Guest Post: The Experiments of Dr. Robert Koch: A Reconsideration of the Scientific Method for Evaluating Treatments for Tuberculosis

Today we are pleased to feature five guest posts from students in Tom Ewing’s Virginia Tech Introduction to Data in Social Context class! This post is from Christian Averill, Robbie D’Amato, Nathan Gibson, and Jonathan Silbaugh.

During the nineteenth century, a widespread desire for a cure for tuberculosis prompted intense interest in any claims of a medical breakthrough in diagnosing and treating this disease. When German physician Robert Koch announced in 1882 that he had discovered that the cause of the disease was a bacillus known as M. Tuberculosis, his discovery was widely celebrated as a major medical breakthrough. Eight years later, however, his claims to have discovered a cure for tuberculosis aroused more substantive questions about the veracity of his claims as well as the methods, findings, and analysis advanced to support these claims. This post examines some of the evidence involved in this discussion with the goal of evaluating Koch’s claims relative to standard procedures used now to discover, test, and approve cures.

Koch’s discovery of a cure for tuberculosis was hailed immediately as “The Greatest Medical Discovery of the Present Century,” as indicated by the subtitle of a widely circulated publication, Prof. Koch’s Cure for Consumption, authored by Berlin physician Dr. H. Feller (Illustration 1). In this brochure, Feller praised Koch’s quest for “the noble structure of a scientifically supported method of cure for consumption,” (p. 14) which had the “enormous significance” of potentially eliminating a disease that causes more deaths worldwide than any other cause, leading to this summary statement by Feller: “The unsatisfactory medical treatment of consumption has given place to a deliberate well considered method of action, and therapeutic science will no longer fail in consequence of social inequalities; but all, whether rich or poor, will be participators in the blessings of this wonderful discovery.” (p. 49)

Illustration 1

Illustration 1

Yet a more complicated picture emerges when other physicians and researchers attempted to replicate Koch’s findings in their own laboratories and practices. One such effort to duplicate Koch’s findings, was recorded and reported by the American physician, A. Jacobi. The records for fifty patients treated with versions of Koch’s tuberculin were published, first in the journal Medical Record, and then in a separate volume, available from the Medical Heritage Library. The patients ranged in age from infants to the elderly, with about one-half between  20-50 years. The gender distribution was almost exactly even. Most of the patients were described as having pulmonary tuberculosis, although some had the disease in their bones or skin. Illustration 2 provides a visual analysis of the data collected by Dr. Jacobi and published in his report, as classified and recorded by our research team. The left column in the graph includes the identification of the patients by first name and initial (two were anonymous), gender, age, and a brief description of the patient’s disease. Patients covered in this study received as few as one inoculation and as many as thirty two inoculations over a period of many weeks. More than one-half of patients received ten or few inoculations; only about 10% of patients received 25 or more inoculations. This graph vividly illustrates how the effort to duplicate Dr. Koch’s experiments involved a wide range of treatments, with no apparent standardization. In some cases, it appears that treatments were discontinued because patients were diagnosed with another illness, while in other cases, the wishes of patients figured prominently in the treatment regime. The share of patients with negative outcomes (no improvement or died) was 38%, slightly higher than the 34% reporting positive outcomes (condition improved and fair condition), with another 28% recording neutral outcomes (outcome not reported, treatment discontinued, or diagnosis changed).

Illustration 2: Patient Identities, Number of Inoculations, and Recorded Outcomes

Illustration 2: Patient Identities, Number of Inoculations, and Recorded Outcomes

The most revealing interpretation suggested by this visualization of the data reported by Jacobi is the apparent lack of a causal relationship between the number of inoculations and the long term outcomes for patients. As shown in Illustration 3, patients recording more positive outcomes received, on average, more inoculations, certainly by comparison to those who died, whose diagnosis changed, or whose treatment was discontinued. Yet this data also reveals the relatively small gap in average inoculations between those showing improvement (an average of 15.1) and those showing no improvement (12.9), a gap of little more than two inoculations (a difference of just 15%) in treatment regimes that produced such diametrically opposed outcomes. Jacobi’s journal articles and book are revealing of the faith shared by researchers and the public in the process of medical discovery in the early 1890s.

Illustration 3: Patient Outcomes and Average Inoculations

Illustration 3: Patient Outcomes and Average Inoculations

Jacobi’s summary of the outcomes of his trials were cautiously optimistic, because he could compare the outcomes of those undergoing treatment with the usual “very discouraging” fate of those admitted to hospitals, particularly with pulmonary tuberculosis. While praising tuberculin as “a remedy of great power for good,” Jacobi also warned against viewing it as a miracle in ways that exaggerated its potential. Yet Jacobi concluded that tuberculin had done more than other remedies — apart from climatic treatment of pulmonary tuberculosis and surgical interference in cases of local tuberculosis — and thus he expressed gratitude to “great genii like Pasteur and Koch” who “enrich the world with new discoveries in the field of pathology and therapeutics,” yet even with these great scientists, “we must not look for infallibility.” (p. 43)

Under current testing standards, medical researchers today conduct highly regimented experiments following standard protocols, human subject guidelines, and control groups. A study such as Jacobi’s would most likely not meet standard practices common to the current scientific community. In Jacobi’s study, the data was easily measured and recorded. Current researchers, by contrast, use advancing medical technology to acquire higher quality data in greater quantity.  

With the greater accessibility to high quality data, researchers today can make stronger conclusions about treatments. The data provided in Jacobi’s study did not clearly demonstrate the effects regarding the stability, safety, and effectiveness of this treatment for tuberculosis. The data produced by researchers such as Jacobi also reveal that the excitement for a TB cure caused premature conclusions about Koch’s treatment. Instead of testing to see the impact of the treatment, researchers were testing to see if his method was viable, leading to impulsive conclusions. Even though it is unclear that Koch’s treatment was viable as a cure, he still made an impact on the the cure for Tuberculosis.


Jacobi, A. (1891). Inoculations with Professor Koch’s “Tuberculin”. (New York: Trow’s Printing and Bookbinding Co., 1891). Articles originally published in Medical Record, February 29 and march 7, 1891. Digital version available from Medical Heritage Library and Internet Archive. Available from

Feller, H., Professor Koch’s Cure for Consumption (Tuberculosis) Popularly Explained (London: Ward, Lock, & Co., 1890). Digital version available from Medical Heritage Library and Internet Archive. Available from

Guest Post: “Phthisiophobia”: The Tuberculosis Clinic in New York City and Popular Anxieties about Public Health Dangers

Today we are pleased to feature five guest posts from students in Tom Ewing’s Virginia Tech Introduction to Data in Social Context class! The first is from Allyson Manhart, Andrew Pregnall, and Harshitha Narayanan.

TB_Infirmary_OpenToPatientsAt the beginning of the twentieth century the Treasury Department of the United States classified pulmonary tuberculosis as a “dangerously contagious disease” which meant that any immigrant found to have tuberculosis coming to the United States would be denied entrance. The ban led to a swift reaction from the physicians of the New York Academy of Medicine, many of whom argued that the ban created unnecessary fear of those with tuberculosis.

On January 2, 1902 the monthly meeting of the New York Academy of Medicine resulted in the Academy physicians proposing a resolution which rejected the Treasury Department’s new classification of pulmonary tuberculosis.  The physicians felt their plans to establish a clinic for consumptives on Blackwell’s Island was threatened by the Treasury Department’s classification and the unnecessary fear they felt it created. Less than a month later on January 31, 1902, the Tuberculosis Clinic of the Metropolitan Hospital of New York opened its door to patients who needed public healthcare, both the curable and incurable (New York Times 1902).

The Tuberculosis Clinic of the Metropolitan Hospital of New York quickly became the central destination for consumptive patients in New York City as all consumptives in other charity hospitals were removed to the Metropolitan Hospital’s clinic. In the chart above, created by the director of the Metropolitan Hospital’s clinic, we can see the number of patients who were admitted or discharged, the number of patients who died, and the patients remaining in the clinic after a six year period.

While the mortality rate of almost one-in-three patients is high compared to other hospitals, it is important to remember that the Metropolitan Hospital’s clinic took in all patients from the New York City region — regardless of whether they could be cured or not.  This raises a broader question: Who were the hospital’s patients?


The clinic took in 13,610 patients from 1902 to 1908. The graphic above shows the ethnic breakdown of the patients in the clinic versus the breakdown of the entire New York City population. People who were natives of the United States made up about 23% of the New York population and 42.8% of the patient population. The hospital reported that many of these patients were “born of foreign parents.” The second largest demographic group was the Irish, coming at 21.9% of the patient population. The surprising statistic was Germany’s representation. About 23% of the New York City population was German, but they only made up 8.2% of the clinic’s population. They are followed by Russia at 7.5%, Italy at 6%, Austria at 2.7%, and England at 2.5%. Ultimately, by looking at these statistics, it is easy to see that most of the consumption patients in New York City were first or second generation immigrants.


In addition to collecting information on the nationalities of their patients, the Tuberculosis Clinic of the Metropolitan Hospital of New York also collected data on their religions (65% were Roman Catholic and 25% were Protestant), sexes (about 80% male), age (65% were between the ages of 21 and 50), and occupations as seen in the graph above. The biggest takeaway from all of this data is that the patient population of the Tuberculosis Clinic of the Metropolitan Hospital of New York was comprised of poor first or second generation immigrants who likely worked long hours in poor paying, physically demanding service jobs,  with less than ideal conditions, and then returned home to the tenement housing — characterized by poor sanitary conditions, overcrowding, malnutrition, etc — that was so prominent throughout urban centers of the United States at the time. These considerations explain to a large degree why these immigrants were so susceptible to tuberculosis.

Interestingly, the Tuberculosis Clinic of the Metropolitan Hospital of New York was very aware of the background of their patients and the effects they were having on the City of New York hospital system. In the words of the Clinic’s director:

The municipal hospital facilities of New York City have never yet been adequate to house in comfort all the sick poor seeking municipal aid. The main reason of this is the great influx of foreigners each year who never get any further into the United States than New York City. A glance at the nationality of the patients in Tuberculosis Infirmary will show this. [Emphasis added] (New York Times 1902)

Now that we understand who the Clinic’s patients were, one final question must be addressed: What social effects did tuberculosis have on these vulnerable first and second generation immigrant populations?

The simple answer is stigma. In an address to the New York Academy of Medicine on January 2nd 1902, Dr. Sigard Adolphus Knopf, an expert on pulmonary tuberculosis, said:

To my deep regret I learned recently that new difficulties have arisen concerning the site of our future New York State Sanitarium. Phthisiophobia, an exaggerated fear of the vicinity of consumptives, is the cause. What the people must learn is that consumption is not contagious, where the sputum is destroyed. It is hard to estimate how much hardship and suffering is incurred through the fear of consumption. It leads to real inhumanity. Useful citizens may be removed from their chances at success. [Emphasis added] (New York Times 1902)

He went on to say that the classification of pulmonary tuberculosis as a dangerously contagious disease, “plac[es] a stigma wholly undeserved upon every American citizen who is suffering with consumption,” and proposed a resolution, adopted by the Academy at their next meeting, which declared the exclusion of immigrants based on their consumptive status to be “unwise, inhumane, and contrary to the spirit of American justice.” (New York Times 1902)

Ultimately, the Tuberculosis Clinic of the Metropolitan Hospital of New York took in thousands of patients in the six year period, regardless of their curability. While we did not learn when the Tuberculosis Clinic closed from our research, there is still a hospital on those Blackwell Island grounds today (whether it was renamed or is part of a new organization, we are not sure). After analyzing the ethnic and occupational backgrounds of the patients, there is substantial evidence that the majority of the patients were poor first or second generation immigrants who likely worked jobs rife with occupational hazards and lived in unsanitary tenement housing. These occupational and domestic risk factors meant that these immigrants contracted tuberculosis at a substantially higher rate, and subsequently composed the majority of tuberculosis patients in New York City. Unfortunately, as Dr. Knopf explains, tuberculosis was a great source of fear in the early 20th century, and this fear was ultimately projected onto the immigrant populations most in need of public help.

Works Cited

Mills, Walter Sands. 1908. The Tuberculosis Infirmary of the Metropolitan Hospital, Department of Public Charities, New York City. New York: M. B. Brown Company. https//

New York Times. 1902. “FEAR OF TUBERCULOSIS CALLED EXAGGERATED; Dr. Knopf Says It Leads to Real Inhumanity. Exclusion of Consumptive Immigrants Denounced at Academy of Medicine — Separate Hospital Advocated.,” January 3, 1902.

From Fugitive Leaves: “I Love the Flu”

~Guest post courtesy of Emily T.H. Redman, an Assistant Professor of History at the University of Massachusetts, Amherst where she teaches history of science.

I love the flu.

Don’t get me wrong. I don’t love the fever and chills, the runny nose, the sore throat, or the all-encompassing ache that seems to span from deep in the bones all the way to one’s hair follicles. I don’t love the complications—the respiratory infections, the myocarditis. In particular, I really don’t love the potential for death. What I love the flu for is divorced from these horrors, and lies in the pedagogical value afforded by teaching students about the history of influenza epidemics. Influenza epidemics are fascinating on a micro level, an evolving and mutating virus hitting the body with a slightly different impact every year. But flu season hits us on another level; as we collectively respond to epidemics it shapes our cultures, ideas, and traditions.

It was for additional information about the flu, among other examples from medical history, that I came to the collections of the College of Physicians of Philadelphia in January 2014. I was planning a new seminar on the history of medicine, and sought primary source materials for both lectures and for supplemental independent student research projects. I also used my visit to look for materials useful to my other courses, which span various topics in the history of science, technology, and medicine from my home department as an assistant professor of history at the University of Massachusetts, Amherst.

Nearly every fall semester, I (shamelessly) use my position at the front of the classroom to proselytize getting a flu shot. As a historian of science, I use examples from history to make the argument that it is imperative that most healthy individuals should protect themselves from the flu, for their own health as well as the health of the collective public. With the opportunity afforded by a new seminar in the history of medicine, I came to the archives to strengthen these arguments.

One of the aspects of the 1918-1919 influenza outbreak that makes for such compelling classroom fodder is the fact that this particular strain disproportionately impacted healthy young adults. This flu was fast acting, with a shockingly high rate of mortality. It was a flu that would have ravaged, say, a community of college-aged students living in close proximity in dorms and small apartments. This morbid drama offers the perfect opportunity for teaching about epidemiology and the cultural impact of disease on populations.

The materials I collected during my time researching at the College of Physicians of Philadelphia provided me with a rich assortment of primary source materials to explicate the devastation wrought by the flu. These primary sources

London Ministry of Health. Reports on Public Health and Medical Subjects No. 4: Report on the Pandemic of Influenza 1918-1919. (London, 1920): 17.

London Ministry of Health. Reports on Public Health and Medical Subjects No. 4: Report on the Pandemic of Influenza 1918-1919. (London, 1920): 17.

are crucial, as I have found a major obstacle to teaching about the influenza outbreak (and indeed, convincing students of the need for a yearly flu shot) is debunking the myth that the common flu is at worst a mere annoyance. Many students come to the classroom assuming the flu is nothing more than a more severe cold. One student—not alone in her query—asked why people no longer die from the flu. There are many misconceptions about the disease, and a historical approach can help us address them.


Using materials collected during my research, I developed a lesson beginning with the origins of the influenza outbreak. This history offers a complex view of epidemiology, as the flu spread with rapidity not just by sneezes and coughs, but also by the opportunity afforded by the waning years of WWI, when soldiers congregated in close quarters and civilians joined in large celebrations to mark the end of combat. These gatherings provided the perfect storm of disease propagation.

Unfortunately, this perfect storm was met with a flu unlike most others. This was a flu with an extremely high mortality rate. The chart below dramatically depicts the devastation wrought, with the high peak at the right side of the graph signifying the sharp uptick of deaths related to the flu as compared to earlier years’ epidemics.

A similar chart underscores the relative devastation among communities, particular in cities, by the flu. The figure below charts the total deaths in Philadelphia. Though the reproduction is of poor quality, the chart shows a spike in deaths in the mid fall of 1918. Two lines draw this spike: the outermost indicates the total deaths from all causes in the city, while the inner, nesting spike indicates the total number of deaths from influenza alone. This chart is chilling. The dramatic increase of deaths in Fall 1918 is clearly due almost exclusively to the outbreak of the flu.

Such images certainly lay the groundwork for teaching about the impact of the epidemic, yet numbers and line graphs only go so far in driving home historical reality. To make the winter of 1918-1919 come alive for students, I employ a seemingly benign table of figures to create a hands-on activity that packs a punch.

United States Department of Commerce. Special Tables of Mortality from Influenza and Pneumonia in Indiana, Kansas, and Philadelphia, PA September 1 to December 31, 1918.

United States Department of Commerce. Special Tables of Mortality from Influenza and Pneumonia in Indiana, Kansas, and Philadelphia, PA September 1 to December 31, 1918.

The table below lists the number of cases of influenza (and related pneumonia) among U.S. troops in camps and barracks. I use this example to mimic, somewhat, the close proximity with which our students live (though presumably they do so in a bit more luxury than that afforded by military barracks). In class, I annotate the image, replacing the numbers with figures reflecting the size of the class. I then ask students to take index cards corresponding to the first week, then the second, and so on. Over the course of our simulated autumnal flu season, we see how many students survive into January. This never fails to hit home.

Undoubtedly morbid, this exercise is nevertheless highly effective if implemented with care. Students gripping slips of paper can look around the classroom and begin to internalize what it might have been like, in those days before flu shots, to experience such a dramatic loss of life in their community, to live in fear of succumbing to this pervasive death themselves.

This exercise brings the historical reality of the epidemic from mere charts and tables, and underscores its human aspect.

This is why I love history. Collecting source material from the past—even the seemingly dull charts and graphs full of raw data—helps us understand the social, cultural, and political impact of events of the past. As students more fully comprehend the historical import of this moment in time, I allow them to explore a rich variety of sources related to the flu. One of the most valuable resources I obtained from my visit to the archives came in the form of a thick portfolio of clippings from local Philadelphia newspapers, magazines, posters, and other ephemera produced during and after the peak of the epidemic in 1918 and 1919. The bound collection is full of examples ranging from gruesome images of mass graves within city limits, to published reminders to citizens of hygiene recommendations like handwashing, drinking water, and, improbably, rinsing fruit.

These documents enrich students understanding of the history of medicine in ways my lecturing along cannot convey. They

London Ministry of Health. Reports on Public Health and Medical Subjects No. 4: Report on the Pandemic of Influenza 1918-1919. (London, 1920): 293.

London Ministry of Health. Reports on Public Health and Medical Subjects No. 4: Report on the Pandemic of Influenza 1918-1919. (London, 1920): 293.

allow students to read and experience it as if among the historical actors they are studying. The documents provide important opportunity for critical thinking and historical analysis, placing each within a multifaceted context. The documents, the materials I collected while conducting research at the College of the Physicians of Philadelphia, are crucial tools in my attempts to teach the history of medicine.

Of course, the collections I examined contain far more than only materials on the flu epidemic of nearly a hundred years ago. I feverishly photographed text and images from myriad sources in the collection, helping develop lectures on Progressive Era mental health policies and how these were related to themes of nationalism, tied to the emergence of psychology as a scientific profession. I transcribed documents related to the Northampton Lunatic Hospital, which was once situated just miles from the classroom where I teach. I collected countless ephemera – advertisements, promotional materials, product labels, and essays by medical professionals – on various (and often appallingly humorous in their dated sexism) aspects of women’s health.

My time in the reading room was not just professionally productive, but highly enjoyable, punctuated by laughter over old texts that did not quite stand the test of time, by jaw dropping moments, and by sober reflections on the impact of disease. I left the archives armed with hundreds of photographs and dozens of pages of notes, as well as new friendships forged with staff at the Historical Medical Library and Mütter Museum. I have since directed students to the collections, with one spending time in the archives and others using digital collections for various research projects.

Scrapbook of newspaper clippings (September 14, 1918 to March 1, 1919) concerning the influenza epidemic in Philadelphia, 1918-1919. Philadelphia, PA, 1919.

Scrapbook of newspaper clippings (September 14, 1918 to March 1, 1919) concerning the influenza epidemic in Philadelphia, 1918-1919. Philadelphia, PA, 1919.

Perhaps you should take it with a grain of salt, as I’m a self-proclaimed fan of the flu, but I cannot recommend more highly the collections or the experience of working at the archives of the College of Physicians of Philadelphia.