a very fine needle which is introduced 
through the skin and made to penetrate the skin again at a 
distance of a centimeter or more from the original puncture. 
As soon as the point of the needle is visible through the epi- 
dermis, the serum is injected. In this way, a small white 
wheal is formed, which is the center of the subsequent reaction. 
and Schick: Quoted from Anderson and Frost, Trans. Cong. 
Am. Phys, and Surg., 1910, vlii, 430. 
'In one case 0.25 c.c. of horse serum introduced subepidermally was fol- 
lowed by the exhibition of somewhat alarming symptoms. 248 
INFECTION, IMMUNITY, AND INFLAMMATION 
It is of the utmost importance that the fluid should not enter 
a vein. Such an accident can be guarded against by attempt- 
ing to withdraw the plunger of the syringe before injecting 
the fluid. 
In sensitive individuals, the reaction commences almost im- 
mediately (from 20 to 180 seconds), and consists in its first 
stage of an enlargement of the original wheal, usually in a 
radiating manner. Not infrequently at this stage, the point 
of injection becomes itchy. Surrounding the definitely raised 
area, there appears within from three to five minutes a hyper- 
emia zone, 1 to 5 cm. in diameter, which rapidly increases in 
size until it attains its maximum size about one-half hour after 
injection. 
The results of experiments in one case that I studied proved 
that in certain hypersensitive individuals, 0.25 and even 0.5 
c.c. is too small a dose to prove hypersensitiveness in individ- 
uals who have recently received large doses of serum and who 
are, in consequence, tolerant. 
Should there be no reason for suspecting the patient to be 
highly sensitive or perhaps tolerant, a negative reaction to 
this amount (0.25 c.c.) may be accepted as proof that the in- 
dividual is not hypersensitive to an important degree. On the 
other hand, should the fact that the patient had recently 
received one or more doses of serum lead one to suspect that 
he might be both hypersensitive and tolerant, the injection 
should be repeated about one hour after the first, and a larger 
quantity, 1 to 1.5 c.c. of serum should be employed. 
Desensitization of animals sensitized to milk proteins has 
been accomplished by the rectal administration of milk. (Bes- 
redka.) This is a method which may perhaps be of occasional 
value in desensitizing patients to whom it is necessary to give 
doses of a therapeutic serum and who are suspected or known 
to be hypersensitive to horse serum. The only objection to 
the method is that many hours are necessary for desensitiza- 
tion to take place. 
Friedberger and others have shown that desensitization with- 
out the manifestation of anaphylactic shock may be induced ANAPHYLAXIS IN MAN 
249 
through the slow administration intravenously of very dilute 
antigen. For this purpose, an hour or more must be consumed 
in the administration of the dose required to desensitize. 
Treatment of Anaphylactic Reaction in Man.-In the treat- 
ment of the mild forms of the reaction, little is necessary. In 
my experience, the discomfort arising from the urticaria is 
usually relieved by the administration, either before or after 
its development, of calcium lactate or chloride, followed by a 
dose of magnesia. I have been accustomed to give the patient 
a mixture containing 1 dram of calcium chloride, one-fourth 
of the mixture to be taken every fifteen minutes; and at the 
end of the hour a dose of 4 drams of milk of magnesia is 
given. 
In the treatment of the severe cases of splanchnic dilatation, 
posture, including compression of the abdomen, should be em- 
ployed. Fluids, probably best in the form of hypertonic glu- 
cose (10 per cent) solutions or gum acacia, are administered 
intravenously. Epinephrin, in doses of 5 or 10 minims (1:1000) 
intravenously, should be employed, if available, for its splanch- 
nic effect. In the event of recurrence of symptoms, further 
injections of epinephrin must be employed. 
Although probably less effective than suprarenal extract, 
pituitary extract is, I believe, of value. It is probable that 
although its effect is less prompt than epinephrin, the best 
results are obtained by employing the latter preparation in- 
travenously and injecting the pituitary extract in doses of 
1 c.c., 'Subcutaneously. 
In cases of respiratory reaction, epinephrin should also be 
employed and, in addition, oxygen should be administered. 
As suggested by Auer and Lewis, the effect of atropin upon 
the smooth musculature is of real value in relieving the 
dyspnea. This drug should be administered in doses of 
grain. In view of the fact that animals are apparently more 
resistant to fatal shock when under the influence of anesthesia, 
and in view of the excellent results obtained by Munro (see 
p. 96) in a case reported by him, chloroform or ether may 250 
INFECTION, IMMUNITY, AND INFLAMMATION 
well be administered. Artificial respiration should also be 
employed. 
Clinical Examples of Hypersensitiveness to Nonbacterial 
Proteins 
As early as 1911 von Pirquet4 discussed, as manifestations 
of the allergic phenomenon, satinwood dermatitis, egg albu- 
min hypersensitiveness, buckwheat poisoning, insect poisoning, 
and eclampsia, as well as hay fever and serum sickness. 
Hay fever is an example of a local allergic reaction in indi- 
viduals sensitive to pollen protein. The same is true of the 
asthmatic attacks from which certain individuals suffer when 
in contact with horses or cats or following the ingestion of 
special foods. 
Coca objects to the inclusion of hay fever as an expression 
of hypersensitiveness to plant pollens on account of the nega- 
tive results which have been obtained in efforts to passively 
sensitize guinea pigs. As pointed out by Wells, this is of lit- 
tle significance if we consider that even the serum of guinea 
pigs, highly sensitized to a foreign protein, often contains too 
few free antibodies to confer passive sensitization upon other 
guinea pigs. The tissues of a man may be highly sensitized 
to a foreign protein without there being free antibodies in his 
blood to produce passive sensitization. 
It has been previously pointed out that under certain cir- 
cumstances the individual may become sensitized by means 
of the alimentary, or respiratory, tract. It is believed that 
so-called "food idiosyncrasies," such as that evidenced by 
certain individuals towards articles of food such as strawber- 
ries, eggs, cow's milk, cheese, fish, pork and buckwheat, is 
due to some change in the physiology of the alimentary tract 
whereby these materials are not properly dissociated before 
their absorption into the system. 
Ramirez5 has reported a case of a man who had never had 
asthma, hay fever, urticaria, or any similar condition indicat- 
*von Pirquet: Arch. Int. Med., 1911, vii, 284. 
'Ramirez: Jour. Amer. Med. Assn., 1919, Ixxiii, 984. ANAPHYLAXIS IN MAN 
251 
ing hypersensitiveness to proteins, who received 600 c.c. of 
blood as a transfusion from a man who had typical horse 
asthma. The donor gave a cutaneous reaction to horse dan- 
druff in 1-50,000 dilution. Two weeks after the transfusion 
the recipient went for a carriage ride. Within five minutes 
he had a typical attack of asthma. A skin test gave a positive 
reaction to horse dandruff diluted 1-20,000 but not to numer- 
ous other proteins. 
Hypersensitiveness to Foodstuffs.-Talbot6 has investigated 
extensively the importance of the intestinal tract in sensitiza- 
tion to foodstuffs. In his opinion (as well as that of others), 
asthma, eczema, and certain explosive forms of gastrointes- 
tinal disturbances are often due to hypersensitiveness to arti- 
cles of diet. In children and young adults these diseases are 
not uncommon. As a rule, as the patient grows older, toler- 
ance to the protein is developed and clinical symptoms cease. 
Lust and Hahn7 have shown that in a small percentage of 
babies with digestive disturbances precipitin to the casein of 
cow's milk is demonstrable in the serum. Schloss and Worthen 
found that although the normal intestinal tract ordinarily 
does not permit the passage of undigested foreign protein, cer- 
tain forms of gastrointestinal disorders may permit of the 
absorption of protein in an undigested, or partially undigested, 
state. Foreign proteins may under these conditions appear 
in the urine. 
The difficulty of determining the cause of the exciting agent 
in these conditions is due to the fact that, not infrequently, 
they are caused by bacterial antigens and not by native food- 
stuffs. 
Ascoli, Oppenheimer, and others have observed that if an- 
imals be fed individual proteins in large quantities, the same 
protein may be subsequently discovered, not only in the blood, 
but also in the urine. As a means of identification they em- 
ployed the precipitin reaction. This type of experiment ap- 
pears to indicate the method of active sensitization of individ- 
®Talbot: Boston Med. and Surg. Jour., 1918, clxxix, p. 1. 
'Hahn: Jahrb. f. Kinderh., 1913, Ixxvii, 405. 252 
INFECTION, IMMUNITY, AND INFLAMMATION 
uals to foodstuffs. In view of the extremely minute doses of 
antigen necessary to sensitize when parenterally introduced, 
it is quite conceivable that, from the intestinal content, a suf- 
ficient amount of foodstuff protein may be absorbed to ac- 
tively sensitize the individual. 
Wells has been successful in inducing the hypersensitive 
state in guinea pigs by feeding specific proteins to young 
animals. It will be noted from the following experiments, 
which are quoted from Wells, that not only may hypersensitive- 
ness be thus developed but that, in certain instances, tolerance 
is also induced. In the routine testing of individuals by means 
of the allergic reaction to common articles of diet, it is fre- 
quently noted that patients react to proteins which are habit- 
ually included in their dietary without untoward effects. Such 
an observation may be explained by the assumption that no 
unaltered protein is, in fact, absorbed into the tissues, but is 
more likely to be dependent upon a condition of tolerance 
having been induced. 
In Wells' experiments, "guinea pigs bred from mothers 
fed with oats, were, as soon as weaned, put upon a diet of 
egg albumen and carrots. Other young pigs from the same 
stock were raised upon oats and carrots. The latter animals 
after reaching a weight of 250 to 300 grams, did not give ana- 
phylactic reactions when injected with 0.05 gram of a protein 
obtained from raw oats, and if given small doses, such as 
ordinarily given for sensitizing, they were not rendered sen- 
sitive to subsequent injections of 0.05 gram of oat protein. 
"Some of the pigs which were raised to 200 to 250 grams 
weight without oats were found to give a typical reaction of 
moderate severity when injected once with 0.05 gram oat pro- 
tein. These reactions apparently resulted from passive sen- 
sitization conferred by the mother. Others gave no reaction. 
After the animals fed without oats were somewhat older, 350 
to 400 grams, they reacted much less strongly, or not at all, 
to oat protein, as if this inherited passive sensitization were 
passing off, as passive sensitization normally does; such pigs, 
if given sensitizing doses of oat protein were found to be ANAPHYLAXIS IN MAN 
253 
sensitive to this protein three weeks later and gave well- 
defined reactions of moderate severity." 
Hence, says Wells, the conclusion seems warranted that if 
guinea pigs are raised on oat proteins they cannot be made 
to give anaphylactic reactions with oat proteins, but if raised 
without oats, they may be sensitized to oat protein, just as 
they can be to other proteins not usually in their food. These 
experiments support experience obtained previously with zein, 
that guinea pigs become immune (tolerant) to the chief veg- 
etable proteins of their food. 
In another experiment Wells found that guinea pigs raised 
from the time of weaning on a diet of egg protein and carrots 
were found to give strong anaphylactic reactions when in- 
jected with egg albumen between the thirtieth and sixtieth 
days, but later they reacted less strongly, and after the one 
hundredth day of feeding they gave but slight reactions to 
0.1 gram dried egg albumen. At this time sensitization with 
egg albumen can be obtained to only a slight degree. When 
such guinea pigs were given injections of egg albumen they 
showed but slight reaction to a subsequent dose of egg albu- 
men, while control pigs fed on oats and carrots gave severe, 
usually fatal, reactions to corresponding injections of egg 
albumen. Apparently, the daily absorption of animal pro- 
tein in the food at first renders guinea pigs hypersensitive to 
this protein, but if the feeding is kept up for a long enough 
period the animals become refractory (tolerant) to the food 
protein and are so immunized that they cannot be sensitized 
to this protein. (Wells.) 
"A series of guinea pigs, which were raised on bread and 
cow's milk for two weeks, were found at the end of this time 
to be still highly sensitive to milk. They died promptly when 
given 1 to 3' c.c. of milk intraperitoneally. Apparently this 
length of feeding is not sufficient to render guinea pigs im- 
mune to milk." 
Greer8 believes that there is strong evidence that in infants 
suffering from certain types of gastrointestinal disorders, there 
8Greer: Arch. f. Pediat., 1917, Ixxxiv, 810. 254 
INFECTION, IMMUNITY, AND INFLAMMATION 
is increased permeability of the intestinal wall to incompletely 
digested lactalbumin and to a less extent of caseinogen. Sen- 
sitization consequently takes place. This author's conclusions 
were based upon experiments in which infants were subjected 
to intradermic injections of cow's milk. 
Hypersensitiveness to Serum.-Coca frankly eliminates 
serum sickness entirely from the category of anaphylactic 
reactions. He does not consider that any of the conditions 
characterized by cutaneous hypersensitivity such as the tuber- 
culin reaction, pollen reaction, food and drug idiosyncrasies, 
fall into the domain of anaphylaxis. Kolmer on the other 
hand believes that the cutaneous reactions, such as those which 
are exhibited following the introduction of tuberculin, luetin, 
horse serum, etc., into suitable individuals are true anaphy- 
lactic skin reactions and that they are due to the inter- 
action of a specific anaphylactic antibody and specific ana- 
phylactogen with the formation of diffusible irritants capable 
of producing acute hyperemia, edema and leucocytic infiltra- 
tion of the skin. He thus accepts the theory of local anaphy- 
laxis (allergy) as consequent upon the formation of an irri- 
tant by tissue reactions to foreign proteins introduced into 
the skin. 
That serum disease is related to anaphylaxis is given defi- 
nite support by the observations of C. W. Wells. This author 
found that in several persons who developed such manifesta- 
tions the precipitin titer fell to rise again when the rash faded, 
as if the precipitin had been found in the skin and thus 
caused a local anaphylactic reaction. Also, Weil observed in 
human serum sickness a fall in blood pressure and a decrease 
in the coagulability of the blood, thus adding to the resem- 
blance of this condition to true anaphylactic reactions (Wells). 
Krause has noted that bovine serum does not cause serum 
sickness with as great frequency as does horse serum. Wells 
makes the suggestion that the explanation may be that man, 
since he uses beef protein as a main article of diet, may de- 
velop an actual immunity (tolerance). He has found that ANAPHYLAXIS IN MAN 
255 
guinea pigs do become immune to the proteins which form the 
chief elements of their diet. 
In respect of certain acute serum reactions Wells, referring 
to death of a person suffering from horse asthma a few mo- 
ments after receiving the injection of horse serum, states: "It 
seems evading the obvious to attempt to interpret the occur- 
rence in any other way than as true anaphylactic shock, re- 
sulting from a specific antigen-antibody reaction; and as such a 
sensitized person usually exhibits also typical acute local reac- 
tions immediately after intracutaneous introduction of the 
most minute amounts of horse serum, or of other horse pro- 
teins as well, it seems difficult to deny, at least in such a case, 
that the cutaneous reaction of hypersensitiveness represents 
a true specific antigen-antibody reaction, and is a true man- 
ifestation of anaphylaxis. Furthermore, it is sometimes pos- 
sible to desensitize a person to the protein to which he is 
sensitive, removing both the systemic and cutaneous reac- 
tivity. ' ' 
There are still many phenomena of intoxication which 
have not yet been subjected to sufficiently careful investiga- 
tion to make it possible to make positive statements regard- 
ing their nature. Among the most important are the irritant 
effects occasionally exhibited by transfused blood, and by the 
injection of numerous protein materials which are employed 
under the heading of "nonspecific protein therapy." The 
irritative effects noted in these conditions may be due to either 
protein split product intoxication or to embolic occlusion of 
vessels. The emboli responsible for the vessel occlusion may 
be developed as the result of agglutination of red blood cells, 
fibrin formation or flocculation of colloids. 
Loeb, Strickler, and Tuttle,9 as the result of an investiga- 
tion into the cause of death which follows injection of normal 
dog or beef serum into rabbits, have published the following 
conclusions: "Death following the injection of foreign serum 
is brought about by obstruction of the pulmonary circulation 
''Loeb, Strickler and Tuttle: Quoted from Zinsser: Infection and Re- 
sistance. 256 
INFECTION, IMMUNITY, AND INFLAMMATION 
either by heaps of agglutinated erythrocytes or by fibrinous 
plugs. Dog serum and beef serum represent two different 
types. In the case of dog serum hemolysis of the blood cells 
of the recipient liberates substances attached to the stromata, 
which hastens coagulation. In consequence fibrin is formed 
which is carried into the pulmonary vessels and occludes them. 
In the case of beef serum death is due to hemagglutination." 
The so-called traumatic fever, which so frequently accom- 
panies injuries, and surgical operations, is apparently the re- 
sult of the absorption of toxic autolytic products of hemor- 
rhagic or serous exudates. Although such intoxications are 
obviously not examples of anaphylaxis, there is much which 
suggests that the irritant product, responsible for the clinical 
symptoms, is closely related to that which is explosively de- 
veloped in anaphylaxis. 
Recent experiments by Carrell regarding the absence of 
reparative changes in wound healing, if the tissues are pro- 
tected from any form of irritant, indicate that the irritative 
property assumed by extravasated blood during autolysis 
serves a positively useful purpose in stimulating cellular 
activity. 
Kohler, Moldovan, Doerr, and others found that if some 
means is taken whereby clotting of blood is delayed or pre- 
vented, as for instance, receiving it into paraffined vessels, by 
defibrination, or by citrating, it may become toxic automat- 
ically, and cause death upon reinjection into animals of the 
same species, or even into the same animal from which it was 
taken. DeKruif extended observations which had been made 
by Slatineau, and Ciuca, and showed that rabbit blood can 
be rendered toxic and even fatal to guinea pigs and white 
rats, if transfused in the preclot period, or after defibrination. 
Guinea pig blood transferred unchanged within three minutes, 
or defibrinated, or occasionally even the serum of such blood 
obtained by rapid clotting and centrifugation, was often fatal 
to animals of the same species. 
Zinsser summarizes DeKruif's conclusions regarding this 
phenomenon, as follows: "The spontaneous toxicity of nor- ANAPHYLAXIS IN MAN 
257 
mal blood develops in a similar manner as does the toxicity 
of blood treated with agar, peptone, etc. Poison production 
and fibrin formation go hand in hand, and occur in the pre- 
clot stage."10 
It is not improbable that, under certain circumstances, the 
normal or natural proteins of the body may be heterologized, 
and thus acquire antigenic properties and induce sensitization 
of the individual to the products of dissociation of his own tis- 
sues. Batty Shaw had suggested that possibly the progressive 
course of certain diseases, such as chronic interstitial nephritis, 
may be due to such a condition. Whether this be so or not, 
must, for the present at least, be considered to be sub judice.11 
In a certain percentage of cases repeated intravenous in- 
jections of salvarsan have been accompanied by a constitu- 
tional reaction characterized by dyspnea, throbbing in the 
head, and collapse. The similarity of this reaction to the 
acute anaphylactic phenomenon is striking. That such a drug, 
containing as it does no nitrogen radicles, should possess the 
property of sensitizing the individual to itself, or of acting 
as an antigen in the anaphylactic reaction, does not seem pos- 
sible if our ideas regarding the essential proteid12 nature of 
antigens be correct. A similar phenomenon is, moreover, noted 
by the use of such a simple drug as iodine in Lugol's solution. 
Experiments by Swift and Ellis, Wolff-Eisner, and others, 
have suggested a manner in which these chemicals may per- 
haps act in inducing true anaphylactic. It has been found 
impossible to employ salvarsan as an antigen in anaphylactic 
experiments in the guinea pig. It is possible, however, under 
suitable conditions, to sensitize guinea pigs against a mixture 
of salvarsan and guinea pig's serum in such a way that a 
second injection of a similar mixture proves fatal. The infer- 
ence drawn is that, as a result of the intravenous injection of 
salvarsan, certain protein constituents of the blood are so 
10It should be mentioned in passing that, although, under the conditions 
of rapid clotting, employed by DeKrulf, such toxic properties were frequently 
developed, in clinical experience they occur but infrequently. 
uFor a more extensive presentation of this subject, the reader is referred 
to articles by Longcope and Boughton. 
uAs mentioned elsewhere Danysz believes all colloids to act as antigens. 258 
INFECTION, IMMUNITY, AND INFLAMMATION 
altered that they act as a protein antigen, and thus induce the 
development of a specific antibody. As a result of the pres- 
ence of this antibody the animal is rendered sensitive to the 
subsequent introduction or presence of the same altered pro- 
tein in the tissues. 
Constitutional Manifestations of Infection and Reaction 
The clinical symptoms and signs of infectious disease depend 
upon: 
a. Rate of growth of bacteria and presence or absence of 
essential toxin production on their part. 
b. The physical characteristics of bacteria with especial ref- 
erence to thickness of ectoplasm and capsule formation. 
c. The location and function of the tissues in which the 
infecting bacteria find the most favorable medium for their 
growth. 
d. The susceptibility of special tissues to intoxication. 
e. Production or nonproduction of decomposition products 
from tissues destroyed by bacteria. 
f. Length of incubation period, which in turn depends upon: 
Degree of hypersensitiveness and tolerance of the tissues to 
the bacteria-protein and factors under "a" and "b." 
g. Type13 or predominant character of reaction employed 
by the tissues: 1. Antibody elaboration; 2. Cellular phago- 
cytosis. 
When viable bacteria gain entrance into the tissues of the 
body, any one of several phenomena may be exhibited. 
1. The protective powers of the body may be sufficient to 
at once overcome the invader and neutralize its poisons, so 
that no evidence of infection and no manifestations of either 
focal or constitutional reaction are provoked. 
2. There may occur no reaction whatever on the part of 
the tissues of the invaded host. In this event the latter is, 
more or less, rapidly overwhelmed as a result of the rapid 
and extensive dissemination of the microorganisms and their 
13The type of reaction employed by the tissues is largely determined by 
relative solubility of the bacterial cytoplasm as under "b". 259 
ANAPHYLAXIS IN MAN 
toxic products throughout the body. Death in such cases 
soon supervenes. The fatal termination is preceded by a 
stage of gradual collapse characterized by mental lethargy, 
lowering of blood pressure, increase in the pulse rate, drop in 
temperature, and leucopenia. In addition to these character- 
istic symptoms, there is usually noted a definite symptom- 
complex marked by weakness and malaise, headache and 
generalized pain, and anorexia. In addition, focal signs of 
tissue injuries, as in gangrene and malignant edema, are ex- 
hibited. The length of time intervening between infection of 
the tissues and death of the individual depends upon the 
importance of the tissue attacked and the rate of growth of 
the infecting microorganism. 
In this combination of symptoms and signs we note the 
usual effect of infection without reaction on the part of the 
body tissues. Death in such cases is due to two factors: (1) 
a loss of normal functioning capacity on the part of paren- 
chymatous tissues, and (2) a direct toxic action upon suscep- 
tible cells, chiefly those of the central nervous system. 
3. Following infection by pathogenic microorganisms, there 
usually occurs a longer or shorter period, usually lasting from 
one to two days to an equal number of weeks, known as the 
incubation period; a period during which the invader contin- 
ues to multiply and during which there is at best an inade- 
quate reaction on the part of the host. The incubation period 
terminates with, either the onset of symptoms of dissolution 
as described in section two, or with the commencement of the 
reaction on the part of the body. The evidence of this onset 
of reaction is clinically exhibited by pyrexia, rapid pulse rate, 
and usually by an increase in white blood cells-leucocytosis. 
The commencement of manifestations of intoxication and 
reactive phenomena is due to the development of the first 
order proteolytic antibody as the result of which the indi- 
vidual bacterial cell becomes not merely a nonirritant foreign 
substance discharging a minimal amount of toxins and lib- 
erating a small amount of poisonous products, dissociated 
from the tissues as a result of the biologic activities of the 260 
INFECTION, IMMUNITY, AND INFLAMMATION 
bacterium, but each individual bacterium which is brought 
in contact with body fluid is at once so acted upon by this 
antibody (anaphylactin) that an irritant (anaphylatoxin) is 
set free. There follow symptoms of irritation of various tis- 
sues, notably the blood vessels, and generalized increased 
metabolism as indicated by elevation of temperature, accel- 
eration of respiration and pulse rate, and increase in total 
nitrogen elimination. The phagocytes, both fixed tissue cells 
and polymorphonuclear leucocytes are stimulated to attack 
the irritant particles. In consequence of this increased de- 
mand of leucocytes, the myelogenous tissues, unless they them- 
selves be overwhelmed, increase the manufacture and dis- 
charge of leucocytes into the blood. Thus, not only does a 
leucocytosis develop but it is found, if a differential count 
of the lucocytes according to the method of Arneth be made, 
that less mature cells make their appearance in the blood 
stream. 
Should the demand for leucocytes, arising from the local 
accumulation and destruction of the same, be increased beyond 
the capacity of the myelogenous tissues to supply such cells, 
leucopenia ensues. It is thus evident that in the course of an 
acute infection, such as streptococcus cellulitis, pneumonia, 
appendicitis, etc., diminution in the number of leucocytes must 
be interpreted as indicating, either that the demand for cells 
has lessened, and that, therefore, a more or less immediate 
recovery of the individual from the disease is likely, or that 
the capacity of the myelogenous tissue for the production of 
cells has been overtaxed. When exhaustion of the leucocyte 
producing function has thus been brought about an early fatal 
termination of the disease may be expected. In the latter 
event the examination of the blood shows an undue proportion 
of immature leucocytes. 
Isaeff was the first to draw attention to the fact that if, 
prior to the onset of symptoms of reaction to infection, a leu- 
cocytosis was induced, by means of the introduction of vari- 
ous substances such as nuclein, salt solution, or normal serum, 
parenterally into the tissues, the subsequent course of the ANAPHYLAXIS IN MAN 
261 
disease was shortened. The explanation of the usefulness of 
this reaction is comparatively readily understood, since the 
simultaneous activity of a large number of phagocytes may 
frequently be the determining factor in accomplishing the 
destruction of the infecting bacteria. 
4. Still another series of phenomena may occur which is 
exemplified by diseases which are termed chronic inflamma- 
tions, such as tuberculosis, syphilis and blastomycosis, as well 
as other essentially local diseases such as furunculosis, acne, 
and gonorrheal urethritis. If as a result of a natural or in- 
herent slow rate of proliferation on the part of the infecting 
microorganisms, or on account of their localization in such 
a place, or in such a manner, that the natural production of 
proteolytic antibodies is inadequately stimulated, it is noted 
that the incubation period is considerably prolonged or that 
the onset of reaction is exhibited only locally. 
If the development of the sensitizing first order antibody 
(anaphylactin) proceed sufficiently slowly or be sufficiently 
long delayed a state develops analogous to, or identical with, 
that found in the immune or tolerant animal. A second anti- 
substance appears which is potent to render the product 
of the reaction between anaphylactic antibody and protein 
antigen, innocuous and nonirritating. As a result the in- 
fected individual does not show the same symptoms of intox- 
ication nor are the leucocytes stimulated to attack the bacte- 
rial cells. Leucocytosis is not exhibited. Although there is 
proof that the body fluids can, under certain conditions, de- 
stroy certain types of bacterial and animal parasites, this 
effect is more rapidly and economically brought about, if the 
body cells, more particularly the polymorphonuclear leuco- 
cytes, are stimulated to activity. We note that, in infections 
in which leucocytic accumulation is not a marked feature of 
the reactive process, the eradication of the invader from the 
tissues proceeds comparatively slowly. For instance, at no 
time during the course of a syphilitic infection do evidences 
of constitutional disturbances attain the severity of those 
which characterize pneumococcus infection. Nevertheless, the 
ultimate outcome in syphilis is more often fatal than in pneu- 262 
INFECTION, IMMUNITY, AND INFLAMMATION 
monia, unless specific chemotherapy, in the treatment of the 
former disease, be employed. 
We thus note that there is a group of infectious diseases 
characterized by a prolonged clinical course, moderate or 
slight pyrexia, and accompanied with but little increase in 
pulse rate, in which leucocytosis is either absent or moderate 
in amount. Such affections are called chronic. The chief 
primary factor determining chronicity is the slow growth of 
the infecting bacteria and protection of their cytoplasm from 
the action of body fluids. The most important property de- 
termining such protection is capsule formation. Especially 
are these phenomena noted if the bacterial accumulations be 
so situated, anatomically, that their intimate contact with 
body fluid is more or less precluded. As the result of either 
or both of these circumstances, tolerance to the bacterio- 
protein is developed almost as rapidly as is hypersensitive- 
ness. Cellular reaction (phagocytosis) is, therefore, stimulated 
but little. 
5. If, for any reason, reaction against a rapidly proliferating 
microorganism be prolonged for any considerable length of 
time, the whole body may become inundated with bacterial 
units. If the anaphylactic body be produced in sufficient 
quantities the bacterial cytoplasm may form the substrate 
from which a quantity of irritant (endotoxins of older writ- 
ers) sufficient to overwhelm the tissues, is produced. Thus 
we find that other factors being constant, the longer the ter- 
mination of the incubation period is delayed, the more severe 
are the clinical symptoms of disease. 
The Role of Anaphylaxis in Resistance to Infection (Vaughan's 
Conception) 
Vaughan14 performed a series of experiments15 which were 
carried out with bacterial cell bodies grown in large quanti- 
ties. The bacterial substance was washed with salt solution 
"Vaughan: Proc. Instit. Med., Chicago, 1920, iii, 39. 
"An interesting phenomenon was noted in carrying out these experiments. 
It was found necessary to wear masks during the grinding process, and 
even when this was done the person who ground typhoid bacillus for the 
first time suffered within from four to six hours a severe chill followed 
by a temperature which ran as high as 106° F. ANAPHYLAXIS IN MAN 
263 
and then extracted for three days with absolute alcohol, and 
for four days with ether. This treatment left a white powder 
as all the coloring matter was removed by the extraction. 
The extracted cell substance was ground first in porcelain, 
and then in agate mortars. Under the microscope the bacte- 
rial substance had the same appearance as in fresh specimens. 
The dead cellular substance injured normal animals, and 
"strange to say it harmed in inverse proportion to the infec- 
tivity of the living organism." For instance, prodigiosus, a 
nonpathogenic bacterium, killed guinea pigs when injected 
into the abdominal cavity in the proportion of one part of 
bacterial extract to two or three million parts of body weight. 
In no amount did the tubercle bacillus kill fresh animals. 
Vaughan found that the dead substance when injected into 
animals produced the same lesions that follow inoculation with 
the living bacillus. He, therefore, concludes that it is not 
the growth and multiplication of bacillus in the animal body 
that cause the symptoms and lesions of the disease. In an 
earlier section of this chapter the author has discussed the 
factors which may be instrumental in determining a specific 
type of reaction. 
Vaughan noted in his experiments that the effects of the 
dead substance upon animals are inversely proportional to the 
infectivity of the living organism. He explains this apparent 
paradox as follows: Bacteria, such as the prodigiosus, are, 
he believes, nonpathogenic because the body cells are already 
sensitized to this organism. As a result, small doses of bac- 
teria are destroyed as soon as they enter the body and infec- 
tion is prevented, while if larger doses of the dead bacterial 
substance are injected the normal fluids of the body immedi- 
ately split up the cells of the prodigiosus, and if the quantity 
injected be sufficient the toxin split product kills the animal. 
Vaughan sums up fhe facts upon which depend the infectivity 
of bacilli or other viruses as follows: 
"1. Will it grow in the animal body? If it will not grow 
in the animal body, it cannot cause infection. A given or- 
ganism must grow and multiply in the body in order to be 264 
INFECTION, IMMUNITY, AND INFLAMMATION 
infectious, and in doing so it must be able to feed on the sub- 
stance of the body. If it is not able to do this, it cannot be 
infectious to that animal. 
"2. Whether a given microorganism is pathogenic to a 
given animal or not, will depend on whether the fluids16 of 
the body kill that organism as soon as it is introduced into 
the body. If this does not happen, and if these two condi- 
tions are favorable, the microorganism grows and multiplies 
in the body and causes infection." 
When a guinea pig receives an intraperitoneal injection 
of typhoid bacilli, the following phenomena are noted: 
"For some hours there is no recognizable difference between 
the inoculated animal and his fellows. Their behavior is the 
same. Then, rather suddenly, something goes wrong with 
the inoculated animal. It begins to shiver; its coat gets 
rough; it huddles up among its fellows; it goes off its food; 
something is wrong. For a while its temperature may be 
above the normal, but in a short time it begins to fall and con- 
tinues to do so until the animal dies. At necropsy one finds 
an exudative hemorrhagic peritonitis. If something like the 
minimum fatal dose has been administered, it will be about 
twelve hours before the animal shows any change. This is 
the period of incubation, and it occurs in every infectious 
disease. During this time, the bacilli multiply in the body. 
They are feeding on body substances. They are converting 
guinea-pig substance into typhoid substance, and the process 
is a synthetic one. They are taking relatively simple bodies, 
probably only amino acids, and building them into typhoid 
protein. During the period of incubation of an infectious 
disease, the invading organism furnishes the ferments and the 
body of the host supplies the substrate or food, and the proc- 
esses are synthetical. Simple bodies are built into more com- 
plex ones. There is no poison set free, there are no lesions, 
and there are no symptoms. Therefore, it is not directly the 
16It is to be noted that Vaughan's views in this respect are practically 
identical with those conceived by von Pirquet. The author agrees with 
Vaughan's conception, but believes that it is not so much the body fluids, 
as the stimulation of the phagocytic activity of the tissue cells which de- 
termines protection of the hypersensitive individual from infection. ANAPHYLAXIS IN MAN 
265 
growth and multiplication of bacteria in the body that cause 
the symptoms and lesions of the infectious diseases." Vaughan 
explains the usefulness of prophylactic vaccinating against 
typhoid fever in the following way,-"We vaccinate against 
typhoid fever by taking the dead bacillus and injecting it into 
the individual three or four times at intervals. In so doing 
we are training the body cells to digest the typhoid protein 
and subsequently, when the man drinks water that contains 
typhoid bacilli, as soon as the first organisms get into the 
body they are split up and destroyed, and the man escapes 
typhoid fever." 
Vaughan believes the tissue changes, during infectious dis- 
ease, to be as follows: The invading organisms multiply in 
the body until the body cells become sensitized and pour out 
a secretion that splits up and destroys the invading organisms. 
During the active stage of an infectious disease the body cells 
supply the ferment, the invading organisms furnish the sub- 
strate or food; the processes are analytic; complex bodies are 
split into simple ones; a poison is set free, and the symptoms 
and lesions of the disease develop. 
Vaughan (1920) and his associates have made many at- 
tempts to induce immunity in animals with his protein poison. 
They have found, and their observations have been confirmed 
by others, that a certain degree of tolerance may be estab- 
lished by repeated doses of this substance. Normal guinea 
pigs or rabbits that have been treated with successive doses 
of the protein poison may be able to withstand without harm, 
two or three times the original fatal dose. If such animals 
are inoculated with the living organism it requires more of 
the culture to kill these animals than it does to kill fresh 
animals. Vaughan interprets this type of experiment as 
indicating that increased tolerance to the protein poison en- 
ables an animal to bear at least one fatal dose of the living 
organism. It must be pointed out that another explanation 
may be offered, namely, that such animals are in fact ren- 
dered hypersensitive in consequence of unaltered protein con- 
tained in the poisonous material, and protection from injec- 266 
INFECTION, IMMUNITY, AND INFLAMMATION 
tion of such animals is, in fact, due to a development of hyper- 
sensitive condition with consequent immediate reaction fol- 
lowing the entrance of viable bacteria into the tissues. 
Factors Determining Relative Susceptibility to Infection 
It is apparent that there must be factors, other than simple 
exposure to pathogenic microorganisms, concerned in the in- 
stitution of infection. An analysis of these contributing fac- 
tors is of value since we are thereby enabled to indicate the 
proper means for the maintenance of health. 
To return to our definition of infection: we noted that two 
conditions must prevail in order that infection may occur. 
First, it is necessary that the microorganism be enabled to gain 
entrance to the body tissues, and, secondly, the site of their 
localization must present conditions adapted to the cultural 
requirements of the invading germs, so that after having ob- 
tained a foothold they may be permitted to proliferate. 
The initiation of infection depends, in part, upon the bac- 
terium gaining entrance to the tissues and, in part, upon the 
properties of the tissues themselves. Thus, we note that even 
though bacteria are of a species which is capable of continued 
proliferation in the animal tissues, the resistance of the tissues 
to the invader may be such that unless a considerable number 
of bacteria are introduced, they are instantly destroyed. This 
fact is in all probability explained by the phenomenon of 
absorption. For instance we may assume that the available 
antibody, using this term in its broadest sense, in a given 
focus, represents a total of 100 units. If, into the tissues of 
such an animal, there be introduced a suspension of bacteria 
representing 10 units, all will be destroyed; whereas if the 
dose be increased to 150 units, absorption of the antibody may 
take place without the death of a single organism. 
In order that infection may occur, the infecting microorgan- 
isms must be capable of maintaining their vitality and prolifer- 
ating under such circumstances, as regards temperature, mois- 
ture, oxygen supply and quality of foodstuffs, as are found in anaphylaxis in man 
267 
the animal employed. For this reason the majority of bac- 
teria and protozoa are incapable of infecting the warm blooded 
animals, including man, unless as a result of trauma, excessive 
heat or cold, the normal conditions as regards these factors 
are disturbed. Thus true infection by anaerobes, such as the 
B. aerogenes capsulatus, and the bacillus of malignant edema 
cannot occur unless the tissues are injured by trauma. Growth 
of bacteria of this type takes place, only, in those tissues 
whose vitality and consequent oxygenation has been destroyed. 
To sum up, in order that infection may be accomplished, 
microorganisms must possess sufficient virulence and be intro- 
duced in sufficiently large numbers that the natural protective 
properties of the focus of introduction may be neutralized. 
This aspect of the subject of susceptibility to infection is, 
however, of comparatively little interest except insofar as the 
anaerobes are concerned. The surgeon, as well as all other 
practicing physicians, is interested in those factors which 
render one individual more or less susceptible to infection than 
his fellows, or than himself, under different conditions of 
health and environment. 
Insofar as the individual is concerned the resistance against, 
or liability to, infection depends upon one or other of several 
factors, the most important of these being the immune body 
content of his body fluid and tissues. This is influenced by a 
variety of circumstances and may be natural depending either 
upon an absence of sensitive cells, or inherited from parents 
(natural immunity). On the other hand previous attacks by 
the same or closely allied microorganisms may have stimulated 
antibody production (active immunization), similarly subinfec- 
tion or therapeutic inoculation with vaccines may have brought 
about a like result; again too, immunity may be exalted for 
a short period by means of the introduction of serum from 
a highly immune animal (passive immunization). Since the 
greater proportion of available antibodies are present in the 
blood and lymph fluids, and since the most actively phagocytic 
cells are those of the blood, protection from infection depends 
upon the maintenance of an adequate blood supply, particu- 
larly to those parts of the body subject to insult. 268 
INFECTION, IMMUNITY, AND INFLAMMATION 
Two nonspecific protecting properties are liable to depres- 
sion or decrease under certain conditions of exhaustion and 
exposure. These are phagocytic activity of the body cells and 
alexin. These factors which affect the susceptibility of the 
individual are adversely affected by: 
a. Malnutrition (starvation or dehydration). 
b. Injury (loss of blood and shock). 
c. Exhaustion from overstrain, physical or mental. 
d. Chilling of the body or excessive heat. 
e. Certain chronic diseases. 
It is as a result of the action of one or more of these de- 
pressing influences that terminal or terminating infections oc- 
cur, e.g., bronchopneumonia and dysenteric affections. 
Equally as important in their effects upon constitutional 
susceptibility to infection as the above influences, are those 
which affect the local resisting power of tissues. In this respect 
we note that there are certain inherently susceptible tissues. 
Thus we note that those areas of the body best supplied by 
blood vessels, especially if such be not ''terminal" in nature, 
are much less susceptible to infection than other parts of the 
body. Recent experiments have shown that certain groups of 
vessels are much more liable to pressor influences as the result 
of irritation, and that those areas supplied by such vessels, 
as, for instance, the anterior aspect of the lower leg, are 
peculiarly liable to infection. This suggests a second and al- 
most equally important factor, namely, the production of rela- 
tive local anemia as the result of nervous influences induced 
by trauma, draughts of cold air, etc. The result of either the 
natural absence of adequate blood supply or an acquired 
ischemia, is the same; viz., a diminution in the amount of 
available protective serum antibodies and blood cells, and a 
lessened vitality of the fixed tissue cells themselves. Similar 
effects are noted, as the result of either arterial or venous 
obstruction, whether these be due to intravascular occlusion 
(thrombosis, endarteritis, etc.) or extravascular pressure as in 
certain forms of edema accompanying frost bites and occur- 
ring in cellulitis from other causes. ANAPHYLAXIS IN MAN 
269 
Injury, either mechanical, chemical or physical, may lower 
the resistance of a part in one or more of several ways: 
1. Direct destruction of tissue cells and occlusion of vessels. 
Severe contusions, burns, frost bites. 
2. Pressor stimulation. 
3. Stimulation of extravascular accumulation of body fluid 
and consequent slowing of the blood stream. 
Impairment of sensory nerve supply of a part, as, for in- 
stance, the fingers and toes in leprosy and syringomyelia, and 
as recently seen exemplified by the large number of nerve in- 
juries consequent upon gunshot wounds, deprives the tissues 
of the natural protection of sensation and consequent reflex 
or purposeful removal of the part from such source of injury 
as intense heat and cutting and bruising instruments. 
Not infrequently the normal protection of the part, such as 
the skin and adequate vascular supply, is interfered with as 
the result of the presence of other forms of disease such as 
tumor, and previous inflammations, either active or healed. 
Under such conditions the tissues are rendered more susceptible 
to infection. 
Relapses.-Relapses during the course of disease may be due 
to one or all of the following causes: 
1 Depression of alexin. 
2. Depression of first order antibody-anaphylactin or 
allergin. 
3. Destruction of leucocytes and inhibition or exhaustion of 
the myelogenous function. 
4. Depression of phagocytosis due to exaltation of second 
order antibody and exhibition of tolerant state. 
Of these four possible reasons for relapse, wearing out of 
the myelogenous tissues and overtaxing of the tissue cells, re- 
sponsible for the elaboration of the antibodies, are doubtless 
the more usual causes. As a matter of fact, it is rarely that 
the gradual progress toward cure is interrupted unless the 
tissues are subject to some added strain, such as exposure to 
undue or too prolonged cold, gastrointestinal intoxication, or 
some intercurrent new type of infection. CHAPTER XXV 
APPLICATION OF IMMUNITY PRINCIPLES TO THE 
PREVENTION AND TREATMENT OF DISEASE 
The fact that infection by various pathogenic agents fre- 
quently results in protection of the individual from subsequent 
contraction of the same disease, has been recognized for cen- 
turies. The first record of any attempt to make use of such 
observations for therapeutic purposes dates back about two 
hundred years. At this time it was the custom among the 
Turks to inoculate their children with the contents of small- 
pox pustules in order that by this means they might be pro- 
tected from the ravages of more severe epidemics. This 
method was introduced into England by Lady Montague. 
Since, however, such a procedure not infrequently resulted in 
very severe "takes," its popularity was not maintained. As 
an outcome of this more or less hazardous procedure, the use 
of cow-pox virus, as introduced in England by Jenner in 1796, 
developed. The subsequent development of immuno-therapeu- 
tics up to the stage at which we meet it today dates from the 
time of Pasteur's epoch making researches (1878-1887) upon 
anthrax, rabies, and chicken cholera. 
Since it is possible to stimulate, by means of inoculation, 
the production of potent immune bodies-active immuniza- 
tion-and, also, to confer a certain degree of immunity-pas- 
sive immunization-through the introduction into the animal 
tissues of antibodies derived from an actively immunized an- 
imal, both of these methods have been employed in the prophy- 
laxis and treatment of disease. 
Serum Therapy 
The first attempt to confer passive immunization upon an 
animal by means of the introduction of blood serum from an- 
270 APPLICATION OF IMMUNITY PRINCIPLES 
271 
other animal, was that of Salmon and Theobald Smith1 in 
1885. These observers were successful in procuring a protec- 
tive serum against hog cholera, which proved of very con- 
siderable value. But little enthusiasm, however, for the new 
method was aroused until the results obtained by von Behring 
and Kitasato, and by Roux and Yersin in the production of 
of a serum which showed itself to be potent to influence favor- 
ably the clinical course of diphtheria, were published. In 1893 
von Behring first introduced his antitoxin for use in human 
diphtheria. The satisfactory result of this form of therapeu- 
tics is a matter of common knowledge. 
If the medical and lay world had previously been apathetic, 
they immediately became correspondingly overenthusiastic 
and were even sanguine that the millennium had arrived, at 
least insofar as the control of acute infectious disease was 
concerned. Numerous investigators directed their efforts to- 
wards the development of sera which it was hoped might be 
used against all the known pathogenic bacteria and against 
numerous toxins, including those of bacterial, vegetable, and 
reptilian origin. 
For a time the most extravagant claims were forthcoming 
with reference to the curative properties of this or that 
serum. Unfortunately, however, it was, before long, evident 
that if it be possible to produce curative or prophylactic sera 
against the majority of bacterial and protozoal diseases, this 
desideratum has not yet been attained, and will be, if ever, 
only when continued investigation and experiment have taught 
us more of the facts regarding the nature, mode of produc- 
tion, and action of immune bodies. 
In general it may be stated that no serum has been produced 
which has proved of such striking usefulness as antidiphthe- 
ritic serum, although those prepared against the toxins of the 
tetanus bacillus and various snake venoms are, under favor- 
able conditions, very valuable. In addition to antitoxic sera 
against the toxins of B. diphtheriae, B. tetani, and the snake 
'Salmon and Theobald Smith: Hept, of Come, of Agric. Washington 
1885-1886. 272 
INFECTION, IMMUNITY, AND INFLAMMATION 
poisons, sera have been developed of considerable potency 
against the B. botulinus,2 and the B. pyocyaneus.3 It will be 
noted that the foregoing sera are essentially antitoxic and 
not bactericidal. It is against the various toxins that sera 
are most readily produced. 
The report of an interesting series of experiments was pub- 
lished in 1921 by Huntoon,4 the results of which may be very 
far reaching. Already clinical application of the principle 
discovered has been made, and favorable results in the treat- 
ment of lobar pneumonia reported.5 
The aim of Huntoon's work was to prepare a serum-free 
solution of antibody. The method employed by Huntoon is 
as follows: 
''Horses are injected at regular intervals with emulsions 
of Types I, II, and III pneumococci. The serum after a num- 
ber of injections develops protective antibodies. To obtain a 
serum which protects mice against 1,000,000 lethal doses or 
more of Type I is readily accomplished. It is more difficult to 
obtain as high a protective power for Type II, and against 
Type HI a serum can seldom be obtained which protects 
against more than 100,000 fatal doses. 
"To this serum is added an equal volume of a heavy emul- 
sion of living pneumococci Types I, II, and HI. The mixture 
is placed at 37° C. for one hour or 20° C. for twelve hours, 
and then centrifuged. The sediment is washed with salt solu- 
tion to rid it of horse serum. The washed sediment is emul- 
sified in salt solution containing 0.25 per cent sodium bicar- 
bonate and heated to 55° C. for thirty minutes to one hour. 
This causes dissociation of the pneumococcus (antigen) and 
antibody. The mixture is centrifuged, and the supernatant 
fluid removed, chilled, recentrifuged, and finally filtered 
through a filter candle. The final solution, which contains 
only 0.03'5 mg. of nitrogen per cubic centimeter, is in many 
lots able to protect mice against as many fatal doses of pneu- 
2Kemper: Ztschr. f. Hyg., 1897. 
'Wassermann: Ztschr. f. Hyg., xxii, 1896. 
♦Huntoon: Jour. Immunol., 1921, vi, 117. 
sCecil and Larsen: Jour. Am. Med. Assn., July 29, 1922, Ixxix, 343. APPLICATION OF IMMUNITY PRINCIPLES 
273 
mococcus Types I, II, and III as the original serum from 
which it was made." 
In this manner the aqueous solution of specific antibodies 
is obtained in a practically serum-free state. Protective sub- 
stances against pneumococcus Types I, II, and III are obtained 
in great concentration: the disadvantages in the use of serum 
due to the serum-proteins are eliminated. As pointed out by 
Cecil and Larsen this solution contains, in addition to anti- 
body, a small amount of pneumococcus protein which may 
conceivably act in the capacity of a vaccine and, therefore, 
produce a certain amount of active immunity. 
Cecil and Larsen employed monkeys in their experimental 
work. 
"The most striking results were observed in experimental 
pneumococcus Type I pneumonia. Following the injection of 
antibody, pneumococci immediately disappeared from the 
blood, and the animal made a rapid recovery. When antibody 
was administered to monkeys that had been inoculated with 
lethal doses of pneumococcus Type II, the results were not so 
striking. A certain number, however, were saved by this 
mode of treatment. In the ease of experimental Type III 
pneumonia, no benefit whatever could be obtained by treat- 
ing the infected monkeys with antibody solution. Since the 
antibody solution displays its highest protective power in 
mice against pneumococcus Type I, next highest against pneu- 
mococcus Type II and least against pneumococcus Type III, 
it would appear that the beneficial effect induced by its ad- 
ministration is, in large measure, proportional to the amount 
of protective substance present." 
The experiments performed by Cecil and Larsen were car- 
ried out on a very large scale: 834 cases of pneumonia due 
to pneumococcal infection, and 166 cases due to streptococcus 
and other infections, were employed in the course of their 
work. Of the twelve medical wards in the hospital six were 
placed in each of the two groups; in the one group patients 
were treated by means of antibody solution, and in the other 274 
INFECTION, IMMUNITY, AND INFLAMMATION 
group this specific form of treatment was not employed. The 
accompanying table summarizes their results. 
It is evident that pneumococcus antibody solution so pre- 
pared is a therapeutic agent of considerable power. The most 
striking results are obtained in pneumococcus Type I pneu- 
monia; in pneumococcus Type II pneumonia the results are 
less impressive; and in pneumococcus Type III the antibody 
solution appears to possess no benefit whatever. In the Type 
IV pneumonia there has been a considerable difference in the 
death rate, the reason for which these authors are unable to 
suggest. 
TYPE 
ANTIBODY WARDS 
CONTROL WARDS 
CASES 
DEATHS RATE % 
CASES 
DEATHS 
RATE % 
Pneumococcus 
I.... 
. . 158 
21 
13.3 
162 
36 
22.2 
Pneumococcus 
II... 
.. 83 
23 
27.7 
67 
27 
40.3 
Pneumococcus 
III.. 
73 
29 
39.7 
60 
24 
40.0 
Pneumococcus 
IV . . 
.. 110 
18 
16.4 
121 
29 
24.0 
Total 
424 
91 
21.4 
410 
116 
28.3 
Streptococcus, 
etc... 
48 
24 
50.0 
35 
12 
34.3 
Unclassified... 
.. 36 
14 
38.8 
47 
20 
42.5 
Comparison of Death Rate in Treated and Control Series 
Doses of from 50 to 100 c.c. of the solution have been given 
once, sometimes twice, and occasionally three times a day. 
The typical reaction is thus described. 
"There is no immediate reaction. From twenty to forty 
minutes after the injection, the patient begins to shiver and 
is soon in the midst of a hard chill. The cyanosis and dyspnea 
become more marked, and the patient often shows extreme 
anxiety. The chill lasts from fifteen to thirty minutes. At 
its conclusion, the patient complains of fever, and the tem- 
perature may have risen to 106° F. or even to 108° or 
109°. In rare cases the temperature may rise to 110°. In 
one case, the rectal temperature was too high to be re- 
corded on the thermometer. When the thermometer was re- 
moved, the bulb was missing, and a careful reading of the 
mercury column recorded 113.1°! The patient was wildly 
delirious during this period of hyperpyrexia, but ice packs 
were followed by a rapid drop, and on the next morning he APPLICATION OF IMMUNITY PRINCIPLES 
275 
showed a normal temperature and made an uncomplicated 
recovery. * * * 
"The high temperature usually persists for only a short 
time: from thirty to sixty minutes. The rapid fall is accom- 
plished by a profuse perspiration, which often drenches the 
patient's linen, and which may continue for several hours. 
The fall may be slight, but is usually extensive, often reaching 
normal or even subnormal limits. It may be temporary or 
permanent. It is more likely to be temporary if treatment 
is started early; permanent if the injection is given when 
the crisis is about due. In some cases, however, one or two 
injections appear to abort the infection completely, and the 
temperature remains normal on the third or fourth day of 
the disease. * * * 
"In three cases, the reaction following injection with anti- 
body appeared to be the immediate cause of death. * * * 
"The average number of injections was 3.6 for each pa- 
tient, and the total amount of antibody administered averaged 
225 cubic centimeters for each patient." 
Cecil and Larsen are of the opinion that the beneficial ef- 
fect of the antibody solution is probably not referable to 
the shock reactions, otherwise an improvement would be- ex- 
pected in pneumococcus Type III, and in streptococcus pneu- 
monia, as well as in other pneumococcus types. 
It is not my intention at this time to attempt to analyze the 
action of the antibody solution; further work is necessary 
before such an analysis can be made. It must, however, be 
pointed out that in view of the marked febrile reaction which 
accompanies introduction of the solution it remains to be 
proved that the curative effect is specific and not due to 
exhaustion of tolerant antibodies in the infected individual 
with consequently more adequate reaction on the part of the 
tissue cells. 
In any event this series of experiments is of very consid- 
erable interest, and probably, as indicated above, will be of 
far-reaching importance. 276 
INFECTION, IMMUNITY, AND INFLAMMATION 
Production and Preparation of Antitoxic Sera 
Since the introduction of heterologous proteins parenterally 
into the tissues is very frequently followed by evidence of 
intoxication, and since the serum from certain animals has, 
naturally, the property of producing hemolysis of human 
erythrocytes, it is essential, in the employment of serum ther- 
apy, that an animal be chosen for immunization purposes 
whose serum is as innocuous to human beings as possible. 
The animals best fitted for purposes of antibody production 
for use in the passive immunization of man are, the horse, 
ram, goat, and rabbit. Of these the horse is by far the most 
serviceable, the more so since the size of the animal makes it 
possible to procure a large amount of blood without injury 
to the donor. 
Method of Production of Antitoxic Sera.-When the tetanus 
bacillus is grown in a suitable medium-neutral or weakly 
alkaline broth containing a minimal amount of carbohydrate- 
two toxins are produced. One, a hemolytic substance, is un- 
important; the other, known as tetanospasmin, is the poison 
responsible for the manifestation of human tetanus. In the 
production of antitoxic sera against tetanospasmin healthy 
young horses are employed. The animals are injected with 
broth in which tetanus bacilli have been growing under 
anaerobic conditions for six or ten days. The first doses of 
the toxin are either weakened by means of chemicals, or are 
treated with twice the neutralizing amount of antitoxin, in 
which case 3000 units or more of the toxin are injected. In- 
jections are repeated at three to five day intervals until the 
animals tolerate from 500 to 600 thousand units of toxin. 
When the horse is sufficiently highly immunized, it is bled 
from the jugular vein. The blood is allowed to coagulate and 
the serum removed after storing for several days in the ice 
chest. As a rule a germicide-0.5 per cent phenol, or 0.25 to 
0.40 per cent tricresol-is added. Horses vary in their immu- 
nizing capacity, only about 10 per cent are able to develop 
high antitoxic potency. If well looked after favorable animals APPLICATION OF IMMUNITY PRINCIPLES 
277 
may be bled at intervals of a month or six weeks over a period 
of two or more years. Six liters may be procured at each 
bleeding. 
If stored at room temperature serum loses about 20 per cent 
of its antitoxic activity in one year; if kept in the ice chest 
(5° C.) this loss is much reduced; but 6 per cent deterioration 
occurs in the same length of time. 
Antitetanic serum is standardized against a standard quan- 
tity of tetanotoxin. One unit of the toxin is the smallest 
amount which will kill a 350 gram guinea pig in four days. 
In the United States the standard toxin is supplied by the 
United States Public Health and Marine Hospital Service. The 
unit of antitoxin is ten times the amount that will protect a 
350 gram guinea pig for ninety-six hours against one official 
dose of the toxin which contains 100 units. The German unit 
is much larger (about seventy-five times) and is determined by 
a method which gives less constant results (Wood). 
Antitoxic Serum-Treatment of Diphtheria 
The signs and symptoms of uncomplicated diphtheria are al- 
most wholly due to the action of the specific diphtheria toxin. 
The treatment is, therefore, directed to the neutralization of 
toxin by antitoxin. Once the effect of the toxin has been 
neutralized in this way, the patient appears to have little diffi- 
culty in overcoming the bacilli themselves. 
When given subcutaneously or intramuscularly, the maxi- 
mum concentration of antitoxin in the blood is not reached 
before from 24 to 72 hours after injection. In severe cases, 
therefore, it is of value to introduce the antitoxic serum di- 
rectly into the blood stream. The antitoxin persists in the 
blood for a number of days. As pointed out by Park, it is 
owing to misunderstanding of this fact that the employment 
of multiple doses is due. Observations carried out by this 
investigator over several years in hospitals in New York City 
have shown that if the first dose injected be sufficiently large, 
a single dose is all that is required in any case. On the other 278 
INFECTION, IMMUNITY, AND INFLAMMATION 
hand, the insufficient first dose cannot be wholly compensated 
for by later injections. The following table is quoted from 
Park6: 
MILD 
CASES 
LATE MOD- 
EARLY 
MODERATE 
ERATE AND 
EARLY SEVERE* 
SEVERE AND 
MALIGNANT* 
Infants 10 to 30 lbs. 
Units 
Units 
Units 
Units 
in weight, under 2 
2,000 
to 3,000 to 
5,000 to 
7,500 to 
years. 
3,000 
5,000 
10,000 
10,000 
Children 30 to 90 lbs. 
in weight, under 15 
3,000 
to 4,000 to 
10,000 to 
10,000 to 
years 
4,000 
10,000 
15,000 
15,000 
Adults 90 lbs. and 
3,000 
to 5,000 to 
10,000 to 
20,000 to 
over in Wt. 
5,000 
10,000 
20,000 
50,000 
Method of administra- 
tration advised. 
Intra- 
Intra- 
Intra- 
Intra- 
muscular. muscular. 
venous 
venous. 
'When given intravenously, the smaller amounts stated. 
"In all cases a single dose of the proper amount as indicated 
in the schedule is recommended." (Park.) 
The various brands of antitoxin which are on the market 
are prepared by a precipitation of soluble globulins, from the 
sera of immunized horses. When this precipitation is carried 
out, it is found that the antitoxin content of the serum is 
removed along with the globulins. When the latter are re- 
dissolved it is possible to procure a concentrated serum which 
minimizes considerably the dangers and discomforts of serum 
disease. It must not be assumed, however, that such concen- 
trated globulins are absolutely harmless. The same precautions 
must be employed that are mentioned in Chapter XXIV 
The Prophylactic and Therapeutic Employment of Tetanus 
Antitoxin 
In man tetanus toxin is fixed only by the tissues of the 
nervous system. When the tissues are infected by the tetanus 
bacillus, the toxin which is manufactured at the bacterial focus 
is absorbed by the nerves in the neighborhood and carried, in 
the nerves themselves and in the perineural lymphatic vessels 
6Park: Jour. Amer. Med. Assn., Jan. 8, 1921, Ixxvi, No. 2. APPLICATION OF IMMUNITY PRINCIPLES 
279 
(Teale and Embleton), along the course of the nerve trunk to 
the central nervous system. When the spinal cord is reached, 
the nerve cells in the anterior horns are injured and clinical 
symptoms of spasm of the muscles which are innervated by 
these cells are exhibited. Although there can be but little 
doubt that the majority of the toxin which is discharged from 
the focus reaches the central nervous system by way of the 
nerve trunks, it is not improbable that a certain amount is 
absorbed into the blood stream and is thus carried to the brain 
or cord. 
Whenever a lacerated wound, burn, frostbite or other type of 
injury which is accompanied by devitalization of tissue is 
incurred, a favorable nidus is produced in which the tetanus 
bacillus may grow. 
Since it is impossible to determine whether a wound is thus 
contaminated or not prior to the onset of symptoms, it is ad- 
visable in every case of injury of this sort to anticipate the 
possible onset of intoxication by the introduction of antitoxin 
in the form of antiserum. As a general rule 750 to 1500 units 
are injected, the dose being determined by the severity of the 
wound and its location; i.e., whether in close proximity to 
larger nerve trunks. In those cases in which necrosis of con- 
siderable masses of tissue occur, the antitoxin should be re- 
injected in the same quantities at weekly intervals until all 
necrotic tissue has sloughed off. In those cases in which the 
wounds are in the neighborhood of nerve trunks, particularly 
if close to the central nervous system as the loin, neck and 
head, it is advisable that the serum be introduced in the 
neighborhood of the injury. 
Treatment of Tetanus with Serum.-In the majority of cases 
it is possible to diagnose tetanus before the spasms have become 
generalized. Since the toxin reaches the central nervous sys- 
tem by way of the nerves, spasms are first exhibited in those 
muscles whose nerve supply is derived from the part of the 
cord to which the nerve trunks transmitting the toxin deliver 
the tetanospasmin. Consequently, in the majority of cases, 
careful observation of the wounded permits diagnosis of the 280 
INFECTION, IMMUNITY, AND INFLAMMATION 
disease before the distribution of the toxin has become general. 
This is not, however, usually possible when wounds affect 
the muscles of the loin or the tissues of the head and neck. In 
injuries of this nature the toxin has such a short distance 
to travel that the symptoms of intoxication are likely to be 
manifest soon after injury and to become rapidly generalized. 
In the treatment of tetanus, in addition to proper surgical 
cleansing of the focal lesion and the employment of absolute 
quiet for the patient, antitoxin should always be employed. 
Antitoxin serum should be administered in large doses. As 
was pointed out in discussing the treatment of diphtheria by 
antitoxin, it is advisable to make the first dose, if possible, the 
total dose. 
There exists at the present time a difference of opinion re- 
garding the route of injection which is most favorable. This 
disagreement, in the author's opinion, is due to the fact that 
experiments which have dealt with intoxication by tetanus 
toxin have been confused with infection by the tetanus bacillus. 
Park and Nicoll found that animals-guinea pigs-which were 
injected into the hind legs with two fatal doses of toxin and 
subsequently, 24 hours later, received immune serum, survived 
in a larger proportion of cases if the serum was injected intra- 
theeally than if introduced into the subcutaneous tissues or the 
blood stream. Sherrington conducted similar experiments upon 
monkeys.. He gives the accompanying table of his results. 
ROUTE OF INJECTION 
TIME BETWEEN 
GIVING OF TOXIN 
AND ANTITOXIN 
RECOV- 
ERIES 
DEATHS 
Lumbar intrathecal 
. 47-78 hours 
14 
11 
Bulbar intrathecal 
. 47-78 ' ' 
13 
12 
Intravenous 
.. 47-78 ' ' 
7 
18 
Intramuscular 
. 47-78 ' ' 
3 
22 
Subcutaneous 
. 47-78 ' ' 
2 
23 
Cerebral subdural, ten cases 
.. 47-78 ' ' 
0 
10 
These experiments prove that when tetanus toxin is injected 
into the muscles, and after an interval an effort is made to 
neutralize the injected toxin by means of antitoxin, the latter APPLICATION OF IMMUNITY PPJNCIPLES 
281 
is more useful if injected into the subdural space. In the ordi- 
nary case of tetanus infection in the human being, the prime 
aim of the surgeon is to prevent the toxin from reaching the 
central nervous system; for this purpose neutralization of the 
toxin, close to the point at which it is being produced, should 
be more useful. 
In all severe cases of tetanus, therefore, intrathecal injections 
of the antitoxin should be made, but never to the exclusion 
of intramuscular injections in the neighborhood of the bacterial 
focus. Since the toxin reaches the central nervous system by 
means of the nerve trunks, an effort should be made to bathe 
the nerve trunks and nerve endings with the antitoxin con- 
taining serum. Since whatever substances are injected into the 
blood stream, must be assumed to eventually reach the central 
nervous system, intravenous injections of serum should also be 
employed. 
In the treatment, therefore, of tetanus, large quantities, forty 
thousand to one hundred thousand units should be injected 
about the focus. A more moderate dose of fifteen to fifty thou- 
sand units should be injected intravenously, and in fulminant 
cases, two or more intrathecal injections. The amount injected 
in the spinal canal will depend upon the potency of the serum 
available and the amount of fluid which can be withdrawn from 
the piaarachnoid space. 
Bactericidal Sera.-Heretofore but indifferent results have 
been obtained in the employment of bactericidal sera. Al- 
though, for several types of antistreptococcic and antipneumo- 
coccic sera, extravagant claims have been made, the favorable 
clinical results following their employment have been very 
meagre. It does not seem improbable, however, that eventually 
more desirable effects may be obtained. Improvement in ef- 
fectiveness will probably depend upon more simple and exact 
methods of serologic classification of bacteria. 
It must be borne in mind that when immune serum is pas- 
sively transferred to the diseased individual, the specific first 
(or first and second) order antibodies alone are introduced. 
We have previously noted that alexin is necessary for the 282 
INFECTION, IMMUNITY, AND INFLAMMATION 
exhibition of the lytic activity of the specific antibodies and 
also that in many instances the phagocytic activity of the leu- 
cocytes is essential if bacteria are to be destroyed. 
Were it possible to transfer active serum (i.e., containing 
alexin) it is probable that more satisfactory results would be 
obtained. Blood transfusion from convalescents to infected 
persons is a method which theoretically, at least, promises much 
in this direction. There are, unfortunately, obvious difficulties 
in the way of such a procedure so that heretofore the reports 
available are meagre. Unger's observations indicate that blood 
transfused without the addition of sodium citrate is more effec- 
tive for this purpose than is blood to which this salt has 
been added. 
Antistreptococcus Serum.-Stimulated by the strikingly fav- 
orable results which attended the use of antidiphtheritic serum, 
von Behring attempted to procure serum which might be of 
service in combating streptococcus infection. The results ob- 
tained by this eminent investigator were of little value, nor 
have subsequent efforts in this direction been crowned by any- 
thing approaching a signal success. 
Many sera have been produced which show bacteriotropic 
activity in vitro and which have a moderate protective potency; 
or five different brands of commercial sera on the market, 
Weaver and Tunnicliff7 found four to demonstrate a certain 
degree of activity in these directions. 
The best method of inducing immune body production, so 
far employed, is by the injection of bacteria of varying degrees 
of virulence obtained from different sources. In this way a 
polyvalent serum is produced. 
Although, as stated above, but relatively little can be ex- 
pected of any of the sera so far prepared, its use in large doses 
-100 to 200 c.c.-repeated every twelve hours, may well be 
employed in all cases in which the prognosis, without some 
such aid, is obviously grave. If proper precautions (page 247) 
are employed, intravenous injection of the serum is indicated 
in such cases. 
'Weaver and Tunnicliff: Jour. Inf. Dis., 1911, ix, 130. APPLICATION OF IMMUNITY PRINCIPLES 
283 
Antistreptococcus serum, as well as other bactericidal sera, 
loses its activity (alexin) when stored; since, however, it is 
possible to reactivate it by the addition of fresh normal serum 
of a suitable animal, it is likely that a similar reactivation oc- 
curs in vivo. 
Antipneumococcus Serum 
The most important contribution to the subject of specific 
treatment of the pneumonias is that of Foie, at the Rockefeller 
Hospital in New York. He has divided pneumonias into four 
groups, dependent upon specific types of pneumococci. The 
differentiation of the infecting microorganism in each individ- 
ual case is determined by what he has called the "mouse 
method."8 
Up to the present a useful serum has been obtained for the 
treatment of acute lobar pneumonia due to pneumococcus Type 
I. The serum is injected intravenously and as soon as possible 
after the type has been determined. Cole gives the following 
outline for employment of the serum: 
"The amount of serum to be injected at the first dose is from 
90 to 100 c.c. and this dose should be repeated every eight 
hours until the fall of temperature and amelioration of symp- 
toms indicate that the infection has been overcome. The serum 
injected should be at body temperature, and it should be in- 
jected very slowly. The total amount required in the average 
case is from 200 to 300 c.c., though in severe cases, treated 
late in the disease, it may be necessary to employ much larger 
amounts, even as much as 1,000 c.c." 
Antimeningococcus Serum.-Flexner and Lewis have been 
successful in perfecting a serum first suggested by Jochmann, 
which has been proved to be of great value in the treatment of 
cerebrospinal meningitis if injected directly into the subarach- 
noid cavity. The effect of the introduction of the serum in 
'The sputum is washed in salt solution and a small quantity injected into 
the peritoneal cavity of a mouse. Twelve hours later the mouse is killed, 
when a practically pure culture of pneumococci is usually obtained. The 
suspension of pneumococcus, washed free from cells and serum, is then 
tested by agglutination against each of the four types of antisera. In this 
way a differential diagnosis is rapidly made. 284 
INFECTION, IMMUNITY, AND INFLAMMATION 
this way is, according to Flexner's views, threefold: the bac- 
teria are destroyed by the direct bactericidal properties of 
the serum, phagocytosis is stimulated, and free toxins are 
neutralized. 
There can be little doubt that the employment of this specific 
serum has revolutionized the treatment of meningococcic men- 
ingitis. The unsatisfactory results which have been reported 
from time to time have been shown to be due to a lack of 
potency on the part of the serum used (Blackfan). Either 
polyvalent, or better, a specific monovalent serum, may be em- 
ployed, the latter only after the type of meningococcus has 
been determined. 
The serum should be employed as early as possible in the 
course of the disease and should be injected directly into the 
spinal canal or cerebral ventricles, or both. It should be in- 
jected at frequent intervals and in as large amounts as are 
safe. It should not be discontinued until after the microor- 
ganisms have disappeared from the spinal fluid and the pa- 
tient's general condition improved. 
The amount of serum introduced into the canal depends upon 
the amount of cerebrospinal fluid which can be withdrawn by 
lumbar puncture. It should not exceed this amount, except in 
those cases in which a thick purulent exudate cannot be with- 
drawn. In such cases only 5 or 10 c.c. of the serum should 
be introduced. It is advisable to employ the gravity method 
only for its introduction, otherwise symptoms due to increased 
cerebrospinal pressure may be encountered. 
Bacillary Dysentery 
Although the results of serum treatment of dysentery have 
proved to be of relative value only, it should always be em- 
ployed, if available. It is of the utmost importance that a 
differential diagnosis between the two types-Shiga and Flex- 
ner-be made, since sera prepared by the immunization of 
horses against one type is of comparatively little use in the 
treatment of disease due to infection by the other bacillus. APPLICATION OF IMMUNITY PRINCIPLES 
285 
The serum is employed subcutaneously, and in severe cases, 
intravenously. According to Flexner, the dose for an adult is 
20 c.c., but in severe cases, he advises giving doses of from 50 
to 100 c.c. intravenously. If sufficient improvement in the con- 
dition of the patient does not follow the first dose, it should 
be repeated in from twelve to twenty-four hours. 
Antigonococcus Serum.-Roger and Torrey9 have prepared 
and introduced a serum of some potency in the treatment of 
gonococcal arthritis and synovitis. Although the serum pre- 
pared after their technic contains a moderately high content 
of recognizable antibodies-agglutinins, precipitins complement 
binding body, and bactericidal {in vitro) bodies, the results 
obtained in practice are by no means striking. 
The serum is prepared by the immunization of rams to dif- 
ferent strains of the gonococcus; it is, therefore, a polyvalent 
serum. Roger and Torrey recommend the employment of 2 
c.c. daily. 
Other Bactericidal Sera.-In addition to antistreptococcus, 
antipneumococcus, antigonococcus and antimeningococcus sera, 
and serum employed in the treatment of dysentery, numerous 
other sera have been introduced by a host of different observ- 
ers, with, however, but very little effect upon the course of 
clinical infections. 
Antityphoid serum has been used more or less extensively, 
and according to Chatemere, with favorable results. In gen- 
eral, however, this method of treatment has not met with any 
great favor. Sera have been used in the treatment of plague 
(Yer sin) and cholera. The results, however, have not been 
strikingly useful. 
Recently Symmers10 has published a resume of the recent 
work on anthrax, in which he recommends that under no cir- 
cumstances should the anthrax pustule be tampered with in 
any way. He recommends as the only permissible form of 
local treatment the injection at the periphery of the pustule of 
broken doses of antianthrax serum at intervals of four or six 
'Roger and Torrey: Jour. Am. Med. Assn., 1907, xlix, 918. 
10Symmers: Ann. of Surg., 1922, Ixxv, 663. 286 
INFECTION, IMMUNITY, AND INFLAMMATION 
hours, each injection not to exceed a total of 10 or 15 c.c. 
Intravenously the dose of 150 to 200 c.c. of antianthrax serum 
is injected, this is supplemented by the intravenous injection 
of 40 c.c. every four or eight hours. He states, "In anthrax 
septicemia the liberal use of antianthrax serum, if commenced 
in time, is capable in many cases of sterilizing the blood with 
astonishing rapidity." 
During the last few years the relatively high mortality, es- 
pecially among the poorer people, from measles has attracted 
attention to this disease. Owing to the highly contagious con- 
dition of children in the early days of prodromal symptoms, 
it is extremely difficult to prevent exposure, therefore pro- 
cedures have been undertaken in an effort to render children 
immune. One of these methods has consisted in purposeful in- 
jection of very young infants, since it is known that during 
the first few months of life infants usually exhibit a natural 
immunity, and it is hoped that by purposeful injection of the 
child during this period that a more lasting immunity may be 
produced. This method is still in the experimental stage. 
There are obvious objections to its employment. 
Another method described by McNeal11 in which children 
exposed to measles received intramuscular injections of 5 c.c. 
of serum obtained from healthy donors between the fifth and 
ninth days after disappearance of the fever accompanying an 
attack of measles. In this way sixteen exposed children were 
injected; twelve remained free from measles and four devel- 
oped a mild form of the disease. As one child contracted 
measles two months after successful injection this author re- 
marks that in some cases, at least, the immunity does not per- 
sist longer than sixty days. As McNeal points out, in institu- 
tions in which large numbers of frail children are intimately 
associated, the procedure may prove to be of great value. 
The recent valuable and interesting work which has been 
carried out by Doctor George F. Dicklla and his wife upon the 
infecting microorganism in scarlet fever, appears to show that 
"McNeal: Jour. Am. Med. Assn., 1922, Ixxxvii, 340. 
IlaDick, G. F-, and Dick. Gladys H.; Scarlet Fever Toxin in Preventive 
Immunization, Jour. Am. Med. Assn., February, 1924, xxcii, p. 544. APPLICATION OF IMMUNITY PRINCIPLES 
287 
the symptoms of scarlet fever are, in fact, due to intoxication 
by the toxins produced by a hemolytic streptococcus. They 
have further shown that when persons with positive skin tests 
for susceptibility to scarlet fever are injected with suitable 
quantities of the toxic filtrate, they may develop scarlatinal 
rash with nausea, vomiting, rise of temperature and general 
malaise. These symptoms appear within a few hours after the 
injection and disappear within forty-eight hours. Following 
this reaction, the skin test is negative, or only slightly positive. 
The short interval between the injection and the beginning of 
the reaction, compared with the incubation period of about 
forty-eight hours described in experimental scarlet fever, and 
the more rapid disappearance of the symptoms, indicate that 
the effect is produced by a soluble toxic substance rather than 
by a filterable virus. The resistance to heat at temperatures 
ordinarily employed to kill bacteria is further evidence that 
we are dealing with a toxin. 
The similarity of the symptoms produced by the filtrate to 
those of scarlet fever, and the resulting modification of the 
skin test, indicate the production of some degree of active im- 
munity to scarlet fever. 
The neutralization of the toxic substance in the filtrate by 
the blood serum of a person who had received injections of the 
filtrate indicates that the toxic substance is a true toxin, capa- 
ble of forming an antitoxin. 
Prophylactic and Therapeutic Employment of Bacterio- 
proteins (Vaccines) and Pollen Extracts 
It is possible by means of vaccine12 or protein extract injec- 
tions to induce one or other of the following alterations in the 
immunologic state of the individual. 
defines a bacterial vaccine as follows:-"Bacterial vaccines are 
sterilized and enumerated suspensions of bacteria which furnish, when they 
dissolve in the body, substances which stimulate the healthy tissues to the 
production of specific bacteriotropic substances (or antibodies) which fasten 
upon and directly or indirectly contribute to the destruction of the corre- 
sponding bacteria." The term vaccine is employed since Pasteur, in appre- 
ciation of the contribution to humanity made by Jenner by the latter's in- 
troduction of vaccinia virus in the prophylaxis of smallpox, applied the 
term vaccination to the prophylactic immunization of individuals against 
rabies. 288 
INFECTION, IMMUNITY, AND INFLAMMATION 
1. The tissues, if normal in their relationship to the protein 
employed, may be rendered hypersensitive so that they become 
subject to exhibition of the allergic phenomenon when the 
same antigen is later introduced into the tissues. 
The prophylactic employment of vaccinia virus, and of bac- 
terial extracts or suspensions, is made use of, chiefly, for this 
purpose. 
2. If the tissues be hypersensitive, tolerance may be induced 
so that they are no longer subject to injury as a result of con- 
tact with the foreign protein to which they may be exposed. 
The employment of pollen extracts, horse serum, and certain 
foodstuffs-in the treatment of individuals suffering from hay 
fever, asthma, eczema, and other diseases, the manifestations 
of which depend upon protein anaphylaxis-is used with a 
view to inducing tolerance to the antigen. 
3. Tolerance, if present, may be depressed in order that 
tissue hypersensitiveness may be exhibited, and inflammatory 
reactions induced at foci of bacterial accumulation. 
Vaccines are employed in the treatment of such diseases as 
furunculosis, localized tuberculosis, and other infections char- 
acterized by a chronic clinical course, as a rule, with a view 
to inducing such focal reactions. 
4. Desensitization may be accomplished if the tissues be hy- 
persensitive. 
Desensitization is employed chiefly in order that individuals 
who are hypersensitive to horse serum may be treated by means 
of serum therapy. In occasional cases, also, severe rapidly 
progressive inflammatory reactions may be temporarily con- 
trolled by exhaustion of the anaphylactic (first order) anti- 
bodies, and the focal reaction, thereby, inhibited. Similarly, 
also, in the treatment of hay fever (pollenosis), if the patient 
does not come under observation sufficiently early in the year 
to gradually induce tolerance, desensitization may, sometimes, 
be employed with benefit. 
It is thus seen that in the employment of vaccines or bacterio- 
proteins for therapeutic purposes, we are, to say the least, 
handling a two-edged sword. In order, therefore, that favor- APPLICATION OF IMMUNITY PRINCIPLES 
289 
able results may follow injections of antigenic substances, it 
is necessary that the physician know, relatively at least, the 
degree of sensitiveness of the individual to be treated and have 
a clear conception of the alterations in the tissue and serum 
reactions which he wishes to induce. 
Protection from infection, on the part of the individual, de- 
pends, almost entirely, upon hypersensitiveness to the bacterial 
protein. If the tissues of the individual have not been pre- 
viously exposed to the presence of the specific bacterial protein, 
the entrance parenterally into the tissues of viable pathogenic 
bacterial cell bodies, is followed by no exhibition of reaction 
on the part of the tissues. In consequence, the bacteria are 
permitted to proliferate unhindered by tissue reaction. The 
invasive power of the infecting bacterium, under such condi- 
tions will depend upon its adaptability for growth under the 
conditions which maintain in the tissues of the host, and upon 
its inherent rate of multiplication. 
If the microorganism finds in the tissue, into which it has 
gained entrance, conditions as regards temperature, moisture, 
oxygen supply, and foodstuffs, suitable, and its natural rate 
of reproduction be rapid, it will spread widely throughout 
the tissues of the body without reaction on the part of the 
tissues taking place. Thus, we find that the Bacillus typhosus 
entering the tissues of the intestinal tract, finds a suitable 
medium for its growth, and thence rapidly invades practically 
the whole body. This general invasion takes place even though 
the infected individual experiences little, or no, symptoms of 
intoxication, or tissue irritation; nor do the tissues make any 
effort to destroy the invader. It is only after the lapse of a 
certain number of days (six to fourteen) that substances are 
produced, which have the capacity for reacting with the bac- 
terial cell. When this occurs the patient immediately appears 
ill, and symptoms of tissue irritation are manifest. 
The course of the disease from this time on, is, in a sense, 
a battle between the serum bodies, assisted by cellular activity, 
and the bacteria. Unless the patient succumb to an extreme 
production of toxic substance, or unless an accidental factor, 290 
INFECTION, IMMUNITY, AND INFLAMMATION 
such as hemorrhage, or intestinal perforation destroy the in- 
dividual, the patient must recover. The disease, however, is 
long drawn out, and the patient is left much weakened and 
exhausted. 
The prolonged incubation period following the introduction 
of bacteria into the tissues, and the development of the reaction 
stage, can be avoided by the previous sensitization of the in- 
dividual to the typhoid protein. This form of prophylactic 
vaccination, has been the one most commonly employed, and 
hitherto, most successful. By means of parenteral injections 
of typhoid protein, the tissues of the individual are rendered 
hypersensitive to the protein. When, subsequently, bacteria 
invade the tissues of such an individual, they are immediately 
subjected to the action of the antibody, and either dissolution 
of the bacterial cell bodies is accomplished by the antibodies 
alone, or, through the production of an irritant substance, 
phagocytic cells are induced to take up and destroy the bacilli. 
In this way the small number of the bacteria which enter the 
tissues, are overcome with a minimum expenditure of energy 
on the part of the body, and without the exhibition of symp- 
toms of tissue irritation. 
Prophylactic Employment of Vaccines 
If the animal body be hypersensitive to the bacterioprotein, 
and if other exhausting factors, such as starvation, loss of 
sleep, intereurrent disease, overwork, or prolonged chilling, 
have not overcome the tissue capacity for reaction, or mechan- 
ical, thermal, or chemical injury of the tissues focally has not 
impaired their vitality, bacterial cell bodies, when introduced 
into the tissues, are immediately destroyed. If the dose of 
infecting microorganisms be not sufficiently large to exhaust 
the first order bodies, the individual bacterial cells are so 
acted upon by these antibodies that they are rendered irritant 
and phagocytosis is stimulated. 
The clinical immunologist's aim in the prophylactic employ- 
ment of vaccines is, in fact, the development of the hyper- APPLICATION OF IMMUNITY PRINCIPLES 
291 
sensitive state on the part of the tissues against the micro- 
organism employed in the injections.13 
It is of importance that it be recognized that it is against 
those bacteria to which the human tissues are but relatively 
infrequently exposed, that the employment for prophylactic 
purposes of bacterioprotein injections has been most successful. 
Rabies 
After Jenner's introduction of purposeful infection of the 
human tissues by the virus of cowpox14 in order that the in- 
dividual might be protected against smallpox, the first form of 
active immunization to be artificially employed was that in- 
stituted by Pasteur in the prophylaxis of rabies. This eminent 
observer discovered that it was possible by passage of rabies 
virus through rabbits to obtain a strain of uniform potency. 
This he called the fixed virus. He also discovered that by 
means of the injection of graduated doses of this virus, as 
contained in the spinal cords of infected rabbits, it was possible 
to protect animals and individuals against the onset of hydro- 
phobia. For this purpose, the cords were dried for a variable 
length of time over hydroxide and, for the purpose of treat- 
ment, an emulsion of the dried cords was made. 
By means of the passage of natural or "street" virus through 
rabbits in the production of fixed virus, there is noted a ten- 
dency to produce the paralytic rather than the violent form of 
the disease. There is also a reduction in infectivity and 
shortening of the incubation period. 
The table on page 292 is quoted from Stimson. 
This table indicates the amount of material in terms of spinal 
cord, plus virus, which is injected in the prophylactic treat- 
ment of the individual who is suspected, or known, to have 
been infected with rabies. 
"Although the author lays stress upon the importance of hypersensitive- 
ness in the prevention of infection, he is familiar with the fact that under 
exceptional circumstances complete destruction of bacteria may be accom- 
plished by serum bodies alone. 
14As the principles underlying vaccinia vaccination have been extensively 
discussed in the chapter on the allergic reaction, this most important of all 
forms of prophylactic Immunization is omitted in this chapter. 292 
INFECTION, IMMUNITY, AND INFLAMMATION 
The following objections to the employment of rabies virus 
are quoted from Stimson.15 ''The administration of rabies 
vaccine is not entirely devoid of danger to the recipient. In a 
very small proportion of those receiving it a paralytic con- 
dition develops which may fairly be attributed to the treatment 
per se or to a combination of this with a peculiar susceptibility 
of the patient. About one-fourth of these cases end fatally, a 
complete recovery usually occurring in the remainder. Ex- 
posure to cold or chilling, fatigue, and the use of alcohol ap- 
parently predispose to the development of this condition, but 
cases are seen in which none of these factors have been opera- 
DAY OF 
TREATMENT 
CORD 
DRIED 
DAYS 
AMOUNT 
OF 
CORD CM. 
DAY OF 
TREATMENT 
CORD 
DRIED 
DAYS 
AMOUNT 
OF 
CORD CM. 
6 
1 
Twelfth 
3 
0-5 
Second 
5 
1 
Thirteenth ... 
3 
0.5 
Third 
4 
1 
Fourteenth ... 
2 
0.5 
Fourth 
3 
0.5 
Fifteenth .... 
2 
0.5 
Fifth 
3 
0.5 
Sixteenth .... 
4 
0.5 
Sixth 
2 
0.5 
Seventeenth .. 
3 
0.5 
Seventh 
2 
0.5 
Eighteenth ... 
2 
0.5 
Eighth 
1 
0.5 
Nineteenth ... 
3 
0.5 
Ninth 
5 
0.5 
Twentieth .... 
2 
0.5 
Tenth 
4 
0.5 
Twenty-first .. 
1 
0.5 
Eleventh 
4 
0.5 
Treatment for Adult 
tive. Other objectionable results of the treatment amount only 
to minor discomforts and inconveniences." 
Antityphoid Vaccinations.-Since the time that Pasteur es- 
tablished a successful method of inducing active artificial im- 
munity in the treatment of rabies, the most outstanding proof 
of the value of prophylactic parenteral administration of dead 
or attenuated bacteria, in order to confer immunity upon the 
injected individual, has been that of the employment of vac- 
cination with typhoid and the paratyphoid bacilli during the 
war. All physicians are familiar with the fact that this form 
of injection-first employed by Wright and Leishman during 
the South African War,-has resulted in great diminution in 
the incidence of, and almost complete elimination of the 
"Stimson: Jour. Am. Med. Assn., Jan. 22, 1921, Ixxvi, No. 4. 293 
APPLICATION OF IMMUNITY PRINCIPLES 
death rate from, typhoid and paratyphoid fevers wherever 
adequate technic in the preparation, and administration, of the 
antigens has been used. 
A satisfactory technic is the employment, upon three suc- 
cessive occasions, of a mixed vaccine containing in each cubic 
centimeter, 1,000,000,000 typhoid bacilli, and 500,000,000 each 
of the paratyphoid bacilli-Alpha and Beta. The first dose 
consists of 0.5 c.c. of the mixed vaccine, and at intervals of 
one week, two further doses are administered, each of 1 c.c. 
It is perhaps impossible to state the length of time during 
which absolute immunity may be expected by such a course of 
treatment; it is surely useful for many years. 
An accidental experiment, reported by Grant10 is of con- 
siderable interest in this connection. A laboratory worker, 
who had never had typhoid fever, but who had been injected 
with the triple typhoid vaccine, received a massive dose of 
living typhoid bacilli. He sucked up a quantity of about 0.5 
c.c. of a culture suspension. Four days later he suffered from 
headache, followed by malaise, and on the eighth day, headache 
and weakness. On the twelfth day, after infection, Bacillus 
typhosus was present in his stools, but by the fifteenth day 
they had disappeared and were not again discovered. This 
case demonstrates that in certain cases, at least, typhoid vac- 
cination protects against even massive infection. At no time 
could microorganisms be cultivated from his blood. 
Physicians should have no hesitation in recommending to 
their patients that they should subject themselves to a course 
of prophylactic treatment with typhoid and paratyphoid vac- 
cine. 
Prophylactic Immunization Against Diphtheria 
A large proportion, probably the majority, of individuals 
are immune to diphtheria. Since the organization of the test 
devised by Schick, it has been possible to determine safely and 
with comparatively little inconvenience to the tested individ- 
ual, whether or not he or she is naturally immune. A number 
18Grant, B. C.: Jour. Am. Med. Assn., 1921, Ixxvi, 514. 294 
INFECTION, IMMUNITY, AND INFLAMMATION 
of observers, more particularly Park, have recommended that 
in public institutions and schools, those children who are found 
by Schick's test to be subject to intoxication by diphtheria 
toxin, should be treated with the purpose of provoking an 
active immunity. 
The Schick test is performed by injecting intradermically 
%o of one M.L.D. of a special toxin contained in 0.2 c.c. of 
salt solution. The injection is made into the skin on the flexor 
surface of the arm or forearm and a control injection is made 
of the same quantity of broth which has been heated to 75° C., 
and is consequently not toxic. If there is no antitoxin present 
in the tissues a positive reaction is obtained. The cells are 
injured and an inflammatory reaction which is characterized 
by redness and swelling appears in from 12 to 24 hours; and 
the reaction lasts for about 48 hours. Such a positive reaction 
indicates that the child is susceptible to diphtheria. 
As early as 1905 Park noted that guinea pigs and horses 
treated with neutral mixtures of toxin and antitoxin produced 
immune sera of moderate potency. From this observation has 
developed the method which has been employed in the active 
prophylactic immunization of human cases. Neutral mixtures 
of toxin and antitoxin are administered. The injection is given 
subcutaneously and is repeated three times at intervals of one 
week. Those who have employed the method on a large scale 
are unanimous in their verdict as to its usefulness in eliminat- 
ing diphtheria from public institutions where children are 
housed. 
Park17 reports experiments of the New York Department of 
Health in the use of Schick test and of toxin-antitoxin injec- 
tions in the prevention of diphtheria. The Department has 
under observation and indexed 180,000 children; of these 90,000 
have been Schick tested. Of these 90,000, about 60,000 orig- 
inally gave a negative test. After injection of toxin-antitoxin 
mixtures, 20,000 of those which had been previously positive 
to the Schick test were negative. The remaining 10,000 either 
remained positive or were not retested. 
17Park: New York State Jour. Med., 1923, xxiii, 1. APPLICATION OF IMMUNITY PRINCIPLES 
295 
In a three months' period there occurred fifty-four cases of 
diphtheria among 90,000 untreated school children, whereas in 
90,000, who had been tested and if positive treated, there were 
only twelve cases. It is thus seen that among untreated chil- 
dren diphtheria developed four and one-half times as fre- 
quently as in tested children. The highest incidences of the 
disease among the tested children was among 1,800 who, in 
spite of injections, developed an insufficient amount of anti- 
toxin to prevent a positive Schick reaction. This result, Park 
points out, emphasizes the necessity of a Schick test months 
after the completion of the injections, and reinjection of those 
who are still positive. 
Prophylactic Vaccination Against Other Diseases.-Although 
in the prevention of no other disease have such strikingly 
successful results been attained by means of the prophylactic 
employment of vaccines, as in the prevention of the enteric 
group of fevers, those who have had experience are well nigh 
unanimous in their opinion that properly employed prophylac- 
tic "immunization" against cholera, bacillary dysentery, and 
bacillus pestis infection, has been successful. 
Vaccines prepared with Bordet's bacillus of whooping cough 
have been employed for several years as a prophylactic agent. 
The results so far obtained are still open to a certain amount 
of doubt as to their efficacy. It would appear, however, that 
in those centers in which adequate dosage had been employed, 
the results not only prove the relationship of the bacillus to 
pertussis, but also that the disease can be prevented by the 
proper administration, parenterally, of the specific protein 
antigen. 
In influenza the doubt which still exists as to the relationship 
of the Pfeiffer bacillus to this disease has perhaps rendered 
attempts at prophylactic vaccination inadequate on the one 
hand, and lacking in proof on the other. The author has had 
no personal experience in the use of such vaccines. In view 
of the fact that the bacillus itself is so extremely minute, it 
is not improbable that the dose of bacillary protein, which has 296 
INFECTION, IMMUNITY, AND INFLAMMATION 
been commonly employed, had been too small to expect to 
induce a high degree of hypersensitiveness to the antigen. 
It is quite possible that in but a relatively few years, it will 
become the custom among communities which are more highly 
developed, from the public health point of view, for children 
to receive sensitizing doses of bacterial antigens of a large 
group of microorganisms. In this group will be the typhoid 
and paratyphoid bacillus, the meningococcus, the viruses of 
anterior poliomyelitis, measles, scarlet fever, and the other 
exanthemata, mumps, pertussis, and influenza. The suggestion 
has already been made that since newborn infants are rela- 
tively immune to measles, they should receive purposeful inocu- 
lation with measles virus, in order that a more permanent form 
of protection should be induced. 
The Therapeutic Employment of Vaccines 
Vaccines (bacterial proteins) are employed in the treatment 
of infective conditions for two purposes. Their ordinary use 
is in order that more adequate inflammatory reactions may be 
induced to take place, at foci of bacterial accumulation 
throughout the body. As previously pointed out bacteria are 
permitted to live and to multiply, without adequate vascular 
and cellular reaction, because the tissues are not hypersensitive, 
or because there is present in the tissues a sufflcient amount of 
the second order antibody to render the tissues tolerant to the 
irritant product of the antigen-first order antibody reaction. 
In such cases, as for instance, furunculosis and chronic gonor- 
rheal vesiculitis, reactions occur only after very large numbers 
of the bacteria have proliferated. The purpose of vaccine ad- 
ministration, in this type of case, is in order that focal reactions 
may be induced to take place before1 the bacteria have accumu- 
lated in such large numbers. 
If the tissues of the infected person be hypersensitive, and 
also tolerant, reactions at the foci of bacterial protein may be 
induced by exhausting the second order antibodies, by means 
of parenteral injections of suitable doses of the same protein 
antigen. APPLICATION OF IMMUNITY PRINCIPLES 
297 
In practice the suitable dose of bacterial protein is deter- 
mined by means of intradermic (subepidermal) injections of 
bacterial suspensions or extracts in salt solution, or other 
vehicle, and observation of the local reaction which ensues. If 
the dose introduced be too small to exhaust the available second 
order antibodies, no reaction other than that due to an essen- 
tial toxicity of the injected material takes place.18 For prac- 
tical purposes, it may be assumed that the reaction induced at 
the infective focus is similar in degree to that which occurs 
at the point of injection of the artificially prepared material. 
If the dose injected be too large an excessive local reaction is 
provoked. 
As a rule the author has found that, unless infective foci are 
situated in vital organs, or are multiple to an extent which 
might result in an overwhelming of the individual in conse- 
quence of the simultaneous discharge from all the foci of the 
irritating product, a reaction about the point of injection char- 
acterized by hyperemia and swelling, and measuring approxi- 
mately 4 to 7 cm. in diameter, indicates a suitable dose. 
The usual method of indicating the size of the dose of bac- 
terial protein employed is in terms of millions of cell bodies. 
If all bacteria were of the same size, and of the same relative 
solubility, and if all vaccines were prepared and stored under 
exactly the same conditions, such a method should be satis- 
factory. Such, however, is not the case. Bacterial cell bod- 
ies, even of the same strain, if grown on different media, vary 
much in size and in thickness of ectoplasm. A dose stated in 
millions, therefore, may actually vary over wide limits of 
volume or weight of bacterial cell substance. The degree of 
heat19 or concentration of chemical germicide which has been 
employed in devitalizing the suspension, also influences mark- 
18It must be borne in mind that if autolysis of bacterial suspensions has 
occurred, a primary toxicity may be exhibited by such a preparation, and 
that the local reaction following the injection of such material is not 
allergic in character, and does not give a true picture of the relative pro- 
portion to first and second order antibodies in the body fluids of the injected 
individual. It is essential in the employment of vaccines that such bacterial 
preparations should not be employed. Again certain bacteria produce a 
true toxin which occasionally obscures the information ordinarily derived 
from allergic reactions, e. g., Schick reaction. 
19More useful vaccines have been obtained by the author if germicides, 
e. g., carbolic acid, are employed to kill the bacterium than if heat is used. 298 
INFECTION, IMMUNITY, AND INFLAMMATION 
edly the solubility and, consequently, the antigenic value of 
the vaccine. 
When the suitable dose of vaccine has been determined by 
means of the intradermic reaction, subsequent administrations 
are injected subcutaneously. In general, vaccines should not 
be repeated more often than once in eight days. I have found 
that if ten days intervene between injections, the dose re- 
quired to induce a given reaction at the infected foci remains 
practically constant. From time to time, however, during the 
course of vaccine treatment, it is advisable to retest the indi- 
vidual by means of the intradermic reaction. 
Too great stress cannot be laid upon the necessity, on the 
part of the clinician who employs vaccines for therapeutic 
purposes, that he realize the alterations for the better which 
he hopes to induce on the part of the infected tissues. The 
working principle should be adopted that, so long as the clin- 
ical progress of an infective condition is satisfactory, no vac- 
cines should be employed. If, on the other hand, it is believed 
that by means of the stimulation of a more severe inflamma- 
tory reaction at the infected focus, the course of the disease 
can be shortened with safety to the patient, vaccines become 
of the utmost usefulness. Obviously, it is absurd to hope that 
vaccines can be of value in cases of chronic suppurative oste- 
itis consequent upon the presence of exfoliated bone fragments 
in the tissues. Nor is it possible to induce the absorption of 
the fibrous membrane covering the lung in cases of chronic 
infective open pneumothorax by means of injections of bac- 
terial proteins. Vaccines have a very definite usefulness in the 
armamentarium of the practicing surgeon, and to a less extent 
of the practicing physician, in the treatment of disease. This 
usefulness is, however, a limited one; nor can vaccine admin- 
istration be expected to perform miracles. 
Vaccine Treatment of Furunculosis 
Furuncules (localized abscesses) are developed by the tis- 
sues in order that focal accumulation of pyogenic cocci (al- 
most invariably staphylococcus aureus) may be destroyed. APPLICATION OF IMMUNITY PRINCIPLES 
299 
The tissues of the great majority of individuals in our mod- 
ern urban communities are periodically subjected to invasion 
by such microorganisms, and in consequence are hypersensi- 
tive to staphylococcal protein. When cocci are introduced 
into the tissues of such an hypersensitive individual a vascular 
and cellular reaction immediately takes place. Unless the 
dose of bacteria which gains an entrance into the tissues be 
excessive, all of the invading microorganisms are immediately 
ingested by the leucocytes and destroyed. In this way a 
minute inflammatory focus is produced, but infection of the 
tissues is prevented. 
An inadequate inflammatory reaction may be exhibited and 
the invading microorganisms consequently permitted to prolif- 
erate from one or other or a combination of the following 
causes. 
1. The tissues may be tolerant to the bacterial protein. As 
a result the tissues are not irritated and consequently prompt 
vascular and cellular reaction does not take place. 
2. The tissues may not be hypersensitive to the bacterial 
protein. In this event no reaction takes place until such time 
as the first order (anaphylactic) antibodies have been pro- 
duced. During this incubation period the infecting micro- 
organisms continue to proliferate. 
3. Alexin may be depressed in consequence of starvation, 
loss of sleep, or exhaustion from other causes. Since the re- 
action between first order antibody and antigen does not re- 
sult in the production of an irritant, except in the presence of 
alexin, depression of the latter body is accompanied by a loss 
of reactivity on the part of the tissues. 
4. The bacteria themselves may be protected from the body 
fluids as a result of their growth upon, rather than within, 
the tissues, e.g., within the lumen of the sebaceous or other 
glands. 
The fact that bacteria may grow upon, rather than within, 
the tissues, and consequently the individual remain a carrier 
for indefinite periods, has been referred to elsewhere. In 
furunculosis and carbuncle formation, massive infection of 300 
INFECTION, IMMUNITY, AND INFLAMMATION 
the tissues occurs in consequence of proliferation of cocci 
within the glandular structures of the skin whence large num- 
bers periodically invade the surrounding tissues. 
The importance of constitutional exhaustion has been re- 
ferred to elsewhere. This phenomenon is commonly exempli- 
fied among university football squads during the commence- 
ment of the season, if early practice is not properly controlled. 
Lack of sufficient hypersensitiveness to staphylococci protein 
to induce adequate morphologic reaction is uncommon amongst 
city dwellers, but the susceptibility of individuals coming from 
agricultural districts is shown by the relatively high incidence 
of staphylococcal infections among medical students and pro- 
bation nurses when they are first brought in contact with 
infective pus during their hospital training. 
The most common cause of furunculosis encountered in city 
practice is dependent upon tolerance of the individual to 
staphylococcal protein. 
In the treatment of recurrent furuncules, suspensions of the 
staphylococcus aureus are employed. I have never found that 
autogenous vaccines are of any special advantage as compared 
with good stock vaccines. Size of the dose to be employed is 
determined by means of the reaction which occurs when the 
vaccine is introduced subepidermically. Unless the vaccine 
which is being employed has an essential toxicity, due to 
autolytic products, the reaction which occurs at the site of the 
injection may be assumed to be comparable to that which 
occurs at the site of bacterial accumulations throughout the 
body. 
As a rule a dose of from five hundred million to one thou- 
sand million cocci is employed. The injection is repeated once 
every seven to ten days, depending upon the clinical symp- 
toms of the case, and upon the reaction which was obtained 
at the last dose. 
The Treatment of Gonorrheal Infection by Means of Vaccines 
It is difficult to believe that, during the acute stage of gon- 
orrheal urethritis or vaginitis, much good can be accomplished 
by means of vaccine administration. Theoretically, at least, APPLICATION OF IMMUNITY PRINCIPLES 
301 
prophylactic vaccination against the gonococcus should be of 
value, although I know of no experimental data which sup- 
ports this opinion. 
Chronic gonorrheal infections persist in consequence of the 
growth of gonococcal colonies upon the surface of, rather than 
within, the tissues. From the foci within the urethral, pros- 
tatic, or vesicular glands the cocci from time to time invade 
the tissues themselves. Since the individual who has suffered 
from a gonococcal infection for any considerable length of 
time, is tolerant, as well as hypersensitive, to the gonococcal 
protein, comparatively little effort is made on the part of the 
tissues to eradicate the foci. In consequence there is a tend- 
ency for the microorganism to prolong its existence indef- 
initely in such situations. 
Metastatic gonococcal infections are hematogenous and are 
determined, in all probability, chiefly by the fact that minute 
infarcts are produced through plugging of terminal vessels 
by clumps of cocci. It is of importance in this connection to 
bear in mind that it is only in tissues which are nourished by 
terminal vessels such as the synovial and serous membranes, 
and upon the heart valves and conjunctivae, that metastatic 
infections ordinarily occur. Although it is apparent that the 
soft tissues of the patient suffering from chronic gonorrhea 
are easily able to destroy the causative microorganisms the lat- 
ter are able to maintain their viability in the infarcted area. 
From such foci they invade, from time to time, the surround- 
ing tissue in which acute inflammatory reactions are immedi- 
ately set up. 
The vaccine treatment of chronic gonorrheal infections is 
of value since, by this means, tolerance of the tissues may be 
exhausted and a maximum focal inflammatory reaction in- 
duced even though but few bacteria are present. Vaccine 
therapy cannot take the place of proper mechanical and top- 
ical treatment. In the presence of a stricture it is unreason- 
able to expect that focal collections of cocci can be completely 
eradicated, and if their eradication be not complete, relapse of 
the condition is sure to occur. 302 
INFECTION, IMMUNITY, AND INFLAMMATION 
The most usual short-coming in vaccine treatment of gon- 
ococcal infection is that too small doses of the microorganism 
are employed to adequately exhaust the tolerant antibodies 
and so induce sufficiently severe focal inflammatory reactions. 
The maximum dose commensurate with safety should be em- 
ployed, although it must be pointed out that, before severe 
reactions are induced by means of gonococcal protein injec- 
tions, the case must be carefully studied in order that the 
involvement of tissues in which interstitial edema is not well 
borne may be excluded. 
Tuberculin Therapy 
Following the introduction by Koch in 1892 of the prepara- 
tions of tubercle bacillus extracts known as T.O. and T.R.,20- 
the medical world was sanguine that a means had been placed 
at its disposal whereby tuberculosis could be cured, not only 
with certainty, but with comparative rapidity. Unfortunately, 
it was soon discovered that such was not the case. The early 
employment of the preparation recommended, as it was, by 
Koch, and with its mode of action appreciated even less than 
at the present time, resulted in its too promiscuous use and 
the employment of too large doses. The unsatisfactory and 
even injurious effects of its use resulted in tuberculoprotein 
preparations falling into disfavor. At the present time it is 
only by such clinicians as have conscientiously studied the 
results obtained and have been careful to employ bacterial 
derivatives in selected cases only, that tuberculin therapy is 
employed to any considerable extent. 
There exist two methods whereby tuberculin may be admin- 
istered, and although the effect of tuberculinization by these 
methods appears to be paradoxical, there are underlying prin- 
ciples which explain the apparent contradictions. To quote 
Baldwin:21 ''The use of tuberculin may produce two oppo- 
site effects * * * according to the method of administra- 
tion. When used in small doses, and not increased, tuberculin 
"T. O.-Tuberculin Oberstand: T. R.-Tuberculin Residuum. 
"Baldwin: Yale Med. Jour., 1909, xv, 257. APPLICATION OF IMMUNITY PRINCIPLES 
303 
maintains the sensitiveness * * * it appears to be a ra- 
tional method for localized forms of tuberculosis. On the 
other hand, a gradual increase in the dosage leads, in favor- 
able conditions of nutrition, to a complete loss of sensitive- 
ness and coincident improvement in health. In pulmonary 
tuberculosis, at least, I feel inclined to select tuberculin im- 
munization as the goal for treatment." 
Clinical Employment of Tuberculin Therapy.22-In order 
that our employment of any drug or bacterial preparation 
may be of value, it is necessary that we have at our command 
data relative to its effects upon animals in so far as this con- 
cerns both its usefulness and its injurious potentialities. Nor 
must this data consist merely in a superficial recognition of 
clinical effects, although it must be granted that without sat- 
isfactory end results no amount of theoretical hypothesis deal- 
ing with its probable effects will be of much avail. In order 
that favorable end results may be obtained and undesired 
sequelae avoided, the usefulness of the procedure augmented, 
and its deleterious effects minimized, it is essential that the 
minute changes in the physiology and morphology of the 
tissues under its stimulus be recognized. 
At first sight it would appear that tuberculin injections 
stimulate the tuberculous host to the production of antibodies 
that inactivate the poisons arising from the tuberculous lesion, 
attack and destroy the bacilli themselves, or accomplish both 
these functions. The tubercle bacillus does not, however, pro- 
duce an important essential toxin, nor does the serum of those 
who have recovered from attacks of tuberculosis contain more 
than a minimal quantity of bactericidal substance. 
The natural defense of the body against the tubercle bacil- 
lus and the means whereby arrest and cure of disease processes 
produced by it are brought about, consist in the exhibition of 
two activities: (1) the microorganisms arc destroyed by cel- 
lular phagocytosis, which in turn is dependent upon the pres- 
22There has recently appeared a little book written by Riviere and Mor- 
land (Tuberculin Treatment, Oxford Press) in which there occurs a very 
clear exposition of the aims of tuberculin therapy and a detailed descrip- 
tion of methods for its therapeutic employment. This monograph the au- 
thor heartily recommends to all those interested in this subject. 304 
INFECTION, IMMUNITY, AND INFLAMMATION 
ence in the body fluids of specific immune bodies (first order 
antibodies); (2) the focus containing the bacilli is walled off 
and isolated by means of the development of a dense connec- 
tive tissue capsule. 
Microscopic examination of tuberculous lesions of any con- 
siderable age, especially if the tissues have exhibited an abil- 
ity to bring about reparative changes, reveals the fact that 
few blood vessels exist within the tubercle itself and that the 
surrounding connective tissue zone in immediate juxtaposition 
is practically lacking in blood vessels. Active cells either 
within or about the focus are, moreover, extremely scant in 
number. It is evident that what really has occurred in such 
a lesion is a more or less complete isolation of the bacilli from 
the surrounding tissues, so that, on the one hand the tissues 
are not exposed to the injurious action of the bacilli, and 
that, upon the other hand the bacteria are protected to a very 
considerable degree from the defensive properties of the body. 
Such a lesion is aptly termed an arrested one and is important 
since, although temporarily at least, the individual is free from 
the effects of the bacilli in the tissues, there is an ever pres- 
ent danger that they may commence to spread beyond their 
confining capsule and thus to set up more active disease. 
In localized lesions, therefore, the stimulation of the tissues 
to increased activity, as evidenced by increased blood supply, 
and hence increased focal content of serum bodies and blood 
cells inimical to the tubercle bacilli and better nutriment for 
the metabolic activities of the cells in situ, cannot fail to in- 
crease the possibility of the total eradication of the bacilli, or 
a more adequate surrounding connective tissue zone produc- 
tion. 
Tuberculin is useful in localized lesions, especially in the 
lymphatic glands, bones and joints, particularly after the 
activity of the process has been arrested by constitutional 
measure. So long as an adequate reaction in any tuberculous 
focus is taking place, it is difficult to believe that the admin- 
istration of tuberculin can be useful. In those lesions which 
have become arrested, the normal processes of complete cure APPLICATION OF IMMUNITY PRINCIPLES 
305 
are so extremely slow that the stimulus afforded by means of 
properly employed tuberculin is of value. 
It is readily appreciated that two unfavorable sequelae may 
follow tuberculin injections if the preparation be used in too 
large doses or in unfavorable cases. In the first place, focal 
reactions in certain organs such as the brain and kidney, may 
prove fatal if a sufficient hyperemia be induced to interfere 
with the functioning of the organ as a whole, and also,- 
the increased toxicity conferred upon the tuberculous focus 
may result not simply in a useful vascular and cellular reac- 
tion but there may occur a necrosis of tissue in which the 
bacteria may multiply unimpeded and spread by means of 
the lymph and blood vessels, as well as by continuity, to more 
or less distant parts. 
Localized necrosis or abscess formation following the em- 
ployment of tuberculin is not necessarily an unfavorable de- 
velopment if it occurs in superficial tissues such as the skin 
or subcutaneous lymph nodes. 
Two other types of tuberculosis may also be aided by the 
use of tuberculin. In certain cases the bacilli, as a result 
usually of an exalted second order antibody content of the 
blood, appear to be allowed to spread throughout the tissues 
with but little attempt on the part of the latter to limit the 
bacterial growth. In these instances, the body may be stimu- 
lated, as it were, to recognize the importance of the invader, 
and to adopt more adequate means for their limitation. It is 
noteworthy, however, that whereas in these cases a sufficiently 
large dose of tuberculin may do very considerable good, its 
repetition may produce harm. 
In many cases presenting signs of toxemic fever, malaise, 
anorexia, loss of weight, etc., and in whom the advance of the 
disease process is evident-"autotoxic" (Riviere and More- 
land), it is frequently possible by means of the exhibition of 
gradually increasing doses, repeated at short intervals, to 
partially exhaust the available supply of first order antibody 
and thus to induce a state of refractoriness or desensitization 
under such circumstances. 306 
INFECTION, IMMUNITY, AND INFLAMMATION 
Two favorable sequelae result from such a procedure: (1) 
The body as a whole is freed from the constant depressing 
influence of the tuberculotoxic substance and is enabled, tem- 
porarily at least, to return to a more normal state of func- 
tion,-the appetite improves, febrile disturbances are amelio- 
rated, and an increase in weight is noted. (2) The tissues in 
the immediate vicinity of the bacilli are given an opportunity 
to readjust themselves so that they may be better able to 
withstand the encroachments of the microorganisms. 
The employment of tuberculin for the purpose of inducing 
desensitization to tuberculoprotein in the manner just de- 
scribed, is much less frequently applicable in surgical practice 
than is the use of constant doses at long intervals, i.e., the 
stimulating method. The repeated injection of small gradu- 
ally increasing doses of tuberculin at relatively short intervals 
(3-5 days) is followed by the development of the tolerant 
state. Pulmonary lesions are influenced more favorably by 
the induction of tolerance than by the stimulation of reactions. 
The use of this method has received its greatest stimulus on 
this Continent from the work of the late Dr. Trudeau and his 
associates at Saranac Lake. The decimal method of dosage, 
devised by this pioneer investigator, is usually employed. 
In the author's opinion, cases which appear to be progress- 
ing favorably under symptomatic and constitutional treat- 
ment, should not be given tuberculin until such time as their 
lesions become inactive. Once this stage has been reached 
the stimulation of mild reactions at moderately long intervals 
will well repay the time expended thereon. Cases which are 
apparently not improving or arresting under careful treat- 
ment by other means should be given minute, but increasing, 
doses at short intervals until such time as the course of the 
disease is altered for the better. The employment of the bac- 
terial preparation in these cases is similar to its use by dis- 
honest cattle dealers in order to pass animals off as healthy 
while in the refractory state. 
In all instances in which the physician is not able to state APPLICATION OF IMMUNITY PRINCIPLES 
307 
clearly to himself the favorable effect which he hopes to pro- 
cure from the employment of tuberculin, it should not be used. 
Dosage and Interval T.R. and B.E. 
Of the various preparations of tuberculin, the insoluble 
preparations have been used most by the author: the doses 
mentioned will, therefore, be in terms of T.R., so prepared 
that 1 c.c. represents 1 mg., dry weight of the derivatives of 
ground tubercle bacilli. With regard to the usefulness of 
other preparations, the author makes no adverse criticism, 
indeed it has been shown by Baldwin and Krause that prac- 
tically all preparations of tubercle bacilli contain sufficient 
bacterial protein to induce the anaphylactic state, which, ac- 
cording to the hypothesis expressed in this chapter, is the 
fundamental principle underlying the therapeutic employment 
of tuberculin. 
In the treatment of tuberculous processes which are ac- 
companied by evidence of tuberculoprotein intoxication and 
in which it is hoped to arrest the process by inducing a stage 
of tolerance, doses of 0.0001 or 0.0002 should be given every 
two or three days, gradually increasing to 0.001 or higher, but 
immediately stopped should the symptoms (temperature, pulse 
rate, etc.) be aggravated by any dose except the first. It 
must be stated, however, in this connection that before insti- 
tuting tuberculin therapy in these cases the patient must 
have been, and must continue to be kept, under a very strict 
regime of absolute "typhoid" rest, in so far as this concerns 
both physical and mental exertion. 
In individuals suffering from localized lesions in which re- 
pair has so far advanced that the process has become relatively 
inactive, the dose of tuberculin injected must be sufficiently 
large to stimulate a focal inflammatory reaction. Care must 
be taken, however, that this be not excessive; a palpable or 
visible or symptomatic evidence of such reaction, unless the 
lesion be situated upon the surface of the body, such as the 
skin, iris, etc., is usually excessive. For this reason it is well 308 
INFECTION, IMMUNITY, AND INFLAMMATION 
to adopt a method whereby the focal reaction is indicated 
by an area of inflammation at the site of injection. 
White and Norman have suggested a method which is use- 
ful for this purpose. By means of the cutaneous reaction of 
von Pirquet, employing a known quantity of T.O., it is pos- 
sible to obtain what has been called by these authors the 
optimum dose for therapeutic purposes. The dose which they 
have found to be productive, if given subcutaneously, of the 
most useful focal reaction without constitutional symptoms, is 
that which will give a reaction area of 4 mm. in diameter in 
from 24 to 48 hours if applied by means of the von Pirquet 
stylet. Thus if 1/100 e.c. of a one per cent solution gives 
such a mild reaction, 1/100,000 gm., or 0.1 mg. is considered 
the optimum dose. These authors have found that such a 
method of estimating the dose is reliable and that, further- 
more, if the dose be repeated at intervals of two weeks the 
sensitiveness of the patient to tuberculin changes but little. 
Cushman23 has recently reported favorably upon the use of 
this method in 30 cases. 
The difficulty of measuring such small quantities of fluid 
as 1/100 c.c. and the care necessary in making the scarifica- 
tion, make such a method as that of White and his coworkers 
somewhat difficult of application. It is, however, a compara- 
tively simple matter to introduce a measured dose of tubercu- 
lin into the superficial layers of the skin by means of a hypo- 
dermic needle. I have found that the amount of T.R. which 
is sufficient to produce a local reaction of 2 cm., when thus 
introduced, is both safe and therapeutically active. As a 
general rule a dose of T.R. equal to from 1/10,000 to 1/1000 
of a milligram of dried tubercle products will be found to be 
adequate. If no reaction or an insufficient reaction be ob- 
tained by the first intradermic inoculation, the injection is 
repeated within two to six days when a larger dose is em- 
ployed. If the original reaction is excessive,-over 2 cm. in 
diameters,-either a second test reaction may be performed 
after the lapse of two weeks or more, or the dose for subse- 
23Cushman: Am. Jour. Med. Sc., 1913, xlvi, 213. APPLICATION OF IMMUNITY PRINCIPLES 
309 
quent inoculations may be calculated on the basis of the 
degree of reaction obtained. 
The Treatment of Hay Fever by Means of Pollen Extracts 
Two methods may be employed in order to relieve the hay 
fever sufferer from symptoms of intoxication. The method 
more commonly employed, and the one which in general prac- 
tice may be counted upon to give the most satisfactory re- 
sults, is that of immunization (induction of tolerance) of the 
individual to the irritant product which results from the 
reaction of the pollen antigen with the first order antibodies. 
In order that tolerance may be induced, it is advisable to 
commence treatment several months before the season at which 
pollenation of the plants responsible for the disease, occurs. 
By means of serial dilutions, the allergic reaction of the tis- 
sues is determined, and the first dose of protein extract in- 
jected is made to correspond to that at which a scarcely 
noticeable reaction occurs. 
The greater amount of work upon this subject has been 
carried out by Chandler Walker in Boston. His method of 
preparing the material to be employed for the injections con- 
sists in extraction of pollen proteins in a 10 per cent alcoholic 
normal sodium chloride solution. After extraction for forty- 
eight hours the material is filtered, and the insoluble pollen 
constituents removed. The material recovered is considered 
as being composed of a dilution of pollen in the original 
concentration before filtering. In other words if 0.5 grams of 
pollen have been extracted in 500 cubic centimeters of the 
alcoholic saline solution and filtered the resulting extract is 
said to consist of a 1 to 1000 dilution. The various dilutions 
are made up varying from 1 to 20,000 to 1 to 100. If, when 
tested, a marked reaction occurs at the point where a dilu- 
tion of 1 to 1000 is brought in contact with the scarified area, 
a moderate reaction at the point of dilution 1 to 5000, and no 
reaction at the point of dilution 1 to 10,000; the first dose 
employed consists of 2 or 3 minims of a dilution of 1 to 7,500. 
At weekly intervals the dose is gradually increased. In 310 
INFECTION, IMMUNITY, AND INFLAMMATION 
Chandler Walker's opinion it is better to avoid reactions if 
possible. Over a period of three or four months gradually 
increasing doses are administered. The last doses of the series 
consist of 0.5 to 1.0 c.c. of the 1-100 dilution. 
If the patient does not present himself sufficiently early in 
the year to undergo the prolonged course of fifteen injections, 
much may be done by more rapidly increasing the dosage and 
permitting a shorter interval (5-6 days) between injections. 
Immunization of the hay fever sufferer to a specific pollen 
antigen is accomplished in this manner with great regularity, 
although it must be pointed out that, as a rule, the tolerance 
so induced does not persist from one year to the next. It is, 
therefore, necessary that treatment should be carried out each 
year prior to the period of onset of pollenation of the plant 
implicated. It is also of the utmost importance to realize that 
should a mistake in diagnosis be made, and treatment be in- 
stituted with a pollen extract to which the individual is not 
hypersensitive, no good can come to the injected individual, 
but on the contrary, with almost absolute certainty, will he 
be rendered susceptible to hay fever for many years during 
the season of pollenation of the individual plant which was 
used. It is, therefore, extremely important that not only 
should the history of the case be carefully enquired into, but 
also that the fact that the patient is actually hypersensitive 
to the pollen injected, be determined. 
Although it is possible for persons who are brought in inti- 
mate contact with the pollen of various plants to be rendered 
hypersensitive to such pollen proteins, practically only three 
types of pollen produce troublesome hay fever. During the 
latter part of May and the early part of June, there are a few 
cases of hay fever due to June grass. Hypersensitiveness to 
this pollen is ordinarily unimportant and does not justify 
treatment. During the latter part of June and part of July, 
there are a moderate number of sufferers from hypersensitive- 
ness to timothy, and closely related grasses. If such cases 
cannot avoid contact with the pollen, they should be treated. 
The most important and disabling hay fever affections are APPLICATION OF IMMUNITY PRINCIPLES 
311 
noted in the latter half of August, throughout September, and 
in the early part of October. Such cases are almost invariably 
due to hypersensitiveness to the protein of ragweed pollen. 
Since through the greater part of the continent of America 
this weed grows prolifically, and since the physical charac- 
teristics of the pollen are such that it may be air borne over 
very wide areas, it is difficult for such sufferers to protect 
themselves from the disease. Sufferers from hypersensitive- 
ness to ragweed pollen may, almost invariably, be profitably 
treated for their affliction. 
Although more favorable results are to be expected by 
means of a prolonged course of parenteral injections of pol- 
len extracts in order that tolerance may be established, it is 
possible to so desensitize that, even during the period of pol- 
lenation of the plants responsible for the disease, the sufferer 
may be rendered free from symptoms. It is to be expected, 
moreover, that if a sufficient amount of protein antigen is 
injected to induce desensitization, in the course of time, al- 
though the patient must in the interval pass through a period 
in which hypersensitiveness is exhibited, tolerance is ulti- 
mately induced. 
In order that desensitization may be accomplished, it is 
necessary that treatment with small doses of the pollen ex- 
tract at short intervals, i.e., two or four, or more times daily, 
be employed. The dose injected is rapidly increased. Theo- 
retically, the method is not without danger, and it is of the 
utmost importance that none of the solution be allowed to enter 
a vein. The author has been afflicted for many years with 
sensitization to ragweed pollen; in consequence my interest 
in this subject has been a very personal one. I have employed 
a technic which has proved useful in inducing desensitization 
and tolerance after the onset of the symptoms of hay fever 
have occurred. The method which I have found to be of value 
in the treatment of myself, and of a limited number of patients, 
has consisted in the employment of small doses of concentrated 
(1/100) solution of ragweed pollen. All injections have been 
made into the subepidermal tissues. Approximately 1 minim 312 
INFECTION, IMMUNITY, AND INFLAMMATION 
of the undiluted solution, or an amount corresponding to 1 
minim, has been injected at each dose. This is uniformly 
followed, within a few minutes, by a moderately severe focal 
reaction attaining a size of about 2.5 centimeters in diameter. 
The reaction is accompanied by slight itchiness and soreness, 
but not by any important feeling of malaise. Three to five 
doses are given at intervals of about twenty minutes on three 
successive days. In my opinion, adequate desensitization can 
usually be obtained in this way, if 1.0 c.c. of the concentrated 
solution be injected within three or four days. 
The clinical course of the cases treated in this way has been 
characterized by relief from severe symptoms of hay fever, 
after the second day. At the end of a week, symptoms are 
again manifest for two or three days, when, apparently, tol- 
erance is induced and the remainder of the season is passed 
through without severe symptoms. 
Nonspecific Protein Therapy24 
During the last six or seven years a method of treating cer- 
tain infective conditions, more particularly the arthritides, by 
the injection of nonspecific proteins has been employed. As 
pointed out by Petersen,25 this method seems of interest, not 
primarily because of the clinical results attained, but rather 
because it promises to exert a far-reaching influence on med- 
ical thought and theory concerning the factors that are active 
in recovery from disease. Throughout the course of this vol- 
ume the author has, on several occasions, referred to this form 
of protein injection. The views expressed by a limited num- 
ber of authors regarding its usefulness and manner of action 
are presented in this section. 
The agents which have been employed include, in addition 
to certain chemicals and drugs, a large number of organic 
materials. Bacterial vaccines, such as typhoid colon and 
staphylococcus, have been employed for their nonspecific 
"For a complete discussion of this subject the reader is referred to a 
monograph by Petersen, "Protein Therapy and Nonspecific Resistance, Mac- 
millan and Co., 1922. 
"Petersen: Jour. Am. Med. Assn., 1921, Ixxvi, 312. APPLICATION OF IMMUNITY PRINCIPLES 
313 
effect. Proteoses, as well as raw and boiled milk, and extracts 
from the tissues, all have their adherents. 
Following the introduction of such agents, the tissues may 
react by the exhibition of a severe rigor, accompanied by a 
febrile reaction of 104 to 106 degrees. This is followed by a 
rapid fall in temperature, accompanied by sweating. Leuco- 
cytosis is provoked. At the infected foci throughout the body 
there is an intensification of the inflammatory reaction which 
later is followed by diminution which may result in the reac- 
tion being less marked than before injection. 
The method has not yet become generally used, nor does it 
seem proper that, until more is known regarding its usefulness, 
its general employment should be adopted. At the present 
time, the best that can be said for the method is that, in occa- 
sional cases of chronic arthritis, spectacular improvement has 
been obtained. Again, in a number of acute inflammatory 
processes such as pneumonia and typhoid fever, the disease 
seems to have been aborted. 
Miller26 answers the question as to whether foreign protein 
therapy is attended with danger in the following way: ''When 
just a sufficient amount of the protein is injected to excite a 
chill, it is practically free from danger." At his hospital- 
The Cook County Hospital, Chicago-at least 2,000 intravenous 
injections of typhoid vaccine, in treatment of various acute 
infections, have been carried out without serious consequences. 
The treatment has not been administered to enfeebled indi- 
viduals or to those with disturbed heart action. At present 
it can be said only that there is some suggestion but no con- 
vincing evidence, that certain forms of sepsis may be benefited 
by this treatment. 
In previous sections the author has referred to the useful 
effect of irritative protein injections in stimulating myelogen- 
ous activity with resultant peripheral leucocytosis. It has 
also been indicated that tolerance, which is a state much less 
specific in nature than is hypersensitiveness, may be exhausted 
by means of certain forms of proteid injection and hypersen- 
Jour. Am. Med. Assn., January, 1921, Ixxvi, 308. 314 
INFECTION, IMMUNITY, AND INFLAMMATION 
sitiveness thus made manifest. These two results may well 
be sufficient to justify the employment of the method, but 
inasmuch as similar results can usually be obtained by more 
specific injections, it would seem more proper that the latter 
technic be used. 
In a review of the subject published in 1921, Petersen27 
quotes observations made by a number of authors upon the 
subject of increased permeability of the capillaries after non- 
specific injections. Studies by von der Velden, Luithlen and 
Starkinstein, have justified a conclusion that such injections 
are followed by marked changes in the permeability of the 
cell membranes. They believe that it is this fundamental 
change that is probably at the basis of the therapeutic effect 
observed in nonspecific therapy. 
"At first the cell membrane seems more permeable. This 
corresponds with the fact that there is an increase in the 
lymph flow, the irritability of the nerve cell is increased, and 
that there is a freer exchange between blood plasma and cell 
content-that is, sensitized cells give up their antibodies, en- 
zymes are mobilized, thrombokinase and fibrinogen increased, 
and the sugar level altered. This period of increased cellular 
permeability corresponds with the clinical period of increased 
general malaise and increase of the inflammatory reaction at 
local foci. This phase is followed by one of diminished per- 
meability. It is in this stage that we find the cellular resist- 
ance to intoxication increased, the threshold for nerve stimuli 
raised and evidences of intoxication and inflammation sub- 
siding while the patient experiences euphoria." (Petersen.) 
Jour. Am. Med. Assn., 1921, Ixxvi, 312. CHAPTER XXVI 
THERAPEUTIC GUIDANCE OF THE ACUTE 
INFLAMMATORY REACTION 
The acute inflammatory process is one of the chief, if not the 
most important, of the means at the disposal of the body for 
protecting itself against invasion by infective microorganisms, 
and for the elimination of infection. It is, at the same time, 
a matter of common clinical experience, that not infrequently 
the inflammatory reaction, per se, results in serious injury to 
the tissues and to the individual. 
The surgeon is frequently called upon to interfere in order 
to guide the tissue reaction. It is of the utmost importance 
that he understand the manner in which the inflammatory 
reaction may be by itself productive of harm. The essential 
phenomena of inflammation are dilatation of vessels, exuda- 
tion into the interstitial tissues of fluid and cellular accumula- 
tion. It is chiefly through an exaggeration of the second 
stage, namely, exudation of fluid, that harm may be accom- 
plished. As the result of too great an amount of fluid in the 
interstitial tissues, the tension in such tissues may be so raised 
that drainage, by means of the blood and lymph vessels, from 
the part may be seriously interfered with, or even altogether 
arrested. 
Under certain circumstances, it is possible for not only the 
efferent blood supply to be so obstructed, but even for the 
arterial circulation to be seriously slowed or arrested. 
The primary object of vessel dilatation, and the budding 
of new vessels, is that an increased amount of oxygen, nutri- 
tion, and antibody and cellular content of the blood may be 
brought to the part. In addition the fluid content of the 
blood serves as a diluent for toxic products. In order that 
these purposes be accomplished, it is necessary that not only 
315 316 
INFECTION, IMMUNITY, AND INFLAMMATION 
an increased amount of blood be present, but that adequate 
circulation through the part occur. It frequently happens 
that as a result of increased extravascular pressure circula- 
tion is inhibited. When, through pressure in the walls of the 
venules or arterioles, adequate circulation has been interfered 
with, relative or absolute ischemia takes place. If the obstruc- 
tion to blood circulation be complete, necrosis or gangrene of 
the tissues naturally ensues. Such an untoward effect is par- 
ticularly likely to occur in narrow masses of tissue in which 
anastomosis of vessels is limited. This phenomenon is com- 
mon as a concomitant of the acute inflammatory process af- 
fecting such tissues as the appendix vermiformis and the distal 
phalanx of the finger. When interstitial tension has become, 
or threatens to become, excessive, surgical interference, op- 
erative or otherwise, is indicated. Such interference should 
be carried out with the purpose of diminishing the extravas- 
cular pressure. 
Clinical Inhibition of Inflammatory Reaction.-For purposes 
of preventing, or correcting, increased extravascular or inter- 
stitial tension, the surgeon has at his disposal one or more of 
several procedures. 
(a) Rest of the inflamed part, by lessening the normal 
demand of the tissues for blood supply, may sufficiently dimin- 
ish the peripheral pressure in the vessels that exudation may 
be minimized. Rest of the body conserves all the reactive 
properties of the body and is consequently an essential in the 
treatment of infective processes. 
(b) Posture assists, by gravity, drainage of the interstitial 
spaces; the same effect can occasionally be obtained by means 
of compression, either by the use of an elastic stocking, or 
elastic bandage, in cases of varicose ulcer of the leg, or by 
means of the employment of adhesive strapping in the treat- 
ment of the same condition. 
(c) Intermittent chilling of the part surrounding the in- 
flammatory focus. By this means, in consequence of the 
induction of vascular spasm, the blood supply of the part is 
temporarily interfered with. During the period of dimin- ACUTE INFLAMMATORY REACTION 
317 
ished pressure in the afferent vessels, an opportunity is af- 
forded for a reestablishment of more normal conditions. If 
the rate of drainage from the tissues remain as before, lim- 
itation of exudate into the interstitial tissue results in diminu- 
tion in tension. 
(d) The application of heat. By this means the vessels sur- 
rounding the inflammatory focus are dilated; insofar as this 
applies to the venules and lymphatic vessels its function is 
entirely useful. On the other hand, as clinical experience fre- 
quently exemplifies, increase in extravascular tension may be 
exhibited and necrosis of tissue hastened. 
(e) The employment of hygroscopic agents, as for instance, 
concentrated salt solutions of various sorts (Wright's solution, 
salt packs,1 and magnesium sulphate), or glycerine. These 
reagents through their ability to withdraw fluid from the tis- 
sues, are frequently potent to so diminish interstitial tension, 
that circulation is completely restored through the part, and 
more important interference is rendered unnecessary. 
(f) Incision with the knife. Of all the means for dimin- 
ishing interstitial tension in surgical practice, incision of the 
part is most important. In order that incision of indurated 
tense tissue may be effective, it is essential that the cut be 
sufficiently long and deep, to permit the discharge from the 
tense tissues of the extravascular fluid responsible for inter- 
ference with the blood circulation. Short superficial incisions 
are for this purpose relatively useless, and simply serve to 
traumatize the already injured tissues. Obviously, unless the 
cutting of the tissues renders it more easy for them to wage 
their war upon the infecting microorganisms, the added injury 
caused by the scalpel can but accomplish harm. In all cases, 
therefore, in which incision is employed in order to restore 
1Although salt packs doubtless owe their usefulness in part to their ac- 
tivity as hygroscopic agents, the experimental work of Donaldson and Joyce 
(Donaldson and Joyce; Lancet, 1917, ,p. 445 ) the bacteriology of wounds 
treated by the method indicates that the favorable environment presented 
by this form of dressing for the growth of the proteolytic nonpathogenic 
Reading bacillus is largely responsible for the favorable results which ac- 
company the use of the "salt pack'' method. As a result of the metabolic 
activity of this microorganism devitalized tissue is rapidly destroyed and 
the tissue freed from these foci of invading microorganisms. Growth of 
the common progenic bacterium is, moreover, practically eliminated by the 
salt concentration present in the dressings. 318 
INFECTION, IMMUNITY, AND INFLAMMATION 
the circulation, which has been interfered with by increased 
interstitial tension, any error must be made in the direction 
of too extensive, and too deep, rather than too limited inci- 
sions. In this connection if surgeons would habitually incise 
the various forms of cellulitis, more particularly of the hand, 
with the intention of afterwards performing secondary suture 
of the wound, more useful surgery would be performed, and 
many disabling end results would be avoided. 
(g) The employment of vaccines, or bacterial proteins. If 
the hypothesis laid down by the author in this volume be ac- 
cepted, it is obvious that the acute inflammatory reaction takes 
place in the tissues only if there be an interaction between 
the bacterial cell bodies, proteins, and the antibodies of the 
first order. If such an interaction takes place, the individual 
accumulations of bacteria become toxic foci, and the normal 
reaction-acute inflammation at irritant foci,-is exhibited. 
Continuation of the inflammatory reaction is dependent upon 
the presence of both of these reagents-bacterial protein and 
first order antibodies. 
In the natural cure of infection, the inflammatory process 
subsides in consequence of the elimination of the invader; it 
is also possible to induce the arrest of the reaction by the 
exhaustion of the antibody. In other words, if the individual 
be desensitized, no reaction is exhibited at the focus of bac- 
terial accumulation. Obviously, the arrest of the inflamma- 
tory reaction by means of desensitization through the admin- 
istration of vaccines, does not bring about cure of the infec- 
tion. A temporary arrest of the irritability of the focus with 
consequent limitation of the inflammatory reaction, may, in 
individual cases, result in a reestablishment, as regards cir- 
culation, of more or less normal conditions. In the author's 
opinion, the above is the explanation of the possible practical 
value of bacterial protein injections in the treatment of acute 
infections. In order that such desensitization may be accom- 
plished without undue danger to the individual under treat- 
ment, it is necessary that frequent, carefully increased, doses 
of the antigen should be employed. 319 
ACUTE INFLAMMATORY REACTION 
Although in my opinion, it is possible in this manner to 
occasionally treat inflammatory foci, in such parts of the 
body, such as the lungs, which have not been hitherto readily 
accessible for operative interference, it is a method which 
should be undertaken only with extreme caution, and em- 
ployed only by those who are thoroughly familiar with the 
administration of bacterial proteins, and of the danger sig- 
nals which accompany the use of any heterologous protein 
introduced parenterally. 
Clinical Stimulation of Inflammatory Reaction.-If reaction 
on the part of the tissues to the presence of infection be insuf- 
ficient, it may be necessary to so stimulate the tissues that a 
more marked reaction may be exhibited. Stimulation of the 
tissues for this purpose may be brought about by rendering 
the focus of bacterial accumulation more irritating. 
Absence of adequate reaction may be due to one or other 
of the following causes: (a) the tissues may not be hyper- 
sensitive to the bacterial protein; (b) the tissues may be tol- 
erant to the bacterial protein to a degree which masks their 
hypersensitiveness; (c) the bacteria may be located in such a 
situation that their cytoplasm is not exposed to the effect of 
whatever antibodies are present in the body fluids. 
Theoretically, if the tissues be not hypersensitive, the de- 
velopment of the hypersensitive state may be accelerated by 
means of the parenteral introduction of vaccines or other prep- 
aration of bacterial protein. In practice, the only example of 
induction of hypersensitiveness after infection is known, or is 
presumed to have taken place, is in the employment of Pas- 
teur's technic in the prophylaxis of rabies. 
If the tissues be tolerant to such a degree that their hyper- 
sensitiveness is masked, and inflammatory reactions are conse- 
quently not stimulated, the second order of antibodies (tolerant 
antibodies) may be exhausted by means of the parenteral in- 
jection of a sufficient amount of bacterial protein. In the 
treatment of infectious diseases such as furunculosis, chronic 
gonorrheal affections, focal tuberculosis, etc., by means of 320 
INFECTION, IMMUNITY, AND INFLAMMATION 
vaccines, this is the aim of the physician.2 In place of vac- 
cines the tissues may be induced to absorb, from the infected 
focus, a larger quantity of the bacterial protein than usual 
by means of any method which will increase the blood supply 
to, and through, the affected part. For this purpose we may 
employ active exercise or passive manipulation. A similar 
result may also be obtained by means of the employment of 
either active or passive hyperemia, according to the methods 
introduced by Thomas and Bier. 
In those eases in which, as the result of fibrous tissue encap- 
sulation of the infected focus, the patient has ceased to suffer 
from active clinical manifestations of disease, excision of the 
part-if this be anatomically possible-removes the danger 
of subsequent "lighting up" of the infected focus. Again, 
excision of an infected focus-even though it be moderately 
active-may be properly undertaken if the condition has be- 
come delimited, as for instance in the case of tuberculous 
infection of the knee joint. 
Surgical Removal of Irritants.-If foreign bodies are pres- 
ent in the tissues they must be removed, if elimination of the 
microorganisms is to be hoped for. It makes little difference, 
in this connection, whether the foreign body consist of a 
shell fragment, a retained rubber tube, an unabsorbed liga- 
ture or suture, necrotic fascia, exfoliated bone fragment, or 
pus. All of these substances act as foci in which bacteria may 
continue to proliferate and whence the tissues in the vicinity 
may be reinfected. Sterilization of wounds, whether trau- 
matic or operative, cannot be hoped for in the presence of 
foreign bodies. It is of no value to attempt secondary suture 
of wounds so long as necrotic fascia or dead bone sequestra 
are present. Unless the foreign bodies are removed, it makes 
no difference what form of adjuvant such as Dakin's solu- 
tion, B.I.P.P., flavine, etc., is employed. 
The essential reason for the excision and evacuation of 
abscesses, which are not complicated by the presence of inter- 
2For a more detailed consideration of the employment of vaccines for this 
purpose, see Chapter XXV. ACUTE INFLAMMATORY REACTION 
321 
stitial tension, is in order that the dead material, pus, and 
necrotic tissue may be removed. Obviously, therefore, the 
incision required in such cases need not be larger than one 
which suffices to permit adequate removal of the foreign body. 
At the same time, it is obvious that, granted all foreign body 
has been removed, there is little to be gained by insertion of 
other substances such as rubber drains, which tend by their 
very presence to injure the tissues. As a working rule, it 
can be asserted that if excessive interstitial tension be not 
present and if all necrotic tissue and pus pockets have been 
emptied, drainage in the ordinary sense of abscesses or perito- 
neal or joint cavities is not necessary and can only be pro- 
ductive of harm. INDEX 
Abderhalden on anaphylactoid re- 
actions, 124 
Adami on infection, 24 
subinfection, 23 
Aerobes, definition of, 50 
Aggressins, definition of, 50 
Agglutination, nature of, 212 
Widal's reaction of, in typhoid, 
210 
Agglutinins, 210 
Alexin, characteristics of, 199 
definition of, 198 
in anaphylaxis, 105 
multiplicity of, 203 
origin of, 200 
Allergic reaction, of Auer, 181 
characteristics of, 174 
clinical manifestations of, 176 
factors determining specificity 
of, 182 
to vaccination, 179 
von Pirquet's work on, 175, 180 
Weil's experiment, 180 
Allergy, definition of, 77 
Amboceptor, definition of, 198 
Bordet on, 204 
Ehrlich's hypothesis of, 199 
method of action, 203 
reciprocal activity of complement 
and, 205 
resistance to heat and desiccation 
of, 204 
sensitizing experiments with, 204 
Anaerobes, definition of, 43 
Anaphylactic antibody, Ehrlich's 
hypothesis, 143 
nature of reaction between, and 
antigen, 154 
site of reaction between, and 
antigen, 142 
Weil's theory regarding, 142 
reaction, Doerr and Russ on, 125 
Hektoen's experiments, 126 
specificity of, 125 
treatment of, 125 
Uhlenhuth's work on, 126 
Wells and Osborne's experi- 
ments, 126, 127 
shock, 80 
clinical phenomena of, 84, 86 
Anaphylactic shock-Cont'd 
effect of, on coagulation of 
blood, 103 
on leucocytes, 104 
on temperature, 104 
in man, 90 
physiology of, 97 
Anaphylactin, 77 
Bordet on reaction of, 219 
relation of, to other immune 
bodies, 215 
Friedberger's experiments on, 218 
Anaphylactogen, relation of proteins 
to, 122 
Wells' work on, 121, 124 
Anaphylactoid reactions, Abder- 
halden on, 124 
Karsner and Hanzlik's observa- 
tions, 140 
Kopacrewski's work on, 141 
Osborne's work on, 124, 125 
phenomena due to flocculation 
of colloids, 140 
Wolff-Eisner theory regarding, 
124 
Anaphylatoxin, 77, 38, 39, 130 
Friedberger's experiments on, 130 
Friedmann's work on, 130 
Novy and DeKruif's work on the 
nature of, 162 
Rosenau's observations regarding, 
132 
Zinsser and Dwyer's experiments 
regarding tolerance to 
typhoid, 120 
Anaphylaxis, Anderson's experiment 
with guinea pigs, in, 85 
characteristics of, 79 
Coca's work on, 99 
definition of, 76 
delayed, 76 
depletion of complement in, 105 
Fall's work on, 102 
Flexner's experiment in, 73 
in dogs, 88, 89 
in man, reactions of, 90, 243 
in rabbits, 87 
increase in lymph flow in dogs in, 
105 
influence of, on immunology, 62 
323 324 
INDEX 
Anaphylaxis-Cont'd 
in the guinea pig, 154 
Longcope and Boughton's find- 
ings in, 99 
Manwaring and Crowe's investiga- 
tions in, 99, 102 
nonspecific, 139 
phenomena of, 74 
relation of, to parenteral diges- 
tion, 158 
hypothesis of, 164 
in resistance to infection, 262 
relationship of hypersensitiveness 
and tolerance in, 82, 83 
role of the liver in, 101 
Rosenau and Anderson on charac- 
teristics of, 74 
Schittenhelm and Weichardt's 
work on, 88 
Schultz-Dale reaction, 106 
Simonds' work on, 99, 103 
tissues affected in, 98 
transferred, 109 
Anderson and Frost's work on, 
109 
cellular theory regarding, 145 
Doerr and Pick on, 149 
experiments of Schultz in, 147 
from mother to offspring, 112 
humoral theory regarding, 146 
incubation period in, 145, 148 
Pearce and Eisenbrey's work 
on, 149 
result of, 145 
Vaughan's work on, 262 
Anderson and Frost on transferred 
anaphylaxis, 109, 110 
Anderson's experiments with guinea 
pigs in anaphylaxis, 86 
rabbits, 87 
dogs, 89 
Antianaphylatoxin, definition of, 194 
Antibodies, effect of, in serum of 
sensitized guinea pigs, 
216 
effect of heat on, 219 
first order, 215 
identity of all first order, 215 
location of, 144 
overproduction of, 70 
reaction of, in immunity, 62 
second order, 169 
specificity of, 69 
Zinsser on their reaction to one 
another, 218 
Antibody, formation of, 66 
Antigen antibody reaction, effect of 
normal serum on, 165 
Manwaring and Kusama's 
work on, 151 
site of, 150 
Wells' discussion of, 150 
Antisensitization, 120 
Antitoxic sera, employment of, in 
diphtheria, 277 
in meningitis, 279 
in tetanus, 278 
method of production, 276 
Antitoxins, characteristics of, 70 
Auer's allergic reaction, 181 
Bacteria, acid fast properties of, 29 
capsules, 29, 47 
cause of chemical changes in, 32 
characteristics of, 31 
conditions necessary for growth 
of, 42, 43 
definition of, 24 
desiccation of, 45 
destruction of, 46 
effects of heat and cold on, 45 
exaltation of virulence of, 49 
factors determining death of, 44 
invasion of, in the body, 33, 53 
reactive processes of, 32 
size of, 29 
spore formation of, 30 
structure of, 28 
Pasteur's work on, 50 
temperature, 44 
tinctorial differentiation of, 31 
Bacterial cell body, effects of en- 
vironment on, 36 
Cramer's experiments with, 
37 
Pfeiffer's work on, 38 
phagocytosis of, 187 
proteins, 38 
Bactericidal sera, 281 
Bacterioproteins, hypersensitiveness 
to, 289 
prophylactic and therapeutic use 
of, 34 
Baldwin on tuberculin therapy, 302 
Besredka and Strobel, their investi- 
gation of peptotoxin, 41 
Besredka, his work on desensitiza- 
tion, 115 
on proteins, 122 
Biedl and Krause on peptone poison- 
ing, 136 
Blood serum, contents of, 172 INDEX 
325 
Bordet, on amboceptors, 204 
on parenteral digestion, 162 
on toxin and antitoxin, 72 
Bordet-Wassermann reaction, 206 
in syphilis, 208 
Brown's observations upon the B. 
welchii, 38 
Carriers, definition of, 54 
Cecil and Larsen's experiments on 
serum agglutination, 217 
Cell receptors, 66 
Cells, nature and origin of, in in- 
flammation, 227 
Cellular theory of transferred 
anaphylaxis, 145 
Chemotaxis, 28 
Chronic infection, 262 
Chandler-Walker's employment of 
pollen extracts, 309 
Coca on hypersensitiveness, 250 
on anaphylaxis, 99 
Colloids, flocculation of, 140 
Complement, definition of, 198, 199 
Denys' work on, 202 
effect of temperature on, 201 
relationship of, to leucoprotease, 
201 
Complement fixation, 206 
Bordet-Wassermann reaction, 206 
Noguchi's work on, 209 
Cramer's experiments with bacterial 
cell body, 37 
Dakin's racemized proteins, 123 
Dale's work on parenteral digestion, 
165 
Danysz on parenteral digestionL161 
Denys on complement, 202 
Desensitization, 78 
Besredka's work on, 115 
cause of, 114 
definition of, 113 
method of, 247 
specificity of, 114 
time necessary for, 248 
Dick, Geo. F. and Gladys, on scarlet 
fever immunization, 286 
Diphtheria, Park's experiments in, 
294 
prophylactic immunization against, 
293 
Schick's test in, 294 
Doerr and Pick on transferred 
anaphylaxis, 149 
Doerr and Russ on anaphylactic re- 
action, 125 
on endotoxins, 131 
Drug tolerance, 20 
Ehrlich, hypothesis of the ambo- 
ceptor, 199 
of anaphylactic antibody, 
143 
on the principle of chemotaxis, 28 
receptors, 66 
work on immunology, 59 
Endotoxins, 38 
Doerr and Russ on, 131 
Pfeiffer's hypothesis, 129 
Wolff-Eisner's theory regarding, 
130 
Fall's work on anaphylaxis, 102 
First order antibodies, identity of, 
215 
Fixed virus, 291 
Flexner'si experiments on anaphy- 
laxis, 73 
Flocculation of colloids, 140 
Formation of antibody, 66 
Friedberger's work on anaphyla- 
toxin, 130 
on tolerance, 167 
Furunculosis, vaccine treatment of, 
298 
Gibson on leucocyte count, 222 
Grant's experiment on vaccinations, 
293 
Granules, metachromatic, 29 
Granulomata, 241, 236 
Hay fever, treatment of, 309 
Heilner on parenteral digestion, 160 
Hektoen 'g experiment in anaphy- 
lactic reaction, 126 
Hemocellular reaction, 18, 220 
Hess, on entrance of bacteria into 
the body, 53 
Hewitt, on leucocyte count, 221 
Histamine, definition of, 137 
relation to anaphylactic shock, 
138 
Horiuchi, on capsule formation, 47 
Humoral theory, 146 
Huntoon's experiments in serum 
agglutination, 272 
Hypersensitiveness, 78 
Coca on, 250 326 
INDEX 
Hypersensitiveness-Cont'd 
clinical examples of, to non- 
bacterial proteins, 250 
determination of, 247 
Loeb, Strickler and Tuttle's ex- 
periments, 255 
Ramirez's experiment on, 250 
relationship of, to the phagocytic 
reaction, 193 
Talbot on, 251 
to foodstuffs, 251 
to serum, 254 
Immunity, acquired, 21, 59, 64 
definition of, 55 
history of, 57 
natural, 21, 63 
passive, 21, 64, 68 
principles of application, to the 
prevention and treatment 
of disease, 270 
reaction of antibodies in, 62 
Immunization, definition of, 55 
early methods of, 58 
Ehrlich's work on, 59 
Immunologic reaction to foreign 
proteins, 156 
Immunology, definition of, 17, 55 
Incubation period in transferred 
anaphylaxis, 145, 148 
Infection, adaptation of bacteria in 
tissues in, 54 
chronic, 262 
constitutional manifestations of, 
258 
definition of, 24 
diagnosis of, 25 
factors influencing, 53 
leucocyte count in, 260 
relative susceptibility to, 268 
Infective agents, 24 
Inflammation, acute, process of, 231 
bacterial vaccine injections in, 
235 
chronic, 233 
definition of, 17, 223 
effect of presence of foreign 
bodies in, 229 
Lister on, 231 
microscopic lesion in, 234 
nature and origin of cells in, 237 
nature and quality of serum in, 
225 
phenomena of, 226 
spread of, 228 
Inflammatory reactions, arrest of, 
318 
classification of, 230 
clinical inhibition of, 316 
in leprosy, 238 
in syphilis, 237 
in tuberculosis, 236 
therapeutic guidance of, 315 
Thomas and Bier's methods, 
320 
Isaeff's work on leucocytes, 260 
Jenner, on immunization, 58 
on vaccinia inoculation, 27 
Jordan, on bacteria, 52 
Karsner and Hanzlik on anaphy- 
lactic reactions, 140 
Kendall, on preference of bacteria 
for carbohydrate food- 
stuffs, 35 
on capacity for toxin production, 
51 
Knorr on production of antitoxic 
units, 70 
Koch on tuberculin therapy, 302 
Koch's postulates, 26 
Kopacrewski on anaphylactic reac- 
tions, 141 
Krause on precipitins, 213 
Leprosy, inflammatory reaction in, 
238 
location of bacilli in, 240 
Lesions, in chronic inflammation, 
235 
in leprosy, 238 
in syphilis, 237 
Leucocyte count, Gibson's work on, 
222 
Hewitt on, 221 
in diagnosis and prognosis, 220 
in infection, 260 
Leucocytes, bactericidal power of, 
228 
function of, in immunologic 
process, 185 
in anaphylactic shock, 188 
in infection, 260 
Isaeff's work on, 260 
Metalnikow's study of, 187 
polymorphonuclear, 227 
protective property of, 192 
Wright's work on, 189 
Leucoprotease, 202 
Lister, on inflammation, 231 INDEX 
327 
Loeb, Strickler and Tuttle on hyper- 
sensitiveness, 78 
Longcope and Boughton's findings 
in anaphylaxis, 99 
Lyons ' table, composition of bac- 
teria, 37 
Macrophages, 241 
Manwaring and Crowe on anaphy- 
laxis, 99, 102 
Manwaring and Kusama on antigen 
antibody reaction, 151 
Metalnikow, on relationship of 
phagocytosis to anaphy- 
laxis, 187 
Metastatic infections, 301 
Metazoa, definition of, 24 
Metchnikoff, 60 
Miller, on protein lysin immunity, 
313 
Montague, Lady, introduction of im- 
munization by, 58 
Noguchi, on complement fixation, 
209 
Osborne, on anaphylactoid reactions, 
124, 125 
Parasites, definition of, 42 
Parenteral digestion, Bordet on, 162 
Dale's work on, 165 
Danysz on, 161 
definition of, 159 
experiments of Abderhalden, 
159 
Heilner's work on, 160 
objections to theory of, 161 
relation of, to anaphylaxis, 158 
theory of, 157 
Weil on, 164, 165 
Park's experiments on diphtheria, 
294 
Pasteur's discovery of bacteria, 26 
exaltation of bacteria, 50 
fixed virus, 291 
investigations of acquired im- 
munity, 58, 59 
work on rabies, 291 
Pearce and Eisenbrey on transferred 
anaphylaxis, 149 
Peptone poisoning, increase of lymph 
flow in, 137 
observations of Biedl and 
Krause in, 136 
symptoms of, 136 
Peptotoxin, definition of, 40 
Pfeiffer, his hypothesis of endo- 
toxins, 129 
on toxin, 38 
Phagocytosis, definition of, 22 
Pollen extracts, employment of, 288 
author's method, 311 
Chandler-Walker's method, 309 
Precipitins, definition of, 213 
effect of heat on, 214 
Krause's work on, 213 
practical use of reactions of, 214 
Prophylactic vaccination, 295 
Prophylaxis, definition of, 21 
Protein immunity, 198 
therapy, nonspecific, 312 
Proteins, Besredka on, 122 
Dakin's racemized, 123 
effect of heat on, 122 
immunologic reactions to foreign, 
156 
in anaphylactic shock, 156 
in anaphylaxis, 122, 125 
Ten Broeck on, 123 
Protein split products, 133 
relation of, to immunity, 133 
Vaughan's conception of, 133 
Protozoa, definition of, 24 
Ptomaines, definition of, 36 
Pus, composition of, 231 
Rabies, Pasteur's work on immun- 
ization against, 291 
Stimson's table of administration 
of vaccine in, 292 
Ramirez on hypersensitiveness, 250 
Receptors, cell, 28 
effect of, on irritants, 60 
of Ehrlich, 66 
production of, 59 
Relapses, possible reasons for, 269 
Richet's phenomenon of anaphy- 
laxis, 61 
Rosenau and Anderson on character- 
istics of anaphylaxis, 74 
in guinea pigs, 154 
on tolerance, 120 
Salmon and Theobald Smith on 
serum therapy, 271 
Salvarsan reactions, 257 
Saphrophytes, definition of, 42 
Savtchenko, results of his study of 
the growth of bacilli, 52 
Schick's hypothesis of the cause of 
hyperemia, 62 
test in diphtheria, 294 328 
INDEX 
Schittenhelm and Weichardt on ana- 
phylaxis, 88 
Schultz and Dale's work on ana- 
phylactic reaction, 106 
Schultz on transferred anaphylaxis, 
147 
Serum agglutination, 217 
nature and quality of, in in- 
flammation, 225 
bactericidal, 281 
reactions, 20 
sickness, methods of inducing, 247 
reactions of, 244, 245 
symptoms of, 66, 243 
therapy, 270 
anthrax, 285 
Cecil and Larsen's experiments, 
273 
diphtheria, 277 
dysentery, 284 
gonorrhea, 285 
Huntoon's experiment, 272 
measles, 286 
meningitis, 283 
pneumonia, 283 
Salmon and Theobald Smith on, 
271 
streptococcus infection, 282 
tetanus, 279 
Second order antibody, 169 
Sherrington, on tetanus treatment, 
280 
Simonds, on anaphylaxis, 99, 103 
Smith, Theobald, on diphtheria 
bacillus, 35 
Stimson's table of administration 
of vaccine in rabies, 292 
Subinfection, 23 
Suppuration, definition of, 231 
spread of, 228 
Syphilis, inflammatory reactions in, 
237 
Tetanus antitoxin, prophylactic and 
therapeutic employment 
of, 278 
immunity from, 68, 69 
Sherrington's experiments, 280 
toxin, action of, 34 
treatment of, with serum, 279 
Ten Broeck, on proteins, 123 
Thomas and Bier on inflammatory 
reactions, 320 
Thomsen, on tolerance, 119 
Tissue irritation, Abderhal den's 
work on, 155 
cause of, 154 
Tolerance, 116 
explanation of phenomena of, 166 
Friedberger on, 167 
relation of tolerant state to the 
anaphylactic, 168 
results of experiments, 119 
Rosenau and Anderson on, 120 
protocol of experiments, 119 
Thomsen's work on, 119 
transference of, 170 
Vaughan on, 169 
Vaughan's method of developing, 
119 
Toxicity, effects of environment up- 
on, 36 
Toxin-antitoxin immunity, 67, 68 
Toxins, bacterial, 33, 35 
Traumatic fever, explanation of, 
256 
Tuberculin, clinical employment of, 
303 
dosage and interval, 307 
therapy, 302 
Tuberculosis, effects of subcutaneous 
injection of tuberculin 
on, 195 
inflammatory reaction in, 236 
Uhlenhuth's work on anaphylactic 
reaction, 126 
Vaccination, antityphoid, 292 
Grant's experiment, 293 
process of, 177 
von Pirquet's "immediate reac- 
tion" in, 178 
Wright and Leishman's method 
of, 292 
Vaccines, employment of proper 
dose of, 191 
prophylactic employment of, 290 
therapeutic employment of, 296 
treatment of gonorrheal infec- 
tions, 301 
Vaughan, his experiments on ana- 
phylaxis, in resistance to 
infection, 263 
in transferred anaphylaxis, 262 
his method of developing toler- 
ance, 119 
on transference of tolerance, 170 
on protein split products, 133 
on proteins, 155 
Virus, filterable, definition of, 25 INDEX 
329 
Wassermann reaction, 208 
Weil, on cell receptors, 66 
on parenteral digestion, 164, 165 
on purpose of immunological 
study, 55 
Weil's experiment on allergic reac- 
tion, 180 
theory regarding anaphylactic 
antibody, 142 
Welch, on exaltation of virulence of 
bacteria, 52 
Wells and Osborne on anaphylactic 
reaction, 126, 127 
Wells' discussion of antigen-anti- 
body reaction, 150 
experiments in hypersensitiveness, 
255, 254, 250 
on acute serum reactions, 255 
on anaphylactogen, 121, 124 
Wells-Cont'd 
on antigen-antibody reaction, 150, 
151 
on parenteral digestion, 160 
Widal's agglutination reaction, 210 
Wolff-Eisner theory regarding ana- 
phylactoid reactions, 124 
endotoxins, 130 
Wright and Leishman's method of 
vaccination, 292 
Wright's work on leucocytes, 189 
Zinsser on antibodies, 218 
on leucoprotease, 202 
on poison secreting bacteria, 33 
on relation of endotoxins to toxic 
split products, 39 
on toxicity of blood, 256