“I certainly haven’t noticed any,” he replied; “and, as you say, the presence of an elephant’s hair in a room in the middle of London is a rather remarkable circumstance. And yet, perhaps, if we consider all the other circumstances, it may not be impossible to form a conjecture as to how it came here. I recommend the problem to my learned friend for consideration at his leisure; and now, as we have seen all that there is to see--which is mighty little--we may as well leave Polton to finish the collection of data from the floor. We can take your little selection with us.” He folded the paper containing the hairs that I had picked out into a neat packet, which he slipped into his pocket; then, having handed the key of the outer door to Polton, for return to Mr. Bidwell, he went out and I followed. We descended the stairs slowly, both of us deeply reflective. As to the subject of his meditations I could form no opinion, but my own were occupied by the problem which he had suggested; and the more I reflected on it, the less capable of solution did it appear. We had nearly reached the ground floor when I became aware of quick footsteps descending the stairs behind us. Near the entry our follower overtook us, and as we stood aside to let him pass, I had a brief vision of a shortish, dapper, smartly-dressed coloured man--apparently an African or West Indian--who carried a small suit-case and a set of golf-clubs. “Now,” said I, in a low tone, “I wonder if that gentleman is the late owner of that negro hair that I picked up. It seems intrinsically probable as he appears to live in this building, and would be a near neighbour of Herrington’s.” I halted at the entry and read out the only name painted on the door-post as appertaining to the second floor--Mr. Kwaku Essien, which, I decided, seemed to fit a gentleman of colour. But Thorndyke was not listening. His long legs were already carrying him, with a deceptively leisurely air, across Tanfield Court in the wake of Mr. Essien, and at about the same pace. I put on a spurt and overtook him, a little mystified by his sudden air of purpose and by the fact that he was not walking in the direction of our chambers. Still more mystified was I when it became clear that Thorndyke was following the African and keeping at a constant distance in rear of him; but I made no comment until, having pursued our quarry to the top of Middle Temple Lane, we saw him hail a taxi and drive off. Then I demanded an explanation. “I wanted to see him fairly out of the precincts,” was the reply, “because I have a particular desire to see what his chambers are like. I only hope his door has a practicable latch.” I stared at him in dismay. “You surely don’t contemplate breaking into his chambers!” I exclaimed. “Certainly not,” he replied. “If the latch won’t yield to gentle persuasion, I shall give it up. But don’t let me involve you, Jervis. I admit that it is a slightly irregular proceeding.”