This paper examines how a family of experimental systems developed in nineteenth-century physiology provided avant-garde painters and poets with key material and conceptual resources that enabled the innovations of early modernism in the arts. I argue that the borrowings moved in two directions. First, I show how artists adopted the materialities of physiology -- instruments and techniques-- as a means to undertake new kinds of aesthetic experiments within the specific media of each cultural art. Second, I show how the converse occurred: early modernist experiments in poetry, the visual arts, dance, and music functioned as experiments on life, aiming to alter the human sensorium and to reconfigure both the artist and spectator. In order to make this argument I show how an array of people, concepts and practices that have not traditionally been discussed together belonged to common networks. I also introduce several new areas of nineteenth-century scientific culture that have not been discussed by historians, including the widely held protoplasm theory of life, the epistemology and social doctrines rooted on the physiology and psychology of movement, and more. Besides developing my claims using the methods of cultural history and the history of science, I support my arguments with readings of works of painting and poetry that reveal the implementation of physiological aesthetics, including Edvard Munch’s The Scream, George Seurat’s late entertainment paintings, Francis Picabia’s prewar cubist paintings, the free verse of Gustave Kahn, and the vocal performances of F. T. Marinetti and the Futurists. With fresh interpretations of canonical works I aim to challenge entrenched assumptions about the art/science “two-cultures” divide and invigorate dialogue between historians of science and specialists in the history of art, literature, and music.