The past twenty years have been an incredibly productive period in science studies. Still, because recent work in science studies puts a spotlight on agency and enabling situa tions, many practitioners in the field ignore, underplay, or dismiss the possibility that historically established, structurally stable attributes of the world may systemically shape practice at the laboratory level. This article questions this general position. Draw ing on data from a participant observation study of a university biology laboratory, it describes five features (...) of the institutional landscape that shape this laboratory's practice. (shrink)