This article traces the shifting geography of 'street-level' science work in the East African city of Kisumu by comparing two generations of local workers in public health research -one working in the present, the other remembering work and the city thirty or more years ago. Contributing to literature on the interaction of science and place -how science has shaped the city (for example, Packard 1990), how the city can be read as an 'archive' of past inscriptions (Quayson 2010), or how it is made part of producing and legitimizing scientific knowledge (see, for example, Gieryn 2006) -the article focuses on the engagement of place and work in the envisioning, and remembrance, of civic projects: the city as 'man's method of expression' in pursuit of association and well-being, a layered work of pasts and futures (Mumford 1961); or as an ensemble of movements and work that calls forth the polis, a material 'space of appearance' through which one's participation (or not) in a larger social entity takes form (see Arendt 1951Arendt , 1958. 1 One's habitation and circulation in a city reflect and shape how (indeed, whether) one experiences the city as a civitas, and oneself as a citizen with entitlements and responsibilities. This civitas extends into multiple pasts (seen and used differently by different people), and forward by way of urban plans, visions and actions, and in the future's embodiment in urban infrastructures. In turn, citizenship can be threatened by erasure and amnesia, dispossession and fragmentation -and found again, or reinvented (see Arendt 1958: 198-9).'Street-level health work' is exemplary civic work. Focusing on citizens' bodies rather than material infrastructure, it is preoccupied with the continuity of life and the future well-being of the polis. Attending to the places and movements of public health research in an African city we discern their civitas -the 'public' in the notion of 'public health' -and attendant 'geographies of responsibility' PAUL WENZEL GEISSLER teaches at the Institute of Social Anthropology at the University of Oslo; he also works with the research group Anthropologies of African Bioscience at the Department of Anthropology, University of Cambridge. His current work is focused on medical research and intervention in Africa, with particular interest in the interaction between perceptions of time and materiality. His recent publications include The Land Is Dying (with Ruth Prince), and the edited volumes Evidence, Ethos and Experiment: the anthropology and history of medical research in Africa (with C. Molyneux) and Rethinking Biomedicine and Governance in Africa (with J. Zenker and R. Rottenburg). Email: p.w.geissler@sai.uio.no 1 For Arendt the polis is not merely 'the city-state in its physical location' but the 'organization of the people as it arises out of acting and speaking together', that is, a 'space of appearance ' (1958: 198). This polis relies upon the intentional work of those united by it; it 'does not survive the actuality of the movement which brought it i...