Beale flushed and laughed.

"My last attempt to be merry," he said. "I suppose that to-morrow she will be well."

"But not receiving visitors," Kitson was careful to warn him. "You will keep your mind off Oliva and keep your eye fixed on van Heerden if you are wise. No man can serve two masters."

Stanford Beale looked at his watch.

"It is the hour," he said oracularly, and got up.

"I'll leave this untidiness for your man to clear," said Kitson. "Where do you go now?"

"To see Hilda Glaum--if the fates are kind," said Beale. "I'm going to put up a bluff, believing that in her panic she will lead me into the lion's den with the idea of van Heerden making one mouthful of me. I've got to take that risk. If she is what I think she is, she'll lay a trap for me--I'll fall for it, but I'm going to get next to van Heerden to-night."

Kitson accompanied him to the door of the hotel.

"Take no unnecessary risks," he said at parting, "don't forget that you're a married man."

"That's one of the things I want to forget if you'll let me," said the exasperated young man.

Outside the hotel he hailed a passing taxi and was soon speeding through Piccadilly westward. He turned by Hyde Park Corner, skirted the grounds of Buckingham Palace and plunged into the maze of Pimlico. He pulled up before a dreary-looking house in a blank and dreary street, and telling the cabman to wait, mounted the steps and rang the bell.

A diminutive maid opened the door.

"Is Miss Glaum in?" he demanded.

"Yes, sir. Will you step into the drawing-room. All the other boarders are out. What name shall I say?"

"Tell her a gentleman from Krooman Mansions," he answered diplomatically.

He walked into the tawdry parlour and put down his hat and stick, and waited. Presently the door opened and the girl came in. She stopped open-mouthed with surprise at the sight of him, and her surprise deepened to suspicion.

"I thought----" she began, and checked herself.

"You thought I was Doctor van Heerden? Well, I am not."

"You're the man I saw at Heyler's," she said, glowering at him.

"Yes, my name is Beale."

"Oh, I've heard about you. You'll get nothing by prying here," she cried.

"I shall get a great deal by prying here, I think," he said calmly. "Sit down, Miss Hilda Glaum, and let us understand one another. You are a friend of Doctor van Heerden's?"

"I shall answer no questions," she snapped.

"Perhaps you will answer this question," he said, "why did Doctor van Heerden secure an appointment for you at Punsonby's, and why, when you were there, did you steal three registered envelopes which you conveyed to the doctor?"

Her face went red and white.

"That's a lie!" she gasped.

"You might tell a judge and jury that and then they wouldn't believe you," he smiled. "Come, Miss Glaum, let us be absolutely frank with one another. I am telling you that I don't intend bringing your action to the notice of the police, and you can give me a little information which will be very useful to me."

"It's a lie," she repeated, visibly agitated, "I did not steal anything.

If Miss Cresswell says so----"

"Miss Cresswell is quite ignorant of your treachery," said the other quietly; "but as you are determined to deny that much, perhaps you will tell me this, what business brings you to Doctor van Heerden's flat in the small hours of the morning?"

"Do you insinuate----?"

"I insinuate nothing. And least of all do I insinuate that you have any love affair with the doctor, who does not strike me as that kind of person."

Her eyes narrowed and for a moment it seemed that her natural vanity would overcome her discretion.

"Who says I go to Doctor van Heerden's?"

"I say so, because I have seen you. Surely you don't forget that I live opposite the amiable doctor?"

"I am not going to discuss my business or his," she said, "and I don't care what you threaten me with or what you do."

"I will do something more than threaten you," he said ominously, "you will not fool me, Miss Glaum, and the sooner you realize the fact the better. I am going all the way with you if you give me any trouble, and if you don't answer my questions. I might tell you that unless this interview is a very satisfactory one to me I shall not only arrest Doctor van Heerden to-night but I shall take you as an accomplice."

"You can't, you can't." She almost screamed the words.

All the sullen restraint fell away from her and she was electric in the violence of her protest.

"Arrest him! That wonderful man! Arrest me? You dare not! You dare not!"

"I shall dare do lots of things unless you tell me what I want to know."

"What do you want to know?" she demanded defiantly.

"I want to know the most likely address at which your friend the doctor can be found--the fact is, Miss Glaum, the game is up--we know all about the Green Rust."

She stepped back, her hand raised to her mouth.

"The--the Green Rust!" she gasped. "What do you mean?"

"I mean that I have every reason to believe that Doctor van Heerden is engaged in a conspiracy against this State. He has disappeared, but is still in London. I want to take him quietly--without fuss."

Her eyes were fixed on his. He saw doubt, rage, a hint of fear and finally a steady light of resolution shining. When she spoke her voice was calm.

"Very good. I will take you to the place," she said.

She went out of the room and came back five minutes later with her hat and coat on.

"It's a long way," she began.

"I have a taxi at the door."