The final decades of the nineteenth century were an era of scientific and medical specialisation, when the ‘common context’ of Victorian culture began to break down and separate disciplines took on their own form, conducted in different settings, by different people, and published in different places.

In particular, this period saw the emergence of a mature neurological profession, as neurology became a specialty of its own, distinct from general medicine on the one hand, and psychology (whether medical, experimental or philosophical) on the other. A new programme of brain research, based around the study of cerebral localisation, appeared to achieve rapid and spectacular results and a large legion of followers. In doing so, neurology cleaved away from psychiatric practice in Britain, and the search for localised functions and organic lesions in the brain – so long a guiding motif of psychiatry – came instead to be associated with the neurological profession, leaving psychiatry to deal with the chronic, awkward and less clear-cut illnesses that affected the brain. In this paper, I will consider the theory of cerebral localisation in this period, looking at the way that clinical, pathological, anatomical, microscopical and experimental evidence was used to construct an understanding, and an image, of the brain. In particular, I will use the development of cerebral localisation as a way to chart the increasing separation between psychiatric and neurological perspectives of the brain, and to explain the different trajectories of the two disciplines going into the twentieth century. With twenty-first century medical specialists now often bemoaning the separation between psychiatry and neurology, and looking to reintegrate the two fields, it is informative to look back to the nineteenth century to understand how, and why, they became separated in the first place.