"And they were poisoned!"

"One of them was. See, somebody had put a poisoned one in among the others."

"That leads back to Thorpe, who else could do that?"

"And we don't know that anybody did, only it might have been."

"Can you smell any prussic acid in the vial?"

"No," and Zizi sniffed at it, "I seem to think I do, but I daresay it's my vivid imagination. Do you suppose a chemist could discern any?"

"Probably not, but we might make a try at it. Pretty slim clue, anyway, Ziz."

"I know it, but I have a hunch it's the real thing. You see, Blair was in the habit of taking these things----"

"How do you know?"

"Carlotta Harper told me. I've quizzed her a lot about Mr. Blair's personal habits, and he always carried soda mints in his pocket, and took one now and then. So, as there was no soda mint bottle found in his pockets, and this was in the basket, it's a logical deduction that he finished this bottle that night that he died. And they all think the poison was given to him through some simple trick, so why not this?"

"It may be. It very likely is. But where does it get us?"

"Dunno yet. But, say it was done that way, it needn't have been done here. Maybe the murderer put a poisoned mint in the bottle when they were somewhere together."

"How could he?"

"Oh, lots of ways. Say Blair had his coat off, playing golf or billiards, or----"

"He'd carry such a bottle in his waistcoat pocket, I think."

"Well, it's all surmise. The thing to do is to begin from the other end.

Who had a motive?"

"That's what I'm trying to trace. Nothing doing as yet. h.e.l.lo, here's that old letter from Joshua, the guide. Look at it! It is in a small, cramped hand, and you know the one purporting to be from him later was in a big, sprawly hand. Somebody faked that letter!"

"Well, there's something to work on, then."

"But maybe Thorpe did it."

"Not he. Why should he? He had nothing to do with that Labrador trip."

"What was the letter about, the other Joshua letter?"

"Advising him not to try to bring Peter Crane's body down to New York, or to postpone the matter, or something like that."

"Queer business, that. Why should anybody want to fake a letter like that?"

"I don't believe anybody did. More likely some one else wrote for the guide. They're an ignorant lot, and writing is an unwelcome task to them."

They were still looking at the guide's letter when Shelby came in.

"I heard you were here," he said, "and thought it would be a good time to come around. I want to see if there's anything in Blair's papers that would help to turn suspicion away from Mac Thorpe. I don't believe that man did it, and I wish we could free him."

"That's what we're after," and Wise made room for Shelby to sit beside him at Blair's desk.

But though they made systematic search of all letters they found none other than friendly. There were some from his mother and sister, pathetic ones, telling of their ill health, for both were invalids.

They had not come East on learning of Blair's death, for they could not well stand the trip, and, too, there was no real reason for their coming. After the police investigation was over Blair's effects were to be sent to them, but for the present everything remained as it was found at his death.

"Let me help you, if I can," Shelby went on to Wise. "You know Blair and I were chums. Poor Gilbert, and Peter Boots, too, both gone, and both by such tragic means. I don't know which death was the worse."

Zizi showed him the small bottle she had found, and asked his opinion of her theory about it.

"What an ingenious notion," Shelby exclaimed; "yes, it might be the truth, of course, but a dozen other ways might have been used either."

"Such as what?" asked Wise, "it's always a help to talk these things over."

"Well, granting that some one administered poison to Blair, secretly, mightn't he have put it in anything that Blair was about to eat or drink?"

"Not this poison," objected Wise. "It acts too quickly. Whatever plan was adopted, it was some scheme by which Blair would take the poison unknowingly, but naturally. As Zizi says, if it had been put in some one of his bottles of medicine, he must take it, sooner or later."

"Yes; well, then say it was put in a cigarette, no that's foolish; why, hang it all, Wise, don't you see there's no plausible theory except that some one put it in a drink Blair took just before going to bed, or even after he was in bed."

"Where's the gla.s.s, then?"

"That's just the point. What's the answer, except that Thorpe washed it and put it away? Of course, Blair would take a drink Thorpe offered him."

"Also, he might have taken a soda mint just as he went to bed or after,"

said Zizi.

"Yes," agreed Shelby, thoughtfully. "He might have done so, but could one introduce poison into one of those things? They're quite hard, you know."

"Yes, it could be done," Wise declared. "I've heard of such a thing before. The little pellet could be soaked in the poison----"

"That would make it taste, and he wouldn't swallow it," Shelby said.

"True. Well, I think, with a hypodermic needle, the poison could be got into the mint."

"Maybe, but I doubt it. However, I don't know much about such things.

You're doubtless experienced."

"Yes, I've had a lot of poison cases. And, if we give up all thought of the soda mint, it does come back to a drink of some sort mixed by Thorpe."

"Or Blair might have mixed his own drink, and Thorpe added the poison, unnoticed."

"But I want to get away from Thorpe," Zizi said, her eyes anxious and worried.

"So do we all," returned Shelby gravely. "But where can we look?"