, by offering a group of vague coincidences that would muddle any
brain but your own."

Thorndyke chuckled softly but pursued the subject no farther.

"Put that paper in your file with your other notes," he said, "and think
it over at your leisure. And now I want a little help from you. Have you
a good memory for faces?"

"Fairly good, I think. Why?"

"Because I have a photograph of a man whom I think you may have met.
Just look at it and tell me if you remember the face."

He drew a cabinet size photograph from an envelope that had come by the
morning's post and handed it to me.

"I have certainly seen this face somewhere," said I, taking the portrait
over to the window to examine it more thoroughly, "but I can't, at the
moment, remember where."

"Try," said Thorndyke. "If you have seen the face before, you should be
able to recall the person."

I looked intently at the photograph, and the more I looked, the more
familiar did the face appear. Suddenly the identity of the man flashed
into my mind and I exclaimed in astonishment:

"It can't be that poor creature at Kennington, Mr. Graves?"

"I think it can," replied Thorndyke, "and I think it is. But could you
swear to the identity in a court of law?"

"It is my firm conviction that the photograph is that of Mr. Graves. I
would swear to that."

"No man ought to swear to more," said Thorndyke. "Identification is
always a matter of opinion or belief. The man who will swear
unconditionally to identity from memory only is a man whose evidence
should be discredited. I think your sworn testimony would be
sufficient."

It is needless to say that the production of this photograph filled me
with amazement and curiosity as to how Thorndyke had obtained it. But,
as he replaced it impassively in its envelope without volunteering any
explanation, I felt that I could not question him directly.
Nevertheless, I ventured to approach the subject in an indirect manner.

"Did you get any information from those Darmstadt people?" I asked.

"Schnitzler? Yes. I learned, through the medium of an official
acquaintance, that Dr. H. Weiss was a stranger to them; that they knew
nothing about him excepting that he had ordered from them, and been
supplied with, a hundred grammes of pure hydrochlorate of morphine."

"All at once?"

"No. In separate parcels of twenty-five grammes each."

"Is that all you know about Weiss?"

"It is all that I actually know; but it is not all that