Nineteenth Century

French Clinical School

Modem Western medicine emerged in France at the Paris Medical School during the first half of the nine­teenth century. After the French Revolution, political developments and a new philosophical outlook radi­cally changed the theoretical and institutional bases of medicine.

The French medical revolution was ushered in by an important change in approach. Arguing that it was not necessary to discover the ultimate causes of health and disease, early leaders of the Paris Medi­cal School, such as Pierre J. Cabanis and Philippe Pinel₁ postulated that physicians could perceive the effects of disease and apprehend the relationships between the disease and the patient, accessible to observation only at the bedside. Thus, only the incon­testable truths of sensory perception had validity in any attempt to understand health and disease. These phenomena were too complex and variable to be placed into the straitjacket of a specific medical theory. Stress was to be placed on practical problem solving, with sense impressions providing the only reliable data.

This skeptical empiricism gave rise to a new method: “analysis.” Disease was composed of many symptoms and signs, and these confusing combina­tions appeared sequentially at the sickbed. The most important task was to record the regular order of such manifestations, correlate them with physical signs, and thus recognize simple patterns. Eventu­ally, practitioners would be able to discern specific disease entities and finally classify them. Pinel urged physicians to walk the hospital wards fre­quently, notebook in hand, recording the hourly and daily progression of illness.

Emphasis on the physician’s powers of observation increased the importance of physical diagnosis and expanded the techniques employed in eliciting physi­cal signs of illness. Until this time, practitioners had relied almost entirely on their patients’ accounts to reach a diagnosis. Although the clinical history re­mained important, French physicians began to ap­ply new methods starting with Jean N. Corvisarfs direct percussion in 1808, the employment of a stethoscope by Rene T. H. Laennec in 1816, and indirect percussion of the body with a plessimeter designed by Pierre A. Piorry in 1826. These proce­dures were, of course, also based on the premise that certain organs in the patient’s diseased body suf­fered a number of structural changes.

Thus, another fundamental development of the Paris Medical School was pathological anatomy, the study of localized changes in bodily organs accom­plished through systematic postmortem examina­tions of the thousands of patients who died in hospi­tals. Correlating clinical symptoms and signs with specific organic lesions enabled practitioners to rede­fine particular disease entities and understand the underlying structural defects. Such Clinicopatho- Iogical correspondences expanded medicine’s knowl­edge of diseases, their effects, and natural evolution. As a corollary, French physicians became more inter­ested in improving their diagnostic rather than their therapeutical skills. ’

Another tool, the “numerical method,” was intro­duced in 1828 by Pierre C. A. Louis to compare clinical findings and identify through medical statis­tics general disease characteristics as well as the efficacy of traditional therapies. Although this ap­proach initially raised a storm of protest among prac­titioners who felt that statistical calculations tended to obscure the significance of individual clinical variations, the method launched a new era of clini­cal investigation, replacing intuitive and impression­istic decision making at the bedside.

By the mid-nineteenth century, however, the French school lost its undeniable leadership in West­ern medical practice. Although tremendously fruit­ful, the clinical approach based on bedside observa­tions and postmortem findings had its limitations. Consciously ignored were questions concerning the causes of disease and the nature Ofbiological events Surroimding the phenomena of health and disease. What had been a realistic approach in an era of speculative chemistry and physiology, imperfect mi­croscopes, and nonexistent pharmacological knowl­edge around 1800 became an anachronism 50 years later. Further answers had to be sought in the labora­tory, not just at the sickbed.

German Scientific Medicine

Before the eclipse of the Paris Medical School, Ger­man medicine began to emerge from its earlier, speculative period, frequently labeled “romantic.” From 1800 to 1825 physicians in the politically di­vided German states made a serious attempt to es­tablish a “science” of medicine using criteria from the critical philosophy of Immanuel Kant. But their efforts were doomed given the elementary state of knowledge of what we consider to be the “basic” medical sciences: anatomy, physiology, biochemistry, pathology, and pharmacology.

By the 1830s, however, the foundations had been laid for less ambitious but more fruitful investiga­tions into the phenomena of health and disease. The 1834 Prussian-German Customs Union and exten­sive railroad network brought a measure of eco­nomic prosperity to the German states, enabling them to support the reform of their autonomous uni­versity system. Armed with an ideology of pure re­search and lack of concern for immediate practical results, German physicians went to work in aca­demic laboratories and dissecting halls. The empha­sis on and prestige accorded to the pursuit of intellec­tual activities was eagerly supported by the highest authorities, who perceived such scientific enter­prises as enhancing national prestige.

Studies in physiology, microscopic anatomy, em­bryology, as well as comparative and pathological anatomy flourished.

Germany’s university system played a central role in the development of scientific medicine in the West after 1840. Unlike the near monopoly of French academic studies in one city, Paris, there were more than 20 institutions of higher learning scattered throughout the German states, each self­governing and intensely competitive. Since degree requirements included the submission of disserta­tions based on original research, the stage was set for a spectacular increase in scientific activity once the universities had established prestigious profes­sorships and built adequate laboratory facilities. Medical research became a respectable career, made possible by the proliferation of fellowships and assis­tantships. Successful individuals were rewarded with academic posts and further facilities, leading to a dramatic rise in scientific professionalization and specialization.

Even in clinical disciplines German academics with proper research experience edged out outstand­ing practitioners. A whole generation of physicians who had trained abroad — especially in Paris - returned with a knowledge of physical diagnosis and pathological anatomy. A new bedside approach com­bined the French methods with German chemical and microscopic examinations based on a growing understanding of human physiology and physio­pathology.

The quest for greater diagnostic precision was aided by the design of new tools for visualizing dis­ease. In 1851, Helmholtz described the ophthalmo­scope, an instrument capable of directly exposing eye disorders and testing visual acuity. The success­ful assembly of a laryngoscope by Johann N. Czermak in 1857 permitted inspection of the throat, especially the larynx and vocal cords. Visualization of the esophagus was accomplished in 1868 by Adolf Kussmaul with an esophagoscope, and the bladder came to be observed with the help of the cystoscope, invented by Max Nitze in 1877. Finally, in 1895, Wilhelm C. Roentgen, a physicist, discovered the rays that carry his name. Henceforth, X-ray photo­graphs and fluoroscopes became common features in clinical diagnosis, especially that of chest diseases.

German advances in the basic medical sciences and clinical diagnosis were not matched at the therapeutic level. In fact, a better understanding of disease processes often led to skepticism - even nihilism - regarding possible cures. To be sure, the conceptual advances in Imderstanding disease were impressive and promised further breakthroughs. At the same time, greater technological assistance and diagnostic complexity shifted medical care to hospi­tals and clinics, significantly raising costs. But the actual practice of medicine remained unaffected. Although the fledgling pharmaceutical industry be­gan to purify a number of traditional remedies and develop a few new drugs, therapeutics lagged. Translating scientific understanding into convinc­ing practical results had to await the development of vaccines, sera, and antisepsis based on a knowl­edge ofbacteriology.

Germ Theory

Since the time of Hippocrates, Western practitioners had blamed factors in the atmosphere for the appear­ance of infectious disease. A “miasma” composed of malodorous and poisonous particles generated by the decomposition of organic matter was implicated in a broad array of fevers, including plague, malaria, and yellow fever. Speculations about the nature of these miasmatic specks waxed and waned, from Girolamo Fracastoro’s seminaria, or “seeds of disease,” in 1546, to microscopic “worms,” or multiplying ferments, zymes, proposed by William Farr in 1842. However, physicians remained generally skeptical of theories that implicated microscopic substances in the genesis of complex disease entities. Moreover, their rudimen­tary microscopes only added to the confusion by re­vealing myriad objects.

Given the clinical behavior of the most common nineteenth-century diseases such as typhus, cholera, typhoid, and yellow fever, most physicians accepted the notion that they were not directly contagious and could occur only because of specific environmen­tal conditions. This anticontagionist posture was strongly reinforced by political and economic groups that sought to avoid the imposition of costly quaran­tines. But others argued that certain contagious dis­eases, such as smallpox, measles, and syphilis, were indeed transmitted by living parasites.

In the 1840s, chemists, including Justus von Liebig, proposed that both contagion and miasma were actually “ferments,” consisting of self-repro­ducing particles of a chemical nature spontaneously generated during the decomposition of organic mat­ter. At about the same time, Henle, a German anato­mist, suggested that such particles were actually alive and behaved like parasites after invading the human organism. He believed that the causes of infectious disease could be found by a careful search for these parasites, believed to be members of the plant kingdom. The proof for this causal relation­ship between disease and parasites was contained in Henle’s three “postulates”: constant presence of the parasite in the sick, its isolation from foreign admixtures, and reproduction of the particular dis­ease in other animals through the transmission of an isolated parasite.

Thanks to the work of Louis Pasteur, a French chemist, fermentation and putrefaction were shown to be indeed mediated by living microorganisms. In 1857 Pasteur claimed that the yeast responsible for lactic fermentation was such a microorganism. In the early 1860s, Pasteur disposed of the doctrine of spontaneous generation, proving through a series of clever experiments that only by exposure to tainted air would processes of fermentation and putrefaction take place. Microbial life could not exist in any or­ganic medium that had been sterilized and subse­quently protected from outside contamination.

With the existence of microscopic germs and some of their actions firmly established, researchers such as Pasteur and the German physician Robert Koch began to study specific diseases. In 1876 Koch pub­lished his findings on anthrax, a deadly illness of animals, especially cattle and sheep. He provided the first proof that a specific microorganism could cause a particular disease in an animal. Koch’s new techniques for obtaining pure cultures and staining pathogenic bacteria further advanced the fledgling field of microbiology and led to a reformulation of Henle’s postulates. According to Koch, three criteria were needed to implicate a particular microorgan­ism in the etiology of a certain disease. First, the parasite must be present in every case of the disease and under circumstances that could account for the clinical course and pathological changes of that dis­ease. Second, this agent should not be present in any other disease as a fortuitous and nonpathogenic para­site. Finally, after being fully isolated from the sick organism and repeatedly grown in pure culture, the parasite should be able to induce the same disease if inoculated into another animal.

The last two decades of the nineteenth century witnessed an unprecedented string Ofbacteriological discoveries based on the Henle-Koch postulates, in­cluding the agents responsible for typhoid fever, lep­rosy, and malaria (1880), tuberculosis (1882), cholera (1883), diphtheria and tetanus (1884), pneumonia (1886), plague and botulism (1894), dysentery (1898), and syphilis (1905). Whereas Koch and his co­workers devoted much time to the development of technical methods for cultivating and studying bacte­ria, Pasteur and his collaborators turned their efforts toward determining the actual mechanisms of bacte­rial infection and host resistance. By 1900 not only were physicians able to diagnose the presence of spe­cific microorganisms in the human body and hence diagnose an infectious disease, but they possessed some knowledge concerning natural and acquired im­munity. In several instances, the latter could be suc­cessfully induced, a belated triumph of modem labo­ratory medicine.

GuenterB. Risse