Craddock had to wait a few minutes whilst Quimper finished his evening surgery, and then the doctor came to him. He looked tired and depressed.

He offered Craddock a drink and when the latter accepted he mixed one for himself as well.

"Poor devils," he said as he sank down in a worn easy-chair. "So scared and so stupid - no sense. Had a painful case this evening. Woman sho ought to have come to me a year ago. If she'd come then, she might have been operated on successfully. Now it's too late. Makes me mad. The truth is people are an extraordinary mixture of heroism and cowardice. She's suffering agony, and borne it without a word, just because she was too scared to come and find out that what she feared might be true. At the other end of the scale are the people who come and waste my time because they've got a dangerous swelling causing them agony on their little finger which they think may be cancer and which turns out to be a common or garden chilblain! Well, don't remind me. I've blown off steam now. What did you want to see me about?"

"First, I've got you to thank, I believe, for advising Miss Crackenthorpe to come to me with the letter that purported to be from her brother's widow."

"Oh, that? Anything in it? I didn't exactly advise her to come. She wanted to. She was worried. All the dear little brothers were trying to hold her back, of course."

"Why should they?"

The doctor shrugged his shoulders.

"Afraid the lady might be proved genuine, I suppose."

"Do you think the letter was genuine?"

"No idea. Never actually saw it. I should say it was someone who knew the facts, just trying to make a touch. Hoping to work on Emma's feelings. They were dead wrong, there. Emma's no fool. She wouldn't take an unknown sister-in-law to her bosom without asking a few practical questions first."

He added with some curiosity:

"By why ask my view? I've got nothing to do with it?"

"I really came to ask you something quite different - but I don't quite know how to put it."

Dr. Quimper looked interested.

"I understand that not long ago – at Christmas-time, I think it was - Mr. Crackenthorpe had rather a bad turn of illness."

He saw a change at once in the doctor's face. It hardened.

"Yes."

"I gather a gastric disturbance of some kind?"

"Yes."

"This is difficult…. Mr. Crackenthorpe was boasting of his health, saying he intended to outlive most of his family. He referred to you - you'll excuse me, Doctor…"

"Oh, don't mind me. I'm not sensitive as to what my patients say about me!"

"He spoke of you as an old fuss-pot." Quimper smiled. "He said you had asked him all sorts of questions, not only as to what he had eaten, but as to who prepared it and served it."

The doctor was not smiling now. His face was hard again.

"Go on."

"He used some such phrase as – 『Talked as though he believed someone had poisoned me.』"

There was a pause.

"Had you - any suspicion of that kind?"

Quimper did not answer at once. He got up and walked up and down. Finally, he wheeled round on Craddock.

"What the devil do you expect me to say? Do you think a doctor can go about flinging accusations of poisoning here and there without any real evidence?"

"I'd just like to know, off the record, if - that idea – did enter your head?"

Dr. Quimper said evasively:

"Old Crackenthorpe leads a fairly frugal life. When the family comes down, Emma steps up the food. Result - a nasty attack of gastro-enteritis. The symptoms were consistent with that diagnosis."

Craddock persisted.

"I see. You were quite satisfied? You were not at all - shall we say - puzzled?"

"All right. All right. Yes, I was Yours Truly Puzzled! Does that please you?"

"It interests me," said Craddock. "What actually did you suspect – or fear?"

"Gastric cases vary, of course, but there were certain indications that would have been, shall we say, more consistent with arsenical poisoning than with plain gastro-enteritis. Mind you, the two things are very much alike. Better men than myself have failed to recognise arsenical poisoning – and have given a certificate in all good faith."

"And what was the result of your inquiries?"

"It seemed that what I suspected could not possibly be true. Mr. Crackenthorpe assured me that he had similar attacks before I attended him - and from the same cause, he said. They had always taken place when there was too much rich food about."

"Which was when the house was full? With the family? Or guests?"

"Yes. That seemed reasonable enough. But frankly, Craddock, I wasn't happy. I went so far as to write to old Dr. Morris. He was my senior partner and retired soon after I joined him. Crackenthorpe was his patient originally. I asked about these earlier attacks that the old man had had."

"And what response did you get?"

Quimper grinned.

"I got a flea in the ear. I was more or less told not to be a damned fool. Well - he shrugged his shoulders – presumably I was a damned fool."

"I wonder." Craddock was thoughtfully.

Then he decided to speak frankly.

"Throwing discretion aside, Doctor, there are people who stand to benefit pretty considerably from Luther Crackenthorpe's death." The doctor nodded. "He's an old man - and a hale and hearty one. He may live to be ninety odd?"

"Easily. He spends his life taking care of himself, and his constitution is sound."

"And his sons - and daughter - are all getting on, and they are all feeling the pinch?"

"You leave Emma out of it. She's no poisoner. These attacks only happen when the others are there – not when she and he are alone."

"An elementary precaution – if she's the one," the inspector thought, but was careful not to say aloud.

He paused, choosing his words carefully.

"Surely - I'm ignorant in these matters - but supposing just as a hypothesis that arsenic was administered - hasn't Crackenthorpe been very lucky not to succumb?"

"Now there," said the doctor, "you have got something odd. It is exactly that fact that leads to believe that I have been, as old Morris puts it, a damned fool. You see, it's obviously not a case of small doses of arsenic administered regularly – which is what you might call the classic method of arsenic poisoning. Crackenthorpe has never had any chronic gastric trouble. In a way, that's what makes these sudden violent attacks seem unlikely. So, assuming they are not due to natural causes, it looks as though the poisoner is muffing it every time – which hardly makes sense."

"Giving an inadequate dose, you mean?"

"Yes. On the other hand, Crackenthorpe's got a strong constitution and what might do in another man, doesn't do him in. there's always personal idiosyncrasy to be reckoned with. But you'd think that by now the poisoner – unless he's unusually timid – would have stepped up the dose. Why hasn't he?"

"That is," he added, 「if there is a poisoner which there probably isn't! Probably all my ruddy imagination from start to finish."

"It's an odd problem, the inspector agreed. It doesn't seem to make sense."

"Inspector Craddock!"

The eager whisper made the inspector jump.

He had been just on the point of ringing the front-door bell.

Alexander and his friend Stoddart-West emerged cautiously from the shadows.

"We heard your car, and we wanted to get hold of you."

"Well, let's come inside." Craddock's hand went out to the door bell again, but Alexander pulled at his coat with the eagerness of a pawing dog.

"We've found a clue," he breathed.

"Yes, we've found a clue." Stoddart-West echoed.

"Damn that girl," thought Craddock unamiably.

"Splendid," he said in a perfunctory manner. "Let's go inside the house and look at it."

"No," Alexander was insistent. "Someone's sure to interrupt. Come to the harness room. We'll guide you."

Somewhat unwillingly, Craddock allowed himself to be guided round the corner of the house and along to the stable yard. Stoddart-West pushed open a heavy door, stretched up, and turned on a rather feeble electric light. The harness room, once the acme of Victorian spit and polish, was now the sad repository of everything that no one wanted. Broken garden chairs, rusted old garden implements, a vast decrepit mowing-machine, rusted spring mattresses, hammocks, and disintegrated tennis nets.

"We come here a good deal," said Alexander. "One can really be private here."

There were certain tokens of occupancy about. The decayed mattresses had been piled up to make a kind of divan, there was an old rusted table on which reposed a large tin of chocolate biscuits, there was a hoard of apples, a tin of toffee, and a jig-saw puzzle.

"It really is a clue, sir," said Stoddart-West eagerly, his eyes gleaming behind his spectacles. "We found it this afternoon."

"We've been hunting for days. In the bushes –"

"And inside hollow trees –"

"And we went all through the ash bins –"

"There were some jolly interesting things there, as a matter of fact –"

"And then we went into the boiler house –"

"Old Hillman keeps a great galvanised tub there full of waste paper –"

"For when the boiler goes out and he wants to start it again –"

"Any odd paper that's blowing about. He picks it up and shoves it in there –"

"And that's where we found it –"

"Found what?" Craddock interrupted the duet.

"The clue. Careful, Stodders, get your gloves on."

Important, Stoddart-West, in the best detective story tradition, drew on a pair of rather dirty gloves and took from his pocket a Kodak photographic folder. From this he extracted in his gloved fingers with the utmost care a soiled and crumpled envelope which he handed importantly to the inspector.

Both boys held their breath in excitement.

Craddock took it with due solemnity. He liked the boys and he was ready to enter into the spirit of the thing.

The letter had been through the post, there was no enclosure inside, it was just a torn envelope - addressed to Mrs. Martine Crackenthorpe, 126 Elvers Crescent, N.10.

"You see?" said Alexander breathlessly. "It shows she was here – Uncle Edmund's French wife, I mean – the one there's all the fuss about. She must have actually been here and dropped it somewhere. So it looks, doesn't it –"

Stoddart-West broke in:

"It looks as though she was the one who got murdered - I mean, don't you think, sir, that it simply must have been her in the sarcophagus?"

They waited anxiously.

Craddock played up.

"Possible, very possible," he said.

"This is important, isn't it?"

"You'll test it for fingerprints, won't you, sir?"

"Of course," said Craddock.

Stoddart-West gave a deep sigh.

"Smashing luck for us, wasn't it?" he said. "On our last day, too."

"Last day?"

"Yes," said Alexander. "I'm going to Stodders' place tomorrow for the last few days of the holidays. Stodders' people have got a smashing house - Queen Anne, isn't it?"

"William and Mary," said Stoddart-West.

"I thought your mother said –"

"Mum's French. She doesn't really know about English architecture."

"But your father said it was built –"

Craddock was examining the envelope.

Clever of Lucy Eyelesbarrow. How had she managed to fake the post mark? He peered closely, but the light was too feeble. Great fun for the boys, of course, but rather awkward for him. Lucy, drat her, hadn't considered that angle. If this were genuine, it would enforce a course of action. There…

Beside him a learned architectural argument was being hotly pursued. He was deaf to it.

"Come on, boys," he said, "we'll go into the house. You've been very helpful."