§ XXV. Now, the truly great artist neither leaves the imagination to itself, like Sir Joshua, nor insults it by realization, like Hobbima, but finds it continual employment of the happiest kind. Having summoned it by his vigorous first touches, he says to it: "Here is a tree for you, and it is to be an oak. Now I know that you can make it green and intricate for yourself, but that is not enough: an oak is not only green and intricate, but its leaves have most beautiful and fantastic forms which I am very sure you are not quite able to complete without help; so I will draw a cluster or two perfectly for you, and then you can go on and do all the other clusters. So far so good: but the leaves are not enough; the oak is to be full of acorns, and you may not be quite able to imagine the way they grow, nor the pretty contrast of their glossy almond-shaped nuts with the chasing of their cups; so I will draw a bunch or two of acorns for you, and you can fill up the oak with others like them. Good: but that is not enough; it is to be a bright day in summer, and all the outside leaves are to be glittering in the sunshine as if their edges were of gold: I cannot paint this, but you can; so I will really gild some of the edges nearest you,[52] and you can turn the gold into sunshine, and cover the tree with it. Well done: but still this is not enough; the tree is so full foliaged and so old that the wood birds come in crowds to build there; they are singing, two or three under the shadow of every bough. I cannot show you them all; but here is a large one on the outside spray, and you can fancy the others inside."