Remembering Africanization: two conversations among elderly science workers about the perpetually promissory

Abstract The ‘Africanization’ of science after decolonization was replete with dreams. Claims to Africa's place in the high-modern world, expectations of national technological and economic progress, and individual dreams of scientific discovery, professional development and fulfilled careers drove scientific work and lives. The term Africanization, coined by the colonizers, reproduced colonial notions of race but also stimulated the imagination of mid-twentieth-century African scientists, who hotly debated and enthusiastically embraced it. Half a century later, some dreams have failed, but many more remain unfulfilled. This article examines two reunions of Tanzanian and European science workers – in Amani in 2015 and in Cambridge in 2013 – who had worked together in the decades after Tanzania's independence at Amani Hill Research Station, then one of Africa's foremost laboratories for research on malaria and other tropical diseases. It explores ideas of good science and experiences of social differentiation, divergent dreams and persistent tensions – and the role of joking in remembering these.


Introduction
This article introduces two transcribed conversations among elderly Europeans and Tanzanians about a moment in their past, when they lived together in one place -Amani Hill Research Station in Tanzaniain a particular mode of anticipation: the 'Africanization' of science. During the 1960s and 1970s, they jointly pursued a dream of social change: 2 the transfer of the tools of natural science, developed by colonial scientists to control disease and improve living conditions and productivity, to the erstwhile colonial subjects. Speaking about this promise after its partial fulfilment, half a century later, raises questions about what science should be, about race and other social differences, and about the relationship between present and past. In this article, we provide contextual information for these conversations, and reflect on how good science and social differentiation were discussed, and joked about, while remembering the tensions and promises of Africanization. The full, annotated transcripts of the two day-length conversations are published online as supplementary material 3 as part of this special issue, with two extracts in the journal, and it is our hope that this article will stimulate the reader to critically engage with this rich source material, which allows a unique insight into the subtle contradictions and ambiguities of the decades surrounding political independence, and of some scientists' dreams during that time.

Africanizing science
Between late 1950s and the 1970s, the 'Africanization' of the civil service, including educational and scientific institutions, was pursued, first by colonial administrators and then by new African governments (Aminzade 2013). What qualified as 'African' was debated: the departing colonial occupantsbut also, initially, young President Nyerere of Tanzaniaequated it above all with local residence and national commitment; others, including many post-independence politicians, opposed this as mere 'localization', advocating instead 'Africanization' sensu stricto, replacing 'white' civil servants with 'black' successors. 4 The timescale of Africanization was similarly contentious: while colonial administrators had hoped for decades of transition, independence came suddenly, and many new governmentsand their junior bureaucrats, who, until independence, had been curtailed in their ambitionspushed for a rapid transition.
In terms of content, some Tanzanians thought that post-independence administration, education and healthcare should be 'Africanized' based on African knowledge and values (Langwick 2011), while others pursued a mere takeover of colonial institutions and attendant opportunitiesless questioning the legacy of colonialism than seeking to appropriate it. Tanzanian dreams of Africanization thus variously referenced universalist aspirations and cultural returns, authenticity and mimesis. 5 Collective visions of civic renewal mixed with individual aspirations for the lifestyle and status of the colonial occupier. Yet, across divergent dreams, and despite the inherent mimetic violence of dreaming colonial-derived dreams bequeathed by one's oppressors (see Fanon 2008Fanon [1952), Tanzanians seem to have considered Africanization as unambiguously positive. 6 For the (former) colonizers, Africanization kindled more ambivalent dreams (see, for example, Bush 1999). Some civil servants' outright resistance to Colonial Office policies towards self-government was silenced after independence, when a new generation of European experts accepted, with more or less enthusiasm, a role as 'good decolonizers', helping to ready Africans to take over their countries (Cruise O'Brien 1972;Lachenal 2011;Tousignant 2017). Some may still have doubted the feasibility of rapid social transformation, but the global 'winds of change' and the new governments' watchful eye precluded dissent. Challenged by suppressed fears, material continuities and unacknowledged racisms, the hegemonic project of good decolonizationrelinquishing colonial guilt by displaying paternalistic virtuewas stabilized by positing the 'colonial' as the antithesis of the present, with independence as a radical watershed. 7 Africanization thus intertwined contradictory dreams: African visions of authentic and egalitarian societal development, with individual longing for appropriation and mimesis; and Europeans' yearning to atone for colonial oppression, seeking a virtuous place for Europeans in Africa, with a lasting desire for overseas opportunity and privilege (underwritten by enduring categories of differentiation). And yet Africanization's contradictions and conflicts did not (usually) erupt. 8 Even when Africanization took decades or never quite arrived, discontent was assuaged by its promissory nature. Just like 'development' or 'modernization', Africanization, as a future-orientated configuration of longing, incorporated and justified its own deferral, up to a point (Iliffe 1998;Geissler 2011;Lachenal 2016;Tousignant 2017).
In scientific institutions in particular, Europeans often retained senior positions until the late 1970s. Hence, the completion of Africanization in terms of research leadership coincided with the dusk of postcolonial nation building and the long 1980s economic and political decline and 'structural adjustment', which incapacitated scientific institutions across sub-Saharan Africa, leaving them without resources to produce quality knowledge, maintain membership in global science, improve local living conditions, or train future generations of scientists and provide them with dignified working conditions (Langwick 2011;Osseo-Asare 2013;Prince 2013;Geissler 2015;Droney 2014;Mika 2016;Geissler and Tousignant 2016;Tousignant 2017). 9 The promise of full scientific autonomy remained unfulfilled. Scientific Africanization, though formally achieved, never quite happened.
This article asks how this promise is remembered by elderly African and European science workers living in the era of twenty-first-century global healtha time when demands for Africanization, albeit not usually deploying this term, resurge in calls for capacity and infrastructure building (e.g.

Amani
Amani Hill Research Station is over a hundred years old and was once a worldleading scientific laboratory and a birthplace of Tanzanian science. It is situated in a vast botanical garden surrounded by forest in the Usambara Mountains of north-eastern Tanzania (Nowell 1933;Bald and Bald 1972;Geissler et al. 2019). During German occupation (from the 1880s to 1919) and the interwar British mandate, it hosted botanical and forestry research (see also Gerrets and Mangesho 2016). After the Second World War, it was repurposed for British-led research on malaria and insect-borne diseases, which continued after independence, when Amani became a key institution of the East African Common Services Organisation (EACSO 1960) (later the East African Community, which dissolved in 1977) (Beck 1973;Hazlewood 1979), with Tanzanian and other East African scientists progressively taking over the posts of their European predecessors. In 1979, Amani became a founding centre of the Tanzanian National Institute for Medical Research (NIMR). 8 See, for example, Amani, 34-5. 9 See, for example, the 'feeling of inadequacy of housing, and transport issuesbecause there were no grants anymore coming, which could furnish out the required, essential items and transport' (Mwaiko,Amani,94). Cross-references to the Amani transcript include the surname of the participant, the location, and the page number in the complete transcripts. Cross-references to the Cambridge transcript include the first name of the participant, the location and the page number in the complete transcript. On the question of names and forms of address used in the two separate reunions see p. S35, note 1, this issue.
Amani was most productive between the 1950s and 1970s. Around independence, it consisted of four laboratory blocks, administration and clinical buildings, an impressive library and its own guesthouse, as well as extensive accommodation. More than ten European scientists, who were housed, many with their families, in bungalows overlooking landscaped hills, worked with a well-trained African workforce of over a hundred, who lived in purpose-built workers' housing below the station and in separate staff 'camps' 10 in the botanical gardens. Most houses were connected to the Institute's piped water and electricity supply, as was the central laboratory complex, and were regularly maintained. These favourable conditions of scientific life lasted for much of the Africanization decades following independence, sustained by metropolitan resource transfers (supplemented by Cold War international aid), and with largely unchanged institutional frames, including pay scales, housing benefits and transport arrangements.
The staff's racial composition changed gradually. In 1966, a Dutchman became the last European Director, and in 1970 he handed over to the first African Director, a Kenyan former technician. The last resident British scientist and technicians left in 1976. From the early 1980s, the station's funding and scientific activity declined due to economic difficulties and externally imposed austerity, but also due to shifting global scientific prioritiesaway from basic (entomological, for example) research, and towards the era of 'global health' disease control trials. When, in the 1990s, British-led global health research on malaria prevention (re)commenced in Muheza, Amani's subsidiary field station in the malarious lowlands, Amani's staff began moving away. By 2005, Muheza had formally become the 'research centre', while Amani itself was demoted to 'field station' without scientists. By 2015, its staff numbered about thirty, composed mainly of caretakers and a handful of qualified elderly staff who regularly opened and locked up laboratories and offices and kept their workspaces meticulously clean. Gradually, since the 1980s, the scientific station had been transformed from a place of the futurepromising scientific contributions to the nation's well-being and an opportunity for personal advancementinto a place of the past, of waiting and quiet contemplation (Geissler and Kelly 2016). 11 Past lives in the present This station-in-stasis served as reference for two reunionsone in Amani's library in 2015, 12 the other in Darwin College, Cambridge, in 2013 13of twenty-seven elderly men and women who had worked and produced science in Amani 10 These were workers' settlements on agricultural estates and in government institutions (railways, forestry, etc.). 11 This stasis is characteristic of Amani Hill Research Station and numerous other older national research stations and institutes. However, elsewhere in Tanzania, at NIMR and other Tanzanian scientific institutions, world-class research is produced in international scientific collaborations. 12 The oldest Tanzanian participant had started working during colonial times, the youngest during the early 1980s (the current Station Director, participating ex officio, was a younger outlier). These 'generations' had different experiences but shared a strong group spirit and institutional knowledge. 13 European participants had been in Amani between the late 1950s and late 1970s; one had brought children and a grandchild, whose largely silent participation encouraged, and possibly shaped, the historical narrations. between the 1960s and the 1980s and had shared, from diverse vantage points, in expectations of change: of knowledge and of society, life courses and social relations. 14 The day-long conversations at the centre of each reunion were transcribed and carefully annotated to serve as a unique source for the history of scientific decolonization and early postcolonial medical research.
This format resembled historical 'witness seminars' (e.g. Reynolds and Tansey 2001), but while 'witnessing' emphasizes documentary value, the reunionswhich also involved informal conversations, slide and film shows, shared meals and outingswere also social events in the present. Participants carried photographs and keepsakes, met lost friends and introduced relatives, and shared old stories and jokes. The relational nature of memory was underscored: for example, when, during the Cambridge reunion, a bottle of 1970s Tanzanian mission wine was presented to the oldest participant as a gesture of filial respect and an occasion for communion. The Tanzanian participants' joint stay in the German-built station guesthouse similarly engendered commemorative conviviality. Assembling relations and heirlooms, architecture and landscape, the reunions thus provided not only complementary, oral historical information to fill gaps in archival documentation, but also an insight into the ongoing trade between past and present that is history.
European and Tanzanian retirees enjoyed these reunions. Their Amani had been a social laboratory for a community of curious people during a period of societal transformation. Remembering together, they enacted old rolesdisplaying, for example, professional success or disinterested scholarship, pragmatic realism or critical moral reflectionand re-enacted past relations among themselves, of generation and gender, scholarly authority and political (dis)agreements, negotiating and contesting the past in the present.
Since bringing together Africans and Europeans in one place would have been disproportionately costly, especially in view of the enduring material inequality between the two groupsthe lasting crux of Africanizationwe arranged two separate reunions, in Tanzania and Britain. This entailed upholding and emphasizing divisions, derived from colonial categories, between scientific workers, and separating a key social relationthat of 'race'which had characterized postcolonial Amani. However, this arrangement also allowed for a certain honesty, shedding light on the two groups' rather different experiences of Africanization (and of their present lives). While this separation also avoided potentially awkward confrontations, a simultaneous reading of the transcripts of the two conversations, with their poignant jokes, muffled expressions of anger and embarrassing offhand statements spoken within somewhat homogeneous groups, is morally and politically challenging. Since the resulting discomfort is at the heart of Africanization, we refrained from editing out tensions, except for removing some personal names. We hope that simulating a conversation that never happened will not exacerbate differences, but will facilitate understanding among, and for, a group of people who, in spite of superficial and political-economic differences, share an attachment to Amani and to the pursuit of science in and for Africa.

Good science and political doubts
Pride Different criteria of scientific quality and diverging evaluations of Amani's achievements between (and sometimes within) the two groups should not distract from their shared pride in scientific pursuits and commitments. In view of some European scientists' doubts about 'whether Amani would survive' political independence at all (Alister, Cambridge, 46), the continuity of scientific work was itself a source of pride. The last Europeans were in that regard satisfied that they had trained their Tanzanian successors (Jan, Cambridge, 47); and the first Tanzanian scientists proudly remembered how they had upheld scientific routines despite dwindling resources and growing practical problems (Mwaiko, Amani, 29-30) and how they had moved on from Amani to join the nation's leading scholars.
Good science requires originality and innovation. Voller's development of ELISA techniques (Graham, Cambridge, 32-3) and White's contributions to malaria control were exemplary, but Wilkes' mastery of a tricky mosquito agegrading technique and Raybould's eccentric naturalism were also celebrated during the European reunion. Despite some paternalistic claims to the contrary among the Europeans, such scientific drive and idiosyncrasy were found across both groupssuch as in Kilonzo's grappling with the technical challenges of introducing plague research for the nation (Kilonzo, Amani, 12-14), or the late Wegesa's enthusiastic parasitological investigationsunderlining that material conditions rather than inherent inclination account for the expression and outward productivity of individual curiosity and inventiveness (Mwaiko, Amani, 28-9). Stories about new lion pathogens or python parasites, the sighting of a rare forest owl or an unidentified tree-breeding crab betray naturalist wonder across racial groups; together with accounts of manual dexterity in mosquito dissection or crab catching, fly rearing or rat trapping, and proud displays of scientific vocabulary and style throughout the reunions, they reveal a common joy in performing science (see Geissler 2011;Tousignant 2017).
This also applies to the other foundation of good science: systematic work. Originality and orderliness had been unequally distributed by racialized colonial labour regimes, which, in practice, had limited Africans to technical roles. Perhaps this was why the Tanzanian science workers took distinct pride in technical routine skills and the virtues of fieldwork (see also Poleykett and Mangesho 2016). Yet, the satisfaction derived from technical prowess and thorough fieldwork was also found in their European colleagues' narratives: in Wilkes' lifelong mastery of mosquito dissection, which he continued teaching at the London School half a century later (see Kelly 2016), in Raybould's meticulous in vitro recreation of blackflies' complex breeding conditions, and in the much-extolled pleasures of field data collection.
An ultimate criterion of 'world-class' science was publications. European scientists referred in the reunions to each other's key papers and their impact, and Tanzanian colleagues recalled their first publications and conference talks as defining moments of scientific life and Africanization: 'so I became "Edith the scientist"' (Lyimo, Amani, 83). Older Tanzanian scientists celebrated their attainment of universal, metropolitan quality standards, for example through publication in respected British and American journals, and acknowledged senior Europeans' last word on validity (Mwaiko, Amani, 29). Younger Tanzanians instead took pride in recognition by senior Tanzanian peers, and praised their 'own' East African Medical Journal. However, the 1990s advent of project-based global health funding and the associated return of charismatic British long-term collaborators tended to reaffirm the role of 'international' standards (e.g. Lyimo, Amani, 82-3).
As for the particular African quality of good science, Tanzanian researchers vividly remembered attempts at adapting Amani's science to African conditions and their young nation's needs, for example by using local resources and plant materials, making do with diminishing resources, or contributing to national planning. 15 They were joined in such national projectssuch as preparations for the new Tanzanian capital, Dodomaby some younger European staff who had supported the progressive Tanzanian government, even if some of them in retrospect acknowledged that these scientific, and political, projects had failed (Vivianne,Cambridge,. Finally, good science should have an impact. The European scientists stressed how Amani's work had shaped subsequent global science, spawning thousands of papers, led to technological progress and policy, and contributed to leading collections such as the London Natural History Museum (Graham, Cambridge, 54). Meanwhile, Tanzanian scientists also emphasized the more social afterlives of their scientific workscholarly careers, scientific networks and national institutions. For them, Amani's legacy was also, importantly, their own positions in national academia and international organizations, the generations of students they had taught, and not least their children's education and families' growthand the respect and pleasures that come with that.

Doubts
Reunions celebrate achievements. But especially for the European participants, Amani's present, somewhat ruined, condition also triggered reflections on failureof Africanization, of their role in it, and of wider 1960s aspirations towards progress and justice. Tanzanian colleagues told a somewhat more nuanced story of scientific transformation and modest progress: Amani had been, they said, their 'school' from which they had successfully moved ahead elsewhere. Yet they, too, expressed chagrinand indeed 'shock'about the decay of their professional place of origin. 15 What Africanness might mean for science was sometimes addressed explicitly (Jan, Cambridge, 37-8) and was implicit in research projects (Kilonzo, Amani, 12-13; Matola, Amani, 35, note 74). Significantly, Amani's medicinal plants were repeatedly discussed in both reunions as potential alternative resources for health, and as a potential direction for a future Amani. In this regard, it is significant that Wegesa, the first African Director, erected at the end of his life a one-man research institute for African medicinal plants in his rural home in Kenya (with the torch of Tanzanian independence as its logo) (see Geissler 2016a).
The Europeans seemed to attribute Amani's failure at least partly to the 'big gap' between available and required scientific capacity among Amani's staff (e.g. Jan, Cambridge, 19-20) and the lack of time to turn the former technicians' recognized 'intelligence' into scientific qualifications (Alister, Cambridge, 24). Despite a palpable desire to speak well of former African colleagues, few original Tanzanian contributions to scientific discovery were acknowledged, and Tanzanian scientists' early studies of plants' insect-repellent or crab-attracting properties and the Tanzanian government's scientific initiatives drew some deprecating comments on 'losing questions'that is, enquiries that did not deserve to or could not be answeredpersonal 'intellectual ceilings' and the overly technical nature and lack of focus of early Tanzanian scientists (e.g., Graham, Cambridge, 57). It should be noted, however, that some of this critique was vigorously contested by younger European colleagues who had worked closely with African age-mates, respected their abilities and expressed understanding of the challenges that they had faced in finding a meaningful scientific orientation under given conditions.
The less frequent negative evaluations of Amani's trajectory by Tanzanian scientists were similarly shaped by more general disappointment with how things had turned out for their country. 16 In a striking moment, a retired Tanzanian scientist, provoked by the sight of his dust-covered 1970s laboratoryand, possibly, by the presence of the comparatively comfortable British visitors and anthropologistsslammed drawers full of glassware, exclaiming 'All kaput!' Such affective responses arose from the juxtaposition of past futures and present ruination. The scientist had once been an esteemed technician, praised by his European mentors and destined for a rich scientific career. As resources dwindled and his station decayed, he had, in his erstwhile bosses' terms, 'become difficult'. His anger was not only an echo of past anticolonial resilience, but above all a response to the broken postcolonial promises of scientific progress, dignity and equality.
The last European Director, Lelijveld, a former Dutch mission doctor who was tasked in the late 1960s with handing Amani over to Tanzanians, questioned more fundamentally whether Amani's science had actually reflected African needs and visions. 17 Rather than attributing failure to his successors, Lelijveld questioned his own role, wondering whether he should not have pursued different areas of research: 'If we had been better trained and better prepared for our jobs, we would have done things quite differently' (Jan, Cambridge, 37). His modest selfdoubts concerning Amani's internationally successful research agenda were briskly rejected by some of his colleagues -'a joke, quite honestly' (Alister, Cambridge, 39)but not all of them. The resulting debate pitched a socialdevelopmental idea of good, locally adapted science against a universalist notion of globally mobile, competitive science, and seemed to revive older tensions among Amani's post-independence Europeans (see excerpt from Cambridge transcript, pp. S37-42, this issue). 16 Discontent was rare andpartly because of the high fertility and cash-crop intensity of the area around Amanimost local retirees lived satisfied and comfortable lives. 17 Lelijveld was chosen as an intermediate Director, partly on account of his non-British descent. The mandate of Africanization resonated with his origins in post-war Dutch anti-colonialism. However, such questions had seemingly not been discussed much in 1970. The elderly Dutch doctor's self-critique was, like the Tanzanian scientist's rage, partly an artefact of remembrance (he in fact lamented the pain of remembering that our project had brought about). There seems to have been little 'political' controversy about scientific directions at the time, probably because this was an era of exceptional material comfort and promise, when problems inspired dreams of solutions, not doubts.

Difference in affluence
The absence of memories of conflict was striking during the reunions. The Tanzanian scientists flatly denied injustice during 'their' time, emphasizing instead conviviality -'no problems', 'we were working here as a family' (Muro, Amani, 41) 18and the Europeans largely agreed that 'there was no apartheid' (Graham, Cambridge, 82) and that, in the 1960s, 'racism' had been a trait of 'old colonials' (Graham, Cambridge, 9, note 14). Amani's staff saw themselves as cosmopolitan, and as a national vanguard. Anecdotes about ignorant or recalcitrant villagers enrolled in medical research (e.g. Matola, Amani, 54) or about pretentious and obstructive local officials (Graham, Cambridge, 25) underlined their shared sense of belonging and progressiveness.
Yet this image of postcolonial conviviality was not quite borne out by descriptions of everyday life and work. Colonial Amani's racialized hierarchy 19 had left behind paternalistic relations between the 'scientific officers' heading diseasespecific laboratories and pursuing long-term research agendas and 'their' staff. The new post-independence European science workers inherited these structures, and they acknowledged during the reunion an attachment to 'their' former technical staff, whose training and personal needs they had taken care of. The older Tanzanian scientists in turn remembered the European 'bosses' more or less respectfully, sometimes fondly. While relations may have been friendly, they were not equal. 20 This inequality was mapped onto the station's geography: in 1963, white officers occupied hilltop bungalows while African staff lived in the settlements 18 Those resisting discrimination, such as the union activist Modestus Chogga, left Amani early (Poleykett and Mangesho 2016), and the reunion participants' dismissiveness towards him confirms their inclination towards accommodation rather than struggle.
19 'Scientific officers' had been white men. African staff could advance from temporary gardeners and laboratory assistants through on-the-job training to permanently employed laboratory technicians, but further progression was precluded by their lack of qualifications, if not by an outright colour bar. In the run-up to decolonization, it appears that racial separations somewhat softened, allowing groups that the racist hierarchies had positioned 'between' Europeans and Africans, such as Tanzanians of Arab descent, to rise through the ranks. Some pre-independence annual reports thus listed 'Assistant Scientific Officers' with Arab names; one of these was the first non-white, along with a 'Goan' administrator, residing in a senior staff house within the central station enclosure (see Geissler 2019). 20 These hierarchies of patronage endured when Tanzanian scientists inherited the authority of the European 'bwana kubwa' (big boss). Yet the young, educated scientists' filial reverence for older technicians carried slightly different affect: during the Amani reunion's group photograph, one younger professor was thus caringly patting the head of an old technologist with whom he had worked as a student. below (Ghyselen et al. 2017). Housing was 'Africanized' particularly slowly, and even by the late 1960s 'the African research officers were not living in the same high-style houses as our European colleagues' (Jan,Cambridge,85). This segregated mode of belonging made housing an issue of open contestation by the late 1970s.
Also, for some years after independence, organized social life around the research station remained divided along colonial, 'racial' linesbetween a European 'Amani Club' (at the top of the station hill) and an African social club on Market Street in the African staff settlement. This division was lifted only gradually, in response to pressure from senior African staff, who successfully claimed access to the formerly exclusive club (Mosha, Amani, 16-18), rendering the African social club into the 'Junior Staff Club'. But even after capturing the club's chairmanship, the old Amani Club remained a European-defined space: tennis never quite caught on among African staff (Graham, Cambridge, 76), nor, apparently, did the club's Christmas parties (Matola, Amani, 31). Ambiguities around the club's identity also shone through anecdotes inflected with racial stereotypes (but told at both reunions) about some of the new African members' excessive drinking and inadequate payment (Mosha,Amani,18;John,Cambridge,78). Conquering the European club was thus largely a symbolic achievement for senior African staff members, while they continued to organize their own social life. At the same time, for the young postcolonial European staffwho had never been barred from either venuethe African club allowed for pleasurable infringements of outdated colonial etiquette; however, judging by the photo albums, which some had brought for the reunions, social life remained somewhat separated. Only a few pictures, mostly of fieldwork situations and of organized events such as the last white Director's farewell party (Amani, Figure 8; Cambridge, Figure 6), show socializing between the groups, especially in the 1960s.
This makes one wonder why, instead of contesting residual racial discrimination, everybody seemed to have been reasonably comfortable with the situation. Comfort might be a key: between the 1960s and the early 1980s, Amani's African and European denizens lived in relative affluence. Staff had regular, relatively high salaries, many on permanent, pensionable contracts; laboratory supplies were readily available; and research was core-funded without competition for grants. The station's enclave had its own school, churches and clinic, and its electricity and water grids were maintained by Institute staff, as were the furniture and houses: 'When it gets damaged you report it to the supplies officer for repairing. For the damaged one he … brings another one the next day' (Muro, Amani, 63). The park-like landscape, tended by dozens of gardeners, nurtured the Institute's dairy herd, which produced milk and meat that was distributed to staff at subsidized prices. And isolation was alleviated by travel for fieldwork and surveys, leisure and sports competitions, conferences and trainingall facilitated by generous allowances.
African scientists had swiftly joined their colonial superiors in spaces and pleasures that for generations had been unattainable, and increasingly liberal cohabitation made the erasure of racial differences probable. Rapid progress promised future improvements, in line with the modernist ideology of science and development, and of mid-twentieth-century politics. And the seemingly stable order of architecture and landscape, work contracts and research plans, lent further credibility to the station's meliorist promise in its postcolonial rendering. This promise assuaged discontent at the time, and lives on in the contradictory memories of youthful past futures.
The Europeans who had come to Amani in the 1960s also positioned themselves on the forward-looking side of the temporal-cum-political threshold of independence. Cosmopolitan conviviality marked by jeans and T-shirts replaced khaki and evening dress (see, for example, Cambridge, Figures 24A and 24B); continued inequalities in salaries and housing were enjoyed as remnants of a vanishing past. Change was coming in terms of racial relations and concerning gender and generations. New social groups arrived: scientists with less privileged backgrounds, unmarried female technicians and young students. Sharing The Beatles and East African rumba, these new Europeans and their African colleagues experimented with more egalitarian relations, nurturing a sense of 'family' (see also Cambridge, Figures 6,7,15,18, and 19). 21 Thus, while Amani in the 1970s may still have looked somewhat 'colonial' to a twenty-first-century student of anthropology, to its inhabitants, experiencing rapid, open-ended forward movement, it was anything but.

Joking and pain
Apart from discussing science, social differentiation and historical change, the reunions were occasions for much laughter that underlined conviviality but could also mark social differences and discomforts. Such laughter can cut across timebeing about the past, exposing ridiculous traits that went unremarked at the timeor it can extend from the past, echoing junior African staff members' joking behind their officers' backs, or Europeans' jokes deriding their 'junior' colleagues.
The Tanzanian reunion was lightened by imitations of European scientists, welcomed by the mirth of recognition that suggested these were re-enactments of older mocking performances (Mwaiko, Amani, 32). Exaggerated 'British' accents and postures brought to life the station's pantheon of idiosyncratic Europeans (see Geissler 2016b), evoking memories of domination, humiliation and resistance, with collective laughter as delayed retribution and consolation. 'Harsh' old colonials were particularly exhilarating: an officer who allegedly hit out at African staff and scared the schoolchildren; an ex-army engineer's famously foul language. These ogres were now amusing anachronisms whose predictable views on Tanzanian post-independence politics had been ridiculous even at the time (Mwaiko, Amani, 48-9). Mockery served here to differentiate oneself from the colonial other, demarcating one's own resilient identity, and to affirm solidarities among one's own.
Cambridge reunion participants partly re-enacted the same 'colonials' to distinguish themselves from their forebears (John, Cambridge, 91). Accents and posture combined historical-political distancing with class differences: a field officer's local accent contrasted with the public-school vowels of a 'top British scientist' and the speech, social conventions and politics of a British Director that had been alien to young 1970s Brits from a different social background. This joking about both upper middle-class imperial pretentiousness and lower middle-class political incorrectness and racism positioned Amani's self-confident 1970s 'last whites' in their isolated scientific station as a progressive vanguard.
Jokes about the younger, post-independence Europeans were of a kinder nature. All remembered the amiable and unconventional naturalist Raybould, nicknamed Kidevu for his long beard, who ignored time and social conventions in pursuit of naturalist observation. Once he allegedly even forgot his own child, heading off to the field after shopping at the market. And he was known for caring little about (as he put it) 'such groupings': that is, racial categorization and class prejudice. Differences among the Europeans were laughed about in the Cambridge reunion, contrasting, for example, Lelijveld's mission-doctor egalitarianism with supposedly more efficient and scientifically productive approaches (Graham, Cambridge, 42); or, conversely, cautiously exposing personal scientific ambition. And one could laugh, if sometimes ruefully, about one's own youthful self, one's illusions and disappointments. The Tanzanian contemporaries, in turn, laughed heartily about some young European men's liking for beer and their resulting antics, or about the beauty or self-confidence of some young women, in remarks that conveyed both an enduring sense of social distance and attempts to relate and move across racial differences.
European scientists' joking about African colleagues had a different flavour. Nicknames such as 'Dr Crab' for a skilful crab-catcher, 'Bucket' for someone by the name of Bukheti, 'KiDusty' for someone called Kivumbi (the Kiswahili for 'dust'), or 'Major' for a young man who arrived wearing his national service uniform had a paternalistic ring. There were very few denigrating jokes about African colleagues' mistakes or failure, but these are particularly offensive as they mock the very mimesis that European visions of Africanization had aimed forencouraging imitation before withdrawing the means, and ridiculing the resulting failure. Postcolonial parvenus were also derided in jokes about allegedly 'immature' Tanzanian officials: their insistence on protocol and veneration of degrees, crude demands, lack of manners and craving for modernity, evidenced by faceless industrial furniture or concrete architecture. While such disparaging comments about senior administrators came mainly from the Europeans, the ignorance or cheekiness of the local 'community'evidenced by their irrational beliefs about scientists as blood stealers or 'mumiani' (Magesa, Amani, 51-2), or their wilful and sometimes creative obstruction of research (e.g. Matola, Amani, 54)entertained both reunions. Across these different registers of humour, the laughter of both the Tanzanian and European research station staff about farmers and politicians, colonials and poncey Brits, underlined a characteristic sense of superiority, associated with the pursuit of scientific knowledge and privileged material conditions.
Commemorative laughter provides some insight into past modes of joking; it is also a mode of remembrance in itself, evincing pain and resilience, laughing off humiliation or failure. In an awkward earlier episode preceding the reunions, an exchange occurred between Raybould and Matola, who had worked together when both were young. In different ways, both had had parallel and equally unusual careers, and neither of them had attained a senior academic post, but the latter seemed less satisfied with the outcomes. After some diffuse taunting, Matola, who had come from his nearby farm to see Raybould during his visit to Amani station, insisted abruptly on exchanging his John Deere baseball cap with Raybould's forty-year-old sun hat. The conversation continued, each awkwardly wearing the other's hat, until, bidding his visitor farewell, Raybould snatched back his old hat. Despite everyone's best attempts to laugh away the awkwardness, a sense of subdued irritation and mutual incomprehension underlay this symbolic usurpation of the other's position. The episode revealed the tensions underlying Africanization's optimism, which are perhaps more tangible now than in the past, and are more easily expressed in jokes than in outright critique or anger.
The potential awkwardness and complexity of postcolonial mirth is also aptly illustrated by the Amani Club's movie programme in the 1970s, which was organized by the younger station staff, and discussed in the Cambridge reunion (Vivianne, Cambridge, 79-80): among the favourite films were 'very English' Carry On comedies, cheap productions full of proud political incorrectness and sexual innuendo, typically featuring 'old colonial' stock characters with bushy moustaches and plummy accents, and at times confronting black-faced English actors (particularly actresses) in grass skirts, in seemingly ironic renderings of classic colonial iconography. The laughter at the nightly outdoor screenings, which were attended by aspiring Tanzanian students, elderly British scientists, leftist English technicians, village youth and Asian tea managerseach with different experiences and concernsis an apt soundscape for a contradictory undertaking such as Africanization.

Dreams of change, longing for continuity
Amani's veterans remembered the postcolonial decades as a time of transformation, driven by decolonization and progressive post-war politics of class, race and gender. Half a century laterafter much social, political-economic and personal disappointmentremembered dreams of rupture are overlaid with a longing for past certainties (see Ferguson 1999). The political-economic destruction of livelihoods, infrastructures and opportunities of the 'long 1980s' nurtures nostalgia for a future that seemed certain, for durable progress. The reunion conversations thus contrast a past in which futures were not only open but inevitable and predictable with a present when futures, if discernible at all, have no clear shapefor the elderly science workers, but also for their children and grandchildren. How does one remember past predictability that proved erroneous (see Yurchak 2005)? What ambiguous longings spring from memories of a reliability that could not be relied on (see, for example, Piot 2010)? What sort of nostalgia contains longing both for calm stability and for adventurous new beginnings?
The memories of collapsed predictabilities mixed with nostalgia for unfulfilled ruptures are not limited to the Tanzanian retirees. Such tensions between past and present temporalitiesbetween presentist stasis and past futurisms, between postneoliberal political-economic dissolution and twentieth-century comfort and order, between dreams of restoration born from impending chaos and a persistent longing for ruptureare shared to some extent by the European pensioners who retired to greater comfort. And they resonate with usanthropologists a generation or two youngerraising the question of how one might rekindle the desire for radical social transformation that once seemed obvious to previous generations, while still mourning bygone stabilities and embracing collective disappointment. We hope that the transcribed voices of elderly scientists that this article introduces will enable readers to engage their own present, and their memories, with those of the interlocutors, thereby extending the process of social memory with which the reunion events briefly engaged.
lives. The term Africanization, coined by the colonizers, reproduced colonial notions of race but also stimulated the imagination of mid-twentieth-century African scientists, who hotly debated and enthusiastically embraced it. Half a century later, some dreams have failed, but many more remain unfulfilled. This article examines two reunions of Tanzanian and European science workersin Amani in 2015 and in Cambridge in 2013who had worked together in the decades after Tanzania's independence at Amani Hill Research Station, then one of Africa's foremost laboratories for research on malaria and other tropical diseases. It explores ideas of good science and experiences of social differentiation, divergent dreams and persistent tensionsand the role of joking in remembering these.