"Ha!" he exclaimed with deep satisfaction, as the light fell on the reverse of the envelope, "we are saved from the necessity of theft—or rather, unauthorized borrowing—'Johann Schnitzler, Darmstadt.' That is all that we actually want. The German police can do the rest if necessary."
He handed me back my probe, pocketed his lamp, released the catch of the lock on the door, and turned away along the dark, musty-smelling hall.
"Do you happen to know the name of Johann Schnitzler?" he asked.
I replied that I had no recollection of ever having heard the name 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
