This paper explores the topological presuppositions that shape the performance of social similarity and difference, using the example of anaemia in tropical medicine. It argues that 'the social' does not exist as a single spatial type but performs in a recursive and topologically heterogeneous manner. The paper examines three social topologies: regions, networks, and fluid spaces. Regions are characterized by clustered objects and clear boundaries, while networks are defined by relational differences and distances. Fluid spaces, however, are neither delineated by boundaries nor linked through stable relations. In fluid spaces, entities may be similar and dissimilar at different locations, and they may transform without creating difference. The paper uses the example of anaemia to illustrate these topologies. In the Netherlands, anaemia is rare and not a major concern, while in Africa, it is common and severe. The differences in anaemia prevalence are often framed in terms of regional topologies, with Africa and the Netherlands being contrasted as regions with distinct anaemia profiles. However, the paper argues that these regional distinctions are not always accurate or stable, as anaemia prevalence varies within regions and across different populations. The paper also examines the network of haemoglobin measurement, which is essential for diagnosing anaemia. This network includes machines, people, and procedures that enable the measurement of haemoglobin levels. However, the network is not always stable or consistent, as it faces challenges in Africa due to limited resources, transportation difficulties, and the need for skilled personnel. Despite these challenges, the network can still function, and the results can be used to diagnose anaemia. The paper also explores the clinical gaze, which is a method of diagnosing anaemia by observing symptoms such as pallor. This method is often used in the absence of a laboratory and is based on experience rather than accuracy. The clinical gaze is not invariant and can vary depending on the context and the availability of resources. The paper concludes that anaemia is not a fixed entity but flows through different spaces and contexts. It is a fluid phenomenon that can be understood through the lens of fluid topology, which allows for transformation without abrupt change. The paper argues that the social is not confined to a single topology but exists in multiple forms, including regions, networks, and fluid spaces.This paper explores the topological presuppositions that shape the performance of social similarity and difference, using the example of anaemia in tropical medicine. It argues that 'the social' does not exist as a single spatial type but performs in a recursive and topologically heterogeneous manner. The paper examines three social topologies: regions, networks, and fluid spaces. Regions are characterized by clustered objects and clear boundaries, while networks are defined by relational differences and distances. Fluid spaces, however, are neither delineated by boundaries nor linked through stable relations. In fluid spaces, entities may be similar and dissimilar at different locations, and they may transform without creating difference. The paper uses the example of anaemia to illustrate these topologies. In the Netherlands, anaemia is rare and not a major concern, while in Africa, it is common and severe. The differences in anaemia prevalence are often framed in terms of regional topologies, with Africa and the Netherlands being contrasted as regions with distinct anaemia profiles. However, the paper argues that these regional distinctions are not always accurate or stable, as anaemia prevalence varies within regions and across different populations. The paper also examines the network of haemoglobin measurement, which is essential for diagnosing anaemia. This network includes machines, people, and procedures that enable the measurement of haemoglobin levels. However, the network is not always stable or consistent, as it faces challenges in Africa due to limited resources, transportation difficulties, and the need for skilled personnel. Despite these challenges, the network can still function, and the results can be used to diagnose anaemia. The paper also explores the clinical gaze, which is a method of diagnosing anaemia by observing symptoms such as pallor. This method is often used in the absence of a laboratory and is based on experience rather than accuracy. The clinical gaze is not invariant and can vary depending on the context and the availability of resources. The paper concludes that anaemia is not a fixed entity but flows through different spaces and contexts. It is a fluid phenomenon that can be understood through the lens of fluid topology, which allows for transformation without abrupt change. The paper argues that the social is not confined to a single topology but exists in multiple forms, including regions, networks, and fluid spaces.