The pulse made visible: the basic technique performed by the sphygmograph, first invented as a sphygmometer by Jules Herisson in 1831, improved upon in 1854 by Karl Vierordt adding a paper recording mechanism, and in 1860 by Etienne-Jules Marey, making the device portable. Laced onto the wrist, the instrument consists of an ivory plate placed on the radial artery, a flexible steel spring, and a wooden recording arm that transcribes the pulse onto a moving strip of paper. The pulse as originally detected through touch, an intimate if wayward sensation, was transformed into an empirical and uniform visual record. From the pulse to movement studies to motion pictures, Marey’s work presents a genealogy of organismal life mapped in iterative bits, sensed and reconstituted within the logic of animating mechanisms.