This dissertation situates the works of Anglo-Swiss artist Henry Fuseli and French artist Anne-Louis Girodet within a vast and heterogeneous epistemological transformation occurring in the late eighteenth and early nineteenth centuries. It examines three distinct but interlocking case studies—physiognomy, electricity, and the guillotine—each of which constellates scientific discourses, representational practices, and popular attractions. Although working in separate contexts and different modalities, Fuseli and Girodet both engaged with these discourses and practices. Yet they did so in ways that also tested and undermined them. They painted bodies that emphatically failed to conform to the scientific discourses they cited; they painted bodies that were similarly unable to represent heroic virtues or legible narratives. In this way Fuseli and Girodet compel us to read the stylistic shift from neoclassicism to romanticism as participating in a significant realignment of the relationship between knowledge, representation, and the body. By the first decades of the nineteenth century, the body no longer served as a privileged agent of knowledge production within the scientific discourses and artistic practices under consideration. The physiognomic body was no longer self-identical; the electric body was no longer internally continuous. The guillotine offered, in their places, bodies without heads and heads without bodies, whose mechanisms of sensation and cognition were only ever partially and provisionally aligned.