The book is now considered a landmark in the history of bacteriology because in its first part, “On Miasmata and Contagion,” the author anticipated the cause of infectious diseases to be an organic element. For Henle, only “foreign” microorganisms had the ability to multiply and produce afflictions in the body of an individual. His analysis constituted the first modern germ theory proposal in Germany. However, the scientific community rejected Henle’s ideas because his observations were reminiscent of “fantastic” contagious theories from the past, and he was unable to provide conclusive proof that directly connected “germs” with specific diseases.2
Henle was a liberal activist of Jewish background who converted to Protestantism at a young age. As a medical student at the University of Bonn, he joined the student society Burschenschaft, a chapter of one of the earliest fraternities in Germany that inspired democratic and national movements in the early nineteenth century. Although branded as a reactionary in the scientific world, Henle shared the same political commitments of many young physicians around this time. In his work on contagion, he summarized the microscopic investigations that predecessors and contemporaries had made in multiple fields of the natural sciences and sought to bring order into the existing chaos regarding the origin of communicable diseases. He divided diseases into contagious, miasmatic, and miasmatic-contagious. According to Henle, contagious diseases were those that could be transmitted directly from person to person, such as syphilis, scabies, other chronic skin diseases, and hydrophobia. Miasmatic diseases were those an individual acquired from the environment without becoming contagious, such as ague, the feverish state of malaria. For Henle, the great majority of diseases fell into the miasmatic-contagious category because they first developed from the miasma of a particular place and then became contagious as they progressed. He considered that diseases such as typhoid, smallpox, measles, rubella, cholera, plague, dysentery, anthrax, influenza, and many others belonged to this category.
The fact that certain miasmatic diseases became contagious was the main logical evidence that Henle provided to support his theory on the organic origin of diseases. Microorganisms had the capacity of multiplying and existing parasitically in the sick body, which would explain why a disease could originate in one miasmatic place and then affect other healthy environments. Moreover, it was well known that, in the case of infection, the morbid matter increased from the moment it entered the body, and only living organisms had the ability to reproduce. Henle’s conclusions derived from life experiences rather than from laboratory science. He did not have the technology to help him identify specific pathogens. His observations stemmed mainly from studies he made on silkworm disease and smallpox.
The lack of experimental basis and scientific foundation led many physicians to dismiss Henle’s theory as a dead hypothesis that dated back to the Renaissance period, if not antiquity. The interesting part is that the miasma theory which skeptics used to explain disease communication at the time was also highly speculative and as old as Hippocrates. In his study, Henle claimed that miasma sympathizers had not been able to demonstrate where the poisonous matter in diseases came from. Nobody knew whether it belonged to the natural kingdom or not. Moreover, they considered the contagious agent a byproduct of the pathological process. As Henle observed, “‘The miasma,’ they say ‘is a noxious matter, originating externally and mixed with the air, which enters into the body, and produces disease even in infinite quantity, in the manner of poisons. The contagious agent on the other hand is a material which is formed by a disease and which occasions the same disease in others.’”3 According to Henle, contagion originated from the disease and not from external forces. Although the miasma theory could not define the exact origins of poisonous matter, one can see in this discussion how the German sciences were already evolving from the more speculative natural philosophy (Naturphilosophie) to the more definite natural science by beginning to value hard evidence.4 Before abandoning their immediate sanitary reforms and turning to another theory, physicians required something more than mere reflections. It took approximately thirty years for Henle’s student, Robert Koch, to produce the experimental techniques that proved germs to be the cause of many infectious diseases.
Henle’s contagionist theories proved significant at the height of migration movements and the colonial expansion the country experienced during the second half of the nineteenth century. This chapter studies the rise and popularization of the germ theory from the perspective of Germany’s colonial drive towards overseas colonies and the Prussian-Polish provinces in the 1870s and 1880s. It analyzes the anticontagionist movement that was prevalent in Europe until the 1850s and 1860s, when the experience of two cholera epidemics (1852–55 and 1865–67) led many physicians to reconsider sanitary methods of quarantine and isolation used to contain the disease.5 The chapter looks at debates about cholera etiology sparked by Koch’s discovery of the comma bacillus in 1883. In approaching this controversy, this work pays particular attention to the connections between disease, locality, and race that began to concern scientists as Germany became officially involved in overseas colonialism and physicians became actively engaged in colonial practices abroad and at home. It also examines Koch’s professional links to the Prussian-Polish provinces and the responses Poles gave to experimental science and the series of discoveries that placed Germany at the center of biomedicine and modern scientific developments.
The chapter shows how nineteenth-century medicine, far from being a neutral science, served to influence colonial and imperial agendas. Debates in the medical profession reflected the social and political tensions that went along with cultural transformations experienced in Germany in the 1860s and 1870s. Physicians actively participated in the defining moments of national unification and imperial expansion in German history. They helped shape projects for the new German nation and overseas colonies. Understanding the particularities of diseases and how to control them opened the doors for overt overseas colonialism and tightened national frontiers in the eastern borderlands. At the same time, the establishment of colonies as “laboratories of knowledge” strengthened the experimental movement in the German sciences. However, the emergence of the medical profession did not turn every physician into a state collaborator and enthusiast of an aggressive colonial policy abroad. A study of the period before Robert Koch’s major discoveries on the germ theory helps us to understand better the support that the medical profession gave to the policy of imperial expansion in the second half of the nineteenth century.
Anticontagionism and the Professionalization of German Medicine
Up to the late 1860s, anticontagionism was a powerful movement throughout Europe. Medical historian Erwin Ackerknecht claims that it originated in the last decades of the eighteenth century with debates over yellow fever and the ongoing frustrations physicians experienced in trying to contain this disease in colonial realms, the United States, and Europe.6 The first anticontagionists were physicians in the English-speaking world, especially in the United States, and the last to convert to contagionism and the germ theory were members of the British medical service in India.7 As states in east and central Europe failed to control the cholera epidemic of 1830–1831 by using antiquated methods such as quarantines and cordons sanitaires, the anticontagionist movement grew in influence and gained more followers. Far from stopping the spread of the disease, as many have observed, these techniques only served to exacerbate the poor conditions of people everywhere, contributing to one of the main factors that triggered a series of revolutions across Europe.
In Ackerknecht’s work, anticontagionism is portrayed as a broad trend in Europe associated with the rise of liberalism. Although the author has been criticized for delineating a too-simplistic, dichotomous model of scientific ideas without exploring possible intersections between the two camps, his analysis, delivered in 1947 to the American Association of the History of Medicine, remains a powerful statement on social medicine and the relationship between physicians and political agendas. More specifically, while some historians have criticized Ackerknecht for not taking into consideration specific national contexts, others have claimed that his description, aimed to be transnational, follows too closely the German model.8 Following the course of German history, anticontagionism is then defined as a set of liberal political and economic values whose decline came about “after the failed
