Reprint from Memphis Medical Monthly, February, 1895. 
Diphtheria—Pseudo • Membranous Croup. 
Read before the Memphis Medical Society, December 11, 1894, 
By G. B. Tikirntom, m.d. 
President Memphis Board of Health. 
As there is a difference of opinion between experienced 
physicians and a number of noted authors as to the etiology 
and pathology of diphtheria and pseudo-membranous croup, 
and I am responsible for the city ordinance regarding them 
as alike infectious, I have thought it well to introduce the 
subject to this society for its consideration. If pseudo-mem- 
branous croup is not an infectious or contagious disease, it is 
so like diphtheria in appearance as to cause confusion in 
diagnosis and might lead to negligence in protecting the 
community against one of the most actively infectious and 
fatal diseases of childhood. Aside from the above reason the 
subject is an especially interesting one just now, in view of the 
recent discoveries in bacteriology and the practical application 
of what is recognized as hemato- and sero-therapeutics. How- 
ever, it is not my purpose to discuss the treatment of either 
disease in a therapeutical sense, but briefly as practicable as 
a public health question, and if possible justify the existing 
city ordinance which regards them as alike infectious. 
That diphtheria is a contagious disease is no longer a debat- 
able question. That being conceded, it follows that all proper 
and available means should be taken to prevent its spread. 
Hence the important question of early and accurate diagnosis, 
both for the attending physician who is to treat the case, the 
family in which it occurs, and the health officer whose duty 
it is to prevent the spread of the infection in the community. 
Some years ago this identical question was before the French 
Academy of Medicine for discussion, and a committee was 2 
I'hornton : Diphtheria—Pseudo-Membranous Croup. 
appointed to investigate the etiology and pathology of both, 
and report the difference if there was any. After due con- 
sideration of the subject the committee reported there was 
practically no material difference. 
Diphtheria is essentially a child’s disease, though not con- 
fined to childhood. One attack does not give immunity from 
a second or third attack. No particular locality can be named 
as its peculiar habitat, nor is the disease limited to either 
season or any particular latitude or longitude. It is more 
prevalent in winter and in cold, damp, miasmatic atmospheres, 
thickly - settled localities, crowded quarters, etc., though it 
sometimes appears in high altitudes and in apparently good 
conditions of atmosphere. Under such circumstances it may 
be due to a transmitted infection or a latent predisposition in 
the individual attacked. 
The question as to its commencing as a local or constitu- 
tional disease, is another disputed point in its etiology. With- 
out wishing to be considered at all dogmatic, especially in 
view of recent discoveries and publications, I have inclined 
to the opinion that it is primarily a constitutional disease, a 
toxaemia, and the local lesions are simply manifestations of 
the morbific influence, as the eruption on the skin is the result 
of variola poison, or the scarlet rash on the surface the first 
clear diagnostic symptom of scarlet fever, etc. There are 
those of unquestioned high authority who contend that the 
disease commences as a local affection, and that constitutional 
disturbance follows the local inoculation. Upon this point I 
quote from the current number of the Journal of the American 
Medical Association for Sept. 22, p. 462 : 
“From the etiology given, based upon the researches of 
Klebs, Loeffler, Welch, and the chemic pathology of Roux, 
Yersin and Sidney Martin, the question may be considered as 
settled that diphtheria is first a local disease caused by the 
bacillus diphtheria with the membrane at the site of inocu- 
lation, and should be treated as such ; also that the bacilli 
diphtheria liberate a ferment which, when absorbed, digests 
the proteids of the body, forming albumoses and an organic 
acid. These are the agents producing death ; fever and par- 
alysis following diphtheria. This is the secondary or consti- 
tutional stage of the disease.” Thornton : Diphtheria—Pseudo-Membranous Croup. 
3 
The presence of nests of diphtheritic bacilli or their exu- 
date, the toxine of the bacillus as described by Loeffler and 
his followers, seems to be now the accepted theory in decid- 
ing or diagnosing diphtheria, but to determine this requires 
skill in bacteriology. Only a few, a very small per cent, of 
general practitioners are sufficiently expert in chemical anal- 
ysis and use of the microscope to decide between the diph- 
theritic bacilli of Klebs and Loeffler and the so-called staphylo- 
and streptococci in exudate or false membrane of anon-specific 
character. Besides, such laboratory work as the cultivation 
of this exudate in glycerin, broth, beef tea, or other media, 
to determine the presence or absence of the nests of bacilli or 
the toxine of diphtheria requires time—from twelve to thirty- 
six hours and possibly longer—and this work must be done by 
an expert. With a case of true diphtheria to relieve and put 
in the way of recovery, to say nothing of the protection of 
other members of the household and the community, at large, 
this is losing valuable time—a loss of opportunity that may 
prove fatal to the patient and allow the infection to be extended 
to others. 
It is sometimes quite an embarrassing position for the 
attending physician to be placed in, to report diphtheria and 
subject the family that gives him its confidence to all the 
inconvenience of official surveillance, placarding the house, 
the isolation of the case, stopping the other children from 
school, and interfering with business and social intercourse, 
etc., and to have the case prove a simple tonsillitis. But 
where true diphtheria, one of the most distressing and fatal 
diseases of childhood, exists, these precautions are necessary 
and made mandatory by city ordinance. It is better for a 
community to have suspicious cases reported, or for mistakes 
in diagnosis to be in favor of isolation and sanitary precau- 
tion, than to have real cases of diphtheria run their course 
and have the infection spread from house to house. I can 
not now give accurate or large statistics as to the mortality 
of diphtheria and croup, but feel justified in stating that the 
mortality in diphtheria is from 30 to 50 per cent. Pseudo- 
membranous croup is no better. “ The average death rate 
in New York city from diphtheria from 1880 to 1884, four 4 
Thornton: Diphtheria—Pseudo-Membranous Croup. 
years, was 42.405 per cent. In Bridgeport, Conn., where 
statistics were very carefully kept from March, 1885, to March, 
1886, one year, there were 131 cases of diphtheria reported 
with 68 deaths, making a death rate of 51.90 per cent.” See 
Journal of the American Medical Association, current number, 
Sept. 22, 1894, p. 464. 
The last annual report of the health commissioner of the 
city of St. Louis for the year ending March, 1894, was received 
a day or two ago at the health office. This official report 
shows that 509 cases of diphtheria were reported and 198 
deaths—a mortality of approximately 40 per cent. The same 
report shows for same time 216 cases of croup and 133 deaths; 
this is a death rate of over 50 per cent. I have no doubt that 
a majority of these cases reported as croup were diphtheria, 
and should have been reported to the health officer to be 
dealt with as any infectious disease. Possibly they were. I 
am not informed as to the details of sanitary regulations in 
that city. But over 50 per cent, of deaths for any one disease 
is a terrible mortality, and is well worth the study of physi- 
cians and sanitarians. 
The official report of the health department of the city of 
Chicago for 1895 shows 975 deaths from diphtheria and 492 
from croup. The report does not give number of cases of 
either disease reported, hence I cannot compare deaths with 
cases. According to this report the death rate of Chicago 
from all causes was 16.90 per thousand, calculated upon an 
estimated population of 1,600,000 ; the total number of deaths 
from all causes was 27,083; the percentage of deaths was 
3.60; with diphtheria and croup added and considered as one 
disease, the rate would be 5.41. Cholera infantum is the only 
disease that leads these singly in the mortality table of zy- 
motic diseases, and the two combined which I am considering 
as one disease, exceeds that several hundred. 
In 1893—last year—there were fifteen cases of diphtheria 
reported at the Memphis health office, with seven deaths—a 
mortality of not quite 50 per cent. This year to date, there 
are twenty-two cases reported inside the city limits, most of 
them since October 1st, with twelve deaths—a mortality of 
a little over 50 per cent. Thornton: Diphtheria—Pseudo-Membranous Croup. 
5 
As stated above, it is not my purpose to discuss the general 
therapeutics of this disease, but will briefly allude to the anti- 
toxin treatment that has gone beyond the experimental stage 
and demonstrated conclusively its value as a curative agent. 
As far as I am informed, the mortality of both diphtheria and 
croup has been approximately 50 per cent, by the best meth- 
ods heretofore practiced. This is an additional argument that 
the etiology and pathology of the two are very similar if not 
identical, and should be dealt with alike by health officers. 
As yet this lymph or “ antitoxin ” has not shown the two 
virtues of vaccine matter, as a therapeutic and prophylactic 
agent. Vaccine matter is a lasting prophylactic against var- 
iola, and if used in the febrile or early eruptive stage of small- 
pox, acts as a valuable therapeutic agent. It will modify the 
disease and render it much more manageable. I know this 
from actual experiment, having tried it in several well-marked 
cases in the epidemic of 1872-73 in this city. Possibly by 
further investigation it will he discovered that a permanent 
prophylactic against the microbes of diphtheria can he pro- 
duced, as is now the antitoxin. My understanding is that 
the sero-therapeutic process of Drs. Roux, Behring and Kit- 
asato is antitoxic, but not prophylactic or antiseptic. That is 
to say, this prepared lymph or antitoxin, when injected into 
the cellular tissue of a child affected with diphtheria, which 
is caused by the toxines or product of the microbes or diph- 
theria bacillus described by Dr. Loeffler, acts therapeutically 
as an antidote to this poison or ferment, hut does not act as a 
preventive to the microbe itself. In other words it is a cura- 
tive agent, but has not yet been proven to be a preventive or 
prophylactic. 
Unless the reports we have of this “ antitoxin ” are exag- 
gerated as a curative agent, it is an inestimable blessing, and 
it is to be hoped will soon be in the possession of all doctors 
who may be called upon to treat this fatal disease of childhood. 
In conclusion I will say, in enforcing this amended ordin- 
ance, regarding diphtheria and pseudo-membranous croup as 
the same disease, the Board of Health does not wish to be 
considered as in captious opposition to the views of reputable 
and honored members of the profession, or to arbitrarily exer- 6 
Thornton : Diphtheria—Pseudo-Membranous Croup. 
cise official authority on a simply theoretical question, but to 
discharge what it conceives to be its duty in practical sanita- 
tion for the public good. 
Dr. W. W. Taylor : The question, as to whether or not 
diphtheria and true croup are identical diseases, has long been 
a debatable and interesting one. However, in the light of 
recent microscopical studies, it seems to me that the matter 
has, at last, been incontestably settled. There are two kinds 
of pseudo membranous inflammations that occur in the upper 
air passages. To the naked eye they are alike, the chemical 
and physical properties have been found to be similar, and 
clinically they are, in almost all respects, identical. A dif- 
ference is only to be seen in a study of their etiology. By 
bacteriological research, there is found in the one, the Klebs- 
Loeffler bacillus, when it is then known to be diphtheria; in 
the other, there is an entire absence of the Loeffler bacillus 
and the micro-organism usually seen and to whose presence 
the inflammation is due, is a streptococcus. When the true 
diphtheria bacillus is absent, the disease is more properly 
called pseudo-diphtheria. The term croup is misleading to 
the laity and presupposes a too exact diagnosis to be made 
by the general practitioner. It is better with our present 
means of diagnosis to use some term showing its close kinship 
to diphtheria. As further evidence to the fact of two kinds 
of pseudo-membranous inflammations, I will cite the result 
of studies made at Willard Parker Hospital by Dr. Park of 
New York. In 159 observations the Loeffler bacillus was 
found in 54 cases, and in the remainder, 105 cases, it was 
absent. The mortality in true diphtheria was 40£ per cent.; 
in pseudo - diphtheria, 5§ per cent. When these exudates 
form in the larynx, the symptoms of the two diseases are 
much the same. With true laryngeal diphtheria constitu- 
tional symptoms are usually absent on account of the scant 
supply of lymphatic vessels and glands. The laryngoscope 
only enables us to see a membrane, but is ot no aid in differ- 
ential diagnosis. That can only be made by a bacteriological 
examination. 
While the facts that have been stated prove to me that 
diphtheria and true croup are separate and distinct diseases, 
yet on account of the impossibility of differential diagnosis 
at the bedside, it is wiser for the general practitioner to always 
treat and manage them as the same. 
Dr. Krauss : As to the ordinance, it is a necessary one and 
should be lived up to. The statistics quoted by the author 
DISCUSSION. 1 hornton: Diphtheria—Pseudo-Membranous Croup. 
7 
and those quoted by Dr. Taylor show how little reliance can 
be placed upon statistics in general, if the cases are not hon- 
estly and properly grouped. 
To be fair, only the laryngeal cases of true diphtheria should 
be contrasted with croup, which is essentially a laryngeal 
affection. The reports from continental hospitals show that 
in laryngeal diphtheria the mortality runs up to 87 per cent.; 
moreover, the figures quoted by Dr. Thornton were not con- 
trolled by bacteriological diagnoses, and many cases were 
undoubtedly true diphtheria. 
I wish to endorse all Dr. Taylor has said. There is no 
longer any doubt about either the primarily local character 
of diphtheria, or the non-identity of the two diseases ; they 
are res adjudicata. The chief clinical points of distinction 
for true diphtheria are : 
1. The membrane is more grayish to brown, surrounded 
by a livid halo, and it bleeds readily from slight friction. 
2. There is fetor of the breath. 
3. There is albuminuria. 
4. It is followed by paralysis. 
Dr. Thornton’s hope that we may find a prophylactic in the 
remedy can only be partially realized, as can be readily under- 
stood if we remember the nature of the serum. It is an 
albuminous mixture which is brought into the circulation, 
and, being foreign to the body, must of necessity be sooner 
or later eliminated. It is not a substance that induces pro- 
cesses iri the body, requiring time to run their course, and 
resulting in an agent generated in the body, like vaccinia, for 
instance. 'Prof. Behring believes that an immunity lasting 
perhaps thirty days may be conferred. 
The heilserum not only destroys the bacillus, as has been 
stated by Dr. Thornton, but contains two separate principles 
which have been isolated ; one is bactero-toxic, the other is 
toxine-neutralizing. 
During my association with Dr. Thornton on the Board of 
Health I suggested that we furnish diagnoses as the New 
York Board was doing. Other boards are now doing this, 
and ours will find it necessary to do so when the serum comes 
into general use among us, for obvious reasons. 
A medicinal dose is said to be harmless, but I do not deem 
it prudent to use so potent a remedy without having it op- 
posed by the diphtheria poison, and indiscriminate use of 
this very promising remedy will more quickly bring it into 
disrepute than anything else. 
I think Dr. Thornton’s paper a timely one, and fully appre- 
ciate the importance of the ordinance. 8 
Thornton: Diphtheria—Pseudo-Membranous Croup. 
Dr. Turner: Thanks Dr. Thornton for essay. lias been 
very close to the hardships of the red tickets, but endorses 
the practice. In sympathy with view of the disease as con- 
stitutional with local manifestations. 
Dr. Holder: Wants to call attention to varying of statis- 
ticians as to results claimed in similar cases. Would ask Dr. 
Taylor, who has mild statistics, whether when case where 
no membrane is visible died, such case is diphtheria or croup. 
Had one case which died and consultant said it was croup. 
Dr. Taylor replies that in laryngeal diphtheritic membrane 
no clinical diagnosis is possible. 
Dr. Jones : Always contended that they were different dis- 
eases. Was startled at the statistics quoted by Dr. Taylor. 
Thinks croup is more dangerous than diphtheria; they die 
from suffocation. Thinks croup always starts in fauces, and 
diphtheria in pharynx, generally at tonsil. In inaccessible 
membrane symptoms are different and distinct; in croup, 
death before involvement of glands, more fever early, and 
death early. Thinks it a wise ordinance and expects to live 
up to it. Does not expect to be censured by patients as an 
alarmist for reporting such cases ; they are very apt to die. 
Chairman : Dr. Taylor’s statistics refer to cases of mem- 
brane, but they say nothing about croup. Croup is an old 
disease; diphtheria more recent. In diphtheria we have par- 
alysis ; but the question is if in croup the child can live long 
enough for paralysis. Three forms: laryngeal, pharyngeal 
and nasal; laryngeal is more fatal. Thinks they should be 
called the same disease and that they are equally fatal. 
Dr. Thornton : Has little to add. Looks at it from point 
of view of a health officer ; does not intend to be arbitrary, 
but believes be is acting in interest of community. As to 
statistics he only quoted official figures, and believes the high 
mortality was due to faulty diagnosis. Wants to bring anti- 
toxin here for use of the profession. Last month an institute 
was started in New Orleans for its propagation, and believes 
it will be a blessing. True diphtheria is a most fatal disease.