Our party was prolonged beyond the time we had expected, but, although he had much on his mind, Kennedy made no move to break it up.  In fact he did everything to encourage it.

At last, however, the others did notice the time, and I think it was with sincere regret that the truce was broken.  Even then, no parting shots were indulged in.

As we left, Inez thanked Kennedy for his consideration, and I am sure that that in itself was reward enough.  We parted from Lockwood, who wished to remain a little while, and rode down in the elevator with Whitney, a changed man.

“I’ll walk over to the elevated with you,” he said.  “I was going to my hotel, but I think I’ll go down to the office instead.”

Evidently he had got Senora de Moche out of his mind, at least temporarily, I thought.  Then for the first time I recalled that during the whole luncheon there had been no reference to either the Senora or Alfonso, though both must have been in our minds often.

“What was it you had Inez drop into Whitney’s coffee?” I asked Craig as we parted from him and rode uptown.

“You saw that?” he smiled.  “It was pilocarpine, jaborandi, a plant found largely in Brazil, one of the antidotes for stramonium poisoning.  It doesn’t work with every one.  But it seems to have done so with him.  Besides, the caffeine in the coffee probably aided the pilocarpine.  Then, too, I made them smoke cigarettes without the dope that is being fed them.  Lockwood’s case, for some reason, hasn’t gone far.  But did you notice how the treatment contracted the pupils of Whitney’s eyes almost back to normal again?”

I had and said so, adding, “But what was your idea?”

“I think I’ve got at the case from a brand-new angle,” he replied.  “Unless I am greatly mistaken, when the person who is doing the doping sees that Whitney is getting better—­why, I think you all noticed it, Inez and Lockwood as well as you—­it will mean another attempt to substitute more cigarettes doped with that drug.  I think it’s by substitution that it’s being done.  We’ll see.”

At the laboratory, Kennedy called Norton and described briefly what had happened, especially to Whitney.

“Now is your chance, Norton,” he added, “to do some real good work.  I want some one to watch the Senora, see if she, too, notes the difference in him.  Understand?”

“Perfectly,” returned Norton.  “That is something I think I can do.”

XIX

THE BURGLAR POWDER

It was not until after dinner that we heard again from Norton.  He had evidently spent the time faithfully hanging about the Prince Edward Albert, but Whitney had not come in, although the Senora and Alfonso were about.

“I saw them leaving the dining-room,” he reported to us in the laboratory directly afterward, “just as Whitney came in.  They could not see me.  I took good care of that.  But, say, there is a change in Whitney, isn’t there?  I wonder what caused it?”