Kennedy smiled.  “I shall be delighted,” he accepted promptly.

“You, too, Mr. Jameson,” she added, turning to me.

I hesitated a moment and Kennedy tried to catch my eye.  I was just about to speak when he brought his heel down sharply on my toe.  I looked at him again and caught just the trace of a nod of his head.  I saw that I was de trop.

“No, thank you,” I replied.  “I’m afraid I’d better not go.  Really, I have too much work staring at me.  I can’t get away—­but it’s very kind of you to think of asking me.”

We chatted, then left a few moments later so that Kennedy could pack.

Around the corner from the laboratory, as we dashed out, had been, as I have said, Wu Fang and Long Sin looking out from the limousine.  No sooner had we disappeared across the campus than their driver started up the car and they sped around to our apartment.

Cautiously they alighted and walked down the street.  Then making sure they were not observed, they entered and mounted the stairs to our doorway.  Long Sin was stationed down the hall on guard while Wu Fang drew from his pocket a blank key, a file and a candle.  He lighted the candle and held the key in its flame until it was covered with soot.

Then he inserted the key in the keyhole, turned it and took the key out.  Working quickly now, he examined the key sharply.  In the soot were slight scratches indicating where it struck and prevented the turning of the lock.  He filed the key, trying it again and again.  Finally he finished, and opened the door.  Beckoning Long Sin, he entered our rooms.

As they stood there, Wu Fang gazed about our living-room, keenly.  He was evidently considering where to place something, for, one after another, he picked up several articles on the desk and examined them.  Each time that he laid one down he shook his head.

Finally his eye rested on the telephone.  It seemed to suggest an idea to him and he crossed over to it.  Carefully holding down the receiver on the hook, he unscrewed the case which holds the diaphragm, while with his clever fingers he held the rest of the instrument intact.  Then he removed from his pocket the vial which the coolie had given him and placed its contents on the diaphragm itself.  Quickly now he replaced the receiver, and, having finished their work, Long Sin and Wu Fang stealthily crept out.

A second time, as we approached our apartment after the visit to Elaine, we were too excited to notice the limousine in which were Wu and Long Sin.  But no sooner had we entered than Long Sin left the car with a final word of instruction from his master.

Up-stairs, in the apartment, Kennedy began hurriedly to pack, and I helped him as well as I could.  We were in the midst of it when the telephone rang and I answered it.

“Hello!” I called.

There was no response.

“Hello, Hello!” I repeated, raising my voice.