Over the past two decades, historians of colonial Australia have greatly enriched our understanding of how Aboriginality was racially constructed in nineteenth and early twentieth settler discourses. However, there is arguably much that is yet to be understood about how racialist perceptions of Aboriginal people owed their cultural suasiveness to medico-scientific investigation of the Aboriginal body. This essay attempts to go some way towards answering this question by exploring in contextualised detail how anatomists and anthropologists, in the century or so after 1820, construed the morphology of the ‘Aboriginal brain’ and its significance in the evolutionary history of humankind. The essay particularly focuses on explicating the goals of these investigators of the ‘Aboriginal’ brain as they themselves saw them evolving through their uses of evidence and modes of reasoning and argument. Fine grained exploration of how the scientific facticity of the ‘Aboriginal’ brain was constructed is arguably essential if we are to understand how in obvious, but also in many subtle ways, the outcomes of this research figured in the construal of the biological and psychic dimensions of Aboriginality within settler culture, and on the development of policies for governing Aboriginal people. Moreover, it also offers us a useful source of vicarious knowledge for assessing contemporary scientific interest in the ‘Aboriginal’ brain.