After my colleague retired, which he did quite early, I sat for a long time pondering upon this singular case in which I found myself involved.  And the more I thought about it the more puzzled I became.  If Thorndyke had no more satisfactory explanation to offer than that which he had given me this evening, the defence was hopeless, for the court was not likely to accept his estimate of the evidential value of finger-prints.  Yet he had given Reuben something like a positive assurance that there would be an adequate defence, and had expressed his own positive conviction of the accused man’s innocence.  But Thorndyke was not a man to reach such a conviction through merely sentimental considerations.  The inevitable conclusion was that he had something up his sleeve—­that he had gained possession of some facts that had escaped my observation; and when I had reached this point I knocked out my pipe and betook myself to bed.

CHAPTER IX

THE PRISONER

On the following morning, as I emerged from my room, I met Polton coming up with a tray (our bedrooms were on the attic floor above the laboratory and workshop), and I accordingly followed him into my friend’s chamber.

“I shan’t go out to-day,” said Thorndyke, “though I shall come down presently.  It is very inconvenient, but one must accept the inevitable.  I have had a knock on the head, and, although I feel none the worse, I must take the proper precautions—­rest and a low diet—­until I see that no results are going to follow.  You can attend to the scalp wound and send round the necessary letters, can’t you?”

I expressed my willingness to do all that was required and applauded my friend’s self-control and good sense; indeed, I could not help contrasting the conduct of this busy, indefatigable man, cheerfully resigning himself to most distasteful inaction, with the fussy behaviour of the ordinary patient who, with nothing of importance to do, can hardly be prevailed upon to rest, no matter how urgent the necessity.  Accordingly, I breakfasted alone, and spent the morning in writing and despatching letters to the various persons who were expecting visits from my colleague.

Shortly after lunch (a very spare one, by the way, for Polton appeared to include me in the scheme of reduced diet) my expectant ear caught the tinkle of a hansom approaching down Crown Office Row.

“Here comes your fair companion,” said Thorndyke, whom I had acquainted with my arrangements, “Tell Hornby, from me, to keep up his courage, and, for yourself, bear my warning in mind.  I should be sorry indeed if you ever had cause to regret that you had rendered me the very valuable services for which I am now indebted to you.  Good-bye; don’t keep her waiting.”

I ran down the stairs and came out of the entry just as the cabman had pulled up and flung open the doors.

“Holloway Prison—­main entrance,” I said, as I stepped up on to the footboard.