As he did so, the Marquess reached it also and actually touched his son.

Heyton drew back a pace, swung up the poker and struck at the figure he could not see; there was a cry, a choked groan, the sound of a body falling to the floor; then a death-like silence.
Shaking in every limb, the poker still grasped in his hand, Heyton leant against the wall, his other hand clinging to it, as if for support.

The clock on the mantelpiece seemed to tick a thousand times as he crouched there, staring, with protruding eyes, into the horrible darkness; then, with a gasp, as if he were suffocating, he felt his way round to the switch, and turned it on.

The light fell on the figure of the Marquess, lying on its back, where he had fallen; his arms were stretched out, he was quite motionless, and a thin stream of blood was trickling from his forehead; it had already reddened his face and made a small pool on the carpet.
Heyton stood and gazed at this horrible sight, as if he were turned to stone.

He was like a man who has been suddenly struck by paralysis; it seemed to him as if the whole of his legs and feet had been turned to lead, and that he should never again be able to move them, that he would be forced to remain there until the servants came and that--that horrible thing lying at his feet were discovered.
For some minutes he remained in this condition of coma, stupor; but presently, gradually, he recovered the use of his limbs, his brain began to work again, and he asked himself whether there was any reason for the terror which had obsessed him.