Justus von Liebig: The Chemical Gatekeeper

Brock defines the curious appellation of his subtitle, “the chemical gatekeeper,” as “the ways in which Liebig acted as an entrepreneur and propagandist for the extension of chemistry’s boundaries” (p. ix). Framed in this way, the subtitle establishes the tenor of this first modern biography of Liebig very accurately—for Brock, one of the foremost historians of chemistry of our time, has taken the liberty of focusing on aspects of Liebig’s multifarious career that are not found in traditional accounts.

Traditionally, Liebig’s role in the development of academic organic chemistry is highlighted: at the backwater University of Giessen, in the 1830s, he established what became the premier European training venue for organic chemists in Europe. A good part of his success was due to his perfection of an efficient and accurate analytical apparatus and procedure, and to his prominent role in the development of organic chemical theory. These achievements receive their due in the first three chapters of Brock’s biography. But by 1840, Liebig withdrew from active leadership in the field to devote his attention to more practical, boundary interests of organic chemistry. It is to these post-1840 interests that Brock devotes the remaining chapters of his book. Moreover, he details these interests with a special focus on Liebig’s relationship with Great Britain, a nation that exercised great fascination on him and for which he felt great affection.

The titles of some of Brock’s chapters will readily convey what these boundary interests were: “Liebig and Commerce,” “Liebig and the Farmers: Agricultural Chemistry,” “Liebig and the Doctors: Animal Chemistry,” “Liebig on Toast: The Chemistry of Food,” “Liebig and London: The Chemistry of Sewage.” With the exception, perhaps, of Liebig and sewage, none of these topics has been ignored in the literature. But never have they been brought into context, interrelation, and synthesis as here. To all of these areas of practical chemistry, Liebig served as “gatekeeper” (in Brock’s sense): he attempted to bring to bear the reason and technique of chemistry—particularly, of course, organic chemistry—to improve them. He viewed chemistry as the central science for the modern age.

One might infer that Brock had written a triumphalist account of Liebig’s applied chemistry, but that is not the case. Rather, his account is complex and full of irony. Liebig was, by and large, an unsuccessful businessman. And his theories on plant and animal metabolism and nutrition, and on human diet, were, at best, only partly correct, often embroiling him in bitter running disputes with opponents who sometimes had more reason on their side. The details of all of this are fascinating in themselves and are also very illuminating about the increasingly intense interaction of science with commerce, industry, and government.

Yet Liebig’s overarching vision of how chemistry would provide insight and guidance to our understanding of boundary sciences and commercial activities did prove to be rapidly and extraordinarily fruitful. To a considerable degree, the ultimate success of Liebig’s “gatekeeping” was due to the activities of his students. They appear at every turn in Brock’s book. This leads me to note some slight restriction in Brock’s purview—perhaps inevitable, given the orientation he has adopted in this study. This has to do with a general eschewal of sustained, explicit analysis of the personal side of Liebig’s life and career after the first few chapters. For example, Brock never really conveys what made the Giessen research school so successful and what inspired such lifelong devotion to Liebig among his students. A few tracings of the individual careers of some of them would have put some flesh on this account.

The last two chapters of the book deal with Liebig’s public pronouncements about science, the final chapter being devoted to his more philosophical and historical meditations. Toward the end of his career, Liebig decided to investigate the roots of the English penchant for inductive and utilitarian science in the writings of Francis Bacon, then...