“Do you believe as I believe,” he said, “that you were acting under the influence of the laudanum in doing all that you did, on the night of Miss Verinder’s birthday, in Lady Verinder’s house?”

“I am too ignorant of the influence of laudanum to have an opinion of my own,” I answered.  “I can only follow your opinion, and feel convinced that you are right.”

“Very well.  The next question is this.  You are convinced; and I am convinced—­how are we to carry our conviction to the minds of other people?”

I pointed to the two manuscripts, lying on the table between us.  Ezra Jennings shook his head.

“Useless, Mr. Blake!  Quite useless, as they stand now for three unanswerable reasons.  In the first place, those notes have been taken under circumstances entirely out of the experience of the mass of mankind.  Against them, to begin with!  In the second place, those notes represent a medical and metaphysical theory.  Against them, once more!  In the third place, those notes are of my making; there is nothing but my assertion to the contrary, to guarantee that they are not fabrications.  Remember what I told you on the moor—­and ask yourself what my assertion is worth.  No! my notes have but one value, looking to the verdict of the world outside.  Your innocence is to be vindicated; and they show how it can be done.  We must put our conviction to the proof—­and You are the man to prove it!”

“How?” I asked.

He leaned eagerly nearer to me across the table that divided us.

“Are you willing to try a bold experiment?”

“I will do anything to clear myself of the suspicion that rests on me now.”

“Will you submit to some personal inconvenience for a time?”

“To any inconvenience, no matter what it may be.”

“Will you be guided implicitly by my advice?  It may expose you to the ridicule of fools; it may subject you to the remonstrances of friends whose opinions you are bound to respect.”

“Tell me what to do!” I broke out impatiently.  “And, come what may, I’ll do it.”

“You shall do this, Mr. Blake,” he answered.  “You shall steal the Diamond, unconsciously, for the second time, in the presence of witnesses whose testimony is beyond dispute.”

I started to my feet.  I tried to speak.  I could only look at him.

“I believe it can be done,” he went on.  “And it shall be done—­if you will only help me.  Try to compose yourself—­sit down, and hear what I have to say to you.  You have resumed the habit of smoking; I have seen that for myself.  How long have you resumed it.”

“For nearly a year.”

“Do you smoke more or less than you did?”

“More.”

“Will you give up the habit again?  Suddenly, mind!—­as you gave it up before.”

I began dimly to see his drift.  “I will give it up, from this moment,” I answered.