"Poor beggar!" he said to himself. "He's just beginning to realise things. Five centigrammes of radium chloride killed eight mice in three days; how long will it take an ounce of radium bromide to render a strong man insensible? That's the problem in rule of three, and it's high time that someone worked out the answer.

"Well?" in reply to the bell.

"Temperature, 102; pulse, 100. Look here, Blyth, I'm going dotty. If you won't have pity on me as a Christian, I appeal to you as a family man.

Your people wouldn't like to hear of this, I'm sure."

"Pulse 100," repeated the Professor. "Jerky, I suppose?"

"Did you hear my appeal to you as a family man?"

"Now, Smithers, you agreed to help me with my scientific observations, and I wish you'd keep to the letter of the agreement. Is your pulse jerky?"

"It is, and my hands are fairly itching to close round your throat, and my toes would like to kick you into eternity. Blyth, if I die, I'll haunt you and your family to the fifth generation. If you don't end up in a madhouse it won't be my fault. You scoundrel! You contemptible----"

Again the Professor hung up the receiver. "Strange," he soliloquised, "how mentally unbalanced these common men are! I can't imagine myself giving way to such ravings, whatever situation I was in. That's the advantage of birth and education. Yet, judging from the way in which Smithers expresses himself, he must be a man of very fair education.

It's birth alone that tells in the long run," and the Professor stroked his stubble chin complacently.

The minutes pa.s.sed. "He ought to be feeling it now. I'll ring him up."

The Professor did so, but there was no reply. "He can't have collapsed already--a horse-soldier of thirty-five." Once more he rang. This time there was a slow response.

"Why didn't you come before?" said the Professor irately.

"I'm not your servant. I was thinking how I'd like to chop you into mincemeat, Blyth, and scatter you to the crows. My head's splitting--splitting, do you hear? I shall go dotty, looking at this infernal heap of fire. Those moving specks of light behind are all alive, Blyth. They're grinning at me. They're choking me. And there you sit like a scientific panjandrum with a little round b.u.t.ton on top. And you call yourself a Christian and a respectable family man. You are a disgrace to your country. Come down and let me out. Send for the police.

I don't care."

"Smithers," said the Professor, "I'm ashamed of you. A horse soldier going on like a nurserymaid! I shall not send for the police. You agreed to this experiment, and you've got to see it through. Please remember that. How's your pulse?"

"Blyth, it's 120! It's ticking like a clock. I believe it's going to strike."

"Keep cool, Smithers. Have your hands a bluish tinge?"

"They seem to be green."

"Green? Preposterous!"

"They may be blue really. I'm colour blind."

"Colour blind, Smithers, and a soldier? I'm surprised at you. I suspect they're only dirty. Do you feel a tingling at the finger tips?"

"Yes, and at my toe-tips too."

"Excellent! And your temperature?"

"One hundred and three. Man, I'm in a fever. I can't breathe. My head's on fire."

"You've only been in there an hour and a quarter. You're just beginning to get acclimatised, Smithers," said Professor Blyth callously, as he hung up the receiver.

"I wish Cantrip were here," he soliloquised. "'Deoxygenation of the blood corpuscles, followed by coma.' Bah! Radium acts on the nerve centres, and will ultimately produce paralysis. Cantrip is an a.s.s. I always told him so."

The bell rang. "Blyth," said the prisoner, "listen to me. If you don't let me out, I'll swallow the radium. It can't make me feel worse, and it may finish me off quicker."

"Nonsense, Smithers, don't talk like a fool. It would only add to any--er--inconvenience you are now experiencing."

"I don't care what it would do. I----"

The Professor cut him off impatiently. "I'm disappointed in John Smithers," he thought. "He has no stamina. A man of low birth, evidently. A mere mountain of muscle. I know the species."

For a while he paced the room. Then he rang the bell, but this time there was no coherent response. The gasps sounded like, "Sit on her head, Blyth--keep her down, man. Whoa, mare!--mind that fencing--snow again--what ho! she b.u.mps--all down the road and round the corner----"

"For heaven's sake, keep cool, Smithers," cried the Professor. "I want some more observations. Don't lose your head yet. You've all the night in front of you."

"Squadron, right wheel! Draw swords! Charge! Down with 'em! Boers, j.a.ps, and Russians. Get home, lads! Give it 'em hot! Hurrah! I've killed a sergeant-major." Then indistinct mumbling and cackling laughter came through the telephone.

The Professor was disturbed. The end had come sooner than he had expected, for John Smithers had only been there an hour and a half, and he had calculated on a much longer time. But the symptoms were, on the whole, what he had expected. Green hands, though. What if the extremities were blue after all, and Cantrip right?

He rang the bell. There was no response. Once more, and yet again. Still there was silence.

The Professor hung up the receiver gloomily. "I'm afraid I shall have to go to him. He's unconscious, and continued exposure might be serious."

He went down the corridor, pulled back the bolts, and opened the door.

The room was in absolute darkness. The Professor was intensely surprised. "What on earth has he done with the radium?" he thought.

"Good heavens! Surely he hasn't really swallowed it!"

He stepped carefully across the threshold towards the electric pendant in the centre of the room. He started. The door had closed behind him with a loud click. He switched on the light, and peered round the floor for John Smithers. He was alone. Neither Smithers nor the radium was there!

At that moment the telephone rang.

"Are you there?" came a voice.

"Is that you, Smithers?" said the Professor, in blank amazement.

"It is, Blyth. How's your temperature? You'll find the thermometer on the telephone where you left it."

"You scoundrel! You consummate scoundrel! How did you get out?"

"For goodness' sake, Blyth, keep cool."

"If you don't release me immediately I'll hand you over to the police."

"You can't get 'em, old man. You can only talk to me."

"What have you done with the radium?"

"Got it here, Blyth; and I'm taking ever such a lot of care of it. I read all about it before I came, and I know just what it fancies. I brought a nice quarter-inch thick lead case, with a smaller one fixed inside, and the half-inch of intervening s.p.a.ce made up with quicksilver.

I've had the radium in the inner case most of the time, and it's as quiet as a lamb, nicely bottled up with its rays. In fact, I think it's gone to sleep. I've had quite a cheerful time with you to talk to, Blyth. You don't know how amusing you've been."

"Smithers," stuttered the Professor, "you are an insolent fellow as well as a consummate scoundrel."

"Tut, tut, Blyth! Do keep cool. Think how humanity will benefit from your present inconvenience. I'll look out for your article in the _British Medical Journal_, and I won't contradict it, though my pulse never went above seventy-three nor my temperature over ninety-nine, and wouldn't have done that if I'd bottled the radium at once instead of stopping to chatter with you. But you really ought to have kept a smarter look-out as you went in. I nearly brushed against you as I closed the door behind me. Well, bye-bye, old man, and many thanks for the radium. It will help my pension out nicely. I'll leave the receiver off the telephone, so that you don't disturb your family. I wouldn't worry, Blyth. Think of the Black Hole of Calcutta, and be a man!"