Crazy impulses stirred in his brain, coming to insane birth at the calling of the Tree's peril--the desperate need to shut out the sight of that thing that was blasphemy, to put out his own sight rather than gaze longer upon the perilous grace of its branches, to slit his own throat that he might not need to dwell in the same world which housed so frightful a sight as the Tree. * * * * * All this was a mad battering in his brain. The strength of him was enough to isolate it in a far corner of his consciousness, where it seethed and shrieked half heeded while he turned the cool control which the spaceways life had taught him to the solution of this urgent question. But even so his hand was moist and shaking on his gun-butt, and the breath rasped in his dry throat. Why--he asked himself in a determined groping after steadiness--should the mere sight of a tree, even so fabulous a one as this, rouse that insane panic in the gazer? What peril could dwell invisibly in a tree so frightful that the living horror of it could drive a man mad with the very fact of its unseen presence? He clenched his teeth hard and stared resolutely at that terrible beauty in the clearing, fighting down the sick panic that rose in his throat as his eyes forced themselves to dwell upon the Tree. Gradually the revulsion subsided. After a nightmare of striving he mustered the strength to force it down far enough to allow reason's entry once more. Sternly holding down that frantic terror under the surface of consciousness, he stared resolutely at the Tree. And he knew that this was Thag. It could be nothing else, for surely two such dreadful things could not dwell in one land. It must be Thag, and he could understand now the immemorial terror in which the tree-folk held it, but he did not yet grasp in what way it threatened them physically. The inexplicable dreadfulness of it was a menace to the mind's very existence, but surely a rooted tree, however terrible to look at, could wield little actual danger. As he reasoned, his eyes were seeking restlessly among the branches, searching for the answer to their dreadfulness. After all, this thing wore the aspect of an old pattern, and in that pattern there was nothing dreadful. The tree of life had made up the design upon that well-top in Illar through whose shadow he had entered here, and nothing in that bronze grille-work had roused terror. Then why----? What living menace dwelt invisibly among these branches to twist them into curves of horror? A fragment of old verse drifted through his mind as he stared in perplexity: What immortal hand or eye Could frame thy fearful symmetry?