o say nothing of Mr. Britton's opinion on
the signatures."

"Still," said Thorndyke, "there must be some explanation of the change
in the character of the signatures, and that explanation cannot be the
failing eyesight of the writer; for that is a gradually progressive and
continuous condition, whereas the change in the writing is abrupt and
intermittent."

I considered Thorndyke's remark for a few moments; and then a
light--though not a very brilliant one--seemed to break on me.

"I think I see what you are driving at," said I. "You mean that the
change in the writing must be associated with some new condition
affecting the writer, and that that condition existed intermittently?"

Thorndyke nodded approvingly, and I continued:

"The only intermittent condition that we know of is the effect of opium.
So that we might consider the clearer signatures to have been made when
Jeffrey was in his normal state, and the less distinct ones after a bout
of opium-smoking."

"That is perfectly sound reasoning," said Thorndyke. "What further
conclusion does it lead to?"

"It suggests that the opium habit had been only recently acquired, since
the change was noticed only about the time he went to live at New Inn;
and, since the change in the writing is at first intermittent and then
continuous, we may infer that the opium-smoking was at first occasional
and later became a a confirmed habit."

"Quite a reasonable conclusion and very clearly stated," said Thorndyke.
"I don't say that I entirely agree with you, or that you have exhausted
the information that these signatures offer. But you have started in the
right direction."

"I may be on the right road," I said gloomily; "but I am stuck fast in
one place and I see no chance of getting any farther."

"But you have a quantity of data," said Thorndyke. "You have all the
facts that I had to start with, from which I constructed the hypothesis
that I am now busily engaged in verifying. I have a few more data now,
for 'as money makes money' so knowledge begets knowledge, and I put my
original capital out to interest. Shall we tabulate the facts that are
in our joint possession and see what they suggest?"

I grasped eagerly at the offer, though I had conned over my notes again
and again.

Thorndyke produced a slip of paper from a drawer, and, uncapping his
fountain-pen, proceeded to write down the leading facts, reading each
aloud as soon as it was written.

"1. The second wi