We present English translations of two French documents to show that the main reason for the rejection of Semmelweis's theory of the cause of childbed (puerperal) fever was because his proof relied on the post hoc ergo propter hoc fallacy, and not because Joseph Skoda referred only to cadaveric particles as the cause in his lecture to the Academy of Science on Semmelweis's discovery. Friedrich Wieger (1821–1890), an obstetrician from Strasbourg, published an accurate account of Semmelweis's theory six months before Skoda's lecture, and reported a case in which the causative agent originated from a source other than cadavers. Wieger also presented data showing that chlorine hand disinfection reduced the annual maternal mortality rate from childbed fever (MMR) from more than 7 per cent for the years 1840–1846 to 1.27 per cent in 1848, the first full year in which chlorine hand disinfection was practised. But an editorial in the Gazette médicale de Paris rejected the data as proof of the effectiveness of chlorine hand disinfection, stating that the fact that the MMR fell after chlorine hand disinfection was implemented did not mean that this innovation had caused the MMR to fall. This previously unrecognized objection to Semmelweis's proof was also the reason why Semmelweis's chief rejected Semmelweis's evidence.

In 2020, the BSHS hosted two major online events, the first of their kind in our collective experience. The first, a Twitter conference, was planned and accomplished before COVID-19 had quite been established as a serious global issue. The conference was planned, rather, as an innovation in travel-free conferencing, something that has been on the BSHS agenda since the IPCC report of 2018, calling for net-zero-carbon activity in all areas by 2050. As we discussed the Twitter conference, and watched the amazing energy, intellect and resourcefulness of its planners and hosts, we quickly saw that online delivery offered other advantages too – chiefly, wider participation. The pandemic offered the society a chance to take these lessons very boldly into the most important event of our scholarly calendar, which usually takes the form of an in-person annual conference, but this time was executed as an online festival.

In the wake of Stalin's death, many Soviet scientists saw the opportunity to promote their methods as tools for the engineering of economic prosperity in the socialist state. The mathematician Leonid Kantorovich (1912–1986) was a key activist in academic politics that led to the increasing acceptance of what emerged as a new scientific persona in the Soviet Union. Rather than thinking of his work in terms of success or failure, we propose to see his career as exemplifying a distinct form of scholarship, as a partisan technocrat, characteristic of the Soviet system of knowledge production. Confronting the class of orthodox economists, many factors were at work, including Kantorovich's cautious character and his allies in the Academy of Sciences. Drawing on archival and oral sources, we demonstrate how Kantorovich, throughout his career, negotiated the relations between mathematics and economics, reinterpreted political and ideological frames, and reshaped the balance of power in the Soviet academic landscape.

In February 2020, the British Society for the History of Science hosted its first entirely digital conference via Twitter, with the dual goals of improving outreach and engagement with international historians of science, and exploring methods of reducing the carbon footprint of academic activities. In this article we discuss how we planned and organized this conference, and provide a summary of our experience of the conference itself. We also describe in greater detail the motivations behind its organization, and explore the good and bad dimensions of this relatively new kind of conferencing. As the climate crisis becomes more acute and, in turn, the pressure to reduce the carbon footprint of academic activities increases, we argue that digital conferences of this style will necessarily become more central to how academia operates. By sharing our own experiences of running such a conference, we seek to contribute to a rapidly growing body of knowledge on the subject that might be drawn on to improve our practices going forward. We also share some of our own ideas about how best to approach digital conference organization which helped us to make the most of this particular event.

It is a cliché of self-help advice that there are no problems, only opportunities. The rationale and actions of the BSHS in creating its Global Digital History of Science Festival may be a rare genuine confirmation of this mantra. The global COVID-19 pandemic of 2020 meant that the society's usual annual conference – like everyone else's – had to be cancelled. Once the society decided to go digital, we had a hundred days to organize and deliver our first online festival. In the hope that this will help, inspire and warn colleagues around the world who are also trying to move online, we here detail the considerations, conversations and thinking behind the organizing team's decisions.