Contribution to the knowledge of relations between Koch and Pasteur
Naturwiss, Technik, Med, Leipzig 20 (1983)1, S 57-65
(Translated by E. T. Cohn, B. H.
Fasciotto-Dunn, U. Kuhn and D. V. Cohn)
Better say it right away; the relationship between
Koch and Pasteur was hateful. After having illustrated it, we will try to
The first meeting of the two scientists was in
London, august 1881, during the International Congress of Medicine. Pasteur,
then 59 years old, has behind him a prestigious series of work and discoveries
on fermentation, spontaneous generation, silkworm’s disease, studies on wine and
beer, anthrax, immunization against chicken cholera and the general principle of
bacterial attenuation. Koch is 38 years old. Even if he began research only
since 1873, he was already famous for his works on wound infection and on
anthrax; the discovery of the anthrax spore gave him 6 years earlier and
exceptional reputation; for the past 2 years he is a member of the
At this London congress, Pasteur presented his
results on viral attenuation; he then attends, in Lister’s laboratory, at King’s
College, a series of demonstrations by Koch who presents his staining procedures
and his films of various microorganisms. Pasteur looks at them for a long time
and says to Koch with admiration: “This is a great advance, Sir”.
Already, on April 30,
1877, at the Science Academy of Paris, Pasteur spoke warmly of Koch’s discovery
of the anthrax spore, stating this his work was a “remarkable achievement”.
justified the violence of the attack against Pasteur, as much from Koch as from
his students. A few months after the London congress, the first volume of
Mittheilungen aus dem Kaiserlichen gesundheitsamtes appears; in this
collection, Koch violently attacks not only the discovery of viral attenuation
presented by Pasteur in London, but also the entire related work of Pasteur.
Thus in the paper Zur Äetiologie de Milzbandes, Koch writes:
It is very likely that there are also other
species of pathogenic germs, resembling the anthrax bacilli in terms of
their length and width and which might also cause pathogenic processes
similar to anthrax… This entire description proves that Pasteur had never
thought of this questionable infectious disease in a simple way… After all
the sentence that birds are immune to anthrax, can not be maintained
especially because chickens, with which Pasteur performed his experiments,
were susceptible to anthrax even without preparation by cooling; therefore
Pasteur's statement about his experiment can't possibly be true: aside from
the still open question in Pasteur's experiment if the claim that chickens
became susceptible to anthrax by cooling, to which they had not been
susceptible in the first place… In Pasteur's theory about the etiology of
anthrax are only a few new findings that are mostly based on errors... To
this point Pasteur's research on anthrax has not supported the etiology of
this infectious disease at all… Rather, we have the famous and quite
ingenious theory of Pasteur about the importance of the earthworm for the
etiology of anthrax and furthermore for many other infectious diseases. Even
in Germany this earthworm theory of Pasteur has found many admirers.
explains why this theory, according to him, is untenable:
condition sine qua non of Pasteur's earthworm‑theory is that the
anthrax spores lay hidden deep in the earth.... One must recollect
that absolutely necessary for spore formation are moisture and a certain
temperature. Deeper layers of the ground do not lack the moisture but
the question remain if the temperature required for the spore formation
exists... In the ground of Berlin at a depth of 3 meters this temperature
can not be attained at any of the observation locations.
Koch concludes as to the naiveté of Pasteur’s theory on
the role of the earthworm in anthrax:
The theory on the role of the earthworm in
the etiology of anthrax, even as with earlier investigations of Pasteur
turned out to be in error; and all the proofs from his anthrax studies allow
one to summarize that up to now thanks to Pasteur our knowledge of anthrax
has not been enlarged; thus in part his work in this field only confuses
what is already fixed or is fast being clarified.
In the same
book Löffler and Gallky also
violently criticize Pasteur’s research: Löffler, in his paper Zur
Immunitätsfrage attacks Pasteurian vaccination by attenuated germs,
asserting that the cultures of the chicken cholera bacilli prepared by Pasteur
weren’t pure because they were not done on gelatin, as recently introduced by
Not less susceptible to question than the
purity of the cultures is the evidence of the reduction in virulence… This
example shows that Pasteur’s investigation at its current state would hardly
be usable in practice regardless of all other raised objections.
then goes on to attack Pasteur’s work on anthrax:
With objective reflection of this brief work
of Pasteur, one can not resist the impression, that his was rather a
theoretical discussion than the result of experimental studies.... If we
nevertheless accept Pasteur’s predicted and overall lucky experimental
result [in Pouilly‑le‑Fort] with a conscious reserve, so this
impression is not baseless. The foundation on which Pasteur's investigation
rests is the experimentally-supported allegation that Bacillus anthracis
cannot form spores at 42‑43 °C in neutral chicken bouillon. In his
numerous experiments on the influence of the temperature on spore formation
of Bacillus anthracis, Koch only has discovered irrefutably, and I
was a witness many times, that the bacillus can strongly form spores at
42‑43 °C in a neutral clear chicken broth just as well as it is able to do
at temperatures between 30 °C and 40 °C.
translation of this attack was published in the February 20 1882's issue of the
Revue of Hygiene and Sanitary Policy: this leads to a violent reaction from
French scientists: H. Bouley publishes in the Recueil de Médecine vétérinaire
of March 1882 an "Appreciation of Prof. Koch, from Berlin, on the works of Mr.
Pasteur". We know by the latter's letters how deeply he was touched by the
criticisms of Koch. However, contrary to his habit, he does not respond
immediately to them, waiting to do so on the occasion of a public meeting with
opportunity was furnished him during the IVth International Congress for Hygiene
and Demography on September 5-9, 1882.
Soon after the London's international medical
congress, where I introduced virus attenuation," recalls Pasteur, "was
published in Berlin the first volume of a book on studies of the German
Imperial Sanitary Office. Not only this discovery on attenuation, but also
all my earlier research on disease microbes were attacked with a strange
ferociousness by Dr. Koch and two of his students. I waited to respond for a
favorable occasion; it was given to me in September 1882. I went to
Geneva, to the International Congress of Hygiene, with hope to meet with Dr.
At this congress, Koch
was imbued with the fame of his discovery of the tuberculosis germ that he had
presented six months earlier in Berlin on March 21, 1882. Pasteur made a
lengthy presentation on the vaccination against anthrax, criticizing Koch’s
opinion that pathogenic bacterial medication was impossible.
one cannot question that we have a general method of attenuation. ... The
general principles are found and one cannot deny that this line of research,
in the future holds out the highest hopes. But, as brilliant as is
demonstrated truth, it is not always privileged to be readily accepted. I
met stubborn contradictors in France and in foreign countries. Allow me to
choose among them the person of merit who has the most right to our
attention. I am talking about Dr. Koch, of Berlin.
Pasteur summarizes and
denies with vehemence the criticism published in the book of research of the
German health office. He hopes to engage in public discussion with Koch:
Perhaps, in this audience, there are some
people who share the same thoughts as my contradictors. Allow me to invite
them to speak up.
While Pasteur was talking, Koch sitting next to
Prof. Lichtheim, Chair of the medical clinic of Berne before being chair of
Kongsberg, was showing his impatience, standing up and trying to disturb Pasteur
while the audience was astounded.
Koch declined all discussion. Getting up on stage
he made according to the Congress report, the following declaration:
knowledge through the program of the congress that Mr. Pasteur would talk
today about virus attenuation, I came in hopes of learning some new facts on
a subject that interests me to the highest degree. I must admit now that I
have been deceived in that there is nothing new in the presentation of Mr.
Pasteur. I do not think it is necessary to answer here the attacks of Mr.
Pasteur and this for two reasons: first, because the points in question
affect only indirectly the hygiene issues, and second, because not knowing
French well and Mr. Pasteur not knowing sufficient German, we could not
start a fruitful discussion. I shall wait and answer Mr. Pasteur through the
channels of medical journals.
He did this three
months later in a small publication: Über
die Milzbrandimpfung. Eine Entgenung auf den von Pasteur in genf gehatenen
Vortrag. The violence of the attack was greater than the one in which he
presented arguments in "Mittheilungen aus dem Kaiserlichen Gesundhieitsamte".
Be the judge:
Pasteur] only well know things were heard about chicken cholera, about the
new rabies disease, and about the preventive vaccination against anthrax,
that until then on so-and-so many thousand animals were vaccinated…. All
this was apparently also a basis for a dispute directed against me, which
was not restricted to the announced topic, but extended over all the
differences on both side of our views in terms of the etiology of anthrax.
These in my opinion on the already answered questions on the cooling of
chickens, the importance of the earthworms, etc., are not of essential
interest to hygiene and a discussion about the same topics should not at all
be a part of a general session of a hygiene congress, in particular the less
as Pasteur’s polemic was not directed to defeat me by real proof, but by
general phrases and to a major part personally direct against me in an angry
tone… As a result of his poor methods Pasteur drifted off course immediately
the moment he started to answer a new question on the contagion of rabies.
Pasteur could not find the rabies microbes, which one hoped to find at that
time and which one looks for today. So the methods followed by Pasteur
must be called full or mistakes and cannot lead to successful results
because they lack microscopic examinations, involve use of impure substances
and use unsuitable experimental animals… Meanwhile Pasteur has only provoked
criticism not only due to the poor quality of his methods, but also to the
way in which he published his results… Whoever claims faith and confidence
in the scientific world is duty-bound to publish the methods followed so
that everybody is able to test their correctness… Rather, Pasteur used the
tactic of telling only that much about his experiments that was in his
favor, but he withheld everything that was unfavorable, even when it was
important for the outcome of the experiment.
Not lacking were even more personal attacks: after
many others, Koch reproaches Pasteur for not being a physician (“kein Arzt zu
sein”) or to make use of the assets that he is privy to:
We do not have that considerable
series of experimental animals to show as Pasteur had with the help of his
annual amount of funding.
And Koch concluded thusly:
When Pasteur was celebrated as the second
Jenner at the Congress in Genf, this occurred slightly prematurely.
Obviously in the desire to be enthusiastic it was forgotten that Jenner’s
beneficial discovery was not in sheep but in humans.
Pasteur's response, dated December 25, 1882,
was simultaneously published in the volume of the Revue Scientific of January
20, 1883, preceded by a French translation of Koch's memoir, and in a brochure
published in Paris by Baillière: "The Anthrax vaccination; Response to Mr.
The tone is as cutting as Koch’s:
This is another mistake on your part ... The
day you would like to be informed on this point and on all the preceding
points, I will be to your disposition during a congress or a commission
where you can designate the members. If you accept … you may not be able to
sustain the tone of assurance reflected in . . your brochure… You, Sir, who
entered in Science, in 1876 only after all the famous names that I just
mentioned, can recognize without derogation that you are a debtor of French
Science" ... There are in your brochure numerous sections where the
impertinence or mistake, the way Pascal would say it, “is really too much."
Pasteur’s argumentation is solid and his presentation clever. He recalls how,
himself, emphasized again and again before the Academy of Science on April 30,
1877 the importance of Koch’s discovery of the anthrax spores in a remarkable
paper. But this is to claim later his priority of his discovery of the spores in
the earthworm disease:
You can see, Sir,
that I was one of the first to recognize the value of your work on the
spores of B. anthrax ... Nevertheless, if you would go back to the first
volume of my work on earthworm diseases, you would see… that the priority of
the discovery of the formation of spores in a pathogenic bacillus belongs to
me... Why, Sir, did you hide all this from the readers of your first
memoir? Would you say that you did not have knowledge of my paper...
published in 1869‑70? Your assertion would have no significance because, in
Science, no one is allow to ignore a discovery.
In 1884, after his
discovery of Vibrio cholera, Koch is named member of the Prussian State Council
and, with this title, travels to Paris and Toulon, in July. He visited various
hospitals but did not go to the laboratory on Ulm Road where Pasteur works; (the
institute will not be created until1888.) This exclusion did not stop Pasteur
from sending a telegram to Koch with his congratulations for his presentation
on tuberculin at the congress of Medicine of Berlin, in August 1890. In the
same way, he defends Koch's discovery in the French scientific press: The
testimony of the Paris correspondent in the Deutsche Medizinische
Wochenschrift who attended the presentation, reports the strength with which
Pasteur defended his opponent:
On Monday the
session of the Science Academy took place, during which we discussed at
length Koch’s publication. Pasteur was present and was bombarded with
questions. He sharply rejected some participants that had doubts.
“there is nothing to discuss”, he screamed, with an energy that stopped all
other questions and that warned the unconvinced that they should express no more
When Pasteur published
his results on rabies vaccination, the Berlin school under the influence of Koch
was initially opposed, but a few years later Koch had to, himself, bow to the
evidence of the results and organized at the Berlin Hygiene institute a rabies
vaccination service in accord with the Pasteurean method. But he did not relent,
however. On 22 December 1892 most of the prominent European scientists attended
the Jubilee for Pasteur's 70th birthday. Perhaps some very personal matrimonial
reasons (wife trouble, dvc) were the cause of Koch’s absence.
died 28 September 1895. Is it for this reason that at the time of his second
voyage to Paris in October 1904, Koch no longer avoided visiting Pasteur's
laboratories? According to Metchnikoff the purpose of this second voyage was
anything but scientific; the second Madam Koch desired to see Paris, its
theaters, cabarets, restaurants and artists. Koch visits the Pasteur Institute
where according to Metchnikoff, (The Founders of Modern Medicine,, Walden
Publications, New York, 1939, p 122-123; D. Berger, transl.):
The welcome he received surpassed the one which was experienced by crowned
heads. The staff assembled in the Library welcomed him with a salvo of
applause. Koch visited the laboratories, the stables and the rest: it
is for the technical details that he manifested the most interest. He took
note of the slightest improvements in the methods of bloodletting of horses,
papers of the time which reported at great length this visit to the Institute
and to the Garche annex failed to mention that the German savant returned to
the crypt of the Institute where Pasteur was interred.
were the relations of Koch and Pasteur. Is one able to attempt to advance some
explanations of the antagonism between the two scientists?
it is necessary at first to emphasize the liveliness ‑ one isn't able to say
less‑ of their spirit: The polemic intensity of Pasteur, his need to convince,
his harshness in discussion, his fits of anger are well known. Koch is
authoritarian, entirely haughty. Here is how Metchnikoff, who was eventually
closely connected to him, relates their first meeting (Ibid. pp 120 ff):
1887 at the Hygiene Congress of Vienna I met his principal assistant who
told me that Koch wished to see the preparations regarding my last work on
recurrent fever and that he asked that they be sent to send to him.
Naturally, I didn't ask more and I added that instead of sending them, I
would deliver them myself. Some well known bacteriologists of Munich advised
me against this; they were convinced that I would be dismissed by Koch; that
he didn't wish to see in my preparations what I found there, and that after
having seen them, he would say thenceforth that he had established the lack
of foundation in my conclusions with a full knowledge of the facts. I
didn't take notice of this warning and I returned to Berlin. There I met his
his pupils. After having announced my visit to Koch, they arranged a meeting
with him for the next day. Between times I had left my preparations and I
showed them to his young collaborators. They affirmed unanimously that all
that they saw in the microscope confirmed my conclusions without
contradiction. Encouraged, I returned to Koch's laboratory the next
day. I saw seated at the microscope a middle-aged man, not old ...his
handsome face had a serious expression, nearly haughty. With great deference
the assistant announced that I had arrived for the meeting which he had
arranged and that I wished to show him my preparations. "What
preparations?", said Koch in a gruff voice. I told you to prepare all that
was necessary for my afternoon course and I see that many things are
missing!" The assistant excused himself humbly and introduced me again
to Koch. He, without offering his hand, said that he was very busy at
this moment and that he was only able to devote a little time to the
examination of my specimens. One hurriedly gathered some microscopes
and I showed him that which in my opinion was the most conclusive.
"Why then have you used a violet coloring when a blue coloring would have
been better?" I explained my motives, which scarcely softened him.
After some moments, he got up and said that my preparations were not at all
conclusive and that they in no way confirmed my point of view. Very offended
by these words and by Koch's attitude, I answered that the few minutes time
allotted weren't enough for him apparently to appreciate the delicacy of the
preparations; and I asked for another, less brief meeting. At this time the
assistant and the students who stood around us and who in my opinion were
now in agreement with him.
curious to note that when Alexandre Yersin, Pasteur's collaborator and Dr.
Roux's assistant returned to Berlin in June 1888 to pursue the teaching given at
the Institute of Hygiene by Koch himself, he wasn't able to succeed in
personally meeting him. In an unedited letter to his mother Yersin writes on
June 29, 1888:
I am thinking of offering a copy of my thesis to the Grand Lama Koch whom I
haven't seen yet and whom I would hope to see before leaving.
who had begun his medical studies in Marburg, spoke fluent German; his thesis
devoted to "The Study on the Development of the Experimental Tubercle", would
have wanted to arouse Koch's attention. Yersin left again without having met
him. In another letter dated July 13, 1888 he writes:
I have now left Berlin on
the morning of July first in order to arrive at Breslau the same day, in the
evening, Breslau isn't a beautiful city and its surrounding neighborhoods very
much resemble those of Berlin. Monday, I went to see Professor Flügge who has
been very friendly and has shown me all I wished to see. He was formerly Koch's
student and right hand. Today he is removed from Koch and a little more free in
his thoughts, he begins to recognize that in France one has also done some
interesting work. He particularly believes in the effectiveness of the
vaccinations against rabies, which is quite rare in Germany.
To take account of the
general climate of exacerbated patriotism which prevailed then in the scientific
community, the quarrel between Koch and Pasteur on the subject of anthrax merely
extended from a earlier quarrel that was placed on the patriotic plane: well
before Koch and Pasteur the priority for the discovery of the anthrax bacteria
was attributed by French writers to Rayer and Davaine (1850); and by the Germans
to Pollender who would have seen the bacteria since 1849 but only published his
observations in 1855. This atmosphere of scientific chauvinism could be seen in
nationalist sentiments of Koch and Pasteur: Koch, violently anti‑French,
volunteered (for the Prussian Army) in 1870. Refused because of his
nearsightedness, he in enlisted in 1871 and served in the Prussian army in
Lorraine at first, then in a military hospital near Orleans. A passionate
patriot, Pasteur detested the Germans. After the war of 1870, writes Metchnikoff
(Ibid p. 89 and In Mollaret, p:62)
When he received German books or brochures he held them at the tip of his
fingers in order to pass them to me, or he put them aside with an air of
repugnance. That didn't prevent him from agreeing to my proposition to send
a congratulatory telegram to Koch concerning his discovery of the remedy
against tuberculosis. The war of 1870 was a sorrow from which he was never
able to recover. At the time of general enthusiasm he wanted to become
a volunteer in the National Guard and not leave Paris during the siege. His
friends dissuaded him and he left for Arbois the morrow of Sedan and the
fall of the empire.
Pasteur writes at that time:
I wish that France will resist until her last man, until her last rampart! I
wish that the war lasts until the heart of winter when the elements come to
our aid, so that all these vandals will perish from cold, misery and
sickness. Each of my efforts until my last day will carry an epigraph:
“Hatred of Prussia, Vengeance, Vengeance!” (Ibid, p 89).
January 18, 1871 Pasteur returns the diploma of Doctor of Medicine to the Dean
of the Faculty of Medicine of the University of Bonn which this university had
awarded him in 1868. He writes:
the sight of this parchment is odious to me, and I feel offended to see my
name with the title of Virum Clarissimum of which it is adorned, placed
under the auspices of a name dedicated to the loathing of my country, the
one of Rex Guilelmus... I obey a call of conscience in requesting you to
erase my name from the archives of your faculty and to take back this
diploma as a sign of indignation which the barbarism and hypocrisy instills
in a French scientist from those who, to satisfy a criminal need, insist on
the massacre of two great nations.
Pasteur received the
following response from the dean:
Sir, the undersigned,
the present Dean of the Faculty of Medicine of the University of Bonn, is
charged to answer the insult which you have dared to make to the German
nation in the sacred person of its noble emperor, the king, William of
Prussia, in sending you the expression of all his contempt! (Signed Dr.
Pasteur wasn’t able to
restrain himself from replying:
I have the honor to tell you ... Monsieur
the Dean, that it is the time where the expression of contempt, in the mouth
of Prussian subjects, is equivalent to a heart truly French, to the Virum
Clarissimum which you awarded me a short time ago.
of this opposition of principle, other elements should be seriously considered.
We said above that Löffler, as did Koch, asserted that certain of Pasteur's
cultures weren't pure. An article by G. Ramon informs us that Chamberland added
Bacillus subtilis to the anthrax vaccine supplied to Germany (and this
without having advised Pasteur) with the aim of preventing commercial German
competition through the reproduction, by subculture of the Pasteur vaccine.
Therefore, the German accusation of the impurity of the Pasteur vaccine was not
is more than probable that the major reason for the animosity between Koch and
Pasteur was a profound reciprocal misjudgment of their work. Pasteur didn't read
German and should have become accustomed to translate the writings of Koch.
Koch understood French imperfectly and over the years had great difficulty in
obtaining the foreign scientific publications. Metchnikoff underlined the
resulting conditions in which Koch worked at Wollstein without a laboratory. In
a letter to Professor Cohn, July 15, 1877, Koch thanks him for sending the
bacteriology publications and expresses his regrets of not being able to read
details on his anthrax bacillus are very interesting. If I only
could study them in the original.
An unedited document in the Museum of
the Pasteur Institute under the number of the inventory 19.648 shows the role
that ignorance of their respective languages played in the relations between
Koch and Pasteur and throws light on the real reason for the development of
their polemic at the Congress of Geneva. It deals with a letter dated September
20, 1925 to Doctor Roux, then director of the Pasteur Institute, by Charles Ruel,
former privat docent at the Faculty of Medicine at Geneva. Of the eight
page letter we extract the following passages:
and very honored colleague, I recently visited the magnificent Pasteur
Museum in Strasbourg and on this occasion, the memory of an incident came
back to me which occurred unexpectedly at the Fourth Hygiene and Demographic
Congress. The incident was marked by an altercation between Pasteur and
Doctor Koch of Berlin of which the true cause is known today … What strange
thing happened at the Congress of Geneva? How to explain Pasteur’s
excessive irritability, his impatience and violent language? Let us see of
they were not provoked more by the inopportune questioning than by the
aggressive tone and singular attitude of the Berlin scholar.
In the course of the remarkable and
conscientious presentation, when he listed and commented appropriately and
properly to the work of Koch and his School, he referred several times to
the German Collected works (Recueil allemand). Now Koch and
his friend Prof. Lichtheim, were sitting side by side; they knew French only
imperfectly and both mistook the word pride
(orgueil) for collection (recueil). They felt their self-respect
profoundly wounded and interpreted the words German pride as a grave
insult. Immediately Doctor Koch at the instigation of his compatriot got up
and tried to interrupt the orator in order to protest the terms which he
regarded disrespectful. The assembly, ill at ease and amazed, witnessed this
quarrel but without understanding. I have this explanation from Professor
Lichtheim himself, who on returning to Berne the day after the congress, we
went to the laboratory of pathological anatomy of the faculty where I
worked, but a little confused, the account of their scorn and the admission
of their unpleasant and awkward intervention of the day before of the old
man.... Such is the basis and the true reason which put the two
scientists at odds and made of the September 5th session, a turbulent and
agitated one. One can easily imagine that interrupted during his masterly
presentation, and understanding nothing of the noisy and out of place
challenge of Doctor Koch, the orator allowed himself some involuntary
movements of impatience and even of anger. Let my evidence bring on a new
day the history of this famous session in restoring to Pasteur although
tardily, the justice which is due him, to erase forever a stain capable of
tarnishing, so little as it is, the glory of the great French scientist.
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