This paper intends to investigate, within the coordinates of the expressionist movement Der blaue Reiter, Franz Marc’s art (1880-1916) in a constant and significant comparison between the visual and theoretical dimensions of his work (see also his correspondence with Else Lasker-Schüler, as well as his war writings). In line with Kandinsky’s position, Franz Marc believes each shape possesses its own ‘content- force’. Far from being objective content, each shape is rather left to be identified with a capability of acting as a psychological stimulus. This content is not captured by the normal eye, but by a ‘second sight’. It connects Umwelt and Innenwelt, which is closer to the heart of nature. Unlike abstract art, however, Marc utilizes shapes in the form of the Nervenkunst, whose metaphor is the animal, i.e. the undisputed protagonist of his art.