“I am answered so far,” I said; “but I am not answered yet as to the effect produced by the opium on myself.”

“I will try to answer you in a few words,” said Ezra Jennings.  “The action of opium is comprised, in the majority of cases, in two influences—­a stimulating influence first, and a sedative influence afterwards.  Under the stimulating influence, the latest and most vivid impressions left on your mind—­namely, the impressions relating to the Diamond—­would be likely, in your morbidly sensitive nervous condition, to become intensified in your brain, and would subordinate to themselves your judgment and your will exactly as an ordinary dream subordinates to itself your judgment and your will.  Little by little, under this action, any apprehensions about the safety of the Diamond which you might have felt during the day would be liable to develop themselves from the state of doubt to the state of certainty—­would impel you into practical action to preserve the jewel—­would direct your steps, with that motive in view, into the room which you entered—­and would guide your hand to the drawers of the cabinet, until you had found the drawer which held the stone.  In the spiritualised intoxication of opium, you would do all that.  Later, as the sedative action began to gain on the stimulant action, you would slowly become inert and stupefied.  Later still you would fall into a deep sleep.  When the morning came, and the effect of the opium had been all slept off, you would wake as absolutely ignorant of what you had done in the night as if you had been living at the Antipodes.  Have I made it tolerably clear to you so far?”

“You have made it so clear,” I said, “that I want you to go farther.  You have shown me how I entered the room, and how I came to take the Diamond.  But Miss Verinder saw me leave the room again, with the jewel in my hand.  Can you trace my proceedings from that moment?  Can you guess what I did next?”

“That is the very point I was coming to,” he rejoined.  “It is a question with me whether the experiment which I propose as a means of vindicating your innocence, may not also be made a means of recovering the lost Diamond as well.  When you left Miss Verinder’s sitting-room, with the jewel in your hand, you went back in all probability to your own room——­”

“Yes? and what then?”

“It is possible, Mr. Blake—­I dare not say more—­that your idea of preserving the Diamond led, by a natural sequence, to the idea of hiding the Diamond, and that the place in which you hid it was somewhere in your bedroom.  In that event, the case of the Irish porter may be your case.  You may remember, under the influence of the second dose of opium, the place in which you hid the Diamond under the influence of the first.”

It was my turn, now, to enlighten Ezra Jennings.  I stopped him, before he could say any more.

“You are speculating,” I said, “on a result which cannot possibly take place.  The Diamond is, at this moment, in London.”