This should make clear to you one of the differences between nature and art. Nature extends in every direction all round the artist, an unending panorama from which he _selects_ some little portion to form the subject of his work of art. But he carries his selection still farther, for even in the part of nature that he has selected there is so much more than he could ever put into his picture. Take another look out of the window. What a mass of details the whole presents! And, if we fix our eye on any one of its parts, it also is made up of a number of details. It would be impossible for the artist to paint them all. And so, also, if your view from the window is a country scene and you look at one object, that elm, for example. Do you think it would be possible for an artist to paint all the scales of the bark, all the spreading limbs, much less all the little branches and twigs and the countless leaves?