before.

"Neither have I," said he; "but I think we may form a pretty shrewd
guess as to his avocation. As you saw, the words 'Herrn Dr.' were
printed on the envelope, leaving the rest of the address to be written
by hand. The plain inference is that he is a person who habitually
addresses letters to medical men, and as the style of the envelope and
the lettering--which is printed, not embossed--is commercial, we may
assume that he is engaged in some sort of trade. Now, what is a likely
trade?"

"He might be an instrument maker or a drug manufacturer; more probably
the latter, as there is an extensive drug and chemical industry in
Germany, and as Mr. Weiss seemed to have more use for drugs than
instruments."

"Yes, I think you are right; but we will look him up when we get home.
And now we had better take a glance at the bedroom; that is, if you can
remember which room it was."

"It was on the first floor," said I, "and the door by which I entered
was just at the head of the stairs."

We ascended the two flights, and, as we reached the landing, I halted.

"This was the door," I said, and was about to turn the handle when
Thorndyke caught me by the arm.

"One moment, Jervis," said he. "What do you make of this?"