In the 1820s and 1830s the heart of power in medical London still lay in the alliance of laymen and medicosurgical elites. The power to act as arbiters of medical truth and its clinical use in correct social circles continued to reside in large measure in the hands of those who held key posts. To physicians and surgeons the Royal Colleges' ruling councils and the major hospital teaching posts offered such access to power. Behind them, conferring patronage, sat the lay hospital governors and financial officers, shoring up the medical men's authority or, on occasion, severing it.

INTRODUCTION: THE CRITICAL DECADES, 1802–1832

Bichat's death in 1802 did not go unnoticed. While not yet a totem for the pride and aspirations of the community, he was still lamented by many in the medical community who felt a claim on his memory. But what sort of claim was it? Had Bichat's ideas, the tissue pathology and the extended canon of pathology that crystallized around his teachings, as yet become insinuated into the marrow and sinew of Paris medical thought? It is not an easy question: Pathological anatomy, ironically, had no formal institutional structure, no official vehicle, until the mid-1830s, when my story in this volume stops. Because institutional changes evolved over such a long time, conventional institutional history cannot account for many of the subtle intellectual shifts that occurred. Such approaches fail adequately to track the infiltrative process through which the internal structure and external audience of the Bichatian system grew.

Yet when people, historians or the historical actors themselves, choose their heroes, they seldom do so randomly. In surveying the growth and assimilation of Bichat's ideas, I will therefore offer not only description of that infiltrative process, but I will also tender some tentative contextual explanations why those ideas were appropriated in certain ways by particular groups and individuals.

THE PROFESSIONAL SETTING

The intellectual and professional circumstances of English medicine in the late Georgian period were dramatically different from those across the Channel. That this was so does not necessarily reinforce the invidious comparisons many English observers at the time made at their own countrymen's expense. Indeed, the truth of the matter was that by the late eighteenth century English hospital planning, medical reform, and surgical anatomy teaching all had had significant impacts on their continental counterparts. Even so, the medical communities of England and Scotland, as the age of Napoleon drew to a close and its members began more broadly to engage the outside world, was in a rather fractious state. In reengaging, English medicine produced a suite of new professional structures. Those new structures, institutions, societies, and a number of other enterprises, including a rash of new medical journals, jostled one another and their ancient predecessors, while their various patrons and designers pursued a variety of interests. Among such interests were the tasks of fostering pathological anatomy and certain other elements, notably chemistry, of an emerging nineteenth-century scientific culture.

The desire to bring pathological anatomy, French-style or otherwise, into medical education and medical practice must be understood against the backdrop of the professional changes that were sought by the new men and their organizations.

THE EXODUS

By the 1820s the British medical world was becoming aware of an exodus of many of its brightest students to France. A migration of this magnitude was repeated and surpassed only a half-century later when a larger number of American, Japanese, and other student groups began trekking to Germany to observe the new laboratory medicine.

ATTEMPTS TO DISARTICULATE MEDICINE AND SURGERY

Throughout the Napoleonic period Michel Thouret, the Paris faculty's director and later dean, would have to struggle, alongside his patron Antoine Fourcroy and his lieutenant François Chaussier, to keep the institution they had crafted on course. Avid republicans all, these men formed its core, provided its ballast. They fought, as did Thouret's successor J. J. Leroux after the first director – dean's 1810 death, to preserve their creation against a series of revanchists.

PATHOLOGY, MEDICAL JOURNALISM, AND THE FRENCH CONNECTION AFTER WATERLOO

Rampant xenophobia had preceded the end of hostilities between France and England. After the Congress of Vienna those sentiments could not be sustained at that early intensity. As malign feelings receded, the new political atmosphere provided a framework in which medical thought might be more freely channeled. The emergence of a new genre of medical periodical, the review journal, for example, had begun before the end of hostilities: the Medical Repository, for example, was introduced in 1814. But after 1815 there was a noticeable increase in both the number of competing journals, and a concomitant desire to monitor Continental developments more closely. Suddenly in demand were the services of Anglophile Europeans like the polymathic Italian Augustus B. Granville, based in Paris, as well as the services of Continent-based Englishmen like James Clark in Rome. In 1816 Granville, for example, began to send résumés of scientific activity in Paris to the Journal of the Royal Institution, and of all medical proceedings to the Medical Repository. So began the process by which English physicians' angle of vision began to be widened, and their images of medicine abroad strengthened and focused.

At first this process, dependent as it was on stringers like Granville, was a desultory one.

The Père Lachaise cemetery in Paris is known to much of the world as one of the most remarkable monumental legacies of Napoleonic France. Opened in 1804, it is a grand baroque gesture made solid in granite and marble. Its monuments, massed and massive, embody the homage of an entire society to its famous and notorious. Nearly overgrown in a corner of the cemetery rests an unprepossessing stub of a monolith bearing the name “Bichat.” Only the most deliberate of wanderers in Père Lachaise would remark it.

Today medical historians revere the name of Marie-François-Xavier Bichat (1771–1802) as a founder of French scientific medicine. He is seen as a pioneer in the study of tissues and the father of dual medical traditions that came to include such luminaries as François Magendie and Claude Bernard in physiology and Théophile Laennec and Thomas Hodgkin in pathology. Thus it seems only natural that Bichat should be immortalized in the stone of Père Lachaise. But it was not always so. An odd tale looms behind the arrival of Bichat's remains, some forty years after his death, in this final place of rest.

By 1802, at the age of thirty, when today's physicians are often still in training, Bichat was already a respected, if not very elevated, member of the Parisian medical community.

To begin, a word of explanation and several words of thanks.

I cannot remember reading a book with an exposition based on selection principles quite like those I ended up using in this work. While the central account of the monograph is of persons who will be well known in at least bare outline to most readers, I have moved off (especially in the second half of the monograph) into territory that is considerably more arcane. Why, after sketching the evolution of pathological anatomy in its fullest development in France, should one allow the story to veer off on paths that seem to fall short of the traditional “important” feat of progress?

The answer, as the reader might expect, lies in my reasons for writing the book in the first place. I have not intended to provide a symmetrical comparison of French and British pathology in the era before the microscope, but sought rather to look at the reception of a suite of medical ideas in one culture after examining how they unfolded in another. My intention was to study the development of pathological anatomy and, in particular, tissue pathology in France and then scrutinize various attempts to implant it in England.

In the first three chapters we saw some of the varied roles that experiment can play in the choice between competing theories or hypotheses. In the case of parity nonconservation, the experiments of Wu, Garwin, and Telegdi and their collaborators were “crucial” experiments that decided the issue between two classes of theories: those that conserved parity and those that did not. The Princeton experiment was an example of a “convincing” experiment. It provided the evidence that persuaded the majority, though not all, of the physics community that CP invariance was violated. That episode also produced experiments refuting or eliminating most of the alternative explanations to CP violation. This was an example of a pragmatic solution to the Duhem–Quine problem.

The episode of the nondiscovery of parity nonconservation illustrated two other roles for experiment. The experiments on Mott double scattering at 0° and 180° did not lead to refutation or rejection of Dirac's theory. They did lead to various unsuccessful ad hoc modifications of the theory and to repetitions of the experiment until the discrepancy was resolved. The double-scattering experiments at 90° and 270°, which, in retrospect, should have been interpreted as showing parity nonconservation, did not seem to have much effect at all. They did not lead to any new theoretical explanations, even though it was recognized at the time that existing theory provided no explanation for their results, nor did they lead to much further experimentation. Their significance was not realized at the time; they were first neglected, and then forgotten, until 1957.

In the previous chapter we mentioned two earlier experiments, performed by Cox, McIlwraith, and Kurrelmeyer, “Apparent Evidence of Polarization in a Beam of β-Rays,” and by Chase, “The Scattering of Fast Electrons by Metals. II. Polarization by Double Scattering at Right Angles,” that, at least in retrospect, provided evidence for nonconservation of parity in the weak interactions. The anomalous nature of those experimental results seems to have been fairly well known (we shall discuss this later), although the exact nature of the anomaly was not clear. However, one thing is certain: The relation of those results to the principle of conservation of parity was not recognized or understood by any contemporary physicists, including the authors themselves. Before discussing the reasons leading to this conclusion, it is worth examining in some detail what those results were, how they were obtained, and whether or not they really provided evidence for nonconservation of parity.

DID THE EXPERIMENTS SHOW NONCONSERVATION OF PARITY?

The intellectual context for those experiments involved the desire to demonstrate the vector nature of electron waves. This had started with the suggestion of de Broglie in 1923 that just as light exhibited both particle and wave characteristics, so should those things that we normally consider particles exhibit wave characteristics. This had been brilliantly confirmed in 1927 in an experiment on the diffraction of electrons by crystals performed by Davisson and Germer. This idea of electron waves was then combined with the concept of electron spin, which had been used by Uhlenbeck and Goudsmit to explain certain features of atomic spectra.

In this chapter we shall examine the history of the 1957 discovery of parity nonconservation, or the violation of mirror symmetry in nature. The discovery began with the suggestion that parity was not conserved, a suggestion put forth as a means of solving a particularly vexing problem that had resisted all conventional attempts at solution. The revolutionary nature of this suggestion was clearly recognized by the authors, and that led them to suggest other experiments that would test the principle. Those experiments were then performed, with positive results, and that led to the overthrow of the principle of mirror symmetry. They were thus “crucial” experiments, in the sense that they unambiguously, and within a short period of time, decided the issue between two theories (or classes of theories) of some importance for a certain segment of the scientific community. We shall examine the evidence for this in Section 1.1.

What was not realized at that time was that there were already two experimental results in the literature, published in 1928 and 1930, that had the same physical and logical content and showed parity violating effects, but whose implications and significance were not recognized either by the authors or by any member of the physics community until after 1957.

It seems clear, then, that it is not only the physical and logical content of an experiment or series of experiments that determines its crucial nature; other conditions must also be present.

If, as I have argued, experiment plays such an important role in physics, then we must have good reasons if we are to believe that experiments give us accurate and reliable information about the physical world. In the next four chapters we shall discuss several questions relating to this issue, including how we come to believe rationally in experimental results, and the question of fraud in science.

In this chapter I shall address a question raised by three historians of science, Peter Galison, Andrew Pickering, and Gerald Holton: the question whether or not the theoretical presuppositions of an experimenter influence the experimental results. There is at least an implicit suggestion that presuppositions may cause an experimenter to exclude data, to overlook unexpected results, and to either overlook or misestimate important sources of error. In Chapter 8 we shall examine the related issue of theoretical or experimental bandwagon effects: whether or not experimental results in disagreement with an accepted theory tend to be suppressed or excluded, and whether or not there is a tendency for experimental results to be in agreement with previous measurements.

In his study of gyromagnetic experiments in the early twentieth century, Peter Galison points out that theory often provides experimenters with quantitative predictions that enable them to find the effects sought or to separate an effect from background sources of error. Such a prediction may also influence the decision to stop looking for such sources of error, declare the experiment ended, and report the result, which may be that predicted by theory.

In this chapter we shall examine the role of the experiment of Christenson, Cronin, Fitch, and Turlay in refuting the concept of invariance of physical processes under CP (combined space inversion and particle–antiparticle interchange). We shall see that this experiment was a “convincing” experiment. It persuaded most of the physics community that CP was violated. There were, however, several alternative explanations offered to explain this result, and we shall also discuss the role that experiment played in refuting or eliminating these alternatives. We begin with the historical background of the experiment and then examine both the experiment itself and the reaction of the physics community to it.

HISTORICAL BACKGROUND

From the time of their discovery in 1947 by Rochester and Butler, the neutral K mesons, or kaons, have exhibited odd features. One puzzle, that certain K particles of equal masses and lifetimes (called θ and τ) seemed to decay into states of opposite parity, was resolved by the discovery of parity nonconservation (see Chapter 1). An equally puzzling observation concerning the kaons was put this way by C. N. Yang: “While the [se] strange particles are produced quite abundantly (say 5% of the pions) at BeV energies and up, their decays into pions and nucleons are rather slow (10−10 sec). Since the time scale of pion-nucleon interactions is of the order of 10−23 sec, it was very puzzling how to reconcile the abundance of these objects with their longevity (1013 units of time scale).”