“I think I ought to tell him,” decided Kennedy as we passed down the lobby.

He seemed surprised to see us, as we strolled up to his writing desk, but pushed aside the few letters which he had not finished and asked us to sit down.

“I don’t know whether you have noticed it,” began Craig, “but I wonder how you feel?”

Whitney had expected something else rather than his health as the subject of a quiz.  “Pretty good now,” he answered before he knew it, “although I must admit that for the past few days I have wondered whether I wasn’t slowing up a bit—­or rather going too fast.”

“Would you like to know why you feel that way?” asked Craig.

Whitney was now genuinely puzzled.  It was perfectly evident, as it had been all the time, that he had not the slightest inkling of what was going on.

As Craig briefly unfolded what we had discovered and the reason for it, Whitney watched him aghast.

“Poisoned cigarettes,” he repeated slowly.  “Well, who would ever have thought it.  You can bet your last jitney I’ll be careful what I smoke in the future, if I have to smoke only original packages.  And it was that, partly, that ailed Mendoza?”

Kennedy nodded.  “Don’t take any pilocarpine, just because I told you that was what I used.  You have given yourself the best prescription, just now.  Be careful what you smoke.  And, don’t get excited if you seem to be stepping on matches up there in your room for a little while, either.  It’s nothing.”

Whitney’s only known way of thanking anybody was to invite them to adjourn to the cafe, and accordingly we started across the hall, after he had gathered up his correspondence.  The information had made more work that night impossible for him.

As we crossed from the writing-room, we saw Alfonso de Moche coming in from the street.  He saw us and came over to speak.  Was it a coincidence, or was it merely a blind?  Was he the one who had got away and now calculated to come back and throw us off guard?

Whitney asked him where he had been, but he replied quickly that his mother had not been feeling very well after dinner and had gone to bed, while he strolled out and had dropped into a picture show.  That, I felt, was at least clever.  The intruder had been a man.

De Moche excused himself, and we continued our walk to the cafe, where Whitney restored his shattered peace of mind somewhat.

“What’s the result of your detective work on Norton?” ventured Kennedy at last, seeing that Whitney was in a more expansive frame of mind, and taking a chance.

“Oh,” returned Whitney, “he’s scared, all right.  Why, he has been hanging around this hotel—­watching me.  He thinks I don’t know it, I suppose, but I do.”

Kennedy and I exchanged glances.

“But he’s slippery,” went on Whitney.  “He knows that he is being shadowed and the men tell me that they lose him, now and then.  To tell the truth I don’t trust most of these private detectives.  I think their little tissue paper reports are half-faked, anyhow.”