The Theorist’s Doctrine and the Collector’s Technique: On The Historicity of Expertise in Microbiology

How does an expert transmit expertise? What genres of scientific writing are available for doing so? Does the choice of genre matter in the long run? In this essay, I approach these questions by comparing two monographs published in the mid 1940s in the field of microbiology. While the works shared a concern with life at its smallest, they were written in different genres. One, entitled L’évolution physiologique: étude des pertes de fonctions chez les microorganismes, was a general survey of research on microbial nutrition.¹ The other, called Pure Cultures of Algae: Their Preparation and Maintenance, was a manual of techniques for cultivating microscopic algae in test tubes.²

The survey and the manual followed different conventions.³ The survey, L’évolution physiologique, took a synoptic view of its topic. It summarized and synthesized not only the work of its author, André Lwoff (1902–1994), but also that of numerous colleagues. At the time, Lwoff directed the Department of Microbial Physiology at the Pasteur Institute in Paris.⁴ His book organized the heterogeneous mass of data on microbial nutrition according to a general theory. Lwoff called the theory, first proposed in his doctoral thesis in 1932, “the doctrine of regressive physiological evolution.” It held that, as life evolved, living things gradually lost their ability to perform various metabolic functions. To compensate, they had to obtain specific substances in their diets, called growth factors. In L’évolution physiologique, this theory served to consolidate decades of diffuse findings on microbial nutrition into a coherent point of view.

The manual, Pure Cultures of Algae, was at once more technical and more intimate. Its author, Ernst Georg Pringsheim (1881–1970), was a German-Jewish phycologist (a scientist who studies algae) living as a refugee in England.⁵ He wrote the manual to provide readers with the knowhow to work with cultures of microalgae. Before fleeing continental Europe, he had directed the Institute of Plant Physiology at the German-speaking Charles University in Prague. There, he had amassed an impressive collection of cultures, refining his techniques in the process.⁶ In the manual’s preface, he explained, “My object is to show that it is by no means difficult to acquire the necessary skill.”⁷ The chapters that followed detailed the materials and protocols that he had found efficacious, such as the “soil-and-water culture method,” in which he used pasteurized soil as culture media, thus replicating the algae’s natural habitat within the confines of the test tube.⁸

The choice to publish in one genre or another reflected and reinforced existing differences in professional identity. Lwoff and Pringsheim were aware of their differences, which had erupted in a brief spat between them in the 1930s. After availing himself of strains from Pringsheim’s collection of microalgae, Lwoff published several articles describing how they fit into his theoretical schema.⁹ These algae were colorless and unable to perform photosynthesis. In nature, they were saprophytes, organisms that lived off decayed organic matter. Grown in a test tube, they needed a supplemental source of carbon. Lwoff pointed to this as evidence of regressive physiological evolution. Photosynthetic green algae could assimilate atmospheric carbon, whereas their saprophytic evolutionary descendants had lost that ability.

Pringsheim took umbrage with Lwoff’s theorizing. He published a critical response, writing, “As laudable as the effort toward a clear demarcation of nutritional forms is, several objections must be made against the generalizations that Lwoff has constructed upon an all-too-narrow foundation. In principle, I think highly of his maxim … but before reaching valid rules, much more must be known.”¹⁰ Pringsheim then provided counterexamples that did not fit neatly into Lwoff’s theoretical view. Privately, he wrote to Lwoff, “I would like to emphasize particularly that I am not against theories as such, but only against rash ones, which disquiet the scientific world without being conducive to progress.”¹¹

Pringsheim’s manual was a testament to his conviction that “much more must be known.” Unlike Lwoff’s survey, it did not advance any overarching doctrine. Rather, it described recipes and procedures matter-of-factly. Pringsheim saw the mastery of technique as a necessary first step in a vast endeavor, opining, “Nobody should therefore overlook the probability that we are at the threshold of a scientific edifice which must be built sooner or later, comprising the specific ecology and physiology of organisms of which only morphological data are as yet known.”¹²

Upon publication, Lwoff’s and Pringsheim’s monographs were both received favorably. One reviewer of L’évolution physiologique called it an “excellent survey in the field of microbiological nutrition,” in which Lwoff “marshals his facts well and makes a convincing argument.”¹³ A review of Pure Cultures of Algae extolled, “In this well-digested booklet of Professor Pringsheim, scientific workers will have the benefit of the experience of an outstanding scientist who has devoted 35 years to intensive research in algal culture.”¹⁴

Over time, however, Lwoff’s theory aged appreciably, whereas Pringsheim’s edifice of culture techniques stood strong. In a Festschrift dedicated to Lwoff in 1971, the microbiologist Roger Stanier called L’évolution physiologique “something of a war casualty.”¹⁵ Indeed, because published in Paris under National Socialist occupation, the book did not circulate outside of France until the end of the Second World War. Because the book “greatly influenced [Stanier’s ] scientific thinking,” he urged Lwoff in 1950 to prepare a revised edition for translation into English.¹⁶ In the interim, however, Lwoff’s scientific interests had turned away from microbial nutrition towards viruses, and the project of revising and translating his old book had little urgency. Rereading the book twenty-seven years after its publication, Stanier remarked, “It could not be recommended to anyone under the age of 35, for whom biology begins with the double helix.”¹⁷ Even prior to the upheaval wrought by biology’s molecular turn, compelling alternatives to Lwoff’s theory of regressive physiological evolution had emerged.¹⁸ In Stanier’s words, “Lwoff’s general view of the course of physiological evolution represented only half the story…. The generally negative slope of physiological evolution perceived in 1944 by Lwoff now assumes its proper place as one component of a more complex evolutionary curve.”¹⁹ L’évolution physiologique became known as “an important and amazingly one-sided book … which grandly neglects progress.”²⁰ It is now something of a relic, revisited by historians of science to evidence the peculiarity of biology in France in the first half of the twentieth century.²¹

In the meantime, Pure Cultures of Algae has gone through numerous reeditions (most recently in 2016) and was translated from English into Pringsheim’s native German.²² The techniques and recipes it contains remain staples of the phycologists’ repertoire and reappear frequently in current manuals and handbooks in the field.²³ The most impressive testament to the longevity of Pringsheim’s expertise, however, is not the manual, but the persistence of his collection itself. On the initiative of his students and successors, it became the basis of four of the largest collections of algal cultures worldwide. Together, these collections now furnish much of the phycological community with its research materials.²⁴

The history of these two monographs suggests that, when it comes to the transmission of expertise, genre matters. Lwoff’s survey relied on a theoretical doctrine to encapsulate the current state of his field. As the field changed and new findings arose, that doctrine lost much of its relevance. Pringsheim’s manual taught its readers his techniques, educating them in what the historian of science Hans-Jörg Rheinberger calls “the choreography of how to get at results.”²⁵ This practical know-how, while less glamorous than a flash of theoretical insight, has proved immensely fecund in the long term.²⁶ Rather than imposing a conceptual order on existing findings, Pringsheim’s manual offered a generation of new researchers the chance to make their own.

Charles A. Kollmer is a PhD student in history at Princeton University, concentrating on the history of the modern biological sciences.