Literature 
Concerning the New Remedy 
For Tuberculosis'. 
(Reprint of Editorial from the AMERICAN NATURALIST 
of February, 1891.) From The American Naturalist, February, 1891. 
EDITORIAL. 
N OW that the first excitement regarding the new remedy for 
tuberculosis has subsided, the time seems opportune to 
glance back at the events of the past eighteen months, which 
have proved rich in scientific research in relation to the tubercle 
bacillus, and to place on record, not only for our own satisfac- 
tion, or even for those more immediately concerned, but especially 
for the benefit of succeeding generations, the announcements that 
have been made public from time to time in regard to that mi- 
crobe, and the means that have been discovered for combating its 
ravages on the animal economy. 
The endless and often embittered controversies which con- 
stantly occupy the literary world almost invariably arise from the 
fact that no plain contemporaneous record was made at the time, 
which would have placed the question beyond the range of argu- 
ment. To cite a case in point, the circumstances surrounding the 
sale by Oliver Goldsmith of the “ Vicar of Wakefield” have proved 
an inexhaustible field for conjecture and surmise, and gallons of 
ink have been wasted over the attempts to reconcile two appar- 
ently conflicting accounts of that transaction. 
In almost all cases of discovery there are rival claimants,—in 
some instances, where the evidence seemed most conflicting, it 
has been afterwards proved beyond question that the same idea 
has come to two workers, hundreds of miles apart, at almost 
identical moments. A little consideration will show that there is 
nothing very surprising in this. In the case of two scientific men 
pursuing an investigation on similar lines and with an identical 
goal in view, it is perfectly possible for them to hit upon the same 
conclusion at nearly the same time, and for both of them to be- 
lieve that the one has been pillaging from the other. 
In the case of the discovery of vaccination, no serious question 
ever arose, and Jenner stands out alone without challenge or dis- 
pute. The same can be said with regard to the discoveries of 1891.] 
Editorial. 
123 
Pasteur; nor is there any doubt as to the claims of Professor 
Koch to the discovery of the tubercle bacillus. 
In the month of March, 1882, Dr. Koch announced to the 
medical world that he had discovered the existence of a microbe 
hitherto unknown, and to which was given the name of the tuber- 
cle bacillus. He described how he had subjected diseased or- 
gans of numbers of men and animals to microscopic examination, 
and found, in all cases, the tubercles infested with a minute, rod- 
shaped parasite, which, by means of a special staining process, he 
differentiated from the surrounding tissue. He says : “ It was in 
the highest degree impressive to observe in the center of the 
tubercle cell the minute organism which had created it.” 
Professor Klein differs from this view. He says: “ I cannot 
agree with Koch, Watson Cheyne, and others, who maintain that 
each tubercle owes its origin to the immigration of the bacilli, for 
there is no difficulty in ascertaining that, in human tuberculosis, 
in tuberculosis of cattle, and in artificially induced tuberculosis of 
guinea-pigs and rabbits, there are met with tubercles in various 
stages, young and old, in which no trace of a bacillus is to be 
found, whereas in the same section caseous tubercle may be 
present containing numbers of tubercle bacilli.” 
Transferring directly by inoculation the tuberculous matter 
from diseased animals to healthy ones he in every instance re- 
produced the disease. To meet the objection that it was not the 
parasite itself, but some virus in which it was embedded, he cul- 
tivated his bacilli artificially for long periods of time and through 
many successive generations. 
This was confirmed by reliable investigations, and thus was 
established the existence of the tubercle bacillus and its discovery 
by him, and up to this time everything is plain sailing. 
From the date of this announcement (1882) by Professor Koch 
up till October, 1889, nothing particularly new was heard on the 
subject, and as far as the literature on the tubercle bacillus goes, 
we have every reason to believe that the search for a toxic agent 
to combat the disease of tuberculosis and the ravages of the 
tubercle bacillus has been fruitless. Indeed, to all outside appear- 
ances, the tubercle bacillus, having been once discovered, was to 124 
The American Naturalist. 
[February, 
be left unmolested to pursue its ravages on helpless humanity. 
But in reality it was being followed up by tireless and relentless 
foes. m 
On October 19th, 1889, was published in the Medical News, 
of Philadelphia, by Dr. Samuel G. Dixon, at that time Professor 
of Hygiene to the University of Pennsylvania, a monograph 
announcing his discovery of the hitherto-unknown forms of the 
tubercle bacillus. 
In the previous summer, whilst investigating different methods 
of technique and manipulation abroad, Dr. Dixon was led to 
believe that the bacillus could be cultivated so as to show lower 
forms of virulent life; and following this idea up by a series of 
experiments, he was in a short time able to produce the hitherto- 
unnoticed forms of the bacilli, some club-shaped, others curved, 
and others again branched. 
From the growths thus obtained he proceeded to make a series 
of tube inoculations, from which he grew bacilli corresponding in 
every respect to the ordinary rod-shaped tubercle bacillus. 
Having obtained these results, he propounded two hypotheses: 
1st, That by a thorough filtering out of bacilli from tuberculous 
material a filtrate might be obtained and attenuated, so that by 
systematic inoculations a change might be produced in living 
animal tissues that would enable them to resist virulent tubercle 
bacilli. 2d, To bring about a chemical change or physical change 
in living tissues that would resist tubercular phthisis, it is possible 
that inoculation with the bacillus would have to be made; yet, 
before this could be done, the power of the virulent bacilli would 
have to be diminished, otherwise the result would be most disas- 
trous. He added further that he had reduced the tubercle bacillus 
to a condition that, when inoculated into the animal economy, 
caused a resistance to the disease. 
To use a military metaphor, this was the first note proclaiming 
that an active campaign had been opened on the tubercle bacillus, 
and specifying in terms as definite as possible the means by which 
the war was carried into the enemy’s country. 
The announcement of this discovery was widely circulated and 
commented upon, and reprints of the article were forwarded to 1891.J 
Editorial. 
125 
Drs. Von Pettenkofer, Koch, Louder-Brunton, and other scientific 
investigators. 
The International Medical Congress was appointed to meet in 
Berlin in August, 1890, and more than usual interest attached to 
its meeting, as it was generally rumored that some important 
papers on the subject of the tubercle bacillus would be read on 
that occasion. 
Nor was this rumor falsified, and the interest of the meeting 
may be said to have culminated as Professor Koch rose to ad- 
dress the assembled physicians, and when he stated that he had 
hit upon a substance which had the power of preventing the 
growth of the tubercle bacillus, it was greeted with loud applause. 
It was then stated that the bacillus of tuberculosis in man and 
chickens was very similar, and he inferred that the latter is a 
special species of the organic matter supposed to lie at the root 
of pulmonary consumption. He also announced that the direct 
action of solar light on the tubercle bacillus destroys in a cer- 
tain length of time, varying from a few minutes to several hours, 
the virulence of this microbe. 
It will be convenient' to quote verbatim from that portion of 
the paper proclaiming his discovery of a toxic agent: “ In spite 
of this failure—to effect any result on tuberculous animals with 
chemical substances—I have not allowed myself to be discouraged 
from prosecuting the search for growth-hindering remedies, and 
I have at last hit upon a substance which has the power of pre- 
venting the growth of tubercle bacilli, not only in a test tube, but 
in the body of an animal. All experiments in tuberculosis are, 
as every one who has had experience of them has sufficiently dis- 
covered, of very long duration. My researches on this substance, 
therefore, although they have already occupied me for nearly a 
year, are not yet completed, and I can only say this much about 
them, that guinea-pigs, which, as is well known, are extraordi- 
narily susceptible to tuberculosis, if exposed to the influence of 
this substance, cease to react to the inoculation of tuberculous 
virus, and that in guinea-pigs suffering from general tuberculosis, 
even to a high degree, the morbid process can be brought com- 
pletely to a standstill without the body being in any way inju- 126 
The American Naturalist. 
[February, 
riously affected. From these researches I in the meantime do 
not draw any further conclusions than that the possibility of ren- 
dering pathogenic bacteria in the living body harmless without 
injury to the latter, which has hitherto been justly doubted, has 
been thereby established.” (Address before the Medical Con- 
gress in Berlin, August, 1890.) 
It will be observed that Professor Koch in his paper makes 
two points: 1st, The action of solar light and a high degree of 
heat in destroying the virulence of the microbe; 2d, The fact 
that he had produced a substance the effect of which was to 
prevent the growth of the tubercle bacilli in the body of an 
animal, and that he produced a condition in that animal that was 
immune to the virulent tubercle bacilli; also that he by the same 
process could overcome tuberculosis already established. 
There are also two facts that cannot fail to strike the observer. 
The first is, that a period of over seven years had elapsed from 
the date of his first publication on the tubercle bacillus and that 
announcing his discovery of the toxic agent; and the second, 
that his researches after the substance must have commenced 
about the period of Dr. Dixon’s publication of October, 1889, 
which, however, no mention is made in his address. It does 
not seem unfair to infer that Professor Koch had been unsuc- 
cessful during the preceding years in arriving at any satisfactory 
results. His own words, “ My researches on this substance, 
therefore, although they have occupied me for nearly a year,” 
etc., seems conclusive on this point. We do not, however, propose 
to do more than call attention to the coincidence of his researches 
after the toxic agent and the publication of Dr. Dixon’s, October, 
1889, the importance of which would be obvious to any bacteri- 
ologist, and the unfruitful nature of the former’s investigations 
previous to that date. 
There was, perhaps, a feeling prevalent in the medical world of 
incompleteness in the terms of Professor Koch’s announcement, 
and it seems as if he had only stimulated curiosity in order to 
deny it satisfaction. Nor was this allayed when the news arrived 
from Berlin that the scientist, having brought his researches to a 
point sufficiently advanced to justify the use of his remedy in 1891.] 
Editorial. 
127 
corpore vili, was prepared to inoculate the human subject. But 
the nature of his remedy and the method of its composition were 
to be kept a profound secret. 
The first inoculation into the human economy took place on 
September 22d, in a case of lupus, but it was not until the first 
week in November that it was given out that Professor Koch 
was ready to make inoculations on a general scale It is not ger- 
mane, however, to our purpose to do more than refer in passing 
to these events, or the exodus to Berlin, which is fresh in the pub- 
lic mind. 
On November 15th Dr. Dixon, in the Philadelphia Times and 
Register (medical), clearly explained his position, as well as the 
result of his experiments up to that date. He wrote : “ The 
hypothesis advanced in my terse article in the Medical News of 
October, 1889, have given the most brilliant results; yet I have 
never felt that the time had arrived for me to experiment on the 
human subject. Nor do I mean to be tempted to take any risks 
until the act would be purely an unselfish one. Even with the 
results that have been obtained in my laboratory, I would be 
sorry to have the general public stimulated with the idea that 
inoculation for tubercular phthisis had been perfected. 
“ Owing to the rumored report that Professor Koch has been, 
and is, inoculating human beings, it behooves me to await his re- 
sults and understand his methods. If, however, it should appear 
that he is working on different lines, and that his plan is less dan- 
gerous than my own, it will be welcomed and adopted by me.” 
On November 18th Dr. Dixon laid before the Academy of 
Natural Sciences a report summarizing in more detail his work of 
investigation on the tubercle bacillus. After alluding to the 
capability of the bacillus of changing from its commonly recog- 
nized rod-form to that of a more compound one, club-shaped, 
curved, or branched, which he believed to be either involution or 
degenerate forms, he went on to say : “ There would appear to 
be in this homogeneous mass something other than the bodies of 
the micro-organisms. This may be the residue of the pabulum 
remaining after the bacilli have selected what was necessary for 
their existence, or a digestive secretion, or again it may be an 128 
The American Naturalist. 
[February 
excretion of the live organism. Let this be as it may, I hoped to 
find a changed functional action in the organism, in secretion or 
its excretion, that would combat tuberculosis in animal life, either 
by stimulating the cells or by causing a chemical reaction in the 
tissues that were susceptible to the digestive secretion of the 
tubercle bacillus. 
An attempt to explain its probable action appears in an article 
I wrote for the Medical News of October 19th, 18 89, and also in the 
Medical and Surgical Reporter and the Times and Register of this 
year. The views expressed are, however, purely hypothetical. 
When the mass that I have already spoken of as being found 
on the pabulum was subjected for a considerable length of time 
to various degrees of heat, and injected into the guinea-pig, the 
animal seemed to sicken, yet only for a short time. The animals 
so treated appear to resist injections of virulent bacilli. Whether 
this would produce immunity for any length of time, provided we 
discontinue the administration of the remedy, I am not sure. 
Some animals injected with the virulent matter after the treatment 
with the changed mass had been discontinued appear to be im- 
mune, and experiments on animals suffering with tuberculosis 
have resulted most satisfactorily. 
It is evident from this report that Dr. Dixon had pushed his 
ideas advanced on October 19th, 1889, to a stage promising to 
confirm in a remarkable degree the hypotheses laid down in his 
monograph, and that inoculation by the toxic agent had yielded 
most satisfactory results. 
It cannot fail also to be remarked that there is a definiteness of 
statement, as far as the circumstances will admit, in Dr. Dixon’s 
announcements which are lacking in those of his German col- 
league. 
It soon became evident to Professor Koch that the attempt to 
withhold the composition of his remedy after it had been supplied 
to the profession was likely to defeat its own object. He there- 
fore published on January 15th, 1891, a statement disclosing the 
nature of the remedy. 
In this communication, after speaking of the preventive and 
curative effects of inoculating by living tubercle bacilli, he says ; 1891.] 
Editorial. 
129 
“ This effect is not exclusively produced with living tubercular 
bacilli, but is also observed with the dead bacilli, the result being 
the same whether, as I discovered by experiments at the outset, the 
bacilli are killed by a somewhat prolonged application of a low 
temperature or boiling heat, or by means of certain chemicals. 
This peculiar fact I followed up in all directions, and this further 
residt was obtained—that killed pure cultivations of tubercular 
bacilli, after rinsing in water, might be injected in great quantities 
under healthy guinea-pigs' skin zvithout anything occurring beyond 
local suppuration. If the injections are continued at intervals of from 
one to two days, the ulcerating inoculation wound becomes small- 
er and finally scars over, which otherwise it never does; the size of 
the swollen lymphatic glands is reduced, the body becomes better 
nourished, and the morbid process ceases, unless it has gone too 
far, in which case the animal perishes from exhaustion. By this 
means the basis of a curative process against tuberculosis was 
established." 
We have italicized these words in order to call the reader’s 
attention in connection with their identical nature with the following 
statement by Dr. Dixon,published months before: “That by sub- 
mitting a mass of growing bacilli to different degrees of heat, etc., 
and injecting the mass into animals, he not only prevented tuber- 
culosis, but also cured the same.” 
Compare this with Koch’s just-published claim, that by inject- 
ing tubercle bacilli that had been submitted to solar light, heat, 
etc., he had produced in guinea-pigs immunity, and also cure, and 
moreover that by this the curative process against tuberculosis 
was established, and if there is any difference between the two, 
we have not been able to detect it. 
With this last utterance of Prof. Koch the literature on the 
subject of the cure for tuberculosis for the present ceases. 
We have endeavored to lay before our readers a succinct and 
chronological account of the history of this great discovery. 
The important question as to whom belongs the credit for it, 
and to whom should be awarded the priority, may well be left to 
them. We venture to think that the material is present here 
before them to enable them to form a correct judgment. 130 
The American Naturalist. 
[February, 
That the use of the remedy has not yielded the results expected 
from it by Prof. Koch is very probable, and it is difficult to 
avoid the reflection that a more conservative policy, such as 
that persistently advocated and followed by Dr. Dixon, would 
have been wiser, and moreover kinder to those whose hope of 
cure had been unduly raised. There is abundant work to be 
done yet in the laboratories before definite conclusions can be 
reached, and the inoculation into the human system is therefore 
to be deprecated as premature. That the main principle has 
been arrived at seems beyond doubt, but much yet remains before 
the discovery can become of permanent benefit to suffering 
humanity. 
Published March 10th, 1891.