The most difficult achievement in colouring, the ideal and consummation of its art, is the colour effect of the human flesh[296], which unites in its perfection all other colour tones, without permitting any particular one to be singly prominent. The healthy red in the cheeks of youth is, no doubt, pure carmine without any admixture of blue, violet, or yellow, but this red is itself only a flush, or rather a sheen, which appears to rise on the surface, and imperceptibly passes into the prevailing flesh-tints. And this is an ideal[297] commixture of all the fundamental colours. Through the transparent yellow of the skin the red of the arteries and the blue of the veins is visible, and along with the light and shade and all the variety of sheen and reflection we have further tones of gray, brown, even green, which at first sight appear as contrary to Nature, but for all that may contribute to the justness and truth of the effect. Moreover, this composite treatment of many apparent tints is wholly without sheen as such, that is, it reflects nothing alien to it on its surface; its vital quality is entirely a result of itself and the living thing it is. It is this rendering of that which is the life shining through the organic integument which constitutes the main difficulty. We may compare it to a lake in the evening glow, in which we behold the objects that it reflects[298] no less than the clear depth and native character of water. The flash of metal combines on the contrary, no doubt, both light of its own and transparency, jewels both flash and are translucent, and something similar is seen in the case of velvet and silk-stuffs, but none of these approaches the life-conferred interfusion of colours apparent on the surface of the living flesh. The skin of animals, whether hair or hide, wool, and so forth, are in like manner of the most varied colouring, but it is a colour capable of more direct and independent definition in its parts, so that the variety is rather the result of different surfaces and planes, it is not a single transfusion and suffusion of many colours such as human flesh is. The nearest approach to it perhaps is the interplay of colour visible in the bunch of grapes, or the exquisitely tender gradations of translucent colour in the rose. And yet even this last example is unable to give us the counterfeit of ideal animation[299] which flesh-colour should possess. It is this volatile emanation of the soul exhibited on a non-transparent surface which is one of the most difficult problems of painting. For this ideality, this reflex of the inward life of soul must not appear on a surface as imported there, must not be pasted there as so many streaks, hatchings, and so forth of material colour, but seem to us itself to belong to the living whole[300], a transparent depth, as the blue of heaven, which offers our vision no repellent surface, but one in which we are infallibly invited to unfold. Already