Long after its alleged demise, phlogiston was still presented, discussed and defended by leading chemists. Even some of the leading proponents of the new chemistry admitted its ‘absolute existence’. We demonstrate that what was defended under the title ‘phlogiston’ was no longer a particular hypothesis about combustion and respiration. Rather, it was a set of ontological and epistemological assumptions and the empirical practices associated with them. Lavoisier's gravimetric reduction, in the eyes of the phlogistians, annihilated the autonomy of chemistry together with its peculiar concepts of chemical substance and quality, chemical process and chemical affinity. The defence of phlogiston was the defence of a distinctly chemical conception of matter and its appearances, a conception which reflected the chemist's acquaintance with details and particularities of substances, properties and processes and his skills of adducing causal relations from the interplay between their complexity and uniformity.

Having coined the word ‘eugenics’ and inspired leading biologists and statisticians of the early twentieth century, Francis Galton is often studied for his contributions to modern statistical biology. However, whilst documenting this part of his work, historians have frequently neglected crucial aspects of what motivated Galton to establish his eugenics research programme. Arguing that his work was shaped more by social than by biological science, this paper addresses these oversights by tracing the development of Galton's programme, from its roots in a debate about political economy to his appeals for it to be taken up by sociologists. In so doing, the paper not only returns Galton's ideas to their original context but also provides a reason to reflect on the place of the social sciences in history-of-science scholarship.

The unconventional correspondence between physicists Albert Einstein and Felix Ehrenhaft, especially at the height of the alleged production by the latter of magnetic monopoles, is examined in the following paper. Almost unknown by the general public, it is sometimes witty, yet it can be pathetic, and certainly bewildering. At one point the arguments they exchanged became a poetic duel between Einstein and Ehrenhaft's wife. Ignored by conventional Einstein biographies, this episode took place during the initial years of the Second World War, but was rooted in disputes dating back to the early years of the twentieth century. The interesting intersection of a series of scientific controversies also highlights some aspects of the personal dramas involved, and after so many years the whole affair in itself is still intriguing.

This paper examines the development of British psychiatrist and psychoanalyst John Bowlby's views and their scientific and social reception in the United States during the 1950s. In a 1951 report for the World Health Organization Bowlby contended that the mother is the child's psychic organizer, as observational studies of children worldwide showed that absence of mother love had disastrous consequences for children's emotional health. By the end of the decade Bowlby had moved from observational studies of children in hospitals to animal research in order to support his thesis that mother love is a biological need. I examine the development of Bowlby's views and their scientific and social reception in the United States during the 1950s, a central period in the evolution of his views and in debates about the social implications of his work. I argue that Bowlby's view that mother love was a biological need for children influenced discussions about the desirability of mothers working outside the home during the early Cold War. By claiming that the future of a child's mind is determined by her mother's heart, Bowlby's argument exerted an unusually strong emotional demand on mothers and had powerful implications for the moral valuation of maternal care and love.

This paper aims to build an integrated account of the history of twentieth-century laboratories. The historical literature is fragmented, which has led to the impression that one type of laboratory has dominated, or has become more important than other types. The university laboratory has also unjustly shaped the conceptualization of other types of laboratory. This paper approaches laboratories as sites of organized knowledge production, and as entities engaged in different activities for different audiences at any point in time. Eight types of laboratory are identified, and their developments in the twentieth century are sketched. The two world wars of that century and models of innovation, building links between knowledge production in the laboratory and the impact of this knowledge outside the laboratory, are important catalysts of this history. The paper underlines that different types of laboratory have existed side by side, and continue to exist side by side.