much deeper than appears on the surface. The first thing that
strike one is the obvious possibility that the person now in the
rooms may be entirely different from the one who engaged them."

"Why should you think so?"

"Well, apart form this cigarette-end, was it not suggestive that
the only time the lodger went out was immediately after his
taking the rooms? He came back--or someone came back--when all
witnesses were out of the way. We have no proof that the person
who came back was the person who went out. Then, again, the man
who took the rooms spoke English well. This other, however,
prints 'match' when it should have been 'matches.' I can imagine
that the word was taken out of a dictionary, which would give the
noun but not the plural. The laconic style may be to conceal the
absence of knowledge of English. Yes, Watson, there are good
reasons to suspect that there has been a substitution of
lodgers."

"But for what possible end?"

"Ah! there lies our problem. There is one rather obvious line of
investigation." He took down the great book in which, day by
day, he filed the agony columns of the various London journals.
"Dear me!" said he, turning over the pages, "what a chorus of
groans, cries, and bleatings! What a rag-bag of singular
happenings! But surely the most valuable hunting-ground that
ever was given to a student of the unusual! This person is alone
and cannot be approached by letter without a breach of that
absolute secrecy which is desired. How is any news or any