how bad his injuries might be. She knew the significance of these quietly ominous summonses, for her father had been fatally injured in a street accident only three years before.
In a few minutes she was ringing the bell of Number seven, Cornwallis Road, and almost immediately the door was opened by a butler.
'Miss Tregarth?' he guessed at once, for there was no mistaking her distress. 'Professor Raxel told me to expect you.'
'Where's my brother?'
The man threw open a door.
'If you will wait here, Miss Tregarth, I will tell the Professor that you have arrived.'
She went in. The room was furnished as a waiting room, and she wondered what the professor's profession was. There were a couple of armchairs, a bookcase in one corner, and a table in the centre littered with magazines. She sat down and strove to possess herself in patience; but she had not long to wait.
In a few moments the door opened, and a tall, thin, elderly man entered. She sprang up.
'Are you Professor Raxel?'
'I am. And you, of course, are Miss Tregarth.' He took her hand. 'I am afraid you will not be able to see your brother for a few minutes, as the doctor is still with him, Please sit down again.'
She sat down, struggling to preserve her composure.
'Tell me--what's happened to him?'
Before answering, the Professor produced a gold cigarette case and offered it. She would have refused, but he insisted.
'It doesn't take a professor to see that you are in a bad state of nerves,' he said kindly. 'A cigarette will help you.'
She allowed him to light a cigarette for her, and then repeated her demand for information.
'It is difficult to tell you,' said Raxel slowly, and suddenly she was terrified.
'Do you mean--'
He placed the tips of his fingers together.
'Not exactly,' he said, 'In fact, I have no doubt that your brother is in perfect health. I must confess, my dear Miss Tregarth, that I lured you here under false pretenses. I have not seen your brother this evening, but I have been told that he went out a little over an hour ago. There is no more reason to suppose that he has met with an accident to-night than there would be for assuming that he had met with one on any other night that he chose to go put alone.'
She stared.
'But you told me--'
'I apologize for having alarmed you, but it was the only excuse I could think of which would bring you here immediately.'
At first he had been geniality itself; but now, swiftly and yet subtly, a sinister element had crept into his blandness. She felt herself go cold, but managed somehow to keep her voice at its normal level.
'Then I fail to see, Professor. Raxel, why you should have brought me here,' she remarked icily.
'You will understand in a moment,' he said. He took a small automatic pistol from his pocket, and laid it on the table in front of her. She stared at it in amazement mingled with fear
'Please take it,' he smiled. 'I particularly want you to feel safe, because I am going to say something that might otherwise frighten you considerably.'
She looked blankly at the gleaming weapon, but did not touch it.
'Take it!' insisted the Professor sharply. 'You are here in my power, in a strange house, and I am offering you a weapon. Don't be a fool. I will explain.'
Hesitantly she reached out and took the automatic in her hand. Since he had offered it she might as well accept it--there could be no harm in that; and, as he had remarked, it was certainly a weapon of which she might be glad in the circumstances. Yet she could not understand why, in those circumstances, he should offer it to her. Certainly he could i-not imagine that she would make use of it.
'Of course, it isn't loaded,' she said lightly.
'It is loaded,' replied the Professor. 'If you don't believe me, I invite you to press the trigger.'
'That might be awkward for you. A policeman might be within hearing, and he would certainly want to know who was firing pistols in this house.'
The Professor smiled.
'You could shoot me, and no one would hear,' he said. 'I ask you to observe that there are no windows in this room. The walls are thick, and so is the door--the room is practically sound-proof. Certainly the report of that automatic would not be audible in the street. I can be quite positive about that because I have verified the statement by experiment.'
'Then--'
'You may understand me better,' said the Professor quietly, 'if I tell you first of all that I intend to keep you here for a few hours.'
'Really?'
She was becoming convinced that the man was mad, and somehow the thought made him for a moment seem less alarming. But there was nothing particularly insane about his precise level voice, and his manner was completely restrained. She settled back in her chair and endeavoured to appear completely unperturbed. Then she thought she saw a gleam of satisfaction light up in his eyes as she took another puff at the cigarette he had given her, and her fingers opened and dropped it suddenly as though it had been red hot.
'And I suppose the cigarette was doped?' she said shakily.
'Perhaps,' said the Professor.
He rose and went quickly to a bell-push set in the wall beside the mantelpiece, and pressed it.
Betty Tregarth got to her feet feeling strangely weak.
'I make no move to stop your going,' said Raxel quickly. 'But I suggest that you should hear what I have to say first.'
'And you'll talk just long enough to give the dope in that cigarette time to work,' returned the girl. 'No--I don't think I'll stay, thanks.'
'Very well,' said Raxel. 'But if you won't listen to me, perhaps you will look at something I have to show you.'
He clapped his hands twice, and the door opened. Three men came in. One was the butler who had admitted her, the other was a dark, heavy-jowled, rough-looking man in tweeds.
The third man they almost carried into the room between them. He was tall and broad-shouldered, and he was so roped from his shoulders to his knees that he could only move in steps of an inch at a time unaided. His face was divided into two parts by a black wooden ruler, which had been forced into his mouth as a gag, and which was held in position by cords attached to the ends, which passed round the back of his head.
'Does that induce you to stay?' asked Raxel.
'I think it means that I am induced to go out at once, and find a policeman,' said the girl, and took two steps towards the door.
'Wait!'
Raxel's voice brought her to a stop. The command in it was so impelling that for a moment it was able to overcome the panicky desire for flight which was rapidly getting her in its grip.
'Well?' she asked, as evenly as she could.
'You are a chemist, Miss Tregarth,' said Raxel, 'and therefore you will be familiar with the properties of the drug known as bhang. The cigarette you half-smoked was impregnated with a highly concentrated and deodorized preparation of bhang. According to my calculations, the drug will take effect about now. You still have the automatic I gave you in your hand, and there, in front of you, is a man gagged and bound. Stand away, you two!'
The Professor's voice suddenly cracked out the order with a startling intenseness, and the two men who had stood on either side of the prisoner hurried into the opposite corner of the room and left him standing alone.
Betty Tregarth stared stupidly at the gleaming weapon in her hand, and looked from it to the bound man who stood stiffly erect by the door.
Then something seemed to snap in her brain, and everything went black; but through the whirling, humming
