Session: Working in biology: how laboratory and field practices shape biological knowledge (Nicole Nelson, Jesse Olszynko-Gryn, Kristoffer Whitney, Caitlin Wylie)

After World War II, laboratories around Britain began using two kinds of toads for human pregnancy diagnosis: the South African clawed toad Xenopus laevis and the ordinary British Bufo bufo. This talk examines the divergent sourcing strategies adopted by competing laboratories, and so moves beyond the dominant historical account of (a) pregnancy testing, which centres on a single large Xenopus laboratory in Edinburgh, and (b) the supply of laboratory animals, which posits a simple shift from a free market of small commercial dealers to centralised state control. While the Ministry of Health in Britain and the Department of Inland Fisheries in South Africa did regulate the postwar trade in Xenopus, alternative means of obtaining exotic and domestic toads also flourished. For instance, the Family Planning Association, a registered charity, sourced Xenopus from the private shipping and tourism company Thomas Cook and Son, and a few pathologists managed to breed their own stock on a small scale. Only a handful of large and specialised ‘pregnancy diagnosis centres' including the one in Edinburgh could afford the elaborate and expensive equipment required to maintain a healthy Xenopus colony, so many small hospital laboratories in London and the South of England preferred the locally abundant Bufo, which they could obtain and discard indiscriminately and so did not have to domesticate at all. Specialised commercial breeders continued to supply research and teaching laboratories with Xenopus and many other amphibians well after immunological test kits decisively replaced bioassays in the 1960s.