As one can read in the works of Alexander von Humboldt, Henry David Thoreau and Élisée Reclus, ecology made an entrance into 19th c. literature through a modest, sensitive, and empirical interpretation of the essay genre, finding a way outside the Cartesian systematicity of the treatise. As a whole and fragmented form, the essay provides an adequate poetic sphere for experimenting the romantic dialectics of totality and detail, and for building the problematic unity of the world, in between universal ideals and non negotiable local discrepancies. As a tribune for emancipatory knowledge itself distinquished from academic discourse, it leaves room for a freely speculative thought to go far and wide. As a utopian and critical laboratory, it predicts a better world, and works towards the unison of the sphere of ideas, and the sphere of things.