Once the trio were in the operating-room Bell gave one rapid glance at Heritage. But the latter seemed to have forgotten all his fears. There was an alert air about him; he was quiet and steady. There was something of the joy of battle in his eyes.

"Now go and fetch Van Sneck in," Bell said.

The patient came at length. Everything was ready. Van Sneck murmured something and looked vaguely about him, like a man suddenly aroused from a deep sleep. But he obeyed quite willingly when Bell commanded him to get on the table. A moment or two later and he was gone under the influence of the ether administered by Bell.

A case of glittering instruments lay on the table. The strong electric light was switched on and hung just over the head of the unconscious patient.

"You hold the sponge," Bell whispered to David. "There will be very little blood. I like to have a man with me who has coolness and courage. Oh, here is the spot. Feel the depression of the skull, Heritage. That is where the pressure lies, and no larger than a pea."

Heritage nodded, without reply. He took up the knife, there was a flash of steel in the brilliant light and a sudden splash of blood. There was a scrape, scrape that jolted horribly on David's nerves, followed by a convulsive movement of Van Sneck's body.

"Beautiful, beautiful," Heritage murmured. "How easily it comes away."

Bell was watching in deep admiration of the strong hand that was yet light as thistledown. The big electric light flickered for just a moment, and Heritage stood upright.

"Don't be a fool," Bell said, sternly. "It's a mere matter of current." Heritage muttered that it must be. Nevertheless it had given him quite a turn. His face was set and pale and his hand shook ever so slightly. The knife was cutting deep, deeper—

A snarling oath broke from Bell's lips as the light flickered again and popped out suddenly, leaving the whole room in intense darkness. Heritage cried aloud. David felt a hand guiding his fingers to the patient's head.

"Press the sponge down there and press hard," Bell whispered. "It's a matter of life and death. Another minute and Van Sneck would have gone. Heritage, Heritage, pull yourself together. It was no fault of yours the light went out—the fault is mine."

Bell stumbled down the kitchen stairs and returned with a candle. The electric lights were out all over the ground floor with the exception of the hall. One of the circuits had given out completely, as sometimes happens with the electric light. Bell leapt on a table and turned the hall light out. A second later and he was dragging the long spare flex from the impromptu operating-room to the swinging cord over the hall lamp. With a knife he cut the cord loose, he stripped the copper wires beneath, and rapidly joined one flex to the other.

"It's amateur work, but I fancy it will do," he muttered. "Anyway, that rascal is powerless to interfere with the circuit that controls the hall light."

Snap went the hall switch—there was a sudden cry from Heritage as the big lamp over the head of Van Sneck flared up again. Bell raced into the study and shut the door.

"A trick," he gasped. "The light was put out. For Heaven's sake, Heritage, don't get brooding over those fancies of yours now. I tell you the thing was done deliberately. Here, if you are too weak or feeble, give the knife to me."

The request had a sting in it. With an effort Heritage pulled himself together.

"No," he said, firmly, "I'll do it. It was a cruel, dastardly trick to play upon me, but I quite see now that it was a trick. Only it's going to make a man of me instead."

Bell nodded. His eyes were blazing, but he said nothing. He watched Heritage at work with stern approval. Nothing could have been more scientific, more skilful. It seemed a long time to David, looking on, but it was a mere matter of minutes.

"Finished," Heritage said, with a triumphant thrill. "And successful."

"And another second would have seen an end of our man," Bell said. "He's coming round again. Get those bandages on, Heritage. I'll look after the mess. Give him the drug. I want him to sleep for a good long time."

"Will he be sensible to-morrow?" David asked.

"I'll pledge my reputation upon it," Bell said. "Hadn't you better telephone down to your electrician to come and see to those lights? I see the fuse in the meter is intact; it is only on the one circuit that they have gone."

Van Sneck opened his eyes and stared languidly about him. In a clear, weak, yet wholly sensible voice he asked where he was, and then lapsed into slumber. A little later and he lay snug and still in bed. There was a look of the deepest pleasure in the eyes of Heritage.

"I've saved him and he's saved me," he said. "But it was touch and go for both of us when that light failed. But for Bell I fancied that I should have fainted. And then it came to me that it was some trick, and my nerve returned."

"Never to leave you again," Bell said. "It tried you high, and found you not wanting."

"Heaven be praised," Heritage murmured. "But how was it done?"

Bell's face was stern as he took the kitchen candlestick from the table and went in the direction of the dining-room.

"Come with me, and I'll explain," he said, curtly.

The dining-room was in pitchy darkness, for the lights there had been on the short circuit; indeed, the lights on the ground floor had all failed with the exception of the hall, which fortunately had been on another circuit. The fact had saved Van Sneck's life, for if Bell had not speedily used that one live wire the patient must have perished.

Henson looked up from his sofa with a start and a smile.

"I am afraid I must have been asleep," he said, languidly.

"Liar," Bell thundered. "You have been plotting murder. And but for a mere accident the plot would have been successful. You have worked out the whole thing in your mind; you came here on purpose. You came here to stifle the light at the very moment when we were operating on Van Sneck. You thought that all the lights on the floor would be on the same circuit; you have been here before."

"Are you mad?" Henson gasped. "When have I been here before—"

"The night that you lured Van Sneck here by a forged letter and left him for dead."

Henson gasped, his lips moved, but no words came from them.

"You have a little knowledge of electricity," Bell went on. "And you saw your way pretty clear to spoil our operation to-night. You got that idea from yonder wall-plug, into which goes the plunger of the reading lamp on the cabinet yonder. At the critical moment all you had to do was to dip your fingers in water and press the tips of them against the live wire in the wall-plug. You did so, and immediately the wires fired all over the circuit and plunged us in darkness. But the hall light remained sound, and Van Sneck was saved. If it is any consolation to you, he will be as sensible as any of us to-morrow."

"Hensen had risen to his feet, pale and trembling, He protested, but it was all in vain. Bell approached the china wall-plug and pointed to it.

"Hold the candle down," he said. "There! You can see that the surface is still wet, there is water in the holes now, and some of it has trickled down the distemper on the wall. You ought to be shot where you stand, murderous dog."

Henson protested, with some dignity. It was all so much Greek to him, he said. He had been sleeping so quietly that he had not seen the light fail. Bell cut him short.

"Get out," he cried. "Go away; you poison the air that honest men breathe, and you are as fit and well as I am. Why don't you pitch him into the street, Steel? Why don't you telephone to Marley at the police-station, and say that the Huddersfield swindler is here? Oh, if you only knew what an effort it is to keep my hands off him!"

Henson made for the door with alacrity. A moment later and he was in the street, dazed, confused, and baffled, and with the conviction strong upon him that he had failed in his great coup. Van Sneck would be sensible to-morrow—he would speak. And then—

But he dared not think of that at present. He wanted all his nerve and courage now. He had just one last chance, one single opportunity of making money, and then he must get out of the country without delay. He almost wished now that he had not been quite so precipitate in the matter of James Merritt. That humble tool might have been of great advantage to him at this moment. But Merritt had threatened to be troublesome and must be got out of the way. But then, the police had not picked Merritt up yet. Was it possible that Merritt had found out that—

But Henson did not care to think of that, either, He would go back to the quiet lodgings he had taken in Kemp Town for a day or two, he would change his clothes and walk over to Longdean Grange, and it would go hard if he failed to get a cheque from the misguided lady there. If he were quick he could be there by eleven o'clock.

He passed into his little room. He started back to see a man sleeping in his armchair. Then the man, disturbed by the noise of the newcomer, opened his eyes. And those eyes were gleaming with a glow that filled Henson's heart with horrible dread. It was Merritt who sat opposite him, and it was Merritt whose eyes told Henson that he knew of the latter's black treachery. Henson was face to face with death, and he knew it.

He turned and fled for his life; he scudded along the streets, past the hospital and up towards the downs, with Merritt after him. The start was not long, but it was sufficient. Merritt took the wrong turn, and, with a heart beating fast and hard, Henson climbed upwards. It was a long time before his courage came back to him. He did not feel really easy in his mind until he had passed the lodge-gates at Longdean Grange, where he was fortunate enough, after a call or two, to rouse up Williams.

The latter came with more alacrity than usual. There was a queer grin on his face and a suggestion of laughter in his eyes.

"There seems to be a lot of light about," Henson cried. "Take me up to the house, and don't let anybody know I am here. Your mistress gone to bed?"

"She's in the drawing-room," Williams said, "singing. And Miss Enid's there. I am sure they will be glad to see you, sir."

Henson doubted it, but made no reply. There was a chatter of voices in the drawing-room, a chatter of a lightsomeness that Henson had never heard before. Well, he would soon settle all that. He passed quietly into the room, then stood in puzzled fear and amazement.

"Our dear nephew," said a cool, sarcastic voice. "Come in, sir, come in. This is quite charming. Well, my sweet philanthropist and most engaging gentleman, and what may we have the pleasure of doing for you to-night?"

"Lord Littimer?" Henson gasped. "Lord Littimer here?"