What was the reason back of it all, I asked, as I thought of those wonderful eyes of hers?  Was it a sort of auto-hypnotism?  There was, I knew, a form of illusion known as ophthalmophobia—­fear of the eye.  It ranged from mere aversion at being gazed at all the way to the subjective development of real physical action from an otherwise trivial objective cause.  Perhaps Inez was right about the eyes.  One might fear them, and that fear might cause the precise thing to happen which the owner of the eyes intended.  Still, as I reflected before, there was a much more important problem regarding eyes before us, that of the drug that was evidently being used in the cigarettes.  What was it?

There was no chance of our gleaning anything now from these two who made such a strange pair.  Kennedy turned and went out of the nearest entrance of the hotel.

“Central Park, West,” he directed a cab driver, as we climbed in his machine; then to me, after giving the number, “I must see Inez Mendoza again before I can go ahead.”

Inez was not expecting us so soon after leaving her at the hotel, yet I think was just a little glad that we had come.

“Did anything happen after I left?” she asked eagerly.

“We went back and saw Mr. Whitney,” returned Craig.  “I believe you are right.  He is acting queerly,”

“Alfonso called me up,” she volunteered.

“Was it about anything I should know?” queried Craig.

“Well,” she hesitated, “he said he hoped that nothing that had taken place would change our own relations.  That was about all.  He was the dutiful son, and made no attempt to explain anything that was said.”

Kennedy smiled.  “You have not seen Mr. Lock, wood since, I suppose?” he asked.

“You always make me tell what I hadn’t intended,” she confessed, smiling back.  “Yes, I couldn’t help it.  At least, I didn’t see him.  I called him up.  I wanted to tell him what she had said and that it hadn’t made any difference to me.”

“What did he say?”

“I can’t remember just how he put it, but I think he meant that it was something very much like that anonymous letter I received.  We both feel that there is some one who wants to make trouble between us, and we are not going to let it happen.”

If she had known of Kennedy’s discovery of the shoe-prints, I feel sure that, as far as we were concerned, the case would have ended there.  She was in no mood to be convinced by such a thing, would probably have insisted that some one was wearing a second-hand pair of his shoes.

Kennedy’s eye had been travelling around the room as though searching for something.

“May I have a cigarette out of that case over there?” he asked, indicating a box of them on a table.

“Why—­that is Mr. Lockwood’s,” she replied.  “He left it here the last time he was here and I forgot to send it to him.  Wait a minute.  Let me get you some of father’s.”