My observations of No. 427 Park Lane did little to clear up the problem in which I was interested.  The house was separated from the street by a low wall and railing, the whole not more than five feet high.  It was perfectly easy, therefore, for anyone to get into the garden, but the window was entirely inaccessible, since there was no waterpipe or anything which could help the most active man to climb it.  More puzzled than ever, I retraced my steps to Kensington.  I had not been in my study five minutes when the maid entered to say that a person desired to see me.  To my astonishment it was none other than my strange old book collector, his sharp, wizened face peering out from a frame of white hair, and his precious volumes, a dozen of them at least, wedged under his right arm.

“You’re surprised to see me, sir,” said he, in a strange, croaking voice.

I acknowledged that I was.

“Well, I’ve a conscience, sir, and when I chanced to see you go into this house, as I came hobbling after you, I thought to myself, I’ll just step in and see that kind gentleman, and tell him that if I was a bit gruff in my manner there was not any harm meant, and that I am much obliged to him for picking up my books.”

“You make too much of a trifle,” said I.  “May I ask how you knew who I was?”

“Well, sir, if it isn’t too great a liberty, I am a neighbour of yours, for you’ll find my little bookshop at the corner of Church Street, and very happy to see you, I am sure.  Maybe you collect yourself, sir.  Here’s British birds, and catullus, and the holy war—­a bargain, every one of them.  With five volumes you could just fill that gap on that second shelf.  It looks untidy, does it not, sir?”

I moved my head to look at the cabinet behind me.  When I turned again, Sherlock Holmes was standing smiling at me across my study table.  I rose to my feet, stared at him for some seconds in utter amazement, and then it appears that I must have fainted for the first and the last time in my life.  Certainly a gray mist swirled before my eyes, and when it cleared I found my collar-ends undone and the tingling after-taste of brandy upon my lips.  Holmes was bending over my chair, his flask in his hand.

“My dear Watson,” said the well-remembered voice, “I owe you a thousand apologies.  I had no idea that you would be so affected.”

I gripped him by the arms.

“Holmes!” I cried.  “Is it really you?  Can it indeed be that you are alive?  Is it possible that you succeeded in climbing out of that awful abyss?”

“Wait a moment,” said he.  “Are you sure that you are really fit to discuss things?  I have given you a serious shock by my unnecessarily dramatic reappearance.”

“I am all right, but indeed, Holmes, I can hardly believe my eyes.  Good heavens! to think that you—­you of all men—­should be standing in my study.”  Again I gripped him by the sleeve, and felt the thin, sinewy arm beneath it.  “Well, you’re not a spirit anyhow,” said I.  “My dear chap, I’m overjoyed to see you.  Sit down, and tell me how you came alive out of that dreadful chasm.”