A priest and a boy entered some time ago a hollow in the hills and passed into a sort of subterranean tunnel that led into a labyrinth of such sealed and secret corridors of rock. They crawled through cracks that seemed almost impassable, they crept through tunnels that might have been made for moles, they dropped into holes as hopeless as wells, they seemed to be burying themselves alive seven times over beyond the hope of resurrection. This is but the commonplace of all such courageous exploration; but what is needed here is some one who shall put such stories in the primary light, in which they are not commonplace. There is, for instance, something strangely symbolic in the accident that the first intruders into that sunken world were a priest and a boy, the types of the antiquity and of the youth of the world. But here I am even more concerned with the symbolism of the boy than with that of the priest. Nobody who remembers boyhood needs to be told what it might be to a boy to enter like Peter Pan under a roof of the roots of all the trees and go deeper and deeper, till he reach what William Morris called the very roots of the mountains. Suppose somebody, with that simple and unspoilt realism that is a part of innocence, to pursue that journey to its end, not for the sake of what he could deduce or demonstrate in some dusty magazine controversy, but simply for the sake of what he could see. What he did see at last was a cavern so far from the light of day that it might have been the legendary Domdaniel cavern that was under the floor of the sea. This secret chamber of rock, when illuminated after its long night of unnumbered ages, revealed on its walls large and sprawling outlines diversified with coloured earths; and when they followed the lines of them they recognised, across that vast and void of ages, the movement and the gesture of a man’s hand. They were drawings or paintings of animals; and they were drawn or painted not only by a man but by an artist. Under whatever archaic limitations, they showed that love of the long sweeping or the long wavering line which any man who has ever drawn or tried to draw will recognise; and about which no artist will allow himself to be contradicted by any scientist. They showed the experimental and adventurous spirit of the artist, the spirit that does not avoid but attempt difficult things; as where the draughtsman had represented the action of the stag when he swings his head clean round and noses towards his tail, an action familiar enough in the horse. But there are many modern animal-painters who would set themselves something of a task in rendering it truly. In this and twenty other details it is clear that the artist had watched animals with a certain interest and presumably a certain pleasure. In that sense it would seem that he was not only an artist but a naturalist; the sort of naturalist who is really natural.