"Like the perfumer distils the perfume from rose and lilac and lily of the valley to create an essence a hundredfold stronger, these watercolours are compacted essence of colour, often with a stunning splendour, mixtures, about which Huysmans romances, are transferred into the coloristic. The plant which once was the model, or one should rather say, which inspired the artist with visions of colour, has disappeared, as a superfluous and too earthly material residue, behind the fabric of brushstrokes, interlaced like loops. Chords of colour sounds which emanate from themselves, coalescing like melted ore, turning into a wavy entity of unheard-of glow. There can be nothing in art which could be more immaterial. However, in the end such a furioso in colours is nothing but sensuality taken to the highest degree, but if you want, a decided contrast to what Kandinsky is doing with colour. The colour as material seems to have been taken from the objects, it does not, as with Nolde, want to be a statement about the sense of the being, its significance is not mystically symbolic; it remains the scent of the bodily, joy of the eye and the senses, a huge treasure of undiscovered possibilities of optical experience."
Translated from: Paul Westheim, Christian Rohlfs, in: Das Kunstblatt, vol.2, 1918