The Problem of the Green Capsule

by John Dickson Carr

  Major Crow stared at it.

  “Nonsense,” he said. “Nothing easier. Like this——”

  He turned the clock round again with its face outwards. Opening the round glass door protecting the face of the clock, he laid hold of the hands.

  “All you’ve got to do,” he continued, “is simply push——”

  “Steady on, sir!” said Elliot.

  Even Major Crow left off, and knew himself beaten. The metal hands were too delicate. To attempt to push them in either direction was only to bend them in half or break them off; quite plainly, their position could not be altered by the fraction of a second. Elliot stood back. He began to grin in spite of himself. The hands continued their derisive course, the metal screw holding them fast winked back at him, and the ticking of the clock touched in him such a deep inner chord of amusement that he almost laughed in the Chief Constable’s face. Here was a symbol. He was looking at the fiction-writer’s nightmare—a clock that could not be tampered with.

  “So that’s that,” he said.

  “That is not that,” said Major Crow.

  “But, sir——”

  “There is some jiggery-pokery about that clock,” declared the other, with such slow and measured emphasis that he seemed to be making a vow. “I admit I don’t know what it is. But you’ll see it proved before we’re many hours older.”

  It was at this point that the Photoflood bulb, after flaring up with a dense and smoky glare, abruptly burned itself out. It startled them all, and the green-shaded lamp over in the corner now seemed dusky by contrast. But Dr. West had already drawn back; he was an elderly man with a pince-nez, who looked tired.

  “What would you like me to tell you about this?” he said to Major Crow.

  “Well, what killed him?”

  “It is prussic acid or one of the cyanides. I will do a postmortem in the morning and let you know.”

  “‘One of the cyanides?’ Joe Chesney said it was cyanide.”

  Dr. West looked apologetic. “You are probably thinking of potassium cyanide. That is one of a group of cyanide salts derived from prussic acid. But I agree it is the most common.”

  “Let me acknowledge my ignorance,” said Major Crow. “I read up on strychnine for that other business, but I’m out of my depth here. Well, say someone killed Chesney with prussic acid or its cyanide derivatives. Where does the stuff come from? How would you go about getting it?”

  “I have some notes here,” the doctor told him, fumbling in his pocket with what can only be called a sort of slow hurry. He spoke with modest satisfaction. “It’s not often we get the opportunity to see a case of prussic-acid poisoning, you know. It is rare, very rare. I made some notes in the case of Billy Owens, and I thought I had better bring them along.”

  He went on in his grateful way:

  “Pure prussic acid (HCN) is almost inaccessible to the layman. On the other hand, any good chemist could easily prepare it from non-poisonous (I mean unscheduled, not on the poison-list) substances. Its salt, potassium cyanide, is used in a variety of ways. It is used in photography, as you probably know. It is sometimes used as an insecticide on fruit trees——”

  “Fruit trees,” muttered Major Crow.

  “It is used in electro-plating. It is used in killing-bottles——”

  “What’s a killing-bottle?”

  “Entomology,” said the doctor. “Catching butterflies. The painless killing bottle contains five per cent of KCN; they can be bought at a taxidermist’s. But for all these things, of course, the buyer would have to sign a poison-book.”

  Elliot interposed. “May I ask a question, doctor? It’s true, isn’t it, that there is prussic acid in peach-stones?”

  “Yes, that is true,” agreed Dr. West, rubbing his forehead.

  “And that anybody could distil prussic acid by crushing ordinary peach-stones and boiling them?”

  “I have been asked that question before,” said Dr. West, rubbing his forehead still harder. “It is certainly true. But I have estimated that to produce a lethal dose from peach-stones would require the kernels of approximately five thousand six hundred peaches. This hardly seems practicable.”

  After a pause Superintendent Bostwick spoke heavily. “That poison came from SOMEWHERE,” he pointed out.

  “It did. And this time you’re going to trace it,” said the Chief Constable. “We missed the strychnine, but we’re not going to miss the cyanide if we have to comb through every poison-book in England. That’s your job, Superintendent. But, incidentally, doctor—you know those big green capsules, castor-oil capsules?”

  “Yes?”

  “Suppose you were going to give a dose of cyanide in one of those. How would you get the stuff into the capsule. A hypodermic needle?”

  Dr. West reflected. “Yes, that would be practicable. Unless too much were put in, the gelatine and the oil would contain it firmly. It would also conceal odour and taste. Nine-tenths of a grain of anhydrous prussic acid has been fatal. The pharmaceutical preparation of potassium cyanide is, of course, weaker. But two or three grains, I feel justified in saying, would do the work.”

  “And how long would it take to kill?”

  “I do not know the size of the dose,” observed Dr. West apologetically. “Ordinarily I should expect to see symptoms come on within ten seconds. Here, however, the gelatine would have to melt, and the castor-oil would retard the absorption of the poison. Let us say that it might take anything up to two minutes for the symptoms to appear strongly. For the rest, everything would depend on the size of the dose. Complete prostration would quickly follow. But death might occur in three minutes, or it might not occur for half an hour.”

  “Well, that squares with what we know,” said Major Crow. He made a gesture of exasperation. “Anyhow, Inspector, I suggest you go back there and pitch into that gang again.” He nodded malevolently towards the closed double-doors. “Find out if they’re certain that what they saw was really a castor-oil capsule. It may be another piece of hocus-pocus. Find out—oh, get the guts out of all the foolery, and then we shall know where we are.”

  Elliot, glad of an opportunity to work alone, went into the Music Room and pulled shut the doors behind him. Three pairs of eyes were fixed on him.

  “I won’t detain you much longer tonight,” he told them pleasantly. “But if you wouldn’t mind clearing up the rest of these points—”

  Professor Ingram studied him. “One moment,” he suggested. “Could you clear up a point, Inspector? Did you find out that the chocolate-boxes really were switched in the way I said?”

  Elliot hesitated. “Yes, sir, I don’t mind telling you they were.”

  “Ah!” said Professor Ingram, with a rich and evil satisfaction. He sat back, while Marjorie and George Harding looked at him in a puzzled way. “I was hoping for that. Then we are already on the way towards a solution.”

  Marjorie was about to speak, but Elliot gave her no chance.

  “Here is Mr. Chesney’s eighth question, about the man in the top-hat. What did he give me to swallow? How long did it take me to swallow it? You’re all agreed, now, that it was a castor-oil capsule?”

  “I’m positive,” answered Marjorie. “It took two or three seconds for him to swallow it.”

  “It certainly had that appearance,’’’ Professor Ingram said more cautiously. “And he had some difficulty in getting it down.”

  “I don’t know anything about these capsules,” said Harding. His face was white and restless and doubtful: Elliot wondered why. “I should have said it was a grape, a green grape, and I wondered why he didn’t choke on it. But if you both recognised it, all right I agree.”

  Elliot switched the attack. “We’ll return to that. Now a question of very great importance. How long was he in the room?”

  He spoke so gravely, and the satiric expression had become so broad across Ingram’s face, that Marjorie hesitated.

  “Is there a catch in it?” she inquired. “You mean how long was it b
etween the time he walked in through the French window and the time he walked out again? Certainly not very long. Two minutes, I should think.”

  “Two and a half minutes,” said Harding.

  “He was in the room,” said Professor Ingram, “exactly thirty seconds. Over and over again—with such uniformity that it becomes almost boring—people will overestimate time wildly. Actually, Nemo ran little risk. You had almost no opportunity to study him, although you think you had. If you like, Inspector, I will give you the entire time-schedule of the performance, including Chesney’s movements. Shall I?”

  At Elliot’s nod, Professor Ingram closed his eyes.

  “Let’s begin with the time when Chesney slipped through those doors and I turned out the lights in here. After I had turned out the lights, about twenty seconds elapsed before Chesney pulled open the doors to begin the show. Between the time Chesney opened the doors and the time Nemo entered, fully forty seconds elapsed. There is a full minute before Nemo’s entrance. Nemo’s part was over in thirty seconds. After his departure, Chesney sat for another thirty seconds before he flopped forward in pretended death. He rose and closed the doors again. I had some difficulty in getting the lights on: I always grope on the wrong side of the door for that infernal switch. Say another twenty seconds. But the whole performance, from extinguishing the lights to turning them on again, took just two minutes and twenty seconds.”

  Marjorie looked doubtful, and Harding shrugged his shoulders. They did not contradict, but a settled rebellion had got into them. Both were looking white and tired. Marjorie shuddered a little, and her eyes were strained. Elliot knew that the spring could not be pressed much harder to-night.

  “And now the final question,” he said. “Here it is. What person or persons spoke? What was said?”

  “I’m glad it’s the last one,” observed Marjorie, swallowing. “And this time at least I know I can’t be wrong. The thing in the top-hat never spoke at all.” She faced Professor Ingram fiercely. “You don’t deny that, do you?”

  “No, my dear, I don’t deny it.”

  “And Uncle Marcus only spoke once. It was just after the thing in the top-hat had put down that black bag on the table and walked over to the right-hand side of the table. Uncle Marcus said, ‘You have done now what you did before; what else will you do?”

  Harding nodded. “That’s right ‘You have done now what you did before; what else will you do?’ Or something like that, anyway, I won’t swear to the exact order of the words.”

  “And that’s all that was said?” persisted Elliot.

  “Absolutely everything.”

  “I disagree,” said Professor Ingram.

  “Oh, damn you,” Marjorie almost screamed. She leaped to her feet. Elliot was startled and rather shocked at the way her soft face, a face of almost Victorian placidity, could change. “Blast your soul to hell!”

  “Marjorie!” shouted Harding. Then he coughed, and began to make embarrassed gestures in Elliot’s direction, like an adult who wishes to distract the attention of a baby by making faces.

  “There is no need to carry on like that, my dear,” Professor Ingram told her mildly. “I am only trying to help you. You know that.”

  Marjorie stood irresolute during a few bad moments. Then tears came into her eyes, and the colour in her face gave her a very real beauty which was not even destroyed by the twitching of her mouth.

  “I’m s-sorry,” she said.

  “For instance,” pursued Professor Ingram, as though nothing had happened, “it is not literally true to say that nothing else was said during the show.” He looked at Harding. “You spoke, you know.”

  “I spoke?” repeated Harding.

  “Yes. When Dr. Nemo entered, you moved forward to get a better view for your camera, and you said, “Shh! The Invisible Man!’ I think that is correct?”

  Harding rubbed his wiry black hair. “Yes, sir. I may have tried to be funny. But dash it all!—the question doesn’t refer to that It only refers to what the people on the stage said, doesn’t it?”

  “And you,” continued Professor Ingram to Marjorie, “you also spoke, or whispered. When Nemo was giving your uncle that castor-oil capsule, and forced back his head to tilt it down his throat, you uttered a kind of cry or sound of protest. You said or whispered, ‘Don’t! Don’t!’ It was not loud, but it was distinct.”

  “I don’t remember saying anything,” answered Marjorie, blinking. “But what of it?”

  The professor’s tone grew more easy.

  “I am preparing you against Inspector Elliot’s next line of attack. I tried to tell you a long time ago: He has already been wondering whether one of us three could have slipped out of here and murdered your uncle during the two minutes while the lights were out. Now, I am in a position to swear that I both saw and heard you—both of you—all the time Nemo was on the stage. I can swear you never left this room. If you are in a position to do the same for me, we shall present a triple alibi which all the weight of Scotland Yard cannot break. Are you in a position to swear it? What do you say?”

  Elliot braced himself. He knew that the next few minutes would bring him to the crux of the case.

  Chapter IX

  THE TRIPLE ALIBI

  This time Harding was on his feet. His large eyes—“cowlike,” Elliot called them, having already gone through a whole series of animals in finding his similies about Harding—looked alarmed. He retained his mechanical expression of good-nature, nor did his deference towards authority lessen; but his hairy hands twitched a little.

  “But I was taking the picture!” he protested. “Look, there’s the camera. Didn’t you hear it going? Didn’t you——”

  Then he laughed, with very genuine charm. He seemed to hope that someone would laugh with him, and was annoyed when nobody did.

  “I see,” he added, looking far away. “I read a story once.”

  “Did you, now?” inquired Professor Ingram.

  “Yes,” said Harding quite seriously. “Chap had an alibi because they swore they could hear him working his typewriter all the time. It turned out he had a mechanical gadget which made a noise like a typewriter when he wasn’t there. Great snakes, do you think there’s something that will run a ciné-camera for you while you’re not there?”

  “But that’s absurd,” cried Marjorie, as though this were the last point of bedevilment. “I saw you. I know you were there. Is that what you think, Inspector?”

  Elliot assumed his stolidest grin.

  “Miss Wills, I haven’t said anything. It’s the professor here who has made all the suggestions. All the same, we might consider the point, even if we only”—he was broadly sympathetic—“clear it up. It was very dark in here, though, wasn’t it?”

  Professor Ingram answered him, before the others could speak.

  “It was very dark for perhaps twenty seconds, up to the time Chesney opened those double-doors. Afterwards there was enough reflection thrown back from the Photoflood bulb on the far wall of the office so that it could hardly be called altogether dark. Outlines were perfectly clear, as I think my companions will tell you.”

  “Just a moment, sir. How were you sitting?”

  Professor Ingram got up, and carefully arranged three arm-chairs in a row about three feet apart. The chairs faced the double-doors from a distance of some eight or nine feet, so that their full distance from Marcus Chesney would have been about fifteen feet.

  “Chesney arranged the chairs before we got here,” Professor Ingram explained, “and we didn’t disturb them. I sat here, on the right-hand end nearest the lights.” He laid his hand on the back of the chair. “Marjorie was in the middle. Harding sat at the other end.”

  Elliot studied the position. Then he turned to Harding.

  “But what were you doing so far over to the left?’ he asked. “Couldn’t you have got a better picture from the middle? From this position you couldn’t have photographed Nemo as he stepped in through the window.”

 
Harding wiped his forehead.

  “Now, I ask you: how the devil did I know what was going to happen?” he demanded, man to man. “Mr. Chesney didn’t explain what we were to look out for. He just said, ‘Sit there’; and I hope you don’t think I was going to argue with him. Not little Georgie. I was sitting—or, rather, I was standing, about here; and I had a good enough view.”

  “Oh, what’s the good of this arguing?” said Marjorie. “Of course he was here. I saw him move back and forth to get the picture in. And I was here. Wasn’t I?”

  “You were,” Professor Ingram confirmed blandly. “I felt you.”

  “Eh?” said Harding.

  Professor Ingram’s face grew murderous. “I felt her presence, young man. I heard her breathe. I could have reached out and touched her. It is true she is wearing a dark dress; but she has, you observe, a very white skin, and her hands and face were as plain in the dark as the front of your shirt.” Clearing his throat, he turned to Elliot. “What I am trying to tell you. Inspector, is that I will swear neither of these two left the room at any time. Harding was always at the corner of my eye. Marjorie was within touch of me. Now, if they will say the same of me——?”

  He inclined his forehead politely, keenly, towards Marjorie. His manner. Elliot felt, was that of a physician testing a patient’s pulse; and there was a quiet concentration in his face.

  “Of course you were,” cried Marjorie.

  “You’re sure of that?” Elliot insisted.

  “I’m perfectly sure of it. I saw his shirt and his bald head,” she went on with emphasis, “and—oh, I saw everything! I heard him breathe, too. Weren’t you ever at a spirit seance? Wouldn’t you have known if anybody had left the group?”

  “What do you say, Mr. Harding?”

  Harding hesitated.

  “Well, to tell the truth, I had my eye glued on the viewfinder most of the time. So I didn’t get much chance to look about. Hold on, though!” He struck his fist into the palm of his left hand, and such an expression of relief came into his face that it was as though a wheel went round behind his eyes. “Haa! Now wait: don’t hurry me. Just after this top-hatted bloke stepped out of the picture, I looked up, and stepped back, and shut off the camera. I bumped into a chair as I stepped back; I looked around”—he was following this with turns of his wrist—“and I could see Marjorie right enough. I could see her eyes shine, in a way. That isn’t scientifically correct, but you know what I mean. Of course I knew she was there all the time, because I’d heard her speak out and say ‘Don’t.’ But I also saw her; and anyway,” his broad grin cheered the room, “you can be ruddy well certain she’s no more five feet nine inches tall than she is six feet. What’s got into us, anyway?”