After some moments of rather embarrassing silence, I ventured to remark that it was a mild evening; to which he assented with a sort of Scotch “Hm—­hm” and nodded slowly.  Then came another interval of silence, during which I speculated on the possibility of his being a relative of Mr. Weiss and wondered what the deuce he was doing in our chambers.

“Have you an appointment with Dr. Thorndyke?” I asked, at length.

He bowed solemnly, and by way of reply—­in the affirmative, as I assumed—­emitted another “hm—­hm.”

I looked at him sharply, a little nettled by his lack of manners; whereupon he opened out the lease so that it screened his face, and as I glanced at the back of the document, I was astonished to observe that it was shaking rapidly.

The fellow was actually laughing!  What he found in my simple question to cause him so much amusement I was totally unable to imagine.  But there it was.  The tremulous movements of the document left me in no possible doubt that he was for some reason convulsed with laughter.

It was extremely mysterious.  Also, it was rather embarrassing.  I took out my pocket file and began to look over my notes.  Then the document was lowered and I was able to get another look at the stranger’s face.  He was really extraordinarily like Weiss.  The shaggy eyebrows, throwing the eye-sockets into shadow, gave him, in conjunction with the spectacles, the same owlish, solemn expression that I had noticed in my Kennington acquaintance; and which, by the way, was singularly out of character with the frivolous behaviour that I had just witnessed.

From time to time as I looked at him, he caught my eye and instantly averted his own, turning rather red.  Apparently he was a shy, nervous man, which might account for his giggling; for I have noticed that shy or nervous people have a habit of smiling inopportunely and even giggling when embarrassed by meeting an over-steady eye.  And it seemed my own eye had this disconcerting quality, for even as I looked at him, the document suddenly went up again and began to shake violently.

I stood it for a minute or two, but, finding the situation intolerably embarrassing, I rose, and brusquely excusing myself, went up to the laboratory to look for Polton and inquire at what time Thorndyke was expected home.  To my surprise, however, on entering, I discovered Thorndyke himself just finishing the mounting of a microscopical specimen.

“Did you know that there is some one below waiting to see you?” I asked.

“Is it anyone you know?” he inquired.

“No,” I answered.  “It is a red-nosed, sniggering fool in spectacles.  He has got a lease or a deed or some other sort of document which he has been using to play a sort of idiotic game of Peep-Bo!  I couldn’t stand him, so I came up here.”

Thorndyke laughed heartily at my description of his client.

“What are you laughing at?” I asked sourly; at which he laughed yet more heartily and added to the aggravation by wiping his eyes.