He was the first to discover the branching contractile cells on the external wall of the capillaries in amphibians, structures that are now known as "Rouget cells".
Also the eponymous "Rouget's muscle" was described by him, which are circular fibers of the ciliary muscle of the eye.
These fibers are sometimes called "Müller's muscle" after German anatomist Heinrich Müller (1820–1864).