Whilst at dinner, an eminent teacher–scholar asked which pudding he should have that would best keep him awake, as he had a long evening ahead of marking papers. The next day also would be busy with a PhD student meeting and a seminar presentation. After debating the merits of sticky toffee pudding versus cheesecake, we all recommended he could have anything he wanted, as long as a double espresso accompanied it. How little has changed. As John Powers's meticulously researched study demonstrates, Herman Boerhaave was a similarly dedicated professor, renowned for his work ethic, punishing schedule and legions of protégés, though his Calvinist piety would probably have limited his indulgence in sweets.

Boerhaave was also not only diligent but brilliantly innovative, inventing a new ‘philosophical chemistry’ that not only served the pedagogical needs of his medical students, but also reframed chemistry as a form of natural philosophy essential to the university curriculum. Using a variety of archival evidence as well as a deft analysis of Boerhaave's influential textbook – Elements of Chemistry – Powers suggests (without a whiff of Whiggish bias) that Boerhaave and other seventeenth-century chemists undertook conceptual and experimental work that laid the foundations of the chemical revolution. Lavoisier was not Zeus, and ‘modern chemistry’ did not spring anew from his eminent head.

Powers also cogently grapples with current historiographic debates surrounding Boerhaave, particularly to what extent Boerhaave's Calvinism had an effect on his approach to chemistry and medicine. Did Boerhaave's intensely empirical stance have its basis in the work of seventeenth-century Dutch philosophers? These thinkers posited that observation and not the simple use of reason was key in quelling the passions so as to free one's mind from bias. Or did his empiricism stem directly from his Calvinist faith, his study of the natural world a means to praise God's creative plenitude? Powers instead effectively argues that Boerhaave combined these ‘philosophical’ and ‘Calvinist’ perspectives in his empirical approaches, and notes that he also did not hesitate to model complex chemical and medical phenomena with mathematics as well. The Newtonian physician Archibald Pitcairne taught at Leiden whilst Boerhaave was a student there, influencing Boerhaave's decision to incorporate ‘physico-mathematics’ in his chemical approach to medicine.

In establishing chemistry as a legitimate branch of natural philosophy within the university, Boerhaave not only had to position himself with regard to past chemical physicians such as Sylvius, but also considered the work of alchemists. Powers demonstrates that, in his incorporation of physico-mathematics into his work, Boerhaave did not slavishly adopt the acid–alkali iatrochemistry of Sylvius, his predecessor at Leiden, but built upon it. In his strategy to integrate chemistry fully into the Leiden medical faculty, Boerhaave criticized Sylvius for a lack of ‘disciplined self-restraint’ in his theoretical assertions (p. 99), whilst embracing Sylvius's use of chemistry as an important tool when analysing bodily fluids. In a fair-minded fashion, Boerhaave tested Sylvius's assertions (for instance that human salts were alkaline) in the laboratory, discovering that common salt contained in food passes out of the body in the urine. This result not only proved Boerhaave's point about Sylvius; it was also an important insight in chemical physiology.

And far from rejecting alchemy (after all, phosphorus was, Boerhaave reasoned, discovered by alchemical means), he used his methods of philosophical chemistry to subject alchemical tenets to laboratory testing. In particular, he scrutinized the claims of Eirenaeus Philalethes (George Starkey) and Wilhelm Homberg. Publishing his ‘De Mercurio Experimenta’ in the Philosophical Transactions, Boerhaave delivered a ‘devastating experimentalist critique of mercurialist alchemy and reflected his growing scepticism regarding the possibility of metallic transmutation’ (pp. 179–180). Although he had taught mercurialist theory in his classroom for nearly thirty years, Boerhaave ultimately (and I would say heroically) rejected it as another error removed from chemical study. Powers is correct when he states that ‘in his mercurialist experiments, the principles he employed for presenting knowledge in an effective and orderly way to students were the same as those for presenting a coherent philosophical argument’ (p. 191). Boerhaave's alchemical ‘failures’ were transformed into successes for the new experimental philosophy and the establishment of Enlightenment chemistry.

This is an excellent book. If I have any minor criticism, it is that I would have liked to see some more detailed and contextual comparison of Boerhaave's attempts to integrate chemistry into the university curriculum at Leiden with efforts at other universities. Despite this quibble, due to Powers's very fine study, Boerhaave now has his rightful place in the history of chemistry. Boerhaave has finally, as my colleague did, received his ‘just des[s]erts’.